Stainless steel seamless pipe is a steel pipe manufactured using a seamless process. It is characterized by the fact that the entire pipe body has no seams and has the characteristics of high strength, high corrosion resistance, and high purity.
Due to its excellent performance, stainless steel seamless pipes are widely used in many fields such as petroleum, chemical industry, electric power, food, medicine, etc.
The manufacture of stainless steel seamless pipes requires multiple processes, including smelting, rolling, perforation, extrusion, etc. The production cost is high, so the price is relatively high.
316 and 316L seamless pipes are two different models of stainless steel seamless pipes with slightly different compositions and properties.
316L seamless pipe has a maximum carbon content of 0.03% and can be used in applications where annealing cannot be performed after welding and where maximum corrosion resistance is required.
In addition, 316L stainless steel has better resistance to carbide precipitation than 316 stainless steel and can be used within a specific temperature range.
In terms of welding, 316L stainless steel does not require post-weld annealing treatment, while the welded section of 316 stainless steel requires post-weld annealing treatment.
In terms of strength, the tensile strength of 316 stainless steel pipe is higher than that of 316L stainless steel pipe.
This is because carbon is a strong austenite-forming element that can significantly increase the strength of stainless steel pipes.
In general, 316L stainless steel has stronger corrosion resistance and is suitable for strong corrosion areas such as the seaside, while 316 stainless steel has stronger tensile strength
Sizes:1/8″ thru 24″
Grade:304H, 316H, 309/S, 310/S, 317/L, 321/H, 347/H, 904L, 330, 254SMO, 410.
Specifications: ASTM A312, ASTM A358, ASTM A813, ASTM A814
Grade of stainless steel pipe
| Material | ASTM Grade | UNS Grade | DIN Grade | JIS Grade | Steel Name |
| Austenitic | TP 304 | S30400 | 1.4301 | SUS304TB | X5CrNi18-20 |
| TP 304L | S30403 | 1.4306 | X2CrNi19-11 | ||
| TP 304L | S30403 | 1.4307 | SUS304LTB | X2CrNi18-9 | |
| TP 304H | S30409 | 1.4948 | SUS304HTB | X6CrNi18-10 | |
| TP 310S | S31008 | 1.4845 | SUS310STB | X8CrNi25-21 | |
| TP 310H | S31009 | ||||
| 1.4335 | X1CrNi25-21 | ||||
| TP 316 | S31600 | 1.4401 | SUS316TB | X5CrNiMo17-12-2 | |
| TP 316L | S31603 | 1.4404 | SUS316LTB | X2CrNiMo17-12-2 | |
| TP 316H | S31609 | 1.4918 | SUS316HTB | X6CrNiMo17-13-2 | |
| TP 316Ti | S31635 | 1.4571 | SUS316TiTB | X6CrNiMo17-12-2 | |
| TP 321 | S32100 | 1.4541 | SUS321TB | X6CrNiNb18-10 | |
| TP 312H | S32109 | 1.4941 | SUS321HTB | X6CrNiTiB18-10 | |
| TP 347 | S34700 | 1.455 | SUS347TB | X6CrNiNb18-10 | |
| TP 347H | S34709 | 1.4912 | SUS347HTB | X7CrNiNb18-10 | |
| Ferritic & Martensitic | TP 405 | S41500 | 1.4002 | SUS 405TB | X6CrAl13 |
| TP 410 | S41000 | 1.4006 | SUS 410TB | X12Cr13 | |
| TP 430 | S43000 | 1.4016 | SUS 430TB | X6Cr17 | |
| Ferritic / Austenitic | UNS S31803 | ||||
| 2205 | UNS S32205 | 1.4462 | X2CrNiMoN22-5-3 | ||
| 2507 | UNS S32750 | 1.441 | X2CrNiMoN25-7-4 | ||
| UNS S32760 | 1.4501 | X2CrNiMoCuWN25-7-4 |
Standard of stainless steel pipe
| A 213 / SA 213 | Seamless Ferritic and Austenitic Alloy-steel Boiler,Superheater and Heat-Exchanger Tubes |
