Alloy is a mixture of two or more metals and metal or non-metal synthesized by a certain method with metallic characteristics. It is generally obtained by fusion into a uniform liquid and solidification. According to the number of component elements, it can be divided into binary alloy, ternary alloy and multicomponent alloy. Two or more kinds of metals are uniformly fused together through a certain process, which is an alloy, such as copper and zinc composed of brass, copper and tin composed of bronze, copper and nickel composed of white copper, stainless steel are all alloys containing chromium, nickel and titanium and other metals.

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.

Stainless steel round steel belongs to a class of long wood, and belongs to a class of bar, the so-called stainless steel round steel refers to a uniform circular cross-section of long wood, generally about four meters long. It can be divided into light circles and black rods. The so-called light circle refers to the smooth surface and comes from the quasi-rolling treatment; The so-called black rod refers to the black and thick surface and is directly hot-rolled.