Q345 Low-alloy steel

Q345 is a kind of steel material. It is a low alloy steel and is widely used in bridges, vehicles, ships, buildings, pressure vessels, special equipment, etc.

"Q" means yield strength, Q345 means this steel has a yield strength of 345MPa.

Q345 level classification:
Q345 can be divided into Q345A, Q345B, Q345C, Q345D, Q345E by grade. What they represent is mainly that the temperature of the shock is different.

Chemical composition of Q345 steel:

Grade	C	Mn	Si	P	S	V	Al
Q345A	≤0.20	≤1.7	≤0.55	≤0.045	≤0.045	0.02~0.15
Q345B	≤0.20	≤1.7	≤0.55	≤0.040	≤0.040	0.02~0.15
Q345C	≤0.20	≤1.7	≤0.55	≤0.035	≤0.035	0.02~0.15	≥0.015
Q345D	≤0.20	≤1.7	≤0.55	≤0.030	≤0.030	0.02~0.15	≥0.015
Q345E	≤0.20	≤1.7	i≤0.55	≤0.025	≤0.025	0.02~0.15	≥0.015

Mechanical properties of Q345 steel:

Grade	Tensile strength	Yield strength	Elongation
Q345D	490-675MPa	≥345MPa	≥22%
Q345B	490-675MPa	≥345MPa	≥21%
Q345A	490-675MPa	≥345MPa	≥21 %
Q345C	490-675MPa	≥345MPa	≥22%
Q345E	490-675MPa	≥345MPa	≥22%

Q345 has good comprehensive mechanical properties, acceptable low-temperature properties, good plasticity and weld ability, and is used as structures, mechanical parts, building structures, general Metal structural parts, used in hot-rolled or normalized state, can be used for various structures in cold regions below -40°C.

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