Why Q235 steel is generally not heat treated

Q235 steel is low carbon steel with carbon content of about 0.12% - 0.20%. Q235 steel does not have so much requirement on carbon content. Q235 steel is generally purchased without heat treatment. Why Q235 steel is generally not heat treated?

Q235 steel is generally used in places where a large amount of steel is needed in engineering. It is generally used after hot rolling. There are several reasons for not heat treatment for Q235 steel:

1. These situations do not need too high mechanical requirements.
2. The size of Q235 steel structures is too large, and it's not realistic for you to heat treat them.
3. Q235 steel is used for welding in many cases. After heat treatment, the heat treatment of the weld will be destroyed during the welding process.
4. The Q235 steel price is cheap, the quality requirements are relatively low. And Q235 steel is low carbon steel, the effect of heat treatment is not very good.