Stainless Steel Pipe Fitting

Stainless steel pipe fittings are used to connect different sections of piping, enabling the transport of fluids or gases.
Elbow: Used to change the direction of the pipeline. Common angles include 90°, 45°, and 180°.
Tee: Used to connect three pipes, forming a T-shaped structure. Commonly used in liquid and gas transport piping systems.
Reducer: Used to connect pipes of different sizes, allowing fluid to flow from a larger-diameter pipe to a smaller-diameter pipe, or vice versa.
Coupling: Used to join two pipes, providing a secure and leak-proof connection.
Cross: Used to connect four pipes, forming a cross-shaped structure. Commonly used in liquid and gas transport piping systems.
Flange: Used to connect pipes or valves to other equipment (such as pumps or storage tanks). Commonly used in industrial applications.
Cap: Used to close off the end of a pipe, providing a secure and leak-proof seal.
Bend: Used to create a curve in the pipeline, allowing it to be routed along a specific path or direction.

 

Stainless Steel Pipe Fittings Standard

Stainless Steel Pipe Fittings Standard	Description
ASTM A182/A182M	Forged or rolled alloy steel pipe flanges, forged fittings and valves and parts for high temperature service. Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings
ASTM A403/A403M	Wrought austenitic stainless steel 316Ti piping fittings.
ASTM A815/A815M	Wrought ferritic, ferritic/austenitic and martensitic stainless steel 316Ti piping fittings.
AS 2129	This Standard specifies requirements for circular flanges of nominal sizes DN 15 to DN 3000. Flanges for pipes, valves and fittings
ANSI/ASME B1.20.1	Pipe threads, general purpose (inch).
ANSI B16.5	Steel pipe flanges and flanged fittings.
ANSI B16.9	Factory-made wrought steel butt-welding fittings.
ANSI B16.11	Forged steel fittings socket-welding and threaded. Socket Welding and Threaded Forged Fittings
ANSI B16.25	Butt-welding ends.
MSS SP43	Wrought stainless steel butt-welding fittings. Wrought and Fabricated Butt-Welding Fittings for Low Pressure, Corrosion Resistant Applications
BS21	Threading.
ISO 4144	Stainless steel fittings threaded to ISO 7-1.
MSS SP-95	Swage(d) Nipples and Bull Plugs
BS3799	Specification for Steel pipe fittings, screwed and Socket-welding for the petroleum industry
ANSI – B 16.9 ASTM A403 – ASME SA403	‘Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings’
API 590-605 ASME B16.9	‘Factory-Made Wrought Buttwelding Fittings’
ASME B16.25	‘Buttwelding Ends’
ASME B16.28	‘Wrought Steel Buttwelding Short Radius Elbows and Returns’

 

Stainless Steel Flange

Keywords: Welding Neck Flange,Blind Flange,Socket Weld Flange.Lapped Joint Flange,Slip-on Flange,Plate Flange
Size: NPS from 1/2'' to 24'', CLASS from 150 to 2500
Standard: ANSI/ASME B 16.5, DIN, JIS, AWWA, API, ISO etc
Material: Stainless Steel --- ASTM A403 F304/304L, 316/316L,316Ti,321,317L,310S
Ends: Square Ends/Plain Ends (Straight Cut, Saw Cut, Torch Cut), Beveled/Threaded Ends
Delivery : Within 30 Days and Depends on Your Order Quantity
Packing: Packed in Wood Cabins/Wood Tray
Usage: For Conveying Gas, Water and Oil Either in the Oil or Natural Gas Industriei

Stainless Steel Tee

Keywords: Equal Tee, Unequal Tee, Cross Tee, Socket Tee, Short Tee, Forging Tee
Size: NPS from 1/2'' to 36'', DN from 15 to 900, WT: 2-80mm, SCH 40/80/XXS
Material & Standard:Stainless Steel --- ASTM 403 304/304L,316/316L,316Ti,321,317L,310S；
Ends : Square Ends/Plain Ends (straight cut, saw cut, torch cut), Beveled/Threaded Ends
Packing: Packed in Wood Cabins/ Wood Tray
Usage: Oil And Gas Transmissions；Petroleum And Oil Refining；Water Treatment Systems；Chemical Industries； Sanitary Tubing；Power Stations；Machines And Equipment；Heat Exchange

Stainless Steel Elbow

Keywords: 45 Degree/90 Degree/180 Degree Elbow, Long Radius/Short Radius Elbow
Size: NPS: 1/2''~24''(Seamless), 24''~72''(Welded) ；DN: 15~1200, WT: 2~80mm, SCH 5~XXS
Bending Radius: R=1D~10D, R=15D, R=20D
Material & Standard:Stainless Steel --- ASTM A403 304/304L/310/310S/316/316L/317L/321 
Delivery : Within 30 days and Depends on your order quantity
Packing: Packed in Wood Cabins/Wood Tray
Usage: For Conveying Gas, Water and Oil Either in the Oil or Natural Gas Industries

Stainless Steel Cap

Keywords: Pipe End Cap, Pipe Steel Cap, Standard Steel Pipe Cap, Strong Steel Pipe Cap
Size: NPS from 1/2'' to 48'', DN from 12 to 1200,WT: 2-80mm, SCH 40/80/XXS
Material: Stainless Steel --- ASTM 403 304/304L, 316/316L,316Ti,321,317L,310S;
Delivery: BKS, NBK,BK ,BKW, GBK(+A), NBK(+N), BK(+C)
Packing: Packed in Wood Cabins/ Wood Tray
Application: Petroleum, Electricity, Chemicals, Natural Gas, Construction, Shipbuilding And Other Fields Because Of Its High Pressure, High Temperature, Etc .

