The DIN 1629 standard specifies the technical requirements, inspection methods, delivery status, etc. of non-alloy steel seamless steel pipes to ensure that the quality of the steel pipes meets specific requirements.
The material of DIN 1629 seamless structural steel pipes is mainly non-alloy steel, which has good mechanical properties and processing properties. According to the DIN 1629-84 standard, the grades of steel pipes include St37.0, St44.0 and St52.0, etc.
The specifications and sizes of DIN 1629 carbon steel pipes can be customized according to customer needs. Generally speaking, the outer diameter ranges from smaller sizes (such as 21.3mm) to larger sizes (such as 610mm or larger). The wall thickness can also be adjusted as needed to meet the needs of different application scenarios.
The delivery state of DIN 1629 seamless cold-drawn steel pipes can be in a state after cold processing or hot processing. For cold-processed steel pipes, the yield point and tensile strength are allowed to be reduced to a certain extent. In addition, the inner and outer surfaces of the steel pipe should be smooth, and surface defects can be repaired within the allowable deviation range of wall thickness, but repair by welding is not allowed.
Chemical composition:
| Steel Grade | Type of deoxidization (R, killed (including semi-killed)) (RR,fully killed) |
Chemical Composition, % by mass | |||||
|---|---|---|---|---|---|---|---|
| Symbol | Material Number | C | P | S | N¹) | Addition of nitrogen fixing elements (e.g.not less than 0,020% Al total |
|
| St37.0 | 1.0254 | R | 0.17 | 0.040 | 0.040 | 0.009²) | - |
| St44.0 | 1.0255 | R | 0.21 | 0.040 | 0.040 | 0.009²) | - |
| St52.0³) | 1.0421 | RR | 0.22 | 0.040 | 0.035 | - | Yes |
Mechanical properties:
| Steel Grade | Upper Yield Stress ReH for wall thickness, in mm, |
Tensile strength Rm N/mm² |
Elongation(%) A5 | ||||
|---|---|---|---|---|---|---|---|
| Symbol | Material Number | up to 16 | over 16 up to 40 | over 40 up to 65 | Longitudinal | Transverse | |
| St 37.0 | 1.0254 | 235 | 225 | 216 | 350²) to 480 | 25 | 23 |
| St 44.0 | 1.0256 | 275¹) | 265¹) | 255¹) | 420²) to 550 | 21 | 19 |
| St 52.0 | 1.0421 | 355 | 345 | 335 | 500²) to 650 | 21 | 19 |
DIN 1629 Equivalent
| DIN 1629 | EN | BS NFA 49.210/49.112 | ASTM 53 |
|---|---|---|---|
| Grade St 37 | EN 10216.1Grade P235 T1 | Grade TU 37 B TU E 220 A | Grade B |
| Grade St 44 | EN 10216.1Grade P275T1 | Grade TU 42 B TU E 235 A | Grade B |
| Grade St 52-0 | EN 10216-3Grade P355N | NFA Grade P355N | ASME SA 381 Grade Y 52 |
DIN 1629 Temperature Range
| Steel Grade | Yield stress value by working temperature(Thickness increasing) | |||
|---|---|---|---|---|
| 50℃ | 200℃ | 250℃ | 300℃ | |
| St 37 | 235-215 | 185-170 | 165-150 | 140-130 |
| St 44 | 275-255 | 215-200 | 195-180 | 165-155 |
| St 52 | 355-335 | 248-230 | 225-210 | 195-185 |
Tolerance Chart of DIN 1629 Seamless Tubes
| Execution | Size Range | OD Tolerance | Wall tolerance |
| Hot-rolled Tube | OD – 80 mmOD > 80 mmWall < 12 mmWall - 12 mm | ± 0.4 mm± 0.5 % of OD | ± 0.7 mm± (5 % x wallthickness + 0.1 mm |
| Hot-rolled peeled tube | All sizesWall < 12 mmWall - 12 mm | + 0.25/- 0 mm | ± 0.8 mm± (5 % x wall thickness+ 0.2 mm) |
| Cold Worked tubecold-rolled or cold-drawn | OD < 40 mmOD 40 - 80 mmOD > 80 Wall Thickness< 6 mm Wall Thickness6 - 8 mm Wall Thickness > 8 | + 0.30/- 0 mm*+ 0.35/- 0 mm*+ 0.40/- 0 mm* | ± 0.30 mm± 0.35 mm± 0.40 mm |
