What is the effect of the composition of weather-resistant rust steel plate on heat treatment crack

What is the influence of the composition of weather-resistant rust steel plate on heat treatment crack
The carbon content and Al alloy element in weathering resistant steel plate have a key influence on the quenching cracking tendency of weathering resistant steel plate.
(1) When the carbon content of weather-resistant rust steel plate increases, the effect of internal stress becomes weaker and the effect of mechanical ground stress increases.
During heat treatment in water, the surface compressive stress of the workpiece is reduced, and the continuous function of the tensile stress inside is close to the surface. During heat treatment in oil, the surface tensile stress increases. All of this increases the tendency of heat treatment to crack.

Heat treatment cracking produced in the amount of carbon substance above 0.4%, Ms point within 330 ° C weathering rust steel plate. When the mass concentration of carbon is less than 0.4% and the Ms point is about 330℃, the weathering resistant rust steel plate does not cause heat treatment cracks.

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Practical experience in processing and manufacturing has proved that the use of weather-resistant rust steel plates of wc=0.4% can prevent heat treatment cracks of parts.
(2) The effect of Al alloy elements on quenching cracking is intricate. When the element of aluminum alloy increases, the heat transfer of weather-resistant rust steel plate decreases, and the difference of change expands. At the same time, due to the expansion of the aluminum alloy composition, the martensite is strengthened, and the ground stress can not be relaxed according to the plastic deformation, so the heat treatment thermal stress is increased, and the trend of quenching crack is increased. As everyone knows, the improvement of the original composition of aluminum alloy has improved the cutting performance of the weather-resistant rust steel plate. If the heat treatment is used with a more relaxed surface quenching substance, the quenching cracking trend can be reduced.
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In addition, some aluminum alloy elements such as vanadium and titanium have the effect of optimizing martensitic grain size, which can reduce the overtemperature trend of weather-resistant rust steel plates, and therefore reduce the trend of quenching cracking.

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