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Chemical and mechanical properties of Q345R grade spiral steel pipe
1、 Chemical composition
The chemical composition of Q345R spiral steel pipe is based on GB/T 713-2014/2023 standard, and the main elements and contents are as follows:
Carbon (C): ≤ 0.20% (low-carbon design improves weldability);
Silicon (Si): ≤ 0.55%；
Manganese (Mn): 1.20%~1.70% (strengthening strength and toughness);
Phosphorus (P): ≤ 0.025% (low impurity control for cold brittleness);
Sulfur (S): ≤ 0.010% (low sulfur reduces thermal brittleness);
Micro alloy elements:
Niobium (Nb) ≤ 0.050%, Vanadium (V) ≤ 0.050%, Titanium (Ti) ≤ 0.030% (refine grain size, improve overall performance);
Chromium (Cr) ≤ 0.30%, nickel (Ni) ≤ 0.30%, copper (Cu) ≤ 0.30% (enhanced corrosion resistance).
2、 Mechanical performance
Strength index (thickness related):
Yield strength (σ s):
Thickness ≤ 16mm: ≥ 345 MPa；
16~36mm：≥ 325 MPa；
36~60mm：≥ 315 MPa；
60~100mm：≥ 305 MPa；
100~200mm：≥ 265~285 MPa；
Tensile strength (σ b): 470~630 MPa;
Bending strength ratio: not explicitly defined, but must meet plasticity requirements.
Plasticity and toughness:
Elongation rate (δ 5): ≥ 21%~22% (elongation at break);
Low temperature impact toughness:
0 ℃ impact energy ≥ 34 J (some standards require -20 ℃ impact energy ≥ 27 J);
High temperature performance: Yield strength ≥ 180 MPa at 500 ℃ (applicable to high-temperature equipment).
Process performance:
Weldability: Supports various processes such as manual arc welding, submerged arc welding, gas shielded welding, etc., with weld strength matching the base material;
Cold formability: Suitable for spiral steel pipe forming processes such as rolling and bending.
3、 Application Fields
Q345R spiral steel pipe is widely used in the following scenarios:
Pressure vessels: storage tanks, boiler steam drums, nuclear reactor pressure vessels;
Energy and chemical industry: oil and gas transmission pipelines, heat exchangers, separators;
Infrastructure projects: bridge load-bearing structures, high-pressure water pipes for hydropower stations;
Low temperature environment: structural components in cold regions (-20 ℃) and corrosive environments.
(Note: Some parameters may be adjusted due to thickness range, delivery status, and Z-direction performance level.)
ADD：Chengnan Industrial Development Zone, Yanshan County, Hebei Province
Domestic phone number：0086-317-6689999
International call：0086-317-6165555
E-mail:9905791@qq.com
