Name: Stainless Steel Fittings
Brand: R V Metal Corporation

Stainless Steel Fittings

Product Overview

R V Metal Corporation supplies stainless steel pipe fittings in a wide grade range including J7, J4, 201, 202, 301, 302, 304, 304L, 304H, 305, 308, 309, 309S, 310, 310S, 316, 316L, 316H, 316Ti, 317, 317L, 321, 321H, 347, 347H, 409L, 410, 410S, 420, 429, 430, 430Ti, 439, 441, 444 and Duplex S31803—so you can match corrosion resistance, temperature capability, weldability, and cost to the exact service conditions. Our stainless steel fittings range covers common butt-weld fittings (elbows 45°/90°/180°, concentric/eccentric reducers, equal/reducing tees, caps, stub ends), forged socket-weld and threaded fittings (elbows, tees, couplings, unions, plugs, bushings), as well as instrument fittings and pipe accessories as required. Grades like 304/304L are preferred for general fabrication, 316/316L for chloride-rich or marine exposure, 321/347 for stabilized high-temperature duty, 310/310S for heat resistance, 409L/410/420 for specific wear or magnetic/structural needs, and Duplex S31803 for higher strength and improved resistance to pitting and stress corrosion cracking. Fittings are available in standard sizes, schedules and pressure classes, with heat-wise traceability and test certificates on request, and can be supplied as ready stock or cut-to-project quantities for fabrication, piping, HVAC, chemical, marine and industrial applications.

Technical Specifications

Specification Parameter	Butt Weld Fittings (BW)	Socket Weld (SW) & Threaded (THD) Fittings	Coverage / Notes (Grades & Options)
Grades Offered	J7, J4, 201, 202, 301, 302, 304, 304L, 304H, 305, 308, 309, 309S, 310, 310S, 316, 316L, 316H, 316Ti, 317, 317L, 321, 321H, 347, 347H	409L, 410, 410S, 420, 429, 430, 430Ti, 439, 441, 444, S31803 (Duplex)	All grades available subject to size, type & schedule/class. Heat-wise traceability on request.
Fitting Types	Elbows 45°/90°/180° (LR/SR), Equal/Reducing Tees, Concentric/Eccentric Reducers, Caps, Stub Ends, Crosses (on request)	90°/45° Elbows, Tees, Couplings (Full/Half), Unions, Caps, Plugs, Bushings, Reducers, Nipples (on request)	Also available: instrument fittings, pipe accessories, special/custom items as per drawings.
Manufacturing Route	Seamless formed / welded formed; hot formed; solution annealed / heat treated as applicable	Forged (hot forged) / machined; heat treated as required by grade	Final condition depends on standard and grade family (austenitic/ferritic/martensitic/duplex).
End Connection	Beveled ends for welding (standard bevel angles as per code)	Socket weld ends / NPT/BSP threaded ends	Thread type (NPT/BSP/BSPT) as specified by customer.
Size Range	Typically 1/2" NB to 48" NB (project dependent)	Typically 1/8" to 4" (Class dependent)	Custom sizes and special bores available on request.
Wall Thickness / Schedule	Sch 5S, 10S, 40S, 80S, 160, XXS (as applicable)	Sch 80 / Sch 160 / XXS (common), as applicable	For sanitary/thin-wall applications, Sch 5S/10S are common.
Pressure Class / Rating	As per piping code & schedule; project-specific	Class 2000 / 3000 / 6000 / 9000 (typical ranges)	Actual rating depends on material, type, size and design standard.
Applicable Standards	ASTM A403 / ASME B16.9, MSS SP-43, MSS SP-75 (as applicable)	ASTM A182 / ASME B16.11, MSS SP-79 / SP-83 / SP-95 (as applicable)	EN/DIN/JIS equivalents available as per project requirement.
Dimensions & Tolerances	As per ASME B16.9 / MSS; ovality & wall tolerances per standard	As per ASME B16.11 / MSS; thread gauging as per standard	Critical tolerances can be controlled for machined/instrument items.
Surface Finish	Pickled & passivated / blasted / as-fabricated	Machined finish / pickled & passivated / shot blasted	Special finishes: electropolish, satin, mirror (where applicable).
Heat Treatment	Solution annealed / stress relieved as applicable	Solution annealed, normalized/tempered (martensitic), as applicable	Duplex supplied in solution annealed condition for best corrosion resistance.
Inspection & Testing	Visual & dimensional; PMI on request; NDT (PT/RT/UT) on request	Visual & dimensional; thread gauging; PMI on request; NDT on request	Hydro/pneumatic tests are generally system-level, not standard for all fittings unless specified.
Documentation	MTC / Test Certificate, Heat No., Chemical & Mechanical results	MTC / Test Certificate, Heat No., Chemical & Mechanical results	EN 10204 3.1 / 3.2 (on request), third-party inspection (TPI) available.
Marking	Grade, size, schedule, heat number, manufacturer mark	Grade, size, class, heat number, manufacturer mark	Marking style as per applicable standard/customer requirement.
Packaging	Wooden crates / pallets; rust-protection & end protectors as required	Boxes / crates; thread protectors as required	Export packing and barcoding/labeling available.

