The manufacturing Process of seamless steel tubes in china

China is known for its vast manufacturing capabilities and its ability to produce a wide range of products. One industry in which China has made significant strides is the production of seamless steel tubes. These tubes are widely used in various industries, including Oil and gas, automotive, and construction. In this article, we will explore the manufacturing process of seamless steel tubes in China.
| Labels | Outside Diameter (d/mm) | T&C (kg/m) | wall thickness (t/mm) | Type of end-finish | |||||||
| 1 | 2 | J55/ K55 | M65 | L80/ R95 | N80-1/Q | C90/T95 | P110 | Q125 | |||
| 4-1/2 | 9.50 | 114.30 | 14.14 | 5.21 | PS | PS | – | – | – | – | – |
| 10.50 | 114.30 | 15.63 | 5.69 | PSB | PSB | – | – | – | – | – | |
| 11.60 | 114.30 | 17.26 | 6.35 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
| 13.50 | 114.30 | 20.09 | 7.37 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 15.10 | 114.30 | 22.47 | 8.56 | – | – | – | – | – | PLB | PLB | |
| 5 | 11.50 | 127.00 | 17.11 | 5.59 | PS | PS | – | – | – | – | – |
| 13.00 | 127.00 | 19.35 | 6.43 | PSLB | PSLB | – | – | – | – | – | |
| 15.00 | 127.00 | 22.32 | 7.52 | PSLB | PLB | SLB | PLB | PLB | PLB | ||
| 18.00 | 127.00 | 26.79 | 9.19 | – | PLB | SLB | PLB | PLB | PLB | PLB | |
| 21.40 | 127.00 | 31.85 | 11.10 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
| 23.20 | 127.00 | 34.53 | 12.14 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 24.10 | 127.00 | 35.87 | 12.70 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 5-1/2 | 14.00 | 139.70 | 20.83 | 6.20 | PS | PS | – | – | – | – | – |
| 15.50 | 139.70 | 23.07 | 6.98 | PSLB | PSLB | – | – | – | – | – | |
| 17.00 | 139.70 | 25.30 | 7.72 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
| 20.00 | 139.70 | 29.76 | 9.17 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 23.00 | 139.70 | 34.23 | 10.54 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
| 26.80 | 139.70 | 39.88 | 12.70 | – | – | – | – | P | – | – | |
| 29.70 | 139.70 | 44.20 | 14.27 | – | – | – | – | P | – | – | |
| 32.60 | 139.70 | 48.52 | 15.88 | – | – | – | – | P | – | – | |
| 35.30 | 139.70 | 52.53 | 17.45 | – | – | – | – | P | – | – | |
| 38.00 | 139.70 | 56.55 | 19.05 | – | – | – | – | P | – | – | |
| 40.50 | 139.70 | 60.27 | 20.62 | – | – | – | – | P | – | – | |
| 43.10 | 139.70 | 64.14 | 22.22 | – | – | – | – | P | – | – | |
| 6-5/8 | 20.00 | 168.28 | 29.76 | 7.32 | PSLB | PSLB | – | – | – | – | – |
| 24.00 | 168.28 | 35.72 | 8.94 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
| 28.00 | 168.28 | 41.67 | 10.59 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 32.00 | 168.28 | 47.62 | 12.06 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 7 | 17.00 | 177.80 | 25.30 | 5.87 | – | – | – | – | – | – | – |
| 20.00 | 177.80 | 29.76 | 6.91 | PS | PS | – | – | – | – | – | |
| 23.00 | 177.80 | 34.23 | 8.05 | PSLB | PLB | PLB | PLB | PLB | – | – | |
| 26.00 | 177.80 | 38.69 | 9.19 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 29.00 | 177.80 | 43.16 | 10.36 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 32.00 | 177.80 | 47.62 | 11.51 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 35.00 | 177.80 | 52.09 | 12.65 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 38.00 | 177.80 | 56.55 | 13.72 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 42.70 | 177.80 | 63.55 | 15.88 | – | – | – | – | P | – | – | |
| 46.40 | 177.80 | 69.05 | 17.45 | – | – | – | – | P | – | – | |
