全国服务热线Ni Cr alloy and Fe Cr Al alloy have different microstructure and high temperature characteristics. How to grasp the hot workability of alloy is an important link in the bloom and hot rolling production.
The hot workability of Fe Cr Al alloy is as follows
Fe Cr Al alloy has ferrite structure at high temperature. Carbides, nitrides and other precipitates in the alloy at room temperature will be partially dissolved. Fe Cr Al alloy shows the following hot working characteristics. These characteristics should be paid attention to when making hot working process.
1) The ferrite grains begin to grow from 720 ℃ to 780 ℃, and grow rapidly at 900 ℃, and grow rapidly above 1000 ℃. After coarsening, the hot working plasticity of ferritic alloy decreases significantly. Therefore, it is necessary to shorten the residence time in the high temperature zone, especially the residence time above 1000 ℃.
2) Carbides, nitrides and other precipitates in ferritic alloys precipitate during high temperature cooling, which will reduce the cold working plasticity of the alloy. Therefore, the alloy should be rapidly cooled after high temperature blooming and hot rolling to reduce the amount of compounds and precipitates and improve the cold working plasticity of hot rolled products.
3) The thermal conductivity of ferrite alloy is 1.5 times that of austenite alloy. Therefore, the Fe Cr Al alloy can be heated faster to shorten the heating time.
4) The coefficient of linear expansion of ferrite alloy is about 60% lower than that of austenite alloy. The ability to bear the thermal stress produced by quenching and heating is weak, so the temperature of ingot and billet heating should not be too high, so as to avoid the internal stress caused by excessive temperature difference will lead to cracks in the alloy.
To sum up, the above high temperature properties of Fe Cr Al alloy should be considered and paid attention to in the development of bloom and hot rolling process.