Chemical Composition

Grade	Common Use in Fittings	Typical Chemical Composition (Wt. %)	Notes
J4	THD / SW (low-cost utility)	Cr 14–16, Ni 1.0–2.0, Mn 8–10, C ≤ 0.12, Si ≤ 1.0, P ≤ 0.060, S ≤ 0.030, N ≤ 0.20, Fe Bal.	“J” grades are trade/market variants (not a single global standard). Chemistry varies by mill—confirm by MTC.
J7	THD / SW (utility, moderate corrosion)	Cr 15–17, Ni 2.0–4.0, Mn 7–9, C ≤ 0.10, Si ≤ 1.0, P ≤ 0.060, S ≤ 0.030, N ≤ 0.20, Fe Bal.	Often positioned between 202 and 304 performance. Always verify actual chemistry before critical service.
201	THD / SW / fabricated fittings	Cr 16–18, Ni 3.5–5.5, Mn 5.5–7.5, C ≤ 0.15, Si ≤ 1.0, P ≤ 0.060, S ≤ 0.030, N ≤ 0.25, Fe Bal.	Good formability; lower Ni than 304.
202	THD / SW / fabricated fittings	Cr 17–19, Ni 4.0–6.0, Mn 7.5–10.0, C ≤ 0.15, Si ≤ 1.0, P ≤ 0.060, S ≤ 0.030, N ≤ 0.25, Fe Bal.	Improved strength vs 304, less Ni; corrosion varies by environment.
301	Clamps / springy components	Cr 16–18, Ni 6–8, C ≤ 0.15, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Work-hardening grade; used more in strip than heavy fittings.
302	General components	Cr 17–19, Ni 8–10, C ≤ 0.15, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Close to 304 family; less common as a fitting spec.
304	BW / THD / SW (general service)	Cr 18–20, Ni 8–10.5, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Most common stainless for fittings.
304L	BW (welded systems)	Cr 18–20, Ni 8–12, C ≤ 0.03, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Lower carbon for reduced weld sensitization risk.
304H	High-temp BW fittings	Cr 18–20, Ni 8–11, C 0.04–0.10, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Higher carbon for elevated-temperature strength.
305	Deep-drawn parts	Cr 17–19, Ni 10.5–13, C ≤ 0 dis, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Higher Ni reduces work-hardening; not typical for standard piping fittings.
308	Special fabricated parts	Cr 19–21, Ni 10–12, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Common as welding filler classification; less common as wrought fitting grade.
309	Heat service fittings	Cr 22–24, Ni 12–15, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Better oxidation resistance than 304.
309S	Heat service fittings	Cr 22–24, Ni 12–15, C ≤ 0.03, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Lower carbon variant for improved weldability.
310	High-temp fittings	Cr 24–26, Ni 19–22, C ≤ 0.25, Mn ≤ 2.0, Si ≤ 1.5, P ≤ 0.045, S ≤ 0.030, Fe Bal.	High Cr-Ni for extreme heat/oxidation.
310S	High-temp fittings	Cr 24–26, Ni 19–22, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.5, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Lower carbon vs 310 for better weldability.
316	BW / THD / SW (marine/chemical)	Cr 16–18, Ni 10–14, Mo 2–3, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Molybdenum improves pitting resistance.
316L	BW (welded chemical lines)	Cr 16–18, Ni 10–14, Mo 2–3, C ≤ 0.03, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Preferred for welded piping in corrosive service.
316H	High-temp BW fittings	Cr 16–18, Ni 10–14, Mo 2–3, C 0.04–0.10, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Higher carbon for elevated-temperature strength.
316Ti	BW fittings (stabilized)	Cr 16–18, Ni 10–14, Mo 2–3, Ti ≥ 5×C (and ≤ 0.70), C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Titanium stabilized against sensitization.
317	BW fittings (higher Mo)	Cr 18–20, Ni 11–15, Mo 3–4, C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Higher Mo than 316 for tougher corrosion duty.
317L	BW fittings (higher Mo, welded)	Cr 18–20, Ni 11–15, Mo 3–4, C ≤ 0.03, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Low C for welded corrosive applications.
321	BW fittings (heat service)	Cr 17–19, Ni 9–12, Ti ≥ 5×C (and ≤ 0.70), C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Ti-stabilized austenitic for elevated temperature.
321H	BW fittings (high temp)	Cr 17–19, Ni 9–12, Ti ≥ 4×C (and ≤ 0.70), C 0.04–0.10, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Higher carbon variant for creep strength.
347	BW fittings (stabilized)	Cr 17–19, Ni 9–13, Nb+Ta ≥ 10×C (and ≤ 1.0), C ≤ 0.08, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	Nb-stabilized for resistance to sensitization.
347H	BW fittings (high temp)	Cr 17–19, Ni 9–13, Nb+Ta ≥ 8×C (and ≤ 1.0), C 0.04–0.10, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.045, S ≤ 0.030, Fe Bal.	High carbon stabilized grade for elevated temperature service.
409L	Automotive/exhaust, utility	Cr 10.5–11.75, C ≤ 0.03, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.020, Ni ≤ 0.50, Ti stabilized (typ.), Fe Bal.	Ferritic; good oxidation resistance; limited corrosion vs 304.
410	Valves, machined fittings	Cr 11.5–13.5, C 0.08–0.15, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.75, Fe Bal.	Martensitic; hardenable; corrosion lower than 304/316.
410S	Formed parts, weldments	Cr 11.5–13.5, C ≤ 0.08, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.60, Fe Bal.	Lower carbon than 410; better weldability.
420	High hardness parts	Cr 12–14, C 0.15–0.40, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.75, Fe Bal.	Martensitic; higher carbon for hardness.
429	Heat/oxidation duty	Cr 14–16, C ≤ 0.12, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.75, Fe Bal.	Ferritic; good oxidation resistance.
430	Utility fittings, decorative	Cr 16–18, C ≤ 0.12, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.75, Fe Bal.	Ferritic; economical; limited chloride resistance.
430Ti	Welded ferritic fittings	Cr 16–18, C ≤ 0.08, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ti stabilized (typ. 0.30–0.80), Fe Bal.	Ti stabilization helps prevent intergranular corrosion in weld zones.
439	Exhaust/heat service	Cr 17–19, C ≤ 0.03, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.50, Ti+Nb stabilized (typ.), Fe Bal.	Ferritic; improved weldability/corrosion vs 430.
441	Heat service, weldments	Cr 17.5–19.5, C ≤ 0.03, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Nb+Ti stabilized (typ.), Fe Bal.	Ferritic; good high-temp strength and oxidation resistance.
444	High corrosion ferritic fittings	Cr 17.5–19.5, Mo 1.75–2.5, C ≤ 0.025, Mn ≤ 1.0, Si ≤ 1.0, P ≤ 0.040, S ≤ 0.030, Ni ≤ 1.0, Nb+Ti stabilized (typ.), Fe Bal.	Ferritic with Mo; better pitting resistance vs 430/439.
S31803 (Duplex)	BW fittings (chloride/seawater)	Cr 21–23, Ni 4.5–6.5, Mo 2.5–3.5, N 0.08–0.20, C ≤ 0.03, Mn ≤ 2.0, Si ≤ 1.0, P ≤ 0.030, S ≤ 0.020, Fe Bal.	Duplex 2205 family; superior strength and chloride SCC resistance vs 316L.
Important: Values above are typical specification ranges. Exact limits depend on the governing standard (ASTM/ASME/EN/JIS) and product form (BW fittings vs forged SW/THD). For critical applications, always refer to the supplied Mill Test Certificate (MTC) for final chemistry.

