Stainless Steel Fittings
SS Pipe Fittings A403 321
SS Pipe Fittings A403 321 Supplier, ASTM A403 WP321 Stainless Steel Fittings, Reliable Pipes & Tubes.
Reliable Pipes & Tubes – Leading SS Pipe Fittings A403 321 Supplier
Reliable Pipes & Tubes is a leading supplier, stockholder, and exporter of high-grade SS Pipe Fittings A403 321. SS Pipe Fittings A403 321 refers to ASTM A403 standard covering wrought titanium-stabilized austenitic stainless steel piping fittings for pressure service in WP321 or WP321H grades. The addition of titanium (minimum 5 times the carbon content) in SS Pipe Fittings A403 321 prevents intergranular corrosion by stabilizing the material against chromium carbide precipitation during welding or exposure to high temperatures (800°F to 1500°F).
The SS Pipe Fittings A403 321 are designed for forged steel pipe fittings and can be used in many critical engineering fields including chemical processing, energy conversion plants, aerospace, exhaust manifolds, refineries, and various elevated temperature industrial applications. Material under ASTM A403 is named as WP Grade, and for each WP grade stainless steel, several categories of pipe fittings are included to indicate that a seamless or welded structure is used.
We offer a comprehensive range of SS Pipe Fittings A403 321 from 1/2" NB to 48" NB in various schedules to meet custom applications. Every SS Pipe Fittings A403 321 supplied by Reliable Pipes & Tubes undergoes rigorous testing including tensile testing, chemical analysis, and visual inspection to ensure optimal quality and structural integrity.
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What is SS Pipe Fittings A403 321?
SS Pipe Fittings A403 321 refers to ASTM A403 standard for wrought austenitic stainless steel piping fittings, specifically the WP321 titanium-stabilized variant. The SS Pipe Fittings A403 321 are specifically designed for forged steel pipe fittings; cast pipe fittings are not suitable under this standard. The key advantage of SS Pipe Fittings A403 321 is the addition of titanium, which acts as a stabilizer and combines with carbon to form titanium carbides. This prevents the loss of chromium at grain boundaries, securing excellent resistance to intergranular corrosion in the heat-affected zones of welded components. All SS Pipe Fittings A403 321 should be supplied in heat treated condition and all welding work should be done before heat treatment.
SS Pipe Fittings A403 321 Quick Details
| Parameter |
Details |
| Company Name | Reliable Pipes & Tubes |
| Country/Region | India |
| FOB Price | US $2100 - $6800 / Metric Ton |
| Port | Nhava Sheva Port, Mumbai |
| Main Products | Pipe Fittings, Elbows, Tees, Reducers, Caps, Flanges |
| Certification | ISO 9001, ISO 14001 & OHSAS 18001 |
SS Pipe Fittings A403 321 Specifications
| Specification Heading |
Details |
| Specification | ASTM A403 / ASME SA403 |
| Grade | WP321, WP321H |
| UNS Number | S32100, S32109 |
