The structure steel pipe has hot - rolled seamless steel tube and welded steel tube.The seamless steel tube for structure is divided into two types according to the provisions of "seamless steel tube for structure" (GB/ t8162-2008) : hot rolling (extrusion, expansion) and cold drawing (rolling).The outer diameter of hot-rolled steel pipe is 32-630mm and the wall thickness is 2.5-75mm. The outer diameter of cold-drawn steel pipe is 5-200mm and the wall thickness is 2.5-12mm. Welded steel pipe is made of steel plate or steel strip after crimping and forming, which can be divided into straight welded steel pipe and spiral welded steel pipe.The outer diameter and wall thickness of the direct-welded steel pipe are 5-508mm and 0.5-12.7mm respectively, which shall comply with the provisions of GB/ t3793-2008.The welded steel pipe for low-pressure fluid transportation is also called common welded pipe, commonly known as clark pipe. The specification is expressed in mm of nominal diameter, which should comply with the provisions of GB/ t3091-2008 for low-pressure fluid transportation. Manufacturing Process
Chemical Composition
| Grade | C | Mn | P | S | Si | Cr | Mo |
| 1010 | 0.08-0.13 | 0.30-0.60 | ≤0.04 | ≤0.05 | - | - | - |
| 1020 | 0.08-0.23 | 0.30-0.60 | ≤0.04 | ≤0.05 | - | - | - |
| 1045 | 0.43-0.50 | 0.60-0.90 | ≤0.04 | ≤0.05 | - | - | - |
| 4130 | 0.28-0.33 | 0.40-0.60 | ≤0.04 | ≤0.05 | 0.15-0.35 | 0.80-1.10 | 0.15-0.25 |
| 4140 | 0.38-0.43 | 0.75-1.00 | ≤0.04 | ≤0.05 | 0.15-0.35 | 0.80-1.10 | 0.15-0.25 |
Mechanical Properties
| Grade | Condition | Tensile strength Mpa(min) | Yield stength Mpa(min) | Elongation %(min) |
| 1020 | CW | 414 | 483 | 5 |
| SR | 345 | 448 | 10 | |
| A | 193 | 331 | 30 | |
| N | 234 | 379 | 22 | |
| 1025 | CW | 448 | 517 | 5 |
| SR | 379 | 483 | 8 | |
| A | 207 | 365 | 25 | |
| N | 248 | 379 | 22 | |
| 4130 | SR | 586 | 724 | 10 |
| A | 379 | 517 | 30 | |
| N | 414 | 621 | 20 | |
| 4140 | SR | 689 | 855 | 10 |
| A | 414 | 552 | 25 | |
| N | 621 | 855 | 20 |
Bundled package On bundle of steel tube shall be the same in batch number.steel grade and specification.the rest of tubing less than one bundle should be tied into small bundles The weight of each bundle should be less than 50kg.The max weight cannot exceed 80kg of the bundle If there are special requirements. When the length of the steel tube is greater than or equal to 6m.with at least 8 strapping bands for each bundle, divided into 3 groups and 3-2-3 When the length of the steel tube is less than 6mand each bundle is tied at least 5 knots and divided into 3 groups which are 2-1-2 When the length of the tube is greater than or equal to 3m, and each bundle is tied with at least 3 bands.divided into 3 groups, 1-1-1 showed below.Wooden box package The wooden box is suitable for cold rolling or cold drawing seamless steel tube, polished hot rolled stainless steel tube. When the outer diameter of steel pipe is greater than or equal 10mm, the maximum weight of the container should be 50kg. When the outer diameter of steel pipe is less than or equal 10mm,the maximum weight of the container should be 30kg.
