Premium Stainless Steel 321/321H Buttweld Pipe Fittings by Ratnadeep Steel & Engg. Co.
Ratnadeep Steel & Engg. Co. is a leading manufacturer, exporter, and supplier of premium-quality Stainless Steel 321 / 321H Buttweld Pipe Fittings. These fittings are manufactured from titanium-stabilized austenitic stainless steels using advanced production techniques to ensure excellent mechanical strength, precise dimensional accuracy, and long-term service reliability. Our SS 321 and 321H buttweld fittings are widely used in high-temperature and moderately corrosive environments where resistance to intergranular corrosion and structural stability are critical.
Stainless Steel 321 and 321H grades are specifically designed for elevated-temperature service and resistance to carbide precipitation during welding and prolonged exposure to heat. The titanium stabilization prevents intergranular corrosion, while the higher carbon content in 321H provides improved creep strength at elevated temperatures. Their buttweld pipe fittings are supplied with precision-beveled ends, enabling full-penetration welding that results in strong, leak-free, and permanent joints.
These fittings provide a smooth and continuous internal flow path throughout the piping system, minimizing turbulence and pressure loss while enhancing resistance to oxidation, thermal fatigue, and corrosion at high temperatures. As a result, SS 321 / 321H buttweld pipe fittings are ideal for applications in heat exchangers, exhaust systems, petrochemical processing, refinery piping, power generation, and high-temperature chemical service lines.
- Stainless Steel 321 90 Deg Elbow
- ASTM A403 SS 321H 45 Deg Elbow
- UNS S32100 180 Deg Elbow
- UNS S32109 LR Elbow
- DIN 1.4541 SR Elbow
- ANSI B16.9 SS 321 90 Degree Short Radius Elbow
- DIN 1.4878 45 Deg Long Radius Elbow
- SS ASTM A403 WP321 Equal Tee
- ASME B16.9 SS 321 Pipe Tee
- DIN 1.4541 Butt weld Tee
- ASME SA403 Stainless Steel 321H Reducing Tee
- DIN 1.4878 Unequal Tee
- UNS S32100 / S32109 Tees
- A403 WP321H SS Straight Tee
- B16.9 Stainless Steel 321 Eccentric Reducer Supplier
- ASTM A403 Stainless Steel WP321H Eccentric Reducer
- SS UNS S32100 / S32109 Eccentric Reducers
- DIN 1.4541 / 1.4878 Eccentric Reducer
- ANSI B16.9 Stainless Steel 321 Concentric Reducer Supplier
- SS ASME SA 403 WP321H Concentric Reducer
- UNS S32100 / S32109 Concentric Reducers
- SS DIN 1.4541 / 1.4878 Concentric Reducer
- ASME B16.9 SS 321 Long Stub End Supplier
- ASTM A403 WP321H SS Long Stub Ends
- UNS S32100 / S32109 Long Stub End
- SS 321/321H Lap Joint Stub End
- DIN 1.4541 / 1.4878 Long Stub End
- ASTM A403 SS 321 Short Stub End Supplier
- ASME B16.9 Stainless Steel A403 WP321H Short Stub Ends
- SS UNS S32100 / S32109 Short Stub Ends
- DIN 1.4541 / 1.4878 Short Stub End
- ASTM A403 / SA403 Stainless Steel WP321 Pipe Cap Supplier
- ASME B16.9 SS 321H End Pipe Cap
- SS UNS S32100 Pipe End Cap
- UNS S32109 Buttweld Cap
- A403 WP321H Buttweld Pipe Cap
- DIN 1.4541 / 1.4878 End Cap
- ASTM A403 Stainless Steel 321 Equal Cross
- ASME B16.9 SS 321H Buttweld Cross
- ASTM A403 WP321 / WP321H Cross
- SS UNS S32100 / S32109 Unequal Cross
- DIN 1.4541 / 1.4878 Reducing Cross
- ASME SA 403 SS 321 Pipe Bend Exporter
- B16.9 Stainless Steel 321H Piggable Bend
- UNS S32100 / S32109 U Bend
- SS DIN 1.4541 / 1.4878 Long Radius Bend
