Round steel belongs to carbon structural steel for construction and machinery, while square steel belongs to carbon structural steel for machinery.

 Round steel belongs to carbon structural steel for construction and machinery, while square steel belongs to carbon structural

steel for machinery. Both of them are simple section steel, and their section shapes are respectively round and square. Low carbon is mainly used for
drawing wire, forging rivets, bolts, nuts and other metal products of raw materials. Medium carbon round steel and square steel
are generally used to make mechanical structural parts.