UNS Codes & Grades

Grade	UNS / EN Identifier	Common Fitting Types Supplied	Typical Service / Notes
J4	Trade grade (no single UNS) / EN: varies	Elbow, Tee, Reducer, Coupling, Nipple, Socket, Union, Cap	Market grade used in utility piping; confirm chemistry & equivalence by MTC.
J7	Trade grade (no single UNS) / EN: varies	Elbow, Tee, Reducer, Coupling, Nipple, Socket, Union, Cap	Market grade between 202 & 304 performance (supplier dependent); verify by MTC.
201	UNS S20100 / EN 1.4372	Threaded fittings, fabricated fittings, clamps, nipples, couplings, bends	Economical austenitic; moderate corrosion resistance.
202	UNS S20200 / EN 1.4373	Threaded fittings, fabricated fittings, couplings, unions, bends	Higher strength than 304; corrosion depends on environment.
301	UNS S30100 / EN 1.4310	Clamps, light fabricated fittings, formed components	High work-hardening; used more in formed parts than heavy piping fittings.
302	UNS S30200 / EN 1.4310 (common equivalent)	General fabricated fittings, couplings, small components	Close to 304 family; less common as a dedicated fitting spec.
304	UNS S30400 / EN 1.4301	BW: Elbow, Tee, Reducer, Stub End, Cap SW: Elbow, Tee, Coupling, Union, Cap THD: Elbow, Tee, Reducer, Nipple, Coupling	General purpose stainless for fittings.
304L	UNS S30403 / EN 1.4307	BW fittings for welded pipelines; also SW/THD	Low carbon—preferred for welding (reduced sensitization risk).
304H	UNS S30409 / EN 1.4948	BW fittings for high-temperature piping	Higher carbon—better elevated temperature strength.
305	UNS S30500 / EN 1.4303	Special fabricated fittings / deep-drawn components	Not a typical piping fitting grade; used where low work-hardening is needed.
308	UNS S30800 / EN: not commonly specified for wrought fittings	Special fabricated fittings; welding-related applications	Often referenced as welding filler classification; verify project requirement.
309	UNS S30900 / EN 1.4828	BW fittings for heat & oxidation service	Higher Cr-Ni than 304 for heat resistance.
309S	UNS S30908 / EN 1.4833	BW fittings for heat service; welded lines	Low carbon variant—improved weldability vs 309.
310	UNS S31000 / EN 1.4845	BW fittings for high-temperature service	Excellent oxidation resistance at high temperature.
310S	UNS S31008 / EN 1.4845 (commonly used equivalent)	BW fittings for high-temperature welded systems	Low carbon variant—preferred for welded heat service.
316	UNS S31600 / EN 1.4401	BW: Elbow, Tee, Reducer, Stub End, Cap SW: Elbow, Tee, Coupling, Union THD: Elbow, Tee, Reducer, Nipple, Coupling	Mo-bearing for improved pitting resistance.
316L	UNS S31603 / EN 1.4404	BW fittings for corrosive/welded lines; also SW/THD	Most common choice for welded chemical & marine piping.
316H	UNS S31609 / EN 1.4919	BW fittings for high-temperature piping	Higher carbon variant for elevated temperature strength.
316Ti	UNS S31635 / EN 1.4571	BW fittings for stabilized/welded service	Ti-stabilized—good for elevated temperature and sensitization resistance.
317	UNS S31700 / EN 1.4449 (commonly referenced)	BW fittings for aggressive corrosion service	Higher Mo than 316; verify exact EN mapping per project spec.
317L	UNS S31703 / EN 1.4438	BW fittings for aggressive/welded service	Low carbon, higher Mo—useful for chloride/chemical duty.
321	UNS S32100 / EN 1.4541	BW fittings for heat service and welding	Ti stabilized austenitic for elevated temperature lines.
321H	UNS S32109 / EN 1.4878	BW fittings for high-temperature piping	Higher carbon variant for creep strength.
347	UNS S34700 / EN 1.4550	BW fittings for welded/heat service	Nb stabilized—resists sensitization in weld zones.
347H	UNS S34709 / EN 1.4961	BW fittings for high-temperature piping	High carbon stabilized grade for elevated temperature.
409L	UNS S40900 / EN 1.4512 (common equivalent)	Exhaust/utility fittings, fabricated bends, reducers	Ferritic; oxidation/heat resistance; corrosion lower than 304.
410	UNS S41000 / EN 1.4006	Machined fittings, valve parts, forged fittings	Martensitic; hardenable; moderate corrosion resistance.
410S	UNS S41008 / EN 1.4000 (commonly referenced)	Formed/welded components, light fabricated fittings	Lower carbon than 410; improved weldability.
420	UNS S42000 / EN 1.4021 (common) / 1.4034 (higher-C variants)	High hardness fittings, valve parts, machined components	Martensitic; selected for wear resistance.
429	UNS S42900 / EN: varies by spec	Heat/oxidation service fabricated fittings	Ferritic; confirm equivalence by standard/MTC.
430	UNS S43000 / EN 1.4016	Utility fittings, decorative fabricated fittings	Ferritic; economical; limited chloride resistance.
430Ti	UNS S43900 is often used for “Ti stabilized 430” / EN: varies	Welded ferritic fittings, bends, fabricated parts	“430Ti” naming is market-driven; many specs align closer to 439—confirm by MTC.
439	UNS S43035 / EN 1.4510	Heat service fittings, weldments, exhaust piping fittings	Ferritic stabilized grade; better weld performance than 430.
441	UNS S44100 / EN 1.4509	Heat service fabricated fittings, weldments	Ferritic; good oxidation & thermal fatigue resistance.
444	UNS S44400 / EN 1.4521	Corrosion-duty ferritic fittings, fabricated reducers/bends	Mo-bearing ferritic; improved pitting resistance.
S31803 (Duplex)	UNS S31803 / EN 1.4462 (Duplex 2205 family)	BW: Elbow, Tee, Reducer, Stub End, Cap Forged: Flanges, SW/THD fittings (project dependent)	High strength and excellent chloride SCC resistance; widely used in marine/chemical service.
Note: “BW” = Butt Weld, “SW” = Socket Weld, “THD” = Threaded. Trade grades like J4/J7 and some ferritic naming like 430Ti can vary by producer; don’t publish them as fixed UNS unless your MTCs consistently match a defined spec.