- ASTM A403 WP321/321H SS Buttweld Bend
CHEMICAL COMPOSITION OF STAINLESS STEEL 321/321H SEAMLESS AND WELDED PIPE FITTINGS
| Element | Cr | Ni | C | Si | Mn | P | S | N | Ti | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| 321 | min:17.0 max:19.0 |
min: 9.0 max:12.0 |
max:0.08 | max:0.75 | max:2.0 | max:0.045 | max:0.03 | max:0.10 | min:5*(C+N) max:0.70 |
Balance |
| 321H | min:17.0 max:19.0 |
min: 9.0 max:12.0 |
min:0.04 max:0.10 |
min:18.0 max:20.0 |
max:2.0 | max:0.045 | max:0.03 | max:0.10 | min:5*(C+N) max:0.70 |
Balance |
MECHANICAL PROPERTIES OF ASME SA403 SS WP321 / 321H BUTTWELD PIPE FITTINGS
| Grade | Tensile Strength ksi (min.) | Yield Strength 0.2% Offset ksi (min.) | Elongation – % in 50 mm (min.) | Hardness (Brinell) MAX |
|---|---|---|---|---|
| 321/321H | 75 | 30 | 40 | 217 |
SPECIFICATION OF SS 321/321H BUTTWELL FITTINGS
| Specifications | ASTM A403 / ASME SA403 |
|---|---|
| Dimensions | ASME/ANSI B16.9, ASME B16.28, MSS-SP-43, BS4504, BS4504, BS1560, BS10 ASME 16.11, MSS SP-79, 83, 95, 97, BS 3799 |
| Size | Seamless Butt Weld Fittings: ½” to 10″ | Welded Butt Weld Fittings: ½” to 48″ |
| Schedule | SCH10, SCH20, SCH30, STD SCH40, SCH60, XS, SCH 80, SCH 100, SCH 120, SCH 140, SCH 160, XXS available with NACE MR 01-75 |
| Bending Radius | R=1D, 2D, 3D, 5D, 6D, 8D, 10D or Custom |
| Type | Seamless / ERW / Welded / Fabricated |
| Thickness | 20 Swg., 18 Swg., 16 Swg., 14 Swg., 12 Swg., 10 Swg., & Sch. 10, Sch. 40, Sch. 80 etc. |
321/321H STAINLESS STEEL ASTM A403 BUTTWELD FITTINGS EQUIVALENT GRADES
| STANDARD | UNS | WNR. | EN | JIS |
|---|---|---|---|---|
| SS 321 | S32100 | 1.4541 | X6CrNiTi18-10 | SUS 321 |
| SS 321H | S32109 | 1.4878 | X12CrNiTi18-9 | SUS 321H |
PHYSICAL PROPERTIES OF ASTM A403 STAINLESS STEEL 321/321H PIPE FITTINGS
| Density lbm/in³ | Coefficient of Thermal Expansion (min/in) °F | Thermal Conductivity BTU/hr-ft-°F | Specific Heat BTU/lbm-°F | Modules of Elasticity (annealed)²-psi |
|---|---|---|---|---|
| at 68 °F: 0.286 | at 68 – 212°F: 9.2 at 68 – 1832°F: 20.5 |
at 200°F: 9.3 | at 32 – 212°F: 0.12 | in tension (E): 28 × 10⁶ |
💡 Practical Difference in Use
Use Stainless Steel 321 / 321H Buttweld Pipe Fittings when: resistance to intergranular corrosion, excellent stability at elevated temperatures, and reliable mechanical strength under continuous or cyclic heat exposure are required. These grades are ideal for applications involving welding and prolonged service at high temperatures where carbide precipitation must be avoided. → Example: heat exchangers, furnace components, exhaust systems, refinery piping, and high-temperature chemical process lines.
Applications of SS 321 / 321H Buttweld Pipe Fittings
Stainless Steel 321 and 321H Buttweld Pipe Fittings are titanium-stabilized austenitic grades engineered for high-temperature service, offering excellent resistance to oxidation and intergranular corrosion.
- Heat Exchangers & Thermal Equipment: High-temperature fluid lines, shells, and tube connections.
- Petrochemical & Refining: Hot process piping, reformer units, and elevated-temperature service lines.
- Power Generation: Boiler components, superheater connections, and exhaust piping systems.
When to Choose SS 321 / 321H?
These grades are selected for applications requiring improved resistance to intergranular corrosion after welding and enhanced strength at elevated temperatures.
