The working conditions of hot work dies are mainly hot work dies including hammer forging die, hot extrusion die and die casting die three types. So and cold work is not the same, the use of different places, but the production we will also find that some factors will affect its thermal resistance, which is it?
Generally speaking, the main factors that affect the thermal fatigue resistance of die steel are.
1, The thermal conductivity of steel
The high thermal conductivity of steel can make the mold surface metal heat degree is reduced, thus reducing the thermal fatigue tendency of steel. It is generally believed that the thermal conductivity of steel and carbon content, high carbon content when the thermal conductivity is low, so hot work die steel should not use high carbon steel. In the production is usually used in the carbon steel (C0.3%5 ~ 0.6%) carbon content is too low, will lead to a decline in the hardness and strength of steel, is also unfavorable.
2, The impact of the critical point of steel
Usually the higher the critical point of steel (Acl), the lower the tendency of steel to thermal fatigue. Therefore, generally by adding alloying elements Cr, W, Si, cited to improve the critical point of steel. Thus improve the thermal fatigue resistance of steel.
Do we know the performance of hot work die steel when we use it? Here to give you a proper introduction to everyone, I believe that through the analysis can let you have a certain understanding of this product.
1. red hardness in the high-temperature state of the work of the hot work mold, the requirements to maintain the stability of its organization and performance, so as to maintain a high enough hardness, this performance is called red hardness. Carbon tool steel, low-alloy tool steel can usually maintain this performance in the temperature range of 180 ℃ ~ 250 ℃, chromium-molybdenum hot work die steel generally in the temperature range of 550 ℃ ~ 600 ℃ to maintain this performance. The hardness of the steel depends mainly on the chemical composition of the steel and heat treatment process.
2. hardness is the main technical index of die steel, die in the role of high stress want to keep its shape and size unchanged, with a high enough hardness. Cold work die steel in room temperature conditions generally maintain the hardness in HRC60 or so, hot work die steel according to its working conditions, generally required to maintain in the HRC40 ~ 55 range. For the same steel, in a certain range of hardness values, hardness and deformation resistance is proportional; but with the same hardness value and composition and organization of different steel, its plastic deformation resistance may have significant differences.
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