| DIN / EN | 1.4541 / 1.4878 |
| Types | Seamless or Welded |
| Dimension Range | 1/2" NB to 48" NB |
| Wall Thickness Range | Schedule 10S, Schedule 40S, Schedule 80S, Schedule 160S, Schedule XXS |
| Dimension Standards | ASME B16.9, ASME B16.11, MSS SP-43, MSS SP-79, MSS SP-95, MSS SP-97, BS3799, BS21, ISO 4144 |
| Fitting Types | Elbow, Tee, Cap, Reducer, Coupling, Nipple, Bend, Olets, Stubend, Cross |
| Surface Finish | Pickled, Annealed & Pickled, Sand Blasting, Passivated |
| Ends | Plain Ends, Beveled Ends, Threaded Ends |
| Packaging | Wooden Pallet / Wooden Box / Plastic Cloth Wraps / Plastic End Caps |
| Material Test Certificate | EN10204 3.1, 3.2 / Laboratory Test Certificate from NABL Approved Lab. / Under Third Party Inspection Agency like SGS, TUV, DNV, LLOYDS, ABS etc. |
| Equivalent Standards | GOST, AWWA, BS, SS, KS, AISI, JIS, GB, IS, ISO, SAE, DIN, NFA, API, ASTM, CSA, ANSI, EN, UNI |
Referred Standards of SS Pipe Fittings A403 321
| Standard |
Description |
| ASTM A182/A182M | Forged or rolled alloy steel pipe flanges, forged fittings and valves and parts for high temperature service |
| ASTM A403/A403M | Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings |
| ASTM A815/A815M | Wrought ferritic, ferritic/austenitic and martensitic stainless steel piping fittings |
| AS 2129 | 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 |
| ANSI B16.25 | Butt-welding ends |
| MSS SP-43 | Wrought stainless steel butt-welding fittings |
| MSS SP-95 | Swage(d) Nipples and Bull Plugs |
| BS 21 | Threading |
| ISO 4144 | Stainless steel fittings threaded to ISO 7-1 |
| BS 3799 | Specification for Steel pipe fittings, screwed and Socket-welding for the petroleum industry |
| ASME B16.28 | Wrought Steel Buttwelding Short Radius Elbows and Returns |
| AWS A5.4, A5.9, A5.11, A5.14 | Welding Consumables Standards |
Chemical Composition of SS Pipe Fittings A403 321
| Element |
Min (%) |
Max (%) |
| Carbon (C) | 0.04 | 0.10 |
| Manganese (Mn) | - | 2.0 |
| Silicon (Si) | - | 0.75 |
| Phosphorus (P) | - | 0.045 |
| Sulfur (S) | - | 0.03 |
| Chromium (Cr) | 17.0 | 19.0 |
| Nickel (Ni) | 9.0 | 12.0 |
| Titanium (Ti) | 4 x C | 0.60 |
* Note: Titanium stabilization is the key characteristic of SS Pipe Fittings A403 321, preventing chromium carbide precipitation under thermal stress.
Mechanical Properties of SS Pipe Fittings A403 321
| Property |
Value |
| Density | 8.0 g/cm3 |
| Melting Point | 1454 °C (2650 °F) |
| Tensile Strength, min | 515 MPa (75 ksi) |
| Yield Strength 0.2% Offset, min | 205 MPa (30 ksi) |
| Elongation, min % | 35% |
| Hardness Brinell (HB), max | 217 |
Equivalent Grades For SS Pipe Fittings A403 321
| STANDARD |
WERKSTOFF NR. |
UNS |
JIS |
BS |
EURONORM / EN |
| WP321H |
1.4878 |
S32109 |
SUS 321H |
321S51 |
X10CrNiTi18-10 |
| WP321 |
1.4541 |
S32100 |
SUS 321 |
321S31 |
X6CrNiTi18-10 |
* Note: These comparisons are approximate only. If exact equivalents are needed original specifications must be consulted.