| A 249 / SA 249 | Welded Austenitic Steel Boiler,Superheater, Hear Exchanger and Condenser Tubes |
| A 268 / SA 268 | Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service |
| A 269 | Seamless and Welded Austenitic Stainless Steel Tubing for General Service |
| A 312 / SA 312 | Seamless,Welded and Heavily Cold Worked Austenitic Stainless Steel Pipes |
| A 376 / SA 376 | Seamless Austenitic Steel Pipe for High-temperature Service |
| A 688 / SA 688 | Seamless and Welded Austenitic Stainless Steel Feedwater Heater Tubes |
| A 789 / SA 789 | Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service |
| A 790 / SA 790 | Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe |
| A 999 / SA 999 | General Requirement for Alloy and Stainless Steel Pipe |
| A 1016 / SA 1016 | General Requirement for Ferritic Alloy Steel, Austenitic Alloy Steel and Stainless Steel Tubes |
| European Standard | |
| DIN EN 10216-5 | Seamless Steel Tubes for Pressure Purposes |
| DIN EN 10217-7 | Welded Steel Tubes for Pressure Purposes |
| DIN EN 10297-2 | Seamless Steel Tubes for Mechanical and General Engineering Purposes |
| DIN EN 10305-1 | Steel Tubes for Precision Application |
| German Standard | |
| DIN 11850 | Stainless Steel Tubes for the Food and Chemical Industries-Dimensions, Materials |
| DIN 17455 | General Purpose Welded Circular Stainless Steel Tubes |
| DIN 17456 | General Purpose Seamless Circular Stainless Steel Tubes |
| DIN 17457 | Welded Circular Austenitic Stainless Steel Tubes Subject to Special Requirement |
| DIN 17458 | Seamless Circular Austenitic Stainless Steel Tubes Subject to Special Requirement |
| DIN 28180 | Seamless Steel Tubes for Heat-exchanger |
| DIN 11850 | Welded Tubes and Pipe for Food, Beverages,Chemical&Pharmaceuticals Industry |
| Russian Standard | |
| GOST 9941 | Seamless and Warm-deformed Tubes Made from Corrosion-resistant Steel |
| Norsok Standard | |
| Norsok M – 650 | Qualification of Manufacturers of Special Material |
| Norsok M – 630 | Material Data Sheets and Element Data Sheerts for Piping |
Chemical Requirements (%) of stainless steel pipe
| Grade | UNS Desig | C | Mn | P | S | Si | Cr | Ni | Mb | Ti | Nb | Ta | N | Vn | Cu | Ce | B | Al | Other |
| TP304 | S30400 | 0.08 | 2 | 0.045 | 0.03 | 1 | 18.0–20 | 8.0–11 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP304L | S30403 | 0.035 | 2 | 0.045 | 0.03 | 1 | 18.0–20 | 8.0–13 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP304H | S30409 | 0.04 – 0.1 | 2 | 0.045 | 0.03 | 1 | 18.0–20 | 8.0–11 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP310S | S31008 | 0.08 | 2 | 0.045 | 0.03 | 1 | 24.0- 26 | 19.0- 22 | 0.75 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP310H | S31009 | 0.04 – 0.1 | 2 | 0.045 | 0.03 | 1 | 24.0–26 | 19.0–22 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | ||||
| TP310H | S31035 | 0.04 – 0.1 | 0.6 | 0.025 | 0.015 | 0.4 | 21.5–23.5 | 23.5–26.5 | . . . | . . . | 0.40- 0.6 | . . . | 0.20- 0.3 | . . . | 2.5- 3.5 | . . . | 0.002- 0.008 | See Spec | |
