Talk about roll selection
What aspects should be considered in the selection of roller materials
Roll is an important component that determines the efficiency of the rolling mill and the quality of the rolling material. It is an important part of the rolling mill. It uses the pressure generated when the roll rolls to roll the steel. So what factors do we usually need to consider when making rolls in terms of material selection?
1, the roll must have a good bite, so the thickness of the slab is required to be large.
2, roll selection material must have good thermal cracking resistance and thermal fatigue resistance;
3, the material for the roller diameter is large, the length of the roller body is long, and the rolling force is high
4, the material is required to have high fracture resistance and high strength.
5, because the rough rolling and finishing rolling are completed in the same frame, it must be taken into account that the thickness of the rolled piece is large and the width is small when the rough rolling.
Roll operating conditions
Roll is a tool that causes plastic deformation of metal, and it is an important consumption part that determines the efficiency of rolling mill and the quality of rolling material. The following small series introduces their respective working conditions about cold and hot rolls, respectively, as follows:
First, cold roll working conditions
Cold roll in the working process needs to withstand a lot of rolling cycle stress, strong friction, etc. The working conditions of cold roll are mainly:
1, the roller surface needs to have a high and uniform surface hardness, usually the hardness needs to be greater than 62HRC
2, need to have a deep hardening layer, and the hardness of the roller edge must be relatively low;
3, roll neck has low hardness
4, the cold roll should have enough resistance to the cracking and spalling caused by torsional stress, bending stress, shear stress;
5, should have high wear resistance, contact fatigue strength, fracture toughness and thermal impact strength.
Second, hot roll working conditions
The hot roll often works in a high temperature environment of 700 ° C ~ 800 ° C, and it can withstand strong rolling forces. Its working conditions are usually as follows:
1, the hot roll material must have high hardenability
2, must have a low coefficient of thermal expansion
3, must have high heat conductivity and high temperature yield strength;
4, must have high oxidation resistance and high temperature creep strength;
5, it should have excellent tempering resistance and uniform surface hardness
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