Q stands for the yield of this material, and 235 refers to the yield value of this material, which means about 235. And the yield value will decrease as the thickness of the material increases. Q235A, Q235B, Q235C, Q235D are mainly different in impact temperature. Q235A level, no impact; Q235B level, 20 degree normal temperature impact; Q235C level, 0 degree impact; Q235D level, -20 degree impact. At different shock temperatures, the shock values are also different.

In terms of its deoxidation method, F means boiling steel, b means flat killed steel, and z means killed steel. Boiling steel is incompletely deoxidized steel with poor plasticity and toughness. Welded structures made of this material are prone to cracks in the joints when subjected to dynamic loads. It is not suitable to work at low temperature, sometimes it will harden. In contrast, killed steel is fine and uniform, with good plasticity and toughness.