ARK Stainless Inc is a trusted manufacturer, supplier and exporter of high-quality Stainless Steel Buttweld Fittings for industrial piping systems used in oil & gas, chemical processing, power generation, marine, pharmaceutical, food processing, and water treatment applications.
Our manufacturing range includes Stainless Steel Buttweld Elbows, Tees, Reducers, Caps, Stub Ends, and custom pipe fittings in seamless and welded construction according to ASME B16.9, MSS SP-43, and ASTM A403 standards.
We supply Stainless Steel Buttweld Pipe Fittings in SS 304, 304L, 304H, 309, 310, 310S, 316, 316L, 316Ti, 317, 317L, 321, 321H, 347, 347H, and 904L grades for low-temperature, high-temperature, and corrosion-resistant piping applications.
These fittings are manufactured with accurate dimensions, proper bevel preparation, and controlled wall thickness for reliable welding and long service life in process piping systems. Our fittings are widely supplied for refineries, offshore projects, EPC contractors, fabrication companies, and industrial process plants worldwide.
ARK Stainless Inc maintains ready stock of Stainless Steel Buttweld Fittings in multiple schedules and sizes for urgent project requirements and export supply. All fittings are supplied with material test certificates and inspection support as per customer requirements.
| C | Mn | Si | P | S | Cr | Mo | Ni | N | |
|---|---|---|---|---|---|---|---|---|---|
| 304 | 0.07max | 2.0max | 0.75max | 0.045max | 0.03max | min: 18.0 max: 20.0 | - | min: 8.0 max: 10.5 | — |
| 304L | 0.03max | 2.0max | 0.75max | 0.045max | 0.03max | min: 18.0 max: 20.0 | - | min: 8.0 max: 12.0 | 0.10 max |
| 304H | min: 18.0 max:20.0 |
min: 8.0 max: 10.5 |
min: 0.04 max:0.10 |
0.75 max |
2.0 max |
0.045 max |
- | 0.03 max |
0.10 max |
| 309 | 0.20 max | 2 max | 1 max | 0.045 max | 0.030 max | 23 max | - | 14 max | – |
| 310 | 0.25 max | 2 max | 1.50 max | 0.045 max | 0.03 max | 24 – 26 | - | 19 – 22 | – |
| 310S | 0.08 max | 2 max | 1.50 max | 0.045 max | 0.03 max | 24 – 26 | - | 19 – 22 | – |
| 316 | 0.08 max |
2.0 max |
0.75 max |
0.045 max |
0.03 max |
min: 16.0 max: 18.0 |
min: 2.0 max: 3.0 |
min: 10.0 max: 14.0 |
0.10 max |
| 316L | 0.03 max |
2.0 max |
0.75 max |
0.045 max |
0.03 max |
min: 16.0 max: 18.0 |
min: 2.0 max: 3.0 |
min: 10.0 max: 14.0 |
0.10 max |
| 316TI | - | - | - | - | - | 16.0 | 2.00 | 10.0 | - |
| 0.08 | 2 | 0.75 | 0.045 | 0.03 | 18.0 | 3.00 | 14.0 | 0.1 | |
| 317 | 0.08 max | 2 max | 1 max | 0.040 max | 0.03 max | 18 – 20 | 3 – 4 | 11 – 14 | - |
| 317L | 0.035 max | 2 max | 1 max | 0.040 max | 0.03 max | 18 – 20 | 3 – 4 | 11 – 15 | - |
| 321 | max:0.08 | max:2.0 | max:0.75 | max:0.045 | max:0.03 | min:17.0 max:19.0 |
– | min: 9.0 max:12.0 |
max:0.10 |
| 321H | min:0.04 max:0.10 |
max:2.0 | max:0.75 | max:0.045 | max:0.03 | min:17.0 max:19.0 |
– | min: 9.0 max:12.0 |
max:0.10 |
| 347 | 0.08 max | 2.0 max | 0.75 max | 0.04 max | 0.03 max | min: 17.0 max: 20.0 |
