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Q345 Steel Plate
- Oct 13, 2018 -

The Q345 will decrease as the thickness of the material increases. And the homemade one may be less than 345, so the strength must be less than 345 in the mechanical design, otherwise there will be problems.

Reference standard: GB/ t1591-2008 low alloy and high strength structural steel
Note: the most obvious change in the latest standard of Q345, GB/ t1591-2008, is the change in the content of Mn elements, which is corrected to be less than or equal to 1.70 from the original standard of 1.0-1.60, and the minimum value is cancelled.
With the discovery of modern industry and the continuous progress of science and technology, various trace elements are more widely used in steel plate. Mn content is no longer the only factor affecting steel strength and mechanical properties. Therefore, the general administration of quality supervision, inspection and quarantine of the People's Republic of China and the standardization administration of China jointly issued the implementation of the low alloy and high strength structural steel standard, which eliminated the limitation of Mn content interval and only stipulated the maximum value.
For the detection of Q345 steel, on the one hand, whether the element content of steel meets the national standard; on the other hand, whether the mechanical properties of steel (yield strength, tensile test) meet the standard is the most important.
Common specification
Chemical composition
Q345A: C = 0.20, Mn = 1.70, Si = 0.50, P = 0.035, S = 0.035; Q345B: C = 0.20, Mn = 1.70, Si = 0.50, P = 0.035, S = 0.035; Q345C: C = 0.20, Mn = 1.70, Si = 0.50, P = 0.030, S = 0.030, Al = 0.015. Q345D: C = 0.18, Mn = 1.70, Si = 0.50, P = 0.030, S = 0.025, Al = 0.015. Q345E: C = 0.18, Mn = 1.70, Si = 0.50, P = 0.025, S = 0.020, Al = 0.015. All of Q345A, B, C, D and E contain Nb = 0.07, V = 0.15, Ti = 0.20, Cr = 0.30, Ni = 0.012, Mo = 0.10.

Author:Bunny Sun