| 50.10 | 177.80 | 74.56 | 19.05 | – | – | – | – | P | – | – | |
| 53.60 | 177.80 | 79.77 | 20.62 | – | – | – | – | P | – | – | |
| 57.10 | 177.80 | 84.98 | 22.22 | – | – | – | – | P | – | – | |
| 7-5/8 | 24.00 | 193.68 | 35.72 | 7.62 | – | – | – | – | – | – | |
| 26.40 | 193.68 | 39.29 | 8.33 | PSLB | PSLB | PLB | PLB | PLB | – | – | |
| 29.70 | 193.68 | 44.20 | 9.52 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 33.70 | 193.68 | 50.15 | 10.92 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 39.00 | 193.68 | 58.04 | 12.70 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 42.80 | 193.68 | 63.69 | 14.27 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 45.30 | 193.68 | 67.42 | 15.11 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 47.10 | 193.68 | 70.09 | 15.88 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 51.20 | 193.68 | 76.20 | 17.45 | – | – | – | – | P | – | – | |
| 55.30 | 193.68 | 82.30 | 19.05 | – | – | – | – | P | – | – | |
| 7-3/4 | 46.10 | 196.85 | 68.61 | 15.11 | – | – | P | P | P | P | P |
| 8-5/8 | 24.00 | 219.08 | 35.72 | 6.71 | PS | PS | – | – | – | – | – |
| 28.00 | 219.08 | 41.67 | 7.72 | PS | – | – | – | – | – | ||
| 32.00 | 219.08 | 47.62 | 8.94 | PSLB | PSLB | – | – | – | – | – | |
| 36.00 | 219.08 | 53.58 | 10.16 | PSLB | PSLB | PLB | PLB | PLB | PLB | – | |
| 40.00 | 219.08 | 59.53 | 11.43 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 44.00 | 219.08 | 65.48 | 12.70 | – | – | PLB | PLB | PLB | PLB | – | |
| 49.00 | 219.08 | 72.92 | 14.15 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 9-5/8 | 32.30 | 244.48 | 48.07 | 7.92 | – | – | – | – | – | – | – |
| 36.00 | 244.48 | 53.58 | 8.94 | PSLB | PSLB | – | – | – | – | – | |
| 40.00 | 244.48 | 59.53 | 10.03 | PSLB | PSLB | PLB | PLB | PLB | – | – | |
| 43.50 | 244.48 | 64.74 | 11.05 | – | PLB | PLB | PLB | PLB | PLB | – | |
| 47.00 | 244.48 | 69.95 | 11.99 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
| 53.50 | 244.48 | 79.62 | 13.84 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 58.40 | 244.48 | 86.91 | 15.11 | – | – | PLB | PLB | PLB | PLB | PLB | |
| 59.40 | 244.48 | 88.40 | 15.47 | – | – | – | – | P | – | – | |
| 64.90 | 244.48 | 96.58 | 17.07 | – | – | – | – | P | – | – | |
| 70.30 | 244.48 | 104.62 | 18.64 | – | – | – | – | P | – | – | |
| 75.60 | 244.48 | 112.51 | 20.24 | – | – | – | – | P | – | – | |
| 10-3/4 | 32.75 | 273.05 | 48.74 | 7.09 | – | – | – | – | – | – | – |
| 40.50 | 273.05 | 60.27 | 8.89 | PSB | PSB | – | – | – | – | – | |
| 45.50 | 273.05 | 67.71 | 10.16 | PSB | PSB | – | – | – | – | – | |
| 51.00 | 273.05 | 75.90 | 11.43 | PSB | PSB | PSB | PSB | PSB | PSB | – | |
| 55.50 | 273.05 | 82.60 | 12.57 | – | PSB | PSB | PSB | PSB | PSB | – | |
| 60.70 | 273.05 | 90.33 | 13.84 | – | – | – | – | PSB | PSB | PSB | |
| 65.70 | 273.05 | 97.77 | 15.11 | – | – | – | – | PSB | PSB | PSB | |
| 73.20 | 273.05 | 108.94 | 17.07 | – | – | – | – | P | – | – | |
| 79.20 | 273.05 | 117.87 | 18.64 | – | – | – | – | P | – | – | |
| 85.30 | 273.05 | 126.94 | 20.24 | – | – | – | – | P | – | – | |
| 11-3/4 | 42.00 | 298.45 | 62.50 | 8.46 | – | – | – | – | – | – | – |
| 47.00 | 298.45 | 69.95 | 9.53 | PSB | PSB | – | – | – | – | – | |
| 54.00 | 298.45 | 80.36 | 11.05 | PSB | PSB | – | – | – | – | – | |
| 60.00 | 298.45 | 89.29 | 12.42 | PSB | PSB | PSB | PSB | PSB | PSB | PSB | |
| 65.00 | 298.45 | 96.73 | 13.56 | – | – | P | P | P | P | P | |
| 71.00 | 298.45 | 105.66 | 14.78 | – | – | P | P | P | P | P | |