min:10x C max: 1.0 |
min: 9.0 max: 13.0 |
– |
| 347H | min: 0.04 max: 0.10 |
2.0 max | 0.75 max | 0.03 max | 0.03 max | min: 17.0 max: 20.0 |
min:10x C max: 1.0 |
min: 9.0 max: 13.0 |
– |
| 904L | 0.02 max | 4.0 – 5.0 | – | 0.045 max | 0.035 max | 19.0 – 23.0 | 23.0 – 28.0 | 2.0 max | – |
| Grade | Tensile Strength (ksi / MPa) | Yield Strength 0.2% (ksi / MPa) | Elongation (%) | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
|---|---|---|---|---|---|
| 304 | 75 / 515 | 30 / 205 | 40 | 201 | 92 |
| 304L | 70 / 485 | 25 / 170 | 40 | 201 | 92 |
| 304H | 75 / 515 | 30 / 205 | 40 | 201 | 92 |
| 309 | 89.9 / 620 | 45 / 310 | 45 | – | – |
| 310 | 75 / 515 | 30 / 205 | 35 | – | – |
| 310S | 75 / 515 | 30 / 205 | 35 | – | – |
| 316 | 75 / 515 | 30 / 205 | 40 | 217 | 95 |
| 316L | 70 / 485 | 25 / 170 | 40 | 217 | 95 |
| 316Ti | 515 MPa | 205 MPa | 35 | 205 | 75 |
| 317 | 75 / 515 | 30 / 205 | 35 | – | – |
| 317L | 75 / 515 | 30 / 205 | 35 | – | – |
| 321 / 321H | 75 / 515 | 30 / 205 | 40 | 217 | – |
| 347 / 347H | 75 / 515 | 30 / 205 | 40 | 201 | 95 |
| 904L | 490 MPa | 220 MPa | 36 | 150 | 70–90 (typical) |
ARK Stainless Inc is a manufacturer, supplier and exporter of SS 304, 304L, and 304H Buttweld Fittings for corrosion-resistant piping systems used in chemical processing, food processing, pharmaceuticals, heat exchangers, water treatment, and industrial fabrication applications.
These Stainless Steel Buttweld Fittings are supplied in elbows, tees, reducers, caps, stub ends, and custom configurations according to ASME B16.9 and ASTM A403 standards.
SS 304 Buttweld Fittings are widely used for general-purpose stainless steel piping applications due to their corrosion resistance, strength, and fabrication properties. SS 304L grades are preferred for welded piping systems requiring lower carbon content to reduce carbide precipitation during welding. SS 304H Buttweld Fittings are supplied for elevated temperature service applications where higher strength and heat resistance are required.
Our manufacturing range includes seamless and welded Stainless Steel Pipe Fittings in multiple schedules, wall thicknesses, and sizes for industrial process piping systems.
| STANDARD | UNS | WNR. | AFNOR | EN | JIS | BS | GOST |
|---|---|---|---|---|---|---|---|
| SS 304 | S30400 | 1.4301 | Z7CN18-09 | X5CrNi18-10 | SUS 304 | 304S31 | 08?18?10 |
| SS 304L | S30403 | 1.4306/1.4307 | Z3CN18-10 | X2CrNi18-9 / X2CrNi19-11 | SUS 304L | 304S11 | 03?18?11 |
| SS 304H | S30409 | 1.4301 | - | - | - | - | - |
ARK Stainless Inc manufactures, supplies and exports SS 309, SS 310, and SS 310S Buttweld Fittings for high-temperature and corrosion-resistant piping applications used in refineries, heat treatment plants, petrochemical industries, power generation, and industrial process systems.
These Stainless Steel Buttweld Fittings are supplied in elbows, tees, reducers, caps, stub ends, and custom configurations according to ASME B16.9 and ASTM A403 standards.
SS 309 Buttweld Fittings are widely used for applications requiring good oxidation resistance and strength at elevated temperatures. SS 310 Buttweld Fittings offer higher heat resistance and are commonly supplied for furnace components, thermal processing systems, and high-temperature piping lines. SS 310S is the low-carbon version of SS 310 and is preferred for welded applications requiring improved fabrication and reduced carbide precipitation.
Our manufacturing range includes seamless and welded Stainless Steel Pipe Fittings in multiple schedules, wall thicknesses, and custom sizes for industrial piping systems.
| STANDARD | UNS | WNR. | AFNOR | EN | JIS | BS | GOST |
|---|---|---|---|---|---|---|---|
| SS 309 | S30900 | 1.4833 | - | - | - | - | - |
| SS 310 | S31000 | 1.4841 | - | X2CrNi18-9 / X2CrNi19-11 | SUS 310 | 310S24 | 20Ch25N20S2 |
| SS 310S | S31008 | 1.4845 | - | X8CrNi25-21 | SUS 310S | 310S16 | 20Ch23N18 |
SS 316 / 316L / 316Ti Buttweld Fittings are widely used in chemical processing, marine piping, offshore installations, pharmaceutical plants, and food-grade piping systems where higher corrosion resistance is required compared to standard stainless steel grades.
ARK Stainless Inc supplies Stainless Steel 316 Buttweld Elbows, Tees, Reducers, Caps, and Stub Ends in seamless and welded construction according to ASME B16.9 and ASTM A403 specifications.
SS 316 grades are preferred for piping systems exposed to chlorides, moisture, and aggressive chemical environments. For welded process piping applications, SS 316L is commonly selected due to its lower carbon content, helping reduce carbide precipitation after welding. SS 316Ti contains titanium stabilization and is supplied for elevated temperature service where improved structural stability is required.
The fittings are available in multiple schedules, wall thicknesses, and custom sizes for refinery projects, EPC contractors, fabrication companies, and industrial process plants.
| STANDARD | UNS | WNR. | AFNOR | EN | JIS | BS | GOST |
|---|---|---|---|---|---|---|---|
| SS 316 | S31600 | 1.4401 / 1.4436 | Z7CND17-11-02 | X5CrNiMo17-12-2 / X3CrNiMo17-13-3 | SUS 316 | 316S31 / 316S33 | - |
| SS 316L | S31603 | 1.4404 / 1.4435 | Z3CND17-11-02 / Z3CND18-14-03 | X2CrNiMo17-12-2 / X2CrNiMo18-14-3 | SUS 316L | 316S11 / 316S13 | 03Ch17N14M3 / 03Ch17N14M2 |
| SS 316Ti | S31635 | 1.4571 | Z6CNDT17-123 | X6CrNiMoTi17-12-2 | SUS 316Ti | 320S31 | 08Ch17N13M2T |
SS 317 and SS 317L Buttweld Fittings are supplied for piping systems requiring improved corrosion resistance in aggressive chemical and high-temperature service environments. These fittings are widely used in chemical processing plants, fertilizer industries, pulp & paper mills, offshore installations, and industrial process piping systems.
ARK Stainless Inc manufactures SS 317 / 317L Buttweld Elbows, Tees, Reducers, Caps, and Stub Ends according to ASME B16.9 and ASTM A403 standards in seamless and welded construction.
SS 317 grades offer higher molybdenum content compared to standard stainless steel grades, providing improved resistance against chemical exposure and corrosive media. SS 317L is the low-carbon version preferred for welded piping systems requiring reduced carbide precipitation after welding.
