Hot rolling dies are divided into hammering, die forgin […]
Hot rolling dies are divided into hammering, die forging, extrusion and die casting, including hot forging dies, press forging dies, stamping dies, hot extrusion dies and metal die casting dies. In addition to the large mechanical stress, the hot-deformed mould has to withstand repeated heat and cooling, causing great thermal stress. In addition to high hardness, strength, red hardness, wear resistance and toughness, hot work die steel should also have good high temperature strength, thermal fatigue stability, thermal conductivity and corrosion resistance, in addition to high requirements. Hardenability to ensure consistent mechanical properties throughout the section.
For the die-casting mould steel, it should also have the surface layer subjected to repeated heating and cooling without cracking, and subjected to the impact and erosion of the liquid metal flow. This type of steel is generally a medium carbon alloy steel with a carbon mass fraction of 0.30% to 0.60%. It belongs to hypoeutectoid steel, and some steels become eutectoids due to the addition of more alloying elements (such as tungsten, molybdenum, vanadium, etc.). Hypereutectoid steel. Commonly used steels are chrome-manganese steel, chrome-nickel steel, chrome-tungsten steel, and the like.
Plastic moulds include thermoplastic moulds and thermoset plastic moulds. Steel for plastic moulds requires certain properties such as strength, hardness, wear resistance, thermal stability and corrosion resistance. In addition, it also requires good processability, such as small heat treatment deformation, good processing performance, good corrosion resistance, good grinding and polishing performance, good repair welding performance, high roughness, good thermal conductivity and stable working size and shape. Under normal circumstances, hot-working die steel can be used for injection moulding or extrusion moulding; cold-formed die steel can be selected for thermosetting forming and moulds requiring high wear resistance and high strength.