The ST35.8 high-temperature pipe is a seamless carbon structural steel tube specified in the German industrial standard DIN 17175, designed for high-temperature and high-pressure environments, and equivalent to China's 20# steel (GB/T 5310 standard).
Key Characteristics
High-Temperature Performance
Max operating temp: ≤570℃ (short-term up to 600℃)
Guaranteed high-temp yield strength: ≥185MPa (at 400℃)
Chemical Composition
Carbon (C) ≤0.17% → Ensures weldability and toughness
Manganese (Mn) 0.40-1.20% → Enhances high-temp strength and creep resistance
Mechanical Properties
Tensile strength: 360-480 MPa
Room temp yield strength: ≥235 MPa
Core Applications
Boiler Systems
Superheater/reheater tubes, steam conduits (esp. for ultra-supercritical units)
Operating pressure: High-pressure boilers ≥9.8MPa
Energy & Petrochemical
Power plant boiler heating surfaces, petrochemical heat exchangers
High-temp oil/gas pipelines (temp ≤570℃)
Quality Assurance (Mandatory per DIN 17175)
| Test Item | Requirement Description |
|---|---|
| Non-Destructive Test | 100% ultrasonic or eddy current inspection |
| Hydrostatic Test | Test pressure = 1.5x design pressure |
| Dimensional Tolerance | OD ±1%, wall thickness +10%/-0% |
| High-Temp Test | 400℃ yield strength report required |
Comparison with Similar Materials
| Parameter | ST35.8 (DIN) | 20# Steel (GB) |
|---|---|---|
| Max Temperature | ≤570℃ | ≤450℃ |
| Creep Resistance | Superior | Moderate |
| Inspection | Mandatory NDT | Sampling-based |
DIN 17175 ST35.8 High Temperature Steel Pipe Factory