Mechanical, Physical & Fabrication Properties

Grade	Material Family	Typical Mechanical Properties (annealed / solution annealed unless noted)	Physical Properties (typical values)	Fabrication / Welding / Machining Notes (for fittings: BW / SW / THD / forged / fabricated)
J4	Austenitic (trade grade)	UTS: ~520–760 MPa YS (0.2%): ~240–420 MPa Elong.: ~35–45% Hardness: ~150–220 HB	Density: ~7.85–7.90 g/cm³ E: ~190 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Use where cost-driven; performance varies by producer. Welding: generally OK with correct filler; control heat input. Forming: good; work-hardens. Publish as “J4” only if you can back it with MTCs (chemistry varies).
J7	Austenitic (trade grade)	UTS: ~520–780 MPa YS: ~240–450 MPa Elong.: ~35–45% Hardness: ~150–230 HB	Density: ~7.85–7.90 g/cm³ E: ~190 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Similar story as J4: variability is your risk, not the customer’s. Welding: OK with proper consumables; avoid overheating. Best for light/utility fittings, not critical chloride service.
201	Austenitic (200 series)	UTS: ~515–760 MPa YS: ~275–420 MPa Elong.: ~35–45% Hardness: ~150–220 HB	Density: ~7.86 g/cm³ E: ~190 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Better strength than 304 in many conditions; lower corrosion margin. Welding: use suitable filler; manage sensitization & distortion. Forming: very good; work-hardens strongly.
202	Austenitic (200 series)	UTS: ~515–760 MPa YS: ~275–450 MPa Elong.: ~35–45% Hardness: ~150–230 HB	Density: ~7.86 g/cm³ E: ~190 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Common in cost-driven fittings; corrosion depends heavily on environment. Welding: OK; prefer low heat input; pick filler as per service. Not the first choice for marine/chloride duty.
301	Austenitic (work-hardening)	UTS: ~520–930 MPa (condition dependent) YS: ~210–550 MPa Elong.: ~30–45%	Density: ~7.93 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Used more for formed components than heavy piping fittings. Forming: excellent; very high work-hardening. Welding: OK; distortion control needed.
302	Austenitic (304 family)	UTS: ~515–750 MPa YS: ~205–310 MPa Elong.: ~40–55% Hardness: ~150–200 HB	Density: ~7.93 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~17 µm/m·K	Similar fabrication behavior to 304. Welding: good; pick filler per service. Commonly substituted with 304 in fittings supply chains.
304	Austenitic	UTS: ~515–750 MPa YS: ~205–310 MPa Elong.: ~40–55% Hardness: ~150–200 HB	Density: ~7.93 g/cm³ E: ~193 GPa k: ~16 W/m·K CTE: ~17.2 µm/m·K	Welding: excellent; BW/SW/THD/forged/fabricated all common. Forming: very good; work-hardens. Machining: fair; better with optimized tooling/coolant.
304L	Austenitic (low C)	UTS: ~485–740 MPa YS: ~170–290 MPa Elong.: ~40–55%	Density: ~7.93 g/cm³ E: ~193 GPa k: ~16 W/m·K CTE: ~17.2 µm/m·K	Best for welded fittings (reduced sensitization risk). Welding: excellent; post-weld issues minimized vs 304. Same forming behavior as 304.
304H	Austenitic (high C)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~40–55%	Density: ~7.93 g/cm³ E: ~193 GPa k: ~16 W/m·K CTE: ~17.2 µm/m·K	For elevated temperature service fittings. Welding: good but manage sensitization risk if not stabilized/low-C route. Specify clearly for heat service, not general use.
305	Austenitic (low work-hardening)	UTS: ~515–750 MPa YS: ~205–310 MPa Elong.: ~40–55%	Density: ~7.93 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~17 µm/m·K	Chosen for deep drawing/spinning; not typical for piping fittings. Fabrication: excellent formability. Welding: similar to 304.
308	Austenitic (weld-related)	UTS: ~515–760 MPa (varies by product form) YS: ~205–310 MPa	Density: ~7.9 g/cm³ E: ~193 GPa k: ~14–16 W/m·K	Often referenced as filler/consumable designation in industry. If you supply “308” fittings, lock it to a specific standard + MTC or don’t list it.
309	Austenitic (heat-resistant)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.90 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~15–16 µm/m·K	Good oxidation resistance at high temperature. Welding: good; used in heat duty fittings. Not for chloride service just because it’s “more alloyed”.
309S	Austenitic (heat-resistant, low C)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.90 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~15–16 µm/m·K	Preferred over 309 for welding (lower sensitization risk). Great for furnace/heat exchanger lines and hot gas service.
310	Austenitic (high-temp)	UTS: ~515–780 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.90 g/cm³ E: ~200 GPa (typical) k: ~14–16 W/m·K CTE: ~15–16 µm/m·K	High-temperature oxidation resistance fittings. Welding: good; manage distortion/heat input.
310S	Austenitic (high-temp, low C)	UTS: ~515–780 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.90 g/cm³ E: ~200 GPa (typical) k: ~14–16 W/m·K CTE: ~15–16 µm/m·K	Better for welded high-temperature fittings than 310 (lower sensitization risk). Used for furnace parts / hot piping.
316	Austenitic (Mo-bearing)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~40–55% Hardness: ~150–220 HB	Density: ~7.98–8.00 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16.0 µm/m·K	Best general upgrade for chloride/chemical duty fittings vs 304. Welding: excellent; widely used in BW/SW/THD fittings. Machining: fair.
316L	Austenitic (Mo-bearing, low C)	UTS: ~485–740 MPa YS: ~170–290 MPa Elong.: ~40–55%	Density: ~7.98–8.00 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16.0 µm/m·K	Go-to welded fitting grade for marine/chemical lines. Welding: excellent; low risk of sensitization vs 316.
316H	Austenitic (Mo-bearing, high C)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~8.0 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16 µm/m·K	Elevated temperature fittings where creep strength matters. Welding: good but manage sensitization unless stabilized solution is used.
316Ti	Austenitic (Mo-bearing, stabilized)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~8.0 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16 µm/m·K	Better resistance to sensitization at elevated temperature vs 316. Welding: good; common in heat + corrosion duty lines.
317	Austenitic (higher Mo)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~8.0 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~15.5–16 µm/m·K	Improved pitting resistance vs 316 in many environments. Welding: good; ensure correct filler selection. Typically for aggressive chemical service fittings.
317L	Austenitic (higher Mo, low C)	UTS: ~485–740 MPa YS: ~170–290 MPa Elong.: ~35–50%	Density: ~8.0 g/cm³ E: ~193 GPa k: ~14–16 W/m·K	Preferred for welded aggressive-service fittings (low carbon). Welding: excellent; reduced sensitization risk.
321	Austenitic (Ti stabilized)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.9 g/cm³ E: ~193 GPa k: ~14–16 W/m·K CTE: ~16–17 µm/m·K	Strong choice for hot welded piping fittings. Welding: good; stabilization helps resist intergranular corrosion in HAZ.
321H	Austenitic (stabilized, high C)	UTS: ~515–780 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.9 g/cm³ E: ~193 GPa k: ~14–16 W/m·K	High-temp fittings where creep strength matters. Welding: good; specify clearly for heat duty.
347	Austenitic (Nb stabilized)	UTS: ~515–760 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.9 g/cm³ E: ~193 GPa k: ~14–16 W/m·K	Excellent for welded fittings at elevated temperature. Welding: very good; Nb stabilization reduces sensitization risk.
347H	Austenitic (Nb stabilized, high C)	UTS: ~515–780 MPa YS: ~205–310 MPa Elong.: ~35–50%	Density: ~7.9 g/cm³ E: ~193 GPa k: ~14–16 W/m·K	High-temperature fittings; used where creep strength is critical. Welding: good; manage heat input and procedure control.
409L	Ferritic	UTS: ~380–550 MPa YS: ~170–310 MPa Elong.: ~20–30% Hardness: ~140–200 HB	Density: ~7.70 g/cm³ E: ~200 GPa k: ~22–26 W/m·K CTE: ~10–12 µm/m·K	Better heat/oxidation resistance than austenitic cost grades. Welding: workable; control grain growth/embrittlement risk with procedure. Used in exhaust/utility and heat service fittings.
410	Martensitic (hardenable)	UTS: ~450–700 MPa (annealed) YS: ~275–450 MPa Elong.: ~15–25% Hardness: ~170–240 HB (annealed)	Density: ~7.75 g/cm³ E: ~200 GPa k: ~24–28 W/m·K CTE: ~9–11 µm/m·K	Machining: good vs austenitic. Welding: tricky—risk of cracking; preheat/postheat often required. Common in valve parts, machined fittings.
410S	Ferritic / low-C martensitic	UTS: ~380–520 MPa YS: ~205–310 MPa Elong.: ~20–30%	Density: ~7.75 g/cm³ E: ~200 GPa k: ~24–28 W/m·K	Better weldability than 410. Used for formed/welded parts and heat service components.
420	Martensitic (high hardness)	UTS: ~500–800 MPa (condition dependent) YS: ~300–500 MPa Elong.: ~10–20% Hardness: can be very high when heat treated	Density: ~7.75 g/cm³ E: ~200 GPa k: ~24–28 W/m·K	Used where wear resistance matters (valves, seats, machined parts). Welding: generally not preferred; cracking risk without correct procedure.
429	Ferritic	UTS: ~380–550 MPa YS: ~205–345 MPa Elong.: ~20–30%	Density: ~7.70 g/cm³ E: ~200 GPa k: ~22–26 W/m·K	Heat/oxidation duty applications; confirm exact grade spec (less standardized in trade). Welding: workable with controlled procedure.
430	Ferritic	UTS: ~380–550 MPa YS: ~205–345 MPa Elong.: ~20–30% Hardness: ~140–200 HB	Density: ~7.70 g/cm³ E: ~200 GPa k: ~23–26 W/m·K CTE: ~10–11 µm/m·K	Fabrication: good for simple forming; less ductile than austenitic. Welding: OK but needs procedure control to avoid grain coarsening. Not for severe chloride service.
430Ti	Ferritic (stabilized trade name)	UTS: ~380–550 MPa YS: ~205–345 MPa Elong.: ~20–30%	Density: ~7.70 g/cm³ E: ~200 GPa k: ~23–26 W/m·K	Stabilized ferritic for improved weld performance vs plain 430. “430Ti” is often used in trade—many specs align near 439; verify by MTC.
439	Ferritic (stabilized)	UTS: ~380–560 MPa YS: ~205–345 MPa Elong.: ~20–30%	Density: ~7.70 g/cm³ E: ~200 GPa k: ~23–26 W/m·K	Welding: better than 430; common in exhaust/heat service fittings. Good resistance to intergranular corrosion vs unstabilized ferritic.
441	Ferritic (stabilized)	UTS: ~380–560 MPa YS: ~205–345 MPa Elong.: ~20–30%	Density: ~7.70 g/cm³ E: ~200 GPa k: ~23–26 W/m·K	Great thermal fatigue/oxidation resistance. Used for high-heat systems; weld procedure control required.
444	Ferritic (Mo-bearing)	UTS: ~380–560 MPa YS: ~205–345 MPa Elong.: ~20–30%	Density: ~7.70 g/cm³ E: ~200 GPa k: ~22–26 W/m·K	Better pitting resistance than 430/439 due to Mo. Welding: workable; keep heat input controlled.
S31803 (Duplex)	Duplex (austenitic + ferritic)	UTS: ~620–850 MPa YS: ~450–600 MPa Elong.: ~25–35% Hardness: ~200–290 HB	Density: ~7.80 g/cm³ E: ~200 GPa k: ~14–19 W/m·K CTE: ~13–14 µm/m·K	High strength + excellent chloride SCC resistance (big reason to use it). Welding: needs tight heat input control to keep phase balance; follow qualified WPS. Forming: stronger springback; higher forming loads.
Important: Values shown are typical ranges and will vary with product form (BW fittings vs forged vs machined), heat treatment, size, and standard. For critical projects, publish your statement as “Typical” and offer grade-wise MTC on request.

Common Names & International Identifiers

Grade / Trade Name	UNS / EN Identifier (Typical)	Common / Market Names	Common Fitting Types Supplied
J4	Trade grade (no single global UNS)	J4 Stainless (budget austenitic / 200-series equivalent in trade)	ERW/Seamless Pipe Fittings, Elbows, Tees, Reducers, Couplings, Nipples, Flanges, Clamps (as per standard)
J7	Trade grade (no single global UNS)	J7 Stainless (trade name; chemistry varies by producer)	Elbows, Tees, Reducers, Couplings, Nipples, Unions, Flanges (light-duty / utility applications)
201	UNS S20100 / EN 1.4372 (typical)	SS 201, 200 Series Austenitic	Threaded Fittings, Socket-Weld Fittings, Clamp Fittings, Fabricated Fittings (application-dependent)
202	UNS S20200 / EN 1.4373 (typical)	SS 202, 200 Series Austenitic	Threaded Fittings, Socket-Weld Fittings, Couplings, Nipples, Unions, Light-Duty BW Fittings
301	UNS S30100 / EN 1.4310	SS 301 (work-hardening austenitic)	Fabricated / formed fittings, clamps, rings, special parts (less common as standard BW fittings)
302	UNS S30200 / EN 1.4310 (close family)	SS 302 (304 family in trade)	General-purpose fittings (threaded, SW, fabricated), fastener-related components
304	UNS S30400 / EN 1.4301	SS 304, 18/8 Stainless	Butt-Weld Fittings (Elbow/Tee/Reducer/Cap), Threaded Fittings, Socket-Weld Fittings, Flanges, Tri-Clamp Fittings
304L	UNS S30403 / EN 1.4307	SS 304L (low carbon)	BW / SW / Threaded Fittings, Flanges, Fabricated Fittings (preferred for welded lines)
304H	UNS S30409 / EN 1.4948 (typical)	SS 304H (high carbon, heat service)	High-temp BW fittings, forged fittings, flanges (heat-duty services)
305	UNS S30500 / EN 1.4303	SS 305 (low work-hardening)	Fabricated/formed fittings, special components (less common as standard BW fittings)
308	Commonly referenced as weld consumable grade (not a standard fitting grade)	308 / 308L (welding filler designation in market)	Used mainly as filler material; if fittings are offered, specify applicable standard + MTC clearly
309	UNS S30900 / EN 1.4828	SS 309 (heat-resistant)	High-temp BW fittings, fabricated fittings, flanges, furnace/thermal service components
309S	UNS S30908 / EN 1.4833 (typical)	SS 309S (low carbon, heat-resistant)	High-temp welded fittings, BW fittings, fabricated fittings, flanges
310	UNS S31000 / EN 1.4845	SS 310 (high-temp)	Furnace/heat-duty BW fittings, flanges, fabricated components
310S	UNS S31008 / EN 1.4845 (310S variant)	SS 310S (low carbon)	High-temp welded fittings, BW fittings, fabricated fittings, flanges
316	UNS S31600 / EN 1.4401	SS 316 (marine/chemical grade)	BW/SW/Threaded Fittings, Instrumentation Fittings, Flanges, Tri-Clamp/Sanitary Fittings
316L	UNS S31603 / EN 1.4404	SS 316L (low carbon)	Welded BW fittings, sanitary fittings, pharma/food fittings, flanges, instrumentation fittings
316H	UNS S31609 / EN 1.4919 (typical)	SS 316H (high carbon, heat service)	Heat-duty fittings, BW fittings, flanges (elevated temperature service)
316Ti	UNS S31635 / EN 1.4571	SS 316Ti (Ti stabilized)	Heat + corrosion duty fittings, BW fittings, fabricated fittings, flanges
317	UNS S31700 / EN 1.4449 (typical family)	SS 317 (higher Mo)	Corrosion-duty fittings, BW fittings, flanges, fabricated fittings
317L	UNS S31703 / EN 1.4438 (typical family)	SS 317L (low carbon, higher Mo)	Welded corrosion-duty fittings, BW fittings, flanges, fabricated fittings
321	UNS S32100 / EN 1.4541	SS 321 (Ti stabilized)	High-temp welded fittings, BW fittings, flanges, fabricated fittings
321H	UNS S32109 / EN 1.4878 (typical)	SS 321H (high carbon, stabilized)	Heat-duty BW fittings, flanges, pressure/thermal service fittings
347	UNS S34700 / EN 1.4550	SS 347 (Nb stabilized)	High-temp welded fittings, BW fittings, flanges, fabricated fittings
347H	UNS S34709 / EN 1.4961 (typical)	SS 347H (high carbon, stabilized)	High-temp BW fittings, flanges, pressure/thermal service fittings
409L	UNS S40900 / EN 1.4512 (typical family)	SS 409L (ferritic, heat/oxidation)	Utility/heat-service fittings, fabricated fittings, exhaust-related components
410	UNS S41000 / EN 1.4006	SS 410 (martensitic, hardenable)	Machined fittings, valve parts, nipples/couplings (where higher hardness is needed)
410S	UNS S41008 / EN 1.4000 (family)	SS 410S (improved weldability vs 410)	Formed/fabricated fittings for heat duty, transition fittings (application-specific)
420	UNS S42000 / EN 1.4021 (typical)	SS 420 (high hardness)	Wear-duty machined parts, valve seats/components (less common as welded BW fittings)
429	UNS S42900 (typical market reference)	SS 429 (ferritic)	Heat/oxidation-duty fabricated fittings and components (standardization depends on spec)
430	UNS S43000 / EN 1.4016	SS 430 (ferritic, general-purpose)	Threaded fittings, formed/fabricated fittings, architectural/utility components
430Ti	Often marketed; closest standardized references are in stabilized ferritic family	SS 430Ti (stabilized ferritic trade name)	Welded/fabricated fittings, exhaust/heat-service components (confirm by MTC)
439	UNS S43035 / EN 1.4510 (typical)	SS 439 (stabilized ferritic)	Welded fittings for heat duty, fabricated fittings, exhaust/thermal lines
441	UNS S44100 / EN 1.4509	SS 441 (stabilized ferritic)	High-heat fabricated fittings, thermal cycling duty components
444	UNS S44400 / EN 1.4521	SS 444 (Mo-bearing ferritic)	Corrosion-resistant ferritic fittings, fabricated fittings, water/chloride-moderate duty
S31803 (Duplex)	UNS S31803 / EN 1.4462 (duplex family)	Duplex 2205 (common market name)	BW fittings, flanges, forged fittings, high-pressure/chloride duty fittings
Note (be strict on this): “J4/J7” and “430Ti” are often trade identifiers and can vary by manufacturer. If you list them publicly, keep MTC-backed supply only, otherwise customers will treat it as misleading.

