The steel used for fasteners can be divided into hot-rolled steel and cold-rolled steel according to its processing process.
Here, let's first introduce the processing process of hot rolled steel: hot rolling. Hot rolling is the plastic deformation of metal billet through high temperature and pressure to obtain the required shape and size. In this process, the metal billet is first heated to a high temperature, the temperature will be higher than its recrystallization temperature, and then through the roller system to transfer the billet to the mill, through a series of roller rolling, so that the billet gradually thin and change shape, and finally become the required sheet, strip, profiles and other products.
The main feature of hot rolling is that it can greatly reduce the energy consumption of metal deformation, reduce the cost, and the metal plasticity is high during hot rolling, the deformation resistance is low, the work hardening is not obvious, and it is easy to roll.
In addition, hot rolling is commonly used in large ingot, large reduction rolling, the production rhythm is fast, the output is also large, can be large-scale production; Hot rolling can also transform the cast structure into the processing structure, thus greatly improving the plasticity of the material; The rolling method of hot rolling also determines the anisotropy of the rolled sheet, such as the longitudinal, transverse and high direction of the material has obvious performance differences, the material has deformation structure and recrystallization structure, and has obvious directivity in the punching performance.
Because of these characteristics of hot rolling, the classification and application of hot rolled steel are as follows:
Structural steel: steel structural components, Bridges, ships, vehicles and other production;
Weather resistant steel: need to add special elements (such as P, Cu, C, etc.) to obtain good corrosion resistance and atmospheric corrosion resistance, mostly used in containers, special vehicles, building structures and other fields;
Steel for automobile structure: high strength steel plate with superior stamping and welding performance;
Hot rolled special steel: carbon steel, alloy steel and tool steel for general mechanical structure, which can be used for the production of various mechanical parts after heat treatment engineering;
High pressure vessel steel plate: good processing performance and compressive strength, mostly used in the production of high pressure gas pressure vessels;
Stainless steel plate: good corrosion resistance, mostly used in the food industry, surgical equipment, aerospace, petroleum, chemical and other fields.
