Standard:DIN 17175 : Seamless Steel Tubes For Elevated Temperatures
As far as DIN 17175 is concerned, steels that have a good mechanical properties at a higher temperature, up to 6 00 °C, and even under long-term load, are called heat-strength steels.
DIN 17175 St35.8 Seamless Steel Tubes can be used to manufacture steam boilers, pipes, pressure vessels and instruments operating at temperatures up to 600 ° C and at high temperatures.
ST35.8 STEEL PIPE MECHANICAL PERFORMANCE
| Grade | C | Si | Mn | P | S | Cr | Mo |
| St35.8 | ≤0.17 | 0.10-0.35 | 0.40-0.80 | ≤0.040 | ≤0.040 | / | / |
| St45.8 | ≤0.21 | 0.10-0.35 | 0.40-1.20 | ≤0.040 | ≤0.040 | / | / |
| 15Mo3 | 0.12-0.20 | 0.10-0.35 | 0.40-0.80 | ≤0.035 | ≤0.035 | / | 0.25-0.35 |
| 13CrMo44 | 0.10-0.18 | 0.10-0.35 | 0.40-0.70 | ≤0.035 | ≤0.035 | 0.70-1.10 | 0.46-0.65 |
| 10CrMo910 | 0.08-0.15 | ≤0.50 | 0.40-0.70 | ≤0.035 | ≤0.035 | 0.20-0.25 | 0.90-1.20 |
ID TOLERANCE:
| Project | Standard | Size range | Tolerance |
| Outer diameter | DIN17175 | Hot rolled steel pipe | OD ≤ 100mm | ± 0.75%( Min ± 0.5mm ) |
| OD＞ 100~ 320mm | ± 0.9% |
| Cold drawn steel pipe OD ≤ 120mm | ± 0.6%( Min ± 0.25mm ) |
| Wall thickness | DIN17175 | OD ≤ 130mm | WT ≤ 2Sn | +15%~-10% |
| WT ＞ 2Sn~4Sn | +12.5%~-10% |
| WT ＞ 4Sn | ± 9% |
| 130 ＜ OD ≤ 320mm | WT ≤ 0.05OD | +17.5%~-12.5% |
| 0.05OD ＜ WT ≤ 0.11OD | ± 12.5% |
| WT ＞ 0.11OD | ± 10% |
ST35.8 STEEL PIPE DELIVERY CONDITION
1. NBK(+N)
after cold forming, eventually above phase transition point, in a protective atmosphere of annealing oxidation medium
2. GBK(+A)
after cold forming, annealing in non oxidizing medium protective gas
3. BK(+C)
the final heat treatment after cold forming, therefore small steel pipe plastically, the plastically degree does not guarantee
4. BKW(+LC)
after final heat treatment, a tiny cold drawing deformation, continue again when machining steel pipe allowed inside certain limits cold deformation(bending, flaring)
5. BKS(+SR)
have a stress relief after cold forming, heat treatment, steel pipe can be carried out within a certain limit in the appropriate processing again
ST35.8 STEEL PIPE SUPPLY STATUS
The 17175 St35.8 Seamless Steel Tubes Will be delivered through a suitable heat treatment. heat treatment includes:
- Normalizing
- Annealing
- Tempering; from the quenching temperature, it is not cold, but then tempered
- Adjust the mass by the isothermal transformation method.
Original material test
A thin sheet should be taken at the top end of each round or square bar ingot for a pickling test to determine if the top end is adequately cut. Ultrasonic testing can also be performed on the shrinkage hole as selected by the supplier.
Test:
- Chemical composition verification test
- hydrostatictest
- Tensile test
- Notched impact test
- Yield strength test
- Ring test
- Nondestructive testing