SS Pipe Fittings A403 321 Dimensions
1. SS Pipe Fittings A403 321 Elbows and Returns Dimensions
| Nominal Pipe Size (inches) |
Outside Diameter (mm) |
Outside Diameter (inches) |
90° Elbows |
45° Elbows |
180° Returns |
| Long Radius (inches) |
Short Radius (inches) |
Long Radius (inches) |
Center to Center (inches) |
Back to Face (inches) |
| 1/2 | 21.3 | 0.840 | 1 1/2 | - | 5/8 | 3 | 1 7/8 |
| 3/4 | 26.7 | 1.050 | 1 1/8 | - | 7/16 | 2 1/4 | 1 11/16 |
| 1 | 33.4 | 1.315 | 1 1/2 | 1 | 7/8 | 3 | 2 3/16 |
| 1 1/4 | 42.2 | 1.660 | 1 7/8 | 1 1/4 | 1 | 3 3/4 | 2 7/8 |
| 1 1/2 | 48.3 | 1.900 | 2 1/4 | 1 1/2 | 1 1/8 | 4 1/2 | 3 1/4 |
| 2 | 60.3 | 2.375 | 3 | 2 | 1 3/8 | 6 | 4 3/16 |
| 2 1/2 | 73.0 | 2.875 | 3 3/4 | 2 1/2 | 1 3/4 | 7 1/2 | 5 3/16 |
| 3 | 88.9 | 3.500 | 4 1/2 | 3 | 2 | 9 | 6 1/4 |
| 3 1/2 | 101.6 | 4.000 | 5 1/4 | 3 1/2 | 2 1/4 | 10 1/2 | 7 1/4 |
| 4 | 114.3 | 4.500 | 6 | 4 | 2 1/2 | 12 | 8 1/4 |
| 5 | 141.3 | 5.563 | 7 1/2 | 5 | 3 1/8 | 15 | 10 5/16 |
| 6 | 168.3 | 6.625 | 9 | 6 | 3 3/4 | 18 | 12 5/16 |
| 8 | 219.1 | 8.625 | 12 | 8 | 5 | 24 | 16 5/16 |
| 10 | 273.1 | 10.750 | 15 | 10 | 6 1/4 | 30 | 20 3/8 |
| 12 | 323.9 | 12.750 | 18 | 12 | 7 1/2 | 36 | 24 3/8 |
2. SS Pipe Fittings A403 321 Tees, Caps, Stub Ends and Straight Crosses Dimensions
| Nominal Pipe Size (inches) |
Outside Diameter (mm) |
Outside Diameter (inches) |
Caps |
Straight Tees |
Straight Crosses |
Stub Ends |
| Length (inches) |
Center to End (inches) |
Center to End (inches) |
Lap Diameter (inches) |
Long Length (inches) |
Short Length (inches) |
| 1/2 | 21.3 | 0.840 | 1 | 1 | - | 1 3/8 | 3 | 2 |
| 3/4 | 26.7 | 1.050 | 1 | 1 1/8 | - | 1 11/16 | 3 | 2 |
| 1 | 33.4 | 1.315 | 1 1/2 | 1 1/2 | 1 1/2 | 2 | 4 | 2 |
| 1 1/4 | 42.2 | 1.660 | 1 1/2 | 1 7/8 | 1 7/8 | 2 1/2 | 4 | 2 |
| 1 1/2 | 48.3 | 1.900 | 1 1/2 | 2 1/4 | 2 1/4 | 2 7/8 | 4 | 2 |
| 2 | 60.3 | 2.375 | 1 1/2 | 2 1/2 | 2 1/2 | 3 5/8 | 6 | 2 1/2 |
| 2 1/2 | 73.0 | 2.875 | 1 1/2 | 3 | 3 | 4 1/8 | 6 | 2 1/2 |
| 3 | 88.9 | 3.500 | 2 | 3 3/8 | 3 3/8 | 5 | 6 | 2 1/2 |
| 3 1/2 | 101.6 | 4.000 | 2 1/2 | 3 3/4 | 3 3/4 | 5 1/2 | 6 | 3 |
| 4 | 114.3 | 4.500 | 2 1/2 | 4 1/8 | 4 1/8 | 6 1/16 | 6 | 3 |
| 5 | 141.3 | 5.563 | 3 | 4 7/8 | 4 7/8 | 7 5/16 | 8 | 3 |
| 6 | 168.3 | 6.625 | 3 1/2 | 5 5/8 | 5 5/8 | 8 1/2 | 8 | 3 1/2 |
| 8 | 219.1 | 8.625 | 4 | 7 | 7 | 10 5/8 | 8 | 4 |
| 10 | 273.1 | 10.750 | 5 | 8 1/2 | 8 1/2 | 12 3/4 | 10 | 5 |
| 12 | 323.9 | 12.750 | 6 | 10 | 10 | 15 | 10 | 6 |
3. SS Pipe Fittings A403 321 Reducers Dimensions
| Nominal Pipe Size (inches) |
Outside Diameter (mm) |
Outside Diameter (inches) |