Standards & International Equivalents

Grade	UNS / EN (Typical)	Primary Product Standards (Fittings)	Pressure Class / Dimensional Standards	Closest International Equivalents (Typical)	Common Fitting Types
Important: Fittings are specified by product standard + grade + class + NPS/Schedule. “Equivalent” grades vary by standard; always confirm against MTC / EN 10204 3.1. “J4/J7” are trade names (not single global standards).
J4	Trade (no single UNS)	ASTM A403 / A182 / A815 (where applicable by chemistry)	ASME B16.9, B16.11, B16.5, B16.47; MSS SP-43 / SP-83	Often sold as 200-series austenitic equivalent (confirm by chemistry)	BW, SW, THD, Flanges
J7	Trade (no single UNS)	ASTM A403 / A182 / A815 (where applicable by chemistry)	ASME B16.9, B16.11, B16.5; MSS SP-43	Trade-mapped by supplier (confirm by chemistry)	BW, SW, THD
201	S20100 / EN 1.4372	ASTM A403 (BW), ASTM A182 (Flanges/Forged), ASTM A815 (Duplex not applicable)	ASME B16.9 (BW), B16.11 (SW/THD), B16.5/B16.47 (Flanges), MSS SP-43	JIS SUS201 (market reference), GB/T 12Cr17Mn6Ni5N (varies)	BW, SW, THD, Flanges
202	S20200 / EN 1.4373	ASTM A403 / ASTM A182 (when supplied as forged fittings/flanges)	ASME B16.9, B16.11, B16.5; MSS SP-43	JIS SUS202 (market reference)	BW, SW, THD
301	S30100 / EN 1.4310	Typically fabricated parts; if supplied as fittings: ASTM A240/A276 (material) + dimensional B16 standards	ASME B16.9/B16.11 (if applicable)	JIS SUS301	Fabricated, Clamps
302	S30200 / EN family 1.4310	Typically fabricated; less common as standard BW fittings	ASME B16 series (if applicable)	JIS SUS302	Fabricated
304	S30400 / EN 1.4301	ASTM A403 WP304 (BW); ASTM A182 F304 (Flanges/Forged); ASTM A312 (pipe reference)	ASME B16.9, B16.11, B16.5/B16.47; MSS SP-43, SP-83	JIS SUS304; ISO/EN 1.4301	BW, SW, THD, Flanges
304L	S30403 / EN 1.4307	ASTM A403 WP304L; ASTM A182 F304L	ASME B16.9, B16.11, B16.5; MSS SP-43	JIS SUS304L; EN 1.4307	BW, SW, THD, Flanges
304H	S30409 / EN 1.4948 (typ.)	ASTM A403 WP304H (where offered); ASTM A182 F304H	ASME B16.9, B16.5	JIS SUS304H; EN 1.4948	BW, Flanges
305	S30500 / EN 1.4303	Mostly fabricated components; not typical commodity BW fitting grade	As per drawing + ASME B16 if applicable	JIS SUS305	Fabricated
308	Primarily weld filler designation (not standard fitting grade)	If sold as fittings, must specify governing material standard + chemistry limits clearly	ASME B16 series (dimensional)	ER308/ER308L / E308 (welding consumables)	Special / On request
309	S30900 / EN 1.4828	ASTM A403 WP309; ASTM A182 F309	ASME B16.9, B16.5	JIS SUS309; EN 1.4828	BW, Flanges
309S	S30908 / EN 1.4833 (typ.)	ASTM A403 WP309S; ASTM A182 F309S (where used)	ASME B16.9, B16.5	JIS SUS309S	BW, Flanges
310	S31000 / EN 1.4845	ASTM A403 WP310; ASTM A182 F310	ASME B16.9, B16.5	JIS SUS310; EN 1.4845	BW, Flanges
310S	S31008 / EN 1.4845 (variant)	ASTM A403 WP310S; ASTM A182 F310S	ASME B16.9, B16.5	JIS SUS310S	BW, Flanges
316	S31600 / EN 1.4401	ASTM A403 WP316; ASTM A182 F316	ASME B16.9, B16.11, B16.5/B16.47; MSS SP-43	JIS SUS316; EN 1.4401	BW, SW, THD, Flanges
316L	S31603 / EN 1.4404	ASTM A403 WP316L; ASTM A182 F316L	ASME B16.9, B16.11, B16.5; MSS SP-43	JIS SUS316L; EN 1.4404	BW, SW, THD, Flanges
316H	S31609 / EN 1.4919 (typ.)	ASTM A182 F316H; (BW fittings per A403 where applicable)	ASME B16.9, B16.5	JIS SUS316H	BW, Flanges
316Ti	S31635 / EN 1.4571	ASTM A403 WP316Ti; ASTM A182 F316Ti	ASME B16.9, B16.5	JIS SUS316Ti; EN 1.4571	BW, Flanges
317	S31700	ASTM A403 WP317; ASTM A182 F317	ASME B16.9, B16.5	JIS SUS317	BW, Flanges
317L	S31703	ASTM A403 WP317L; ASTM A182 F317L	ASME B16.9, B16.5	JIS SUS317L	BW, Flanges
321	S32100 / EN 1.4541	ASTM A403 WP321; ASTM A182 F321	ASME B16.9, B16.5	JIS SUS321; EN 1.4541	BW, Flanges
321H	S32109	ASTM A182 F321H; (BW fittings per A403 where applicable)	ASME B16.9, B16.5	JIS SUS321H	BW, Flanges
347	S34700 / EN 1.4550	ASTM A403 WP347; ASTM A182 F347	ASME B16.9, B16.5	JIS SUS347; EN 1.4550	BW, Flanges
347H	S34709	ASTM A182 F347H; (BW fittings per A403 where applicable)	ASME B16.9, B16.5	JIS SUS347H	BW, Flanges
409L	S40900 / EN family 1.4512 (typ.)	ASTM A403 (BW) / ASTM A182 (forged) when applicable	ASME B16.9, B16.11, B16.5	JIS SUS409L	BW, Fabricated
410	S41000 / EN 1.4006	ASTM A182 F410 (forged fittings/flanges); BW fittings by A403 where used	ASME B16.5, B16.11, B16.9	JIS SUS410; EN 1.4006	THD, SW, Flanges
410S	S41008	ASTM A240/A276 (material) + ASME B16 (as applicable)	ASME B16 series	JIS SUS410S	Fabricated
420	S42000 / EN 1.4021 (typ.)	ASTM A182 (where forged); commonly as machined parts rather than BW fittings	ASME B16.11 / B16.5 (if supplied as forged fittings)	JIS SUS420	Machined / Special
429	S42900 (market reference)	Material standard depends on supplier; specify chemistry + product standard on MTC	ASME B16 series (dimensional)	Ferritic family equivalents vary (confirm)	Fabricated / Special
430	S43000 / EN 1.4016	ASTM A240/A276 (material) + ASME B16 (as applicable)	ASME B16.9/B16.11/B16.5	JIS SUS430; EN 1.4016	THD, Fabricated
430Ti	Stabilized ferritic (trade / supplier-defined)	Must be supplied with clear standard + chemistry limits on MTC	ASME B16 series	Closest: stabilized ferritic family (confirm)	Fabricated
439	S43035 / EN 1.4510 (typ.)	ASTM A240/A276 (material) + ASME B16	ASME B16 series	JIS SUS439; EN 1.4510	Fabricated
441	S44100 / EN 1.4509	ASTM A240/A276 (material) + ASME B16	ASME B16 series	JIS SUS441; EN 1.4509	Fabricated
444	S44400 / EN 1.4521	ASTM A240/A276 (material) + ASME B16	ASME B16 series	JIS SUS444; EN 1.4521	Fabricated / Special
S31803 (Duplex)	S31803 / EN 1.4462	ASTM A815 WP-S31803 (BW); ASTM A182 F51 (forged/flanges)	ASME B16.9, B16.11, B16.5/B16.47; MSS SP-43 (where used)	Often marketed as Duplex 2205 family (confirm by spec)	BW, SW, THD, Flanges
Fitting Types Legend: BW = Butt-Weld (Elbows/Tees/Reducers/Caps) • SW = Socket-Weld • THD = Threaded • Flanges = Weld Neck / Slip-On / Blind / Socket Weld / Threaded • Also supplied: Stub Ends, Cross, Laterals, Olets (Weldolet/Sockolet/Threadolet), Clamps (Tri-Clamp) — as per requirement.

