Electroslag remelting hot-working die steel and preparing method thereof

Abstract

The invention belongs to the technical field of special steel forge piece and heat treatment, and particularly relates to a low-cost electroslag remelting hot-working die steel material and a preparing method thereof. The hot-working die steel comprises, by weight percent, 0.35 to 0.40% of C, 0.10 to 0.30% of Si, 0.30 to 0.50% of Mn, 4.80 