Reduced to (inches) |
Concentric & Eccentric Length (inches) |
| 1/2 | 21.3 | 0.840 | 1/4, 3/8 | 1 1/2 |
| 3/4 | 26.7 | 1.050 | 3/8, 1/2 | 2 |
| 1 | 33.4 | 1.315 | 3/8, 1/2, 3/4 | 2 |
| 1 1/4 | 42.2 | 1.660 | 1/2, 3/4, 1 | 2 |
| 1 1/2 | 48.3 | 1.900 | 1/2, 3/4, 1, 1 1/4 | 2 1/2 |
| 2 | 60.3 | 2.375 | 3/4, 1, 1 1/4, 1 1/2 | 3 |
| 2 1/2 | 73.0 | 2.875 | 1, 1 1/4, 1 1/2, 2 | 3 1/2 |
| 3 | 88.9 | 3.500 | 1, 1 1/2, 2, 2 1/2 | 3 1/2 |
| 3 1/2 | 101.6 | 4.000 | 1 1/4, 1 1/2, 2, 2 1/2, 3 | 4 |
| 4 | 114.3 | 4.500 | 1 1/2, 2, 2 1/2, 3, 3 1/2 | 4 |
| 5 | 141.3 | 5.563 | 2, 2 1/2, 3, 3 1/2, 4 | 5 |
| 6 | 168.3 | 6.625 | 2 1/2, 3, 3 1/2, 4, 5 | 5 1/2 |
| 8 | 219.1 | 8.625 | 3, 3 1/2, 4, 5, 6 | 6 |
| 10 | 273.1 | 10.750 | 4, 5, 6, 8 | 7 |
| 12 | 323.9 | 12.750 | 5, 6, 8, 10 | 8 |
Fitting Types for SS Pipe Fittings A403 321
| Fitting Type |
Description |
| Elbow | SS Pipe Fittings A403 321 – 45°, 90°, 180° elbows, including 3D/5D/10D bends for directional changes |
| Tee | SS Pipe Fittings A403 321 – Equal and reducing/unequal tees for branching connections |
| Cap | SS Pipe Fittings A403 321 – End caps to safely close pipe ends |
| Reducer | SS Pipe Fittings A403 321 – Concentric and eccentric reducers for size transition |
| Coupling | SS Pipe Fittings A403 321 – Couplings for joining pipes of the same size |
| Nipple | SS Pipe Fittings A403 321 – Barrel nipples, reducing nipples, swage nipples |
| Bend | SS Pipe Fittings A403 321 – Long radius, short radius, and customized piggable bends |
| Olets | SS Pipe Fittings A403 321 – Weldolets, sockolets, threadolets, and branch outlets |
SS Pipe Fittings A403 321 ASTM A403 Standard Scope
The ASTM A403 standard for SS Pipe Fittings A403 321 includes several grades of austenitic stainless steel alloys, and uses the WP or CR prefix to mark the grade of steel. Steel for SS Pipe Fittings A403 321 should be smelted using one of the following methods:
- Electric furnace (with separate refining optional)
- Vacuum furnace
- One of the former followed by vacuum remelting or electroslag consumable electrode remelting
- If secondary melting is used, the furnace number refers to all steel ingots remelted with one smelting furnace number
The forming or forging operation for SS Pipe Fittings A403 321 may be performed by hammer forging, press forging, perforating, extrusion, upsetting, rolling, bending, welding or machining, or two or more methods at the same time. All SS Pipe Fittings A403 321 should be supplied in heat treated condition and all welding work should be done before heat treatment.