| 13-3/8 | 48.00 | 339.72 | 71.43 | 8.38 | – | – | – | – | – | – | – |
| 54.50 | 339.72 | 81.11 | 9.65 | PSB | PSB | – | – | – | – | – | |
| 61.00 | 339.72 | 90.78 | 10.92 | PSB | PSB | – | – | – | – | – | |
| 68.00 | 339.72 | 101.20 | 12.19 | PSB | PSB | PSB | PSB | PSB | PSB | – | |
| 72.00 | 339.72 | 107.15 | 13.06 | – | – | PSB | PSB | PSB | PSB | PSB | |
| 16 | 65.00 | 406.40 | 96.73 | 9.53 | – | – | – | – | – | – | – |
| 75.00 | 406.40 | 111.62 | 11.13 | PSB | PSB | – | – | – | – | – | |
| 84.00 | 406.40 | 125.01 | 12.57 | PSB | PSB | – | – | – | – | – | |
| 109.00 | 406.40 | 162.21 | 16.66 | P | – | P | P | – | P | P | |
| 18-5/8 | 87.50 | 473.08 | 130.22 | 11.05 | PSB | PSB | – | – | – | – | – |
| 20 | 94.00 | 508.00 | 139.89 | 11.13 | PSLB | PSLB | – | – | – | – | – |
| 106.50 | 508.00 | 158.49 | 12.70 | PSLB | PSLB | – | – | – | – | – | |
| 133.00 | 508.00 | 197.93 | 16.13 | PSLB | – | – | – | – | – | – | |
| Item No | product name | standard | Steel grade | size(mm) | Application | |
| 1 | pressure fluid steel Pipe | astm a106 | Gr.A、Gr.B、Gr.C | OD:21.3-1220 | boiler,heat exchanger,medium low pipeline | |
| ASTM A53 | Wall:2.0-100 | |||||
| 2 | casing,oil pipe,coupling | api5ct PSL1、 | group1:J55、 K55、N80、R95 | OD:26.7-762 | Steel tube for oil field | |
| PSL2 PSL3 | group2:L80、 C90、T95 | Wall:2.87-40 | ||||
| group3:P110 | ||||||
| 3 | pipeline transportation system | API5L | A、B、X42、X46、X52、X60、X65、X70、X80 | OD:26.7-1220 | oil and gas pipeline, refining equipment pipeline | |
| PSL1 | Wall:2.87-100 | |||||
| PSL2 | ||||||
| 4 | mechanical high precision seamless pipe | ASTM A519 | SAE1018、SAE1020、SAE1045、SAE1518、SAE1541、SAE4130、SAE4135、SAE4140、SAE8620、ST78、ST52、E215、E235、E355、E410、C35E、C45E、25CrMo4、42CrMo4 | OD:21.3-406 | high precision machined seamless tube,construction machine,automobile engine | |
| EN10305-1 | Wall:2.0-40 | |||||
| DIN2391 | ||||||
| GB3639 | ||||||
| 5 | heat exchanger and condenser low carbon cold drawn seamless pipe | ASTM A179 | A179 | OD:6-76.2 | heat exchanger | |
| Wall:1.0-20 | ||||||
| 6 | high pressure Carbon steel seamless boiler pipe | ASTM A192 | A192 | OD:12.7-177.8 | high pressure boiler tube | |
| Wall:2.0-25.4 | ||||||
| 7 | boder,superheater unit medium carbon seamless steel pipe | ASTM A210 | A210A-1 | OD:12.7-127 | high pressure toiler and heat exchanger | |
| A210-C | Wall:0.9-12.7 | |||||
| 8 | boiler,superheater unit femilic alloy steel pipe | astm a213 | T2、T11、T12、T22、T5、T5b、T5C | OD:6-127 | high pressure boiler,superheater unit, heat exchanger alloy steel tube | |
| Wall:0.4-12 | ||||||
| 9 | seamless steel pipe for pressure purpose | EN10216-1 | 195GH、P235GH、P265GH、20MnNb6、16Mo3、13CrMo4-5 | OD:21.3-762 | pressure piping | |
| EN10216-2 | Wall:2.0-40 | |||||
| 10 | gas cylinder seamless steel pipe | GB18248 | 37Mn、34Mn2V、30CrMo、35CrMo、34CrMo4、30CrMnSiA、STH11、STH12、STH21、STH22、STH31 | OD:76-356 | high pressure gas cylinder | |
| JIS G3429 | Wall:2.5-6.0 | |||||
| 11 | the automotive axle pipe | YB/T 5035 | 45#、45Mn2、40MnB、40Cr | OD:76-121 | automobile application | |
| Wall:7.0-28.5 | ||||||
After the steel is produced, it is cast into billets or blooms, which are semi-finished forms of steel. These billets or blooms are then heated and pierced to create a hollow tube. This process is known as piercing, and it is a critical step in the manufacturing of seamless steel tubes. China has developed advanced piercing technologies that ensure the production of tubes with precise dimensions and smooth surfaces.
