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St 45.8/III-1.0405
keyword St 45.8/III-1.0405 Category Steel pipe material Related products Get a quoteChemical and mechanical properties of spiral steel pipe made of St 45.8/III-1.0405 material
1、 Chemical composition
Range/Requirements of Element Content
Carbon (C) 0.21%~0.28%
Silicon (Si) 0.10%~0.35%
Manganese (Mn) 0.40%~0.80%
Phosphorus (P) ≤ 0.035%
Sulfur (S) ≤ 0.025%
Note: The carbon content is increased to the medium carbon range (0.21%~0.28%) to enhance strength, and sulfur and phosphorus impurities are strictly limited to maintain material purity.
2、 Mechanical performance
Performance indicator numerical range/requirements
Tensile strength (Rm) 410~530 MPa (conventional)/≥ 515~1035 MPa (reinforced type)
Yield strength (ReH) ≥ 245~255 MPa (thickness ≤ 16mm)
Elongation rate (A) ≥ 21%
Hardness (HB) ≤ 229 (conventional)/≤ 300 (special process)
Remarks:
Grade III steel pipes have a wider range of tensile strength (both conventional and reinforced) and are suitable for different load scenarios;
The yield strength slightly decreases with increasing thickness and needs to be designed based on specific thickness parameters;
The elongation rate meets the standard to ensure cold processing and installation plasticity.
3、 Key characteristics
Processing performance:
Support cold stamping, bending, laser cutting, and spiral forming processes, suitable for the production of large-diameter steel pipes;
The surface can be processed into bright pipes or galvanized/epoxy coatings to enhance corrosion resistance.
Weldability:
Carbon equivalent (CE) is controllable, and low hydrogen welding materials (such as E7016) are recommended to reduce the risk of cold cracking;
Suitable for submerged arc welding (SAW) and manual arc welding, the weld quality needs to be tested by ultrasonic testing (UT).
4、 Application scenarios
Power engineering: power plant pipeline system, boiler support structure;
Mechanical manufacturing: gears, transmission shafts, hydraulic system components;
Fluid transportation: medium and high pressure oil, natural gas, and chemical pipelines.
5、 Execution standards and testing
Material standards:
Material standard: Complies with the specifications for high-quality carbon structural steel, referring to German DIN standards and Chinese GB/T 9711.
Testing requirements: Tensile testing, hardness testing, ultrasonic testing (UT), and X-ray inspection of welds are required.
Summary: The St 45.8/III-1.0405 spiral steel pipe is optimized for strength with a medium carbon composition, and has high tensile strength (up to 1035 MPa) and good plasticity. It is suitable for the fields of power, machinery, and high-pressure fluid transportation. The Level III standard further strengthens detection and process control.
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