Surface Finish Requirements for SS Pipe Fittings A403 321
- Surface crack (fish scales) deeper than 1/64 inch (0.4 mm) should be removed from SS Pipe Fittings A403 321
- Mechanical flaws deeper than 1/16 inch (1.6 mm) should be removed from SS Pipe Fittings A403 321
- SS Pipe Fittings A403 321 shall not have a surface discontinuity deeper than 5% of the specified nominal wall thickness
- SS Pipe Fittings A403 321 shall have a good machined surface and shall be free of scale and passivated
Repair by Welding Allowance for SS Pipe Fittings A403 321
- When the defect depth exceeds 33 1/3% of the nominal wall thickness in SS Pipe Fittings A403 321, weld repair is not allowed
- When the defect area exceeds 10% of the surface area of SS Pipe Fittings A403 321, weld repair is not allowed
- Unacceptable defects should be removed by mechanical means or by thermal cutting or gouging methods
- SS Pipe Fittings A403 321 shall be free of scale and shall be passivated
SS Pipe Fittings A403 321 Stock List
- SS Pipe Fittings A403 321 – 90 Deg Elbow (Long / Short Radius)
- SS Pipe Fittings A403 321 – 45 Deg Elbow
- SS Pipe Fittings A403 321 – 180 Deg Elbow (Return Bend)
- SS Pipe Fittings A403 321 – Equal Tee
- SS Pipe Fittings A403 321 – Reducing Tee
- SS Pipe Fittings A403 321 – Concentric Reducer
- SS Pipe Fittings A403 321 – Eccentric Reducer
- SS Pipe Fittings A403 321 – End Cap / Pipe Cap
- SS Pipe Fittings A403 321 – Stubend (Long / Short Length)
- SS Pipe Fittings A403 321 – Barrel / Swage / Reducing Nipple
- SS Pipe Fittings A403 321 – 3D, 5D, 10D Piggable Bend
- SS Pipe Fittings A403 321 – Weldolets / Sockolets / Threadolets
Testing Requirements for SS Pipe Fittings A403 321
| Test Type |
Details |
| Tensile Test | Longitudinal or transverse cut specimens; properties shall comply with tensile requirements per A370 methods |
| Chemical Analysis | Each cast or furnace steel chemical composition shall be determined and comply with WP321 requirements |
| Visual Inspection | All SS Pipe Fittings A403 321 shall be visually inspected for surface discontinuities |
| Liquid Penetrant Test | As per ASTM E165 Practice for Liquid Penetrant Examination for General Industry |
| Grain Size Test | As per ASTM E112 Test Methods for Determining Average Grain Size |
| Radiography Testing | 100% Radiography Tested for welded fittings where specified |
| PMI Testing | Positive Material Identification for SS Pipe Fittings A403 321 |
| Hydrostatic Test | As required per applicable standards |
| Hardness Test | Rockwell and Brinell hardness testing as required |
SS Pipe Fittings A403 321 Price List
| Product Description |
Price (FOB) |
| SS Pipe Fittings A403 321 – Elbow | US $2.40 - 21.00 / Piece |
| SS Pipe Fittings A403 321 – Tee | US $3.40 - 26.00 / Piece |
| SS Pipe Fittings A403 321 – Reducer | US $3.00 - 23.00 / Piece |
| SS Pipe Fittings A403 321 – Cap | US $1.80 - 15.00 / Piece |
| SS Pipe Fittings A403 321 – Coupling | US $1.20 - 10.50 / Piece |
| SS Pipe Fittings A403 321 – Bend | US $5.80 - 68.00 / Piece |
| SS Pipe Fittings A403 321 – Per Ton | US $2600 - 5800 / Ton |
Packaging and Sea Transportation Protection
At Reliable Pipes & Tubes, packaging is processed with standard anti-rust measures and sea transportation security rules. We ensure that your SS Pipe Fittings A403 321 reach safely and in perfect condition via the following packaging modes:
- Bundle packing with steel strips
- Crate packing (wooden cases)
- Naked packing
- End protection with plastic caps or wooden protectors