Applications

Grade / Family	Best-Fit Applications (Typical)	Common Industries / Use-Cases	Recommended Fitting Types (Typical)
J4 (trade)	General-purpose, indoor / low-to-moderate corrosion, budget projects	Decorative plumbing, light fabrication, mild water lines, non-critical process lines	BW elbows/tees/reducers, SW/THD (low pressure), fabricated bends
J7 (trade)	General-purpose fabrication, indoor / moderate exposure (confirm chemistry)	Architectural, light industrial piping, non-critical utilities	BW fittings, SW/THD (as per pressure), fabricated spools
201	Cost-effective austenitic alternative where chloride corrosion is not critical	Building services, furniture/fixtures, indoor pipelines, low-corrosive utilities	BW, SW/THD, clamps; avoid severe chloride service
202	General fabrication, moderate corrosion, indoor / controlled environments	Structural supports, utility lines, architectural & non-critical piping	BW, SW/THD, fabricated fittings
301 / 302	Formed / fabricated components; high work-hardening for formed parts	Clamps, brackets, formed connectors, fabricated transitions	Fabricated elbows/reducers, clamps, custom parts (not typical commodity BW)
304 / 304L	Universal stainless for general corrosion resistance & hygiene	Food & beverage, water pipelines, pharma utilities, chemical transfer (mild), HVAC, general process piping	BW elbows/tees/reducers/caps, SW/THD fittings, flanges (WN/SO/BL), olets
304H	Higher-temperature service vs 304 (creep-strength oriented)	Heat exchangers, boilers, hot process lines, refineries (non-sour), thermal systems	BW fittings, flanges, high-temp forged fittings
305	Deep-drawing / forming focused; niche in standard piping	Fabricated components, formed connectors, special assemblies	Fabricated fittings, custom bends, special parts
308 (weld grade reference)	Used mainly as welding consumable family; fittings only when specified by chemistry	Weld-overlay / repair, fabricated systems with matching filler selection	Custom / project-based fittings; focus on welding consumables selection
309 / 309S	High-temperature oxidation resistance; dissimilar metal transitions	Furnaces, kilns, heat-treatment plants, burner parts, high-temp ducting; transition joints	BW fittings, high-temp flanges, reducers, transition spools
310 / 310S	Higher-temperature service than 309; scaling resistance	Heat furnaces, radiant tubes, high-temp manifolds, petrochemical heater parts	BW fittings, flanges, high-temp forged fittings
316 / 316L	Enhanced chloride & chemical resistance vs 304 (Mo-bearing)	Marine/coastal, chemical plants, desalination utilities, pharma, food processing (salted media), offshore piping	BW/SW/THD fittings, flanges, olets; preferred for seawater splash / brackish exposure
316H	High-temperature variant of 316	Hot chemical/process lines, refineries, high-temp piping & manifolds	BW fittings, flanges, forged fittings
316Ti	Stabilized for improved intergranular corrosion resistance after welding (certain services)	Heat exchangers, welded chemical equipment, elevated-temp chloride-containing process lines	BW fittings, flanges, welded assemblies
317 / 317L	Higher Mo than 316 for stronger chemical resistance	Chemical processing, pulp & paper, acidic media, aggressive industrial service	BW fittings, flanges, olets; heavy-wall & critical joints
321 / 321H	Stabilized austenitic for elevated-temperature welded service	Aerospace/thermal piping, exhaust systems, hot process lines, heat exchangers	BW fittings, flanges, forged fittings
347 / 347H	Stabilized for high-temperature welded service; creep strength in H grade	Refineries, steam lines, high-temp chemical plants, superheaters	BW fittings, flanges, forged fittings
409L	Economical ferritic for oxidation resistance; moderate corrosion	Automotive exhaust, ducts, flue gas lines, heat shields, mild atmospheric exposure	Fabricated elbows, BW fittings (where applicable), clamps
410 / 410S	Martensitic / ferritic-martensitic; strength & moderate corrosion; 410S for better weldability	Pump parts, valves, mechanical fittings, mild chemical lines, hardware	Forged fittings, flanges, threaded fittings, machined parts
420	Higher hardness / wear resistance (heat treatable); corrosion is secondary	Wear parts, valve internals, tools, shafts, surgical & cutting components (not typical piping)	Machined fittings/components; special flanges/parts
429 / 430 / 430Ti	Ferritic general corrosion & oxidation resistance; Ti-stabilized for weldability	Appliance, architectural trims, heat exchangers (mild), indoor ducting, mild service piping	Fabricated fittings, BW where specified, clamps
439 / 441	Stabilized ferritics; improved high-temp & weld performance	Exhaust systems, hot gas ducting, heat recovery systems	Fabricated bends, reducers, manifolds
444	High alloy ferritic; strong pitting resistance for chloride/marine atmospheres (specific services)	Water heaters, desalination auxiliaries, brackish water handling, coastal exposure equipment	BW/fabricated fittings, flanges (project-based), custom spools
S31803 (Duplex)	High strength + excellent chloride stress corrosion cracking resistance	Offshore & marine, chemical processing, seawater lines, desalination, oil & gas, firewater systems	BW fittings (A815), flanges/forged (A182/F51), heavy-wall reducers, olets; high-pressure piping
Common Stainless Steel Fitting Types Supplied: Butt-Weld (Elbows 45°/90° LR/SR, Tees, Reducers Con/Ecc, Caps, Cross, Stub Ends), Socket-Weld (Elbows/Tees/Couplings/Unions), Threaded (Elbows/Tees/Reducers/Couplings/Plugs), Flanges (Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint), Olets (Weldolet/Sockolet/Threadolet), Hygienic (Tri-Clamp Ferrules/Clamps/Reducers) — as per project requirement.