Once the tubes are pierced, they undergo a series of processes to further refine their shape and dimensions. These processes include elongation, rolling, and sizing. Elongation involves stretching the tube to reduce its diameter and increase its Length. Rolling is done to improve the surface finish and remove any imperfections. Sizing is the final step in the process, where the tube is passed through a series of rollers to achieve the desired dimensions.
China has invested heavily in the development of advanced manufacturing technologies for seamless steel tubes. These technologies include the use of computer-controlled machines and automated production lines. These advancements have not only improved the efficiency of the manufacturing process but also ensured the production of tubes with consistent quality.
| Tensile and Hardness Requirements | |||||||||
| Grade | Yield strength MPa | Tensile Strength | Hardness a,c | Specified Wall Thickness | Allowable Hardness Variation b | ||||
| Type | Total Elongation Under Load | min MPa | max | ||||||
| min | max | HRC | HBW | mm | HRC | ||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| H40 | — | 0.5 | 276 | 552 | 414 | — | — | — | — |
| J55 | — | 0.5 | 379 | 552 | 517 | — | — | — | — |
| K55 | — | 0.5 | 379 | 552 | 655 | — | — | — | — |
| N80 | 1 | 0.5 | 552 | 758 | 689 | — | — | — | — |
| N80 | Q | 0.5 | 552 | 758 | 689 | — | — | — | — |
| R95 | — | 0.5 | 655 | 758 | 724 | — | — | — | — |
| L80 L80 | 1 | 0.5 | 552 | 655 | 655 | 23 | 241 | — | — |
| L80 | 9Cr 13Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | — | — |
| 0.5 | 552 | 655 | 655 | 23 | 241 | — | — | ||
| C90 | 1 | 0.5 | 621 | 724 | 689 | 25.4 | 255 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| T95 | 1 | 0.5 | 655 | 758 | 724 | 25.4 | 255 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| C110 | — | 0.7 | 758 | 828 | 793 | 30 | 286 | £12.70 | 3 |
| 12.71 to 19.04 | 4 | ||||||||
| 19.05 to 25.39 | 5 | ||||||||
| ³ 25.40 | 6 | ||||||||
| P110 | — | 0.6 | 758 | 965 | 862 | — | — | — | — |
| Q125 | 1 | 0.65 | 862 | 1034 | 931 | b | — | £12.70 | 3 |
| 12.71 to 19.04 19.05 | 4 | ||||||||
| 5 | |||||||||
| a In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method. | |||||||||
| b No hardness limits are specified, but the maximum variation is restricted as a manufacturing control in accordance with 7.8 and 7.9. | |||||||||
| c For through-wall hardness tests of Grades L80 (all types), C90, T95 and C110, the requirements stated in HRC scale are for maximum mean hardness number. | |||||||||
In conclusion, China has made significant advancements in the manufacturing process of seamless steel tubes. The country’s access to abundant resources, advanced technologies, and strict quality control measures have enabled it to produce high-quality tubes that meet the requirements of various industries. With its commitment to innovation and sustainability, China continues to be a leading player in the global Seamless Steel Tube market.