Choose SS 321 / 321H when:
- Operating temperatures exceed the limits of SS 304 / 304L
- Welded joints will be exposed to prolonged high-temperature service
- Titanium stabilization is required to prevent carbide precipitation
- Higher carbon 321H is needed for improved creep strength at elevated temperatures
- Used in heat exchangers, furnaces, and high-temperature process pipelines
Industries That Use SS 321 / 321H Buttweld Pipe Fittings
These fittings are widely used in industries where high-temperature stability, oxidation resistance, and reliable welded performance are essential.
Designed for continuous exposure to elevated operating temperatures.
Uses
Heat exchanger piping, furnace components, and thermal transfer lines.
Why SS 321 / 321H?
Titanium stabilization prevents intergranular corrosion and maintains strength at high temperatures.
Reliable performance in high-temperature refining and chemical processes.
Uses
Hot process lines, reformers, and elevated-temperature piping systems.
Why SS 321 / 321H?
Excellent resistance to thermal fatigue and oxidation under severe service conditions.
Used where heat resistance and long-term structural stability are critical.
Uses
Boiler internals, superheater connections, and exhaust systems.
Why SS 321 / 321H?
Enhanced creep strength and weld integrity ensure long service life at elevated temperatures.
Usage guide for SS 321 / 321H Buttweld Pipe Fittings
Smooth directional change in high-temperature and welded piping systems.
Choose Elbow when
- 45°, 90°, or 180° direction change is required
- Lines operate at elevated temperatures
- Welded joints must resist intergranular corrosion
- Used in heat exchangers, furnaces, or hot process piping
Creates strong branch connections for high-temperature service lines.
Choose Tee when
- Equal or reducing branch connections are required
- Piping is exposed to continuous or cyclic high temperatures
- Stable welded joints are critical
- Used in refineries, petrochemical plants, or thermal systems
Maintains alignment while reducing pipe size in high-temperature pipelines.
Choose Eccentric Reducer when
- Avoiding air or vapor pockets is important
- Pump suction lines or horizontal hot service piping are used
- Thermal expansion must be accommodated
- High-temperature strength and weld stability are required
Uniform diameter transition for elevated-temperature piping systems.
Choose Concentric Reducer when
- Centered alignment is required
- Vertical high-temperature piping systems are installed
- Smooth flow transition is necessary
- Used in heat exchangers and thermal process lines
Allows easy dismantling using lap joint flanges in hot service lines.
Choose Long Stub End when
- Frequent inspection or maintenance is required
- High-temperature stability at flange joints is needed
- Cost-effective solutions for large-diameter piping are preferred
- Used in refineries, power plants, or thermal systems
Compact lap joint connection for space-restricted high-temperature applications.
Choose Short Stub End when
- Space constraints exist
- Economical lap joint flange connections are required
- Used in heat exchangers or thermal process piping
- Resistance to intergranular corrosion is essential
Securely seals pipe ends in high-temperature service environments.
Choose Pipe Cap when
- Pipe ends must be permanently or temporarily closed
- Used for pressure testing or future line expansion
- Leak-proof sealing at elevated temperatures is essential
- Exposed to thermal cycling or oxidation conditions
Four-way branching for complex high-temperature piping networks.
Choose Cross when
- Flow must be divided into multiple directions
- Used in refineries, petrochemical, or thermal systems
- Strong, stable welded joints are required
- Resistance to thermal fatigue is critical
Large-radius directional change for smooth flow in hot service lines.
Choose Pipe Bend when
- Gradual change in direction is required
- Used in heat exchangers, furnaces, or hot process piping
- Low turbulence and reduced pressure drop are important
- Long-term strength at elevated temperatures is required
Our Buttweld Pipe Fittings are manufactured using advanced processes and undergo extensive quality checks to ensure flawless weldability, durability, and long service life. Each fitting is thoroughly inspected using key NDT techniques such as radiographic testing (RT), ultrasonic testing (UT), hydrostatic testing, and visual/dimensional examination. We also perform detailed chemical composition analysis and mechanical property testing to ensure material compliance with strict industry standards.
Throughout the forming and welding stages, every buttweld fitting is monitored closely to eliminate defects such as misalignment, surface irregularities, and wall-thickness variations. This ensures perfect joint integrity and high-performance reliability in pipelines carrying high temperatures, pressures, and corrosive media. All our buttweld fittings fully comply with ASME, ASTM, MSS-SP, and related global specifications, making them a preferred choice for critical piping systems worldwide.
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