| TP316 | S31600 | 0.08 | 2 | 0.045 | 0.03 | 1 | 16.0–18 | 10.0–14 | 2.00–3 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP316L | S31603 | 0.035 | 2 | 0.045 | 0.03 | 1 | 16.0–18 | 10.0–14 | 2.00–3 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP316H | S31609 | 0.04 – 0.1 | 2 | 0.045 | 0.03 | 1 | 16.0–18 | 10.0–14 | 2.00–3 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP317 | S31700 | 0.08 | 2 | 0.045 | 0.03 | 1 | 18.0–20 | 11.0–15 | 3.0–4 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP317L | S31703 | 0.035 | 2 | 0.045 | 0.03 | 1 | 18.0–20 | 11.0–15 | 3.0–4 | . . . | . . . | . . . | . . . | . . . | . . . | . . . | |||
| TP321 | S32100 | 0.08 | 2 | 0.045 | 0.03 | 1 | 17.0–19 | 9.0–12 | . . . | Ti 5 × (C+N) min, 0.70 max | . . . | . . . | 0.1 | . . . | . . . | . . . | |||
| TP321H | S32109 | 0.04 – 0.1 | 2 | 0.045 | 0.03 | 1 | 17.0–19 | 9.0–12 | . . . | 4(C+N) min; 0.70 max | . . . | . . . | 0.1 | . . . | . . . | . . . | |||
| TP321H | S32654 | 0.02 | 2.0-4 | 0.03 | 0.005 | 0.5 | 24.0–25 | 21.0–23 | 7.0-8 | . . . | . . . | . . . | 0.45- 0.55 | . . . | 0.30-0.6 | . . . | |||
| TP321H | S33228 | 0.04 – 0.08 | 1 | 0.02 | 0.015 | 0.3 | 26.0–28 | 31.0–33 | . . . | . . . | 0.60- 1 | . . . | . . . | . . . | . . . | 0.05 – 0.1 | 0.025 | ||
| TP321H | S34565 | 0.03 | 5.0-7 | 0.03 | 0.01 | 1 | 23.0–25 | 16.0–18 | 4.0-5 | . . . | 0.1 | . . . | 0.40- 0.6 | . . . | . . . | . . . | |||
| TP347 | S34700 | 0.08 | 2 | 0.045 | 0.03 | 1 | 17.0–19 | 9.0–13 | . . . | . . . | See Spec | . . . | . . . | . . . | . . . | . . . | |||
| TP347H | S34709 | 0.04 – 0.1 | 2 | 0.045 | 0.03 | 1 | 17.0–19 | 9.0–13 | . . . | . . . | See Spec | . . . | . . . | . . . | . . . | . . . | |||
| Alloy 20 | N08020 | 0.07 | 2 | 0.045 | 0.035 | 1 | 19.0–21 | 32.0–38 | 2.0–3 | . . . | See Spec | See Spec | . . . | . . . | 3.0– 4 | . . . | . . . | . . . | |
| Alloy 20 | N08367 | 0.03 | 2 | 0.04 | 0.03 | 1 | 20.0–22 | 23.5–25.5 | 6.0–7 | . . . | . . . | . . . | 0.18–0.25 | . . . | 0.75 | . . . | . . . | . . . | |
| Alloy 20 | N08028 | 0.03 | 2.5 | 0.03 | 0.03 | 1 | 26.0–28 | 30.0–34 | 3.0–4 | 0.60–1.4 | |||||||||
| Alloy 20 | N08029 | 0.02 | 2 | 0.025 | 0.015 | 0.6 | 26.0–28 | 30.0–34 | 4.0–5 | 0.6– 1.4 |
Heat Treatment Chart of Seamless steel pipe
| Grade | UNS Designation | Finish | Heating Temperature |
| TP304H | S30409, S30415 | Cold | 1900 °F [1040 °C] |
| TP304H | S30409, S30415 | Hot | 1900 °F [1040 °C] |
| TP310H | S31009 | 1900 °F [1040 °C] | |
| TP310H | S31035 | 2160—2280 °F [1180—1250 °C] | |
| TP316H | S31609 | Cold | 1900 °F [1040 °C] |
| TP316H | S31610 | Hot | 1900 °F [1040 °C] |
| TP321H | S32109, S32615 | Cold | 2000 °F [1100 °C] |
| TP321H | S32109, S32615 | Hot | 1925 °F [1050 °C] |
| TP321H | S32654 | 2100 °F [1150 °C] | |
| TP321H | S33228 | 2050—2160 °F [1120—1180 °C] | |
| TP321H | S34565 | 2050—2140 °F [1120—1170 °C] | |
| TP347H | S34709 | Cold | 2000 °F [1100 °C] |
| TP347H | S34709 | Hot | 1925 °F [1050 °C] |
| Alloy 20 | N08020 | 1700—1850 °F [925—1010 °C] | |
| Alloy 20 | N08367 | 2025 °F [1110 °C] | |
| Alloy 20 | N08028 | 2000 °F [1100 °C] | |
| Alloy 20 | N08029 | 2000 °F [1100 °C] |
Tensile Requirements
| Grade | UNS Designation | Tensile Strength, min ksi [MPa] | Yield Strength, min ksi [MPa] | Other |
| TP304 | S30400 | 75 [515] | 30 [205] | |
| TP304L | S30403 | 70 [485] | 25 [170] | |
| TP304H | S30409 | 75 [515] | 30 [205] | |
| TP304H | S30415 | 87 [600] | 42 [290] | |
| TP310S | S31008 | 75 [515] | 30 [205] | |
| TP310H | S31009 | 75 [515] | 30 [205] | |
| TP310H | S31035 | 95 [655] | 45 [310] | |
