Seamless steel pipe is a steel pipe perforated from a whole round steel, and there is no weld on the surface, which is called seamless steel pipe.
Die steel is a type of steel used to make molds such as cold stamping dies, hot forging dies, and die casting dies.
Square and rectangular pipe is a name for square pipe and rectangular pipe, that is, steel pipes with equal and unequal side lengths. It is made of strip steel that has been processed and rolled. Generally, the strip is unpacked, flattened, coiled, welded to form a round tube, and then rolled into a square tube from the round tube and then cut to the required length.
Rebar is a common name for hot-rolled ribbed steel bars. The grade of ordinary hot-rolled steel bar consists of HRB and the minimum yield point of the grade. H, R, and B are the first letters of the three words, Hotrolled, Ribbed, and Bars, respectively.