The fittings are available in multiple schedules, wall thicknesses, and custom sizes for refinery projects, fabrication companies, EPC contractors, and industrial process plants.
| STANDARD | UNS | WNR. | EN | JIS |
|---|---|---|---|---|
| SS 317 | S31700 | 1.4449 | - | SUS 317 |
| SS 317L | S31703 | 1.4438 | X2CrNiMo18-15-4 | SUS 317L |
SS 321 and SS 321H Buttweld Fittings are supplied for high-temperature piping systems requiring improved resistance against intergranular corrosion after welding. These fittings are widely used in heat exchangers, thermal processing systems, refineries, power plants, and industrial process piping applications.
ARK Stainless Inc manufactures SS 321 / 321H Buttweld Elbows, Tees, Reducers, Caps, and Stub Ends according to ASME B16.9, ASME B16.28, MSS SP-43, and ASTM A403 standards.
SS 321 grades are stabilized with titanium for improved performance in elevated temperature service applications. SS 321H Buttweld Fittings are supplied for higher temperature environments requiring improved creep resistance and mechanical strength.
Our manufacturing range includes seamless, welded, and fabricated Stainless Steel Buttweld Fittings in sizes from 1/8” NB to 48” NB with multiple schedules and wall thicknesses.
All fittings are supplied with material test certificates, third-party inspection support, PMI testing, and radiographic testing as per customer and project requirements.
| STANDARD | UNS | WNR. | EN | JIS |
|---|---|---|---|---|
| SS 321 | S32100 | 1.4541 | X6CrNiTi18-10 | SUS 321 |
| SS 321H | S32109 | 1.4878 | X12CrNiTi18-9 | SUS 321H |
SS 347 and SS 347H Buttweld Fittings are supplied for high-temperature piping systems requiring improved resistance against intergranular corrosion and oxidation. These fittings are widely used in refineries, thermal processing plants, power generation units, chemical processing industries, and high-pressure process piping systems.
ARK Stainless Inc manufactures SS 347 / 347H Buttweld Elbows, Tees, Reducers, Caps, Stub Ends, and custom fittings according to ASTM A403, ASME SA403, ASME B16.9, ASME B16.28, and MSS SP-43 standards.
SS 347 grades are stabilized with niobium for improved performance in elevated temperature service applications and welded piping systems. SS 347H Buttweld Fittings are supplied for higher temperature environments requiring improved creep strength and long-term thermal stability.
Our manufacturing range includes seamless, welded, and fabricated Stainless Steel Pipe Fittings with bending radius options including 1D, 2D, 3D, 5D, and custom requirements as per project specifications.
| STANDARD | UNS | WNR. | EN | JIS | GOST |
|---|---|---|---|---|---|
| SS 347 | S34700 | 1.4550 | X6CrNiNb18-10 | SUS 347 | 08Ch18N12B |
| SS 347H | S34709 | 1.4961 | X6CrNiNb18-12 | SUS 347H | - |
SS 904L Buttweld Fittings are widely supplied for piping systems operating in highly corrosive environments where standard stainless steel grades are not suitable. These fittings are commonly used in chemical processing plants, offshore applications, seawater systems, fertilizer industries, and acid handling process lines.
ARK Stainless Inc manufactures SS 904L Buttweld Elbows, Tees, Reducers, Caps, and Stub Ends according to ASTM B366, ASME SB366, ASME B16.9, ASME B16.28, and MSS SP-43 standards.
The high nickel and molybdenum content of SS 904L provides improved resistance against pitting, crevice corrosion, and chloride exposure in aggressive process environments. These fittings are supplied in seamless, welded, and fabricated construction for industrial piping systems requiring long service life and corrosion resistance.
Available in sizes from 1/8” NB to 48” NB with multiple schedules, wall thicknesses, and custom project requirements.
| STANDARD | WERKSTOFF NR. | UNS | JIS | KS | BS | AFNOR | EN |
|---|---|---|---|---|---|---|---|
| SS 904L | 1.4539 | N08904 | SUS 904L | STS 317J5L | 904S13 | Z2 NCDU 25-20 | X1NiCrMoCu25-20-5 |