| TP316 | S31600 | 75 [515] | 30 [205] | |
| TP316L | S31603 | 70 [485] | 25 [170] | |
| TP316H | S31609 | 75 [515] | 30 [205] | |
| TP316H | S31635 | 75 [515] | 30 [205] | |
| TP317 | S31700 | 75 [515] | 30 [205] | |
| TP317L | S31703 | 75 [515] | 30 [205] | |
| TP317L | S31725 | 75 [515] | 30 [205] | |
| TP317L | S31726 | 80 [550] | 35 [240] | |
| TP317L | S31727 | 80 [550] | 36 [245] | |
| TP317L | S31730 | 70 [480] | 25 [175] | |
| TP317L | S32053 | 93 [640] | 43 [295] | |
| TP321 | S32100 | 75 [515] | 30 [205] | welded & seamless |
| TP321 | S32100 | 75 [515] | 30 [205] | t = 0.375 in. |
| TP321 | S32100 | 70 [480] | 25 [170] | t > 0.375 in. |
| TP321H | S32109 | 75 [515] | 30 [205] | welded & seamless |
| TP321H | S32109 | 75 [515] | 30 [205] | t = 0.375 in. |
| TP321H | S32109 | 70 [480] | 25 [170] | t > 0.375 in. |
| TP321H | S32615 | 80 [550] | 32 [320] | |
| TP321H | S32654 | 109 [750] | 62 [430] | |
| TP321H | S33228 | 73 [500] | 27 [185] | |
| TP321H | S34565 | 115 [795] | 60 [415] | |
| TP347 | S34700 | 75 [515] | 30 [205] | |
| TP347H | S34709 | 75 [515] | 30 [205] | |
| Alloy 20 | N08020 | 80 [550] | 35 [240] | |
| Alloy 20 | N08028 | 73 [500] | 31 [214] | |
| Alloy 20 | N08029 | 73 [500] | 31 [214] | |
| Alloy 20 | N08367 | 100 [690] | 45 [310] | t = 0.187 in. |
| Alloy 20 | N08367 | 95 [655] | 45 [310] | t > 0.187 in. |
They have some differences in manufacturing process, appearance, performance, use and price.
Manufacturing process: Stainless steel welded pipes are usually made by bending steel plates into circles and then welding them into pipes. Stainless steel seamless pipes are round pipes produced by drawing or forging processes using steel billets as raw materials.
Appearance: The stainless steel welded pipe has high appearance precision, uniform wall thickness, high brightness inside and outside the pipe, can be arbitrarily scaled, and can be made into thin-walled pipes.
Stainless steel seamless pipes have low appearance accuracy, uneven wall thickness, low brightness inside and outside the pipe, high cost of cutting to length, pitting and black spots inside and outside the pipe are difficult to remove, and the walls are usually thicker.
Performance: The corrosion resistance, pressure resistance and high temperature resistance of stainless steel seamless pipes are much higher than those of stainless steel welded pipes.
With the improvement of the production process of stainless steel welded pipes, its mechanical properties and corrosion resistance are gradually approaching that of seamless pipes, but in some aspects, such as pressure resistance and corrosion resistance, they are still inferior to seamless pipes.
Price: The production process of stainless steel seamless pipes is complex and the production cost is high, so the price is also more expensive than stainless steel welded pipes.
Purpose: Stainless steel welded pipes are mainly used for decoration, pillars, products, etc. Their pressure-bearing properties are average and they are mainly used to transport water, oil, gas, air and general low-pressure fluids, such as hot water or steam.
Stainless steel seamless pipes are widely used in petroleum, chemical industry, electric power, food, medicine and other fields because of their excellent corrosion resistance and pressure resistance.