 

chemical composition

Grade	ASTM A403 / A815 / A182	UNS	EN / W.Nr	Cr	Ni	Mo	Others
304	WP304 / F304	S30400	1.4301	18.0–20.0	8.0–11.0	—	C ≤ 0.08
304L	WP304L / F304L	S30403	1.4307	18.0–20.0	8.0–12.0	—	C ≤ 0.030
304H	WP304H	S30409	1.4948	18.0–20.0	8.0–11.0	—	C 0.04–0.10
316	WP316 / F316	S31600	1.4401	16.0–18.0	10.0–14.0	2.0–3.0	C ≤ 0.08
316L	WP316L / F316L	S31603	1.4404	16.0–18.0	10.0–14.0	2.0–3.0	C ≤ 0.030
316Ti	WP316Ti	S31635	1.4571	16.0–18.0	10.0–14.0	2.0–3.0	Ti ≥ 5×C
317L	WP317L	S31703	1.4438	18.0–20.0	11.0–15.0	3.0–4.0	C ≤ 0.030
321	WP321 / F321	S32100	1.4541	17.0–19.0	9.0–12.0	—	Ti ≥ 5×C
347	WP347 / F347	S34700	1.4550	17.0–19.0	9.0–13.0	—	Nb ≥ 10×C
310S	WP310S	S31008	1.4845	24.0–26.0	19.0–22.0	—	C ≤ 0.08
904L	WP904L	N08904	1.4539	19.0–23.0	23.0–28.0	4.0–5.0	Cu 1.0–2.0
254SMO	WP S31254	S31254	1.4547	19.5–20.5	17.5–18.5	6.0–6.5	N 0.18–0.22
Duplex 2205	WP S31803 / S32205	S32205	1.4462	22.0–23.0	4.5–6.5	3.0–3.5	N 0.14–0.20
Super duplex 2507	WP S32750	S32750	1.4410	24.0–26.0	6.0–8.0	3.0–5.0	N 0.24–0.32

 

Mechanical properties (minimum, at room temperature)

Grade	Tensile MPa (ksi)	Yield MPa (ksi)	Elongation	Remarks
WP304	515 (75)	205 (30)	per A403 Table 2	—
WP304L	485 (70)	170 (25)	per A403 Table 2	Lower strength — check design stress
WP316	515 (75)	205 (30)	per A403 Table 2	—
WP316L	485 (70)	170 (25)	per A403 Table 2	Dual-certified 316/316L available
WP321 / WP347	515 (75)	205 (30)	per A403 Table 2	Stabilised for 425–815 °C
S31803	620 (90)	450 (65)	≥ 25 %	Duplex — A815
S32205	655 (95)	485 (70)	≥ 25 %	Duplex — A815
S32750	800 (116)	550 (80)	≥ 15 %	Super duplex — A815

 

With extensive export experience in stainless steel pipe fittings and flanges, GNEE has successfully supplied customized orders for chemical, oil & gas, food, and industrial projects worldwide. Our production capability allows us to handle large-volume orders with strict standards, complete documentation, and stable delivery performance.

If you are willing, please let me know:
the application scenario or environment involved (e.g., indoor piping, marine vessels, high-pressure systems, etc.),
as well as the pipe dimensions and connection type (threaded, socket weld, or butt weld).
I can assist you in finding the specific components and materials you need.

Contact now

 

GNEE is an experienced stainless steel pipe fittings manufacturer with professional production equipment, including hydraulic forming machines, CNC machining centers, automatic welding machines, heat treatment furnaces, pickling and passivation lines, and advanced PMI, UT, and dimensional inspection equipment. We maintain regular stock of commonly used fittings in 304, 316L, 321, 310S, and duplex 2205 grades to support fast delivery. With extensive export experience serving customers in Europe, America, the Middle East, and Asia, GNEE provides ASTM A403, ASME B16.9 compliant elbows, tees, reducers, flanges, and customized solutions with EN10204 3.1 certificates and full quality traceability.

Quality Control & Testing

Gate	What is checked	Frequency	Record
IQC Incoming	Heat number & certificate match; PMI on every tube/bar; visual; dimensions; wall thickness	100 % PMI	Incoming inspection report + mill certificate
IPQC In-process	Cut length; forming temperature; ovality; wall map; weld seam RT; furnace chart; quench	Per batch / per furnace load	Process traveller, furnace chart, RT film
FQC Final	Dimensions to B16.9/B16.11/B16.5; wall thickness; bevel; surface; marking; packing	Per lot (AQL or 100 % as specified)	Dimensional record, release note

 

Standard packaging

GNEE applies professional export packaging solutions for stainless steel pipe fittings to ensure product safety during long-distance transportation. Each fitting is inspected before packing and protected with plastic caps, PVC film, EPE foam, or anti-scratch materials according to surface requirements. Products are packed in strong plywood cases, wooden pallets, or steel frames with clear labels showing grade, size, quantity, heat number, and order information. For mirror-polished or sanitary fittings, individual protection is applied to prevent surface damage. Packaging methods comply with international shipping requirements and support safe delivery to customers worldwide.

 

 

FAQ

Q:What is the difference between ASME B16.9 and MSS SP-43 fittings?
A:ASME B16.9 covers the full range of schedules and is the default for pressure piping. MSS SP-43 covers only light-wall stainless fittings (Sch 5S and 10S) and has its own dimension tables for some sizes. SP-43 fittings are lighter and cheaper, and are widely used for low-pressure and non-critical lines — but they must not be substituted for B16.9 in a pressure system without checking the rating. Tell us your design pressure and we will tell you which standard is right, or whether you can save money with SP-43.

 

Q:Seamless or welded fittings — which should I buy?
A:Seamless (ASTM A403 Class S) has no weld seam, which matters for high pressure, high cycle and highly corrosive service. Welded construction (Class W) is made from plate or pipe with the seam 100 % radiographed per A403, and is perfectly acceptable — and considerably cheaper — for large diameters and lower-pressure duty. We will not quote welded where seamless is required, and we always tell you which construction you are being quoted.

 

Q:Can you supply fittings with EN 10204 3.2 certification?
A:Yes. 3.1 is issued as standard. For 3.2 we arrange third-party witness inspection (SGS, BV, TUV, Lloyd's, DNV or your own nominated inspector) at our cost or yours depending on order value. Download a redacted sample MTC to check our format first.

 

Q:Do you provide intergranular corrosion testing to ASTM A262 Practice E?
A:Yes, and we recommend it for any 304/316 assembly that will be welded and not subsequently annealed. It can be performed in-house or witnessed by a third party.

 

Q:Are your fittings suitable for sour service (NACE MR0175 / ISO 15156)?
A:We supply to NACE MR0175 / ISO 15156 on request. This constrains chemistry, heat treatment and maximum hardness, and must be stated on your RFQ so we can control and certify it — it cannot be added after production.

 

Q:What is your minimum order quantity?
Stock sizes can ship from a single piece. For production orders, MOQ depends on size and grade — typically a few hundred kilograms per size. Consolidating several sizes into one container usually gives the best landed cost.

 

Q:Can you make fittings to our drawings?
A:Yes. Send a drawing (PDF, DWG or STEP) with material, quantity and required certification. We will confirm feasibility, tooling and lead time. Machined specials, large-radius bends and non-standard branch connections are routine for us.

 

Q:How do I know the grade is genuine 316L and not 304?
A:Every fitting is PMI-tested and the result is traceable to its heat number on the MTC. You can also appoint a third party to perform independent PMI at our works before shipment, or we can provide a portable XRF report on video.

 

Q:Can we inspect your factory before ordering?
A:Yes — in person or by live video. We can walk you through forming, heat treatment, pickling and the inspection lab, and show the furnace chart and test records for the batch you would receive. Send us a time and we will arrange it.

 

Do ASME B16.9 fittings have their own pressure rating?
A:No. B16.9 fittings take the rating of straight seamless pipe of the same material and wall thickness under the applicable piping code (usually ASME B31.3). This is why we ask for design pressure and temperature rather than just a "class".

 

Q:Can you supply ASME B16.47 Series A and Series B flanges?
A:Yes, both, in welding neck and blind. Please note they are not bolt-compatible — confirm which series your existing piping uses before ordering.

 

Q:What is the lead time for duplex 2205 or super duplex 2507?
A:Longer than austenitic, because the anneal window is tighter and material lead time is longer. Give us your size list and we will quote a firm production slot, typically {{FILL:LEAD_PROD}} days.

 

Q:Do you provide flange bolt sets and gaskets?
A:Yes — stud bolts, nuts and gaskets can be supplied as a matched set so the whole joint arrives together and to the same specification.

 

Q:What payment and trade terms do you accept?
A:T/T, L/C at sight and other terms for established accounts. Trade terms EXW, FOB, CFR, CIF, DAP. We will state the exact Incoterms® 2020 rule in our quotation.

Gnee Steel (Tianjin) Co., Ltd. is well-known as one of the leading stainless steel pipe fitting manufacturers and suppliers in China. Our factory offers customized stainless steel pipe fitting made in China with competitive price. Welcome to contact us for wholesale service.

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