1, high C steel + Cr and with Mo elements, can improve the hardness and wear resistance of steel, good surface finish quality, such as 9Cr3Mo.
2, due to the interaction between Fe-C-Cr three, by the preparation and thermal processing of different organizations obtained, can make the mold steel has different properties.
3, Cr in steel and other elements of the integrated role of Cr on the impact of steel. cr and Fe to form a continuous solid solution; can form intermetallic compounds б phase (FeCr), Cr + C to form a variety of carbides; and C affinity greater than Fe and Mn, and less than W and Mo
4, stainless steel and heat-resistant steel, Cr ≥ 12%, to further promote the formation of passivation film on the surface of the mold steel, enhance the mold oxidation resistance ↑ resistance to high temperature oxidation ↑ corrosion resistance ↑, Cr and Mn, N, Ni joint use, when the need to form austenitic steel, stable ferrite Cr and stable austenite Mn and Ni, need to have a certain ratio, such as Cr18Ni9; when Cr ≥ 15%, the Strength and hardness decline, elongation and section shrinkage rise. Therefore, everything has a "degree", control the element content so that the performance of the actual use of the direction of demand is the king.
5, Cr to improve hardenability can also increase the tempering stability of the mold steel.
Source：https://mp.weixin.qq.com/s/KKz5__0Btasb6d5xfByCHg
