Both Tubing and Pipe are manufactured by the first two methods below. The third is reserved for Tubing only.
Electric Resistance Welded, often abbreviated as ERW, is a process that uses specific machinery to shape the pipe and tubing. A continuous steel sheet is unwound from a coil and shaped using contoured rollers, forcing the edges together under pressure. These edges are then welded together by heating the material to over 2,000 degrees. After welding, the pipe or tubing is cut into the exact size needed.
Seamless Pipe (and tubing) is made by extruding a steel block or by drilling a solid steel bar. Next, the extrusion or the drilled steel bar is cold drawn through a dye to achieve the diameter and thickness needed. Because this process can cause mechanical hardening, sometimes the material is annealed and straightened as a final process. Seamless Pipe & Tubing is subdivided as:
Cold Drawn Seamless, or CDS, exhibits precise tolerances and a good surface finish.
Hot Finished Seamless, or HFS, has less critical tolerances and somewhat scaly finish and is not as strong as CDS.
For Drawn over Mandrel, or DOM tubing, the first stages of manufacturing are identical to ones used to make electric resistance welded tubing, but in the finishing stages the entire flash weld is taken out and the tube is cold drawn over a mandrel. A mandrel is a round object against which material can be forged or shaped. The cold drawn process provides the tube with better dimensional tolerances, improved surface finish and the strongest weld strength achievable.
Typical Pipe Coatings & Finishes:
Galvanized - Covered with a protective zinc coating on steel to prevent the material from rusting. The process can be hot-dip-galvanizing where the material is dipped in molten zinc or Electro-Galvanized where the steel sheet from which the pipe is made was galvanized during production by an electro-chemical reaction.
Uncoated - Uncoated Pipe
Black Coated - Coated with a dark colored iron-oxide
Red Primed - Red Oxide Primed used as a base coat for ferrous metals, gives iron and steel surfaces a layer of protection
Available grades and size range
Carbon steel is an alloy with carbon and iron, with carbon content up to 2.1% by weight. The increase in the carbon percentage will raise steel's hardness and strength, but it will be less ductile. Carbon steel has good properties in hardness and strength, and it is less expensive than other steels.
API SPEC 5CT
Product Name | Executive Standard | Dimension (mm) | Steel Code / Steel Grade |
Casting | API 5CT | Ø114~219 x WT5.2~22.2 | J55, K55, N80, L80, P110 |
Tubing | API 5CT | Ø48.3~114.3 x WT3.2~16 | J55, K55, N80, L80, P110 |
Product Name | Executive Standard | Dimension (mm) | Steel Code / Steel Grade |
Line Pipes | API 5L | Ø10.3~1200 x WT1.0~120 | A, B, X42, X46, X52, X60, X70, X80, PSL1 / PSL2 |
Product Name | Executive Standard | Dimension (mm) | Steel Code / Steel Grade |
Black and Hot-Dipped Zinc-Coated Seamless Steel Pipes | ASTM A53 | Ø10.3~1200 x WT1.0~150 | Gr.A, Gr.B, Gr.C |
Seamless Carbon Steel Pipes for High Temperature Service | ASTM A106 | Ø10.3~1200 x WT1.0~150 | Gr.B, Gr.C |
Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes | ASTM A179 | Ø10.3~426 x WT1.0~36 | Low Carbon Steel |
Seamless Carbon Steel Boiler Tubes for High Pressure | ASTM A192 | Ø10.3~426 x WT1.0~36 | Low Carbon Steel |
Seamless Cold-Drawn Intermediate Alloy Steel Heat-Exchanger and Condenser Tubes | ASTM A199 | Ø10.3~426 x 1.0~36 | T5, T22 |
Seamless Medium-Carbon Steel Boiler and Superheater Tubes | ASTM A210 | Ø10.3~426 x WT1.0~36 | A1, C |
Seamless Ferritic and Austenitic Alloy Steel Boiler, Superheater and Heat-Exchanger Tubes | ASTM A213 | Ø10.3~426 x WT1.0~36 | T5, T9, T11, T12, T22, T91 |
Seamless Carbon and Alloy Steel for Mechanical Tubing | ASTM A333 | Ø1/4"~42" x WT SCH20~XXS | Gr.1, Gr.3, Gr.6 |
Seamless and Welded Carbon Steel Pipes and Alloy Steel Pipes for Low Temperature Use | ASTM A334 | Ø1/4"~4" x WT SCH20~SCH80 | Gr.1, Gr.6 |
Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes | ASTM A556 | Ø10.3~426 x WT1.0~36 | A2, B2 |
Product Name | Executive Standard | Dimension (mm) | Steel Code / Steel Grade |
Seamless Steel Tubes for Elevated Temperature | DIN 17175 | Ø10~762 x WT1.0~120 | St35.8, St45.8, 10CrMo910, 15Mo3, 13CrMo44, STPL340, STB410, STB510, WB36 |
Seamless Steel Tubes | DIN 1629 / DIN 2391 | Ø13.5~762 x WT1.8~120 | St37.0, St44.0, St52.0, St52.3 |
Seamless Steel Tubes | DIN 2440 | Ø13.5~165.1 x WT1.8~4.85 | St33.2 |
Seamless Steel Pipes for Structural Purpose | DIN 2393 | Ø16~426 x WT1.0~36 | RSt34-2, RSt37-2, RSt44-2, St52 |
Product Name | Executive Standard | Dimension (mm) | Steel Code / Steel Grade |
Seamless Steel Tubes for Machine Structure | BS 970 | Ø10~762 x WT1.0~120 | Carbon Steel |
Seamless Steel Tubes for Boiler and Heat Exchangers | BS 3059 | Ø10~762 x WT1.0~120 | 360, 410, 440, 460, 490 |
Term | Symbol | Explanation |
Cold-finished/hard (cold-finished as-drawn) | BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
Cold-finished/soft (lightly cold-worked) | BKW | After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |