The selection of materials for cold-formed steel products is based on user needs. In order to be able to produce a qualified product, the roll profile design must correctly formulate the cold-forming process according to the characteristics of the material. In the process of developing the roll forming process, the following issues need to be carefully studied.
A. Chemical composition of raw materials:
Different materials have different chemical composition, and each composition will have different effects on the properties of steel. Special attention should be paid to the chemical composition of the materials used in the roll design of unconventional new products. According to its characteristics, the influence of different elements on the processing and forming process should be fully considered. E.g:
The strength and other properties of carbon steel mainly depend on the form in which carbon exists and the shape, size, and distribution state of carbides, that is, it mainly depends on the metallographic structure of the steel. Due to the influence of raw materials used in smelting, smelting methods and process operations, a small amount of other elements often exist in carbon steel, such as silicon, manganese, sulfur, phosphorus, copper, chromium, nickel, and so on. These elements are generally considered as impurities or residual elements of carbon steel, rather than as alloying elements. Some of these elements have a beneficial effect on steel, and some have adverse effects, such as copper, chromium, nickel, etc., which have a negative impact on the cold-bending forming and welding performance of carbon steel.
The alloy elements dissolved in the solid solution will generally increase the hardening rate of the cold-bending forming process of the steel, make the steel strip harder and more brittle, which is very unfavorable to the cold-bending forming process.
Sulfur is generally considered to be one of the harmful elements remaining in steel. Sulfur easily leads to thermal cracking of the weld. It is only easy to be oxidized during the welding process. SO2 gas is generated and the wing side escapes, which results in a lot of pores in the weld metal.