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Q355D material steel pipe
Chemical composition and mechanical properties of Q355D spiral steel pipe material
1、 Chemical composition
Carbon (C): ≤ 0.20% (some standards allow ≤ 0.18%)
Silicon (Si): ≤ 0.55%
Manganese (Mn): 1.20%~1.70%
Phosphorus (P): ≤ 0.025%
Sulfur (S): ≤ 0.025%
Alloy elements:
Chromium (Cr), nickel (Ni), copper (Cu): all ≤ 0.30%
Molybdenum (Mo): ≤ 0.10%
Niobium (Nb): ≤ 0.07%, Titanium (Ti): ≤ 0.20%, Aluminum (Al): ≥ 0.015%
Note: C-grade steel has stricter control over impurities such as phosphorus and sulfur than B-grade steel, with a carbon equivalent (Ceq) of ≤ 0.45% to ensure welding performance.
2、 Mechanical performance
Yield strength (Rp0.2): ≥ 355 MPa
Tensile strength (Rm): 470~630 MPa (some standards have an upper limit of 760 MPa)
Bending strength ratio (Rp0.2/Rm): ≤ 0.90, plastic reserve
Elongation (A): ≥ 22% (longitudinal specimen)
Impact toughness:
Impact energy at room temperature: ≥ 34 J
Low temperature toughness: -20 ℃ impact toughness must meet the contractually agreed indicators (some standards require ≥ 27 J)
3、 Other technical requirements
Manufacturing process:
Adopting spiral submerged arc welding (SAWH) process, the weld seam needs to pass non-destructive testing, TVRT radiographic testing, with a coverage rate of 100%
After welding is completed, a hydrostatic pressure test is required, and the test pressure shall be carried out according to the standard requirements
The residual height of the weld seam is ≤ 3.2mm, and there are no defects such as cracks or lack of fusion on the inner and outer surfaces.
Application scenarios:
High pressure fluid transportation: oil and gas pipelines (requiring 3PE anti-corrosion treatment)
Heavy machinery: cranes, load-bearing components of construction machinery
Low temperature environment: bridges and building structures in cold regions
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
