Difference between q345 and q235

1, the lower limit of yield strength is different:

The lower limit of yield strength for Q235 and Q345 steels is different. Specifically, the lower limit of yield strength for Q235 is 235MPa, while the lower limit of yield strength for Q345 is 345MPa. The "Q" here represents the Chinese character "qu", and the following value indicates the lower limit of the yield strength of the steel.

2. Different types of steel:

In the type of steel, Q235 and Q345 are also different. Q235 is a regular carbon steel, while Q345 is a low-alloy steel.

3. Different composition:

In terms of composition, Q235 is carbon structural steel, compared with the old standard GB700-79 grades A3 and C3. The Q345 is a low-alloy structural steel, with the old standard 1591-88 grade 12MnV, 16Mn 16MnRE, 18Nb, 14MnNb. In addition, the lower limit of yield strength for Q235 is 235 pressure, and the lower limit of yield strength for Q345 is 345 pressure.

4, the alloy content of the two is different:

In terms of alloy content, Q235 and Q345 are also different. Q235 is a regular carbon steel, while Q345 is a low-alloy steel. Q235 is carbon structural steel, compared with the old standard GB700-79 grade A3, C3. The Q345 is a low-alloy structural steel, with the old standard 1591-88 grade 12MnV, 16Mn 16MnRE, 18Nb, 14MnNb.

In actual use, Q235 is mainly used for metal structural parts, such as carburized or cyanide parts with low core strength requirements, tie rods, connecting rods, hooks, couplings, bolts and nuts, sleeves, shafts and welding parts. Because of its good comprehensive mechanical properties, low temperature performance, plasticity and weldability, Q345 is often used as low-pressure vessels, oil tanks, vehicles, cranes, mining machinery, power stations, Bridges and other dynamic load bearing structures, mechanical parts, building structures, general metal structural parts, hot rolled or normalizing use. It can be used for various structures in cold areas below minus 40 degrees Celsius