Q: What are the common quality inspection items of Q355 plate?
A: The common quality inspection items are:
Chemical composition analysis: detect the content of C, Si, Mn, P, S and other elements.
Mechanical property test: tensile test, yield strength test, elongation test, impact test.
Dimension inspection: detect thickness, width, length, flatness, etc.
Surface quality inspection: check whether there are defects such as cracks, folds, scratches, and inclusions on the surface.
Non-destructive testing: ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT), etc., to detect internal or surface defects.**
Q: What is ultrasonic testing (UT) of Q355 plate?
A: Ultrasonic testing is a common non-destructive testing method. It uses ultrasonic waves to propagate in the plate. When the ultrasonic waves encounter internal defects (such as cracks, inclusions, porosity), they will be reflected, refracted or scattered. By detecting the reflected signals, the position, size and shape of the defects can be determined. Q355 plates used in important structures (such as bridges, pressure vessels) usually need to pass ultrasonic testing.
Q: What is the flatness requirement of Q355 plate?
A: According to GB/T 3274-2017, the flatness tolerance of Q355 plate is: for plates with thickness ≤10mm, the flatness tolerance is ≤3mm/m; for plates with thickness 10-40mm, the flatness tolerance is ≤2mm/m; for plates with thickness >40mm, the flatness tolerance is ≤1mm/m. For plates with higher flatness requirements, we can provide leveling services.
Q: What are the surface quality requirements of Q355 plate?
A: The surface of Q355 plate should be smooth and clean, without visible defects such as cracks, folds, scratches, inclusions, and bubbles. Minor surface defects (such as slight scratches, pits) that do not affect the use are allowed, but the depth of the defects shall not exceed 1/2 of the thickness tolerance, and the total thickness after repair shall not be less than the minimum allowable thickness.
Q: What quality certificates can be provided for Q355 plate?
A: We can provide the following quality certificates according to customer requirements:
Mill Test Certificate (MTC): issued by the steel mill, including chemical composition, mechanical properties, dimension, delivery state and other information.
Third-party inspection certificate: issued by international authoritative inspection institutions such as SGS, BV, TUV, including inspection results of quality, quantity, packaging, etc.
CE certificate: for products exported to the European Union, to prove that the product complies with the relevant regulations of the European Union.
ASTM certificate: for products exported to the United States, to prove that the product complies with the ASTM standard.**