Common Stainless Steel Fittings Dimensions Chart

Fitting Category	Common Types	Typical Size Range	Pressure Class / Schedule	Typical Ends
Butt-Weld (BW)	90° LR/SR Elbow, 45° Elbow, Equal/Reducing Tee, Concentric/Eccentric Reducer, Cap, Cross, Stub End	1/2" NB to 24" NB (custom up to 48")	Sch 5S / 10S / 40S / 80S / 160 / XXS	Bevel ends (ASME B16.25)
Socket-Weld (SW)	Elbow, Tee, Reducer Insert, Coupling (Full/Half), Union, Cap	1/8" to 4"	Class 3000 / 6000 / 9000	Socket ends (ASME B16.11)
Threaded (THD)	Elbow, Tee, Reducer, Coupling, Union, Plug, Cap, Bushing, Nipple	1/8" to 4"	Class 2000 / 3000 / 6000 (as applicable)	NPT / BSPT / BSPP (as required)
Flanges	Weld Neck (WN), Slip-On (SO), Blind (BL), Socket Weld (SW), Threaded (THD), Lap Joint (LJ), Ring Type Joint (RTJ)	1/2" to 24" (custom larger)	ASME Class 150 / 300 / 600 / 900 / 1500 / 2500	RF / FF / RTJ
Olets	Weldolet, Sockolet, Threadolet, Elbolet, Nippolet, Latrolet	Branch 1/2" to 6" on run 1" to 24"	Sch match / Class match	BW / SW / THD
Hygienic / Sanitary	Tri-Clamp Ferrule, Clamp, Gasket, Reducer, Tee, Elbow	1/2" to 6" (OD tube based)	Light-duty process (as per standard)	Tri-clamp / weld ends

Component	Primary Dimensional Standard	Common Options	Notes
BW Fittings	ASME B16.9 (factory-made), MSS SP-43 (lightweight)	LR/SR elbows, tees, reducers	Dimensions tied to pipe OD; thickness by schedule.
BW Butt-Welding Ends	ASME B16.25	Bevel angles, root face	Critical for welding fit-up.
Forged SW/THD Fittings	ASME B16.11	Class 3000/6000/9000	Small sizes; high-pressure systems.
Pipe Nipples	MSS SP-95 / ASME B36.19/B36.10 (pipe OD)	THD ends, custom lengths	Length tolerances depend on manufacturer.
Flanges	ASME B16.5 (up to 24"), ASME B16.47 (large)	150–2500, RF/RTJ/FF	Drilling (bolt circle) by class & NPS.
Sanitary Fittings	3-A / ASME BPE / DIN 11850 (project dependent)	Tri-clamp, orbital weld	Selected based on food/pharma compliance.

Grade / Family	BW Fittings	SW/THD Forged	Flanges	Typical Notes / Service
Austenitic (General) J7, J4, 201, 202, 301, 302, 304, 304L, 304H, 305, 308, 309, 309S, 310, 310S, 316, 316L, 316H, 316Ti, 317, 317L, 321, 321H, 347, 347H	Yes (most common)	Yes (commonly 304/316 family)	Yes	Best availability in 304/316; high-temp in 309/310/321/347; confirm J grades chemistry before critical service.
Ferritic / Martensitic 409L, 410, 410S, 420, 429, 430, 430Ti, 439, 441, 444	Selective / project-based	Selective (often machined/forged parts)	Selective	Common in exhaust/heat applications (409/439/441) and mechanical parts (410/420). Not typical for high-corrosion piping.
Duplex S31803	Yes (critical service)	Yes (A182/F51 matching)	Yes	Used for chloride / offshore / high-pressure lines; often thicker schedules and stricter QA requirements.

If you need…	Specify this	Typical Example	Why it matters
BW elbows/tees/reducers	NPS/NB, Schedule, Standard, Material Grade	6" SCH 40S ASME B16.9, SS 316L	Schedule controls wall thickness; standard controls center-to-face dimensions.
Forged SW/THD fittings	Size, Class, End type, Thread type, Grade	1" Class 3000 THD NPT, SS 304	Class governs pressure rating & geometry; thread spec prevents mismatch.
Flanges	NPS, Class, Facing, Bore/Schedule, Standard, Grade	4" Class 150 RF, bore SCH 40S, SS 316	Wrong class/facing/drilling = unusable on-site.
Branch connections (Olets)	Run size, Branch size, Schedule, End type, Grade	8"×2" Weldolet SCH 40S, SS 316L	Run/branch must match OD & schedule for weld fit-up.

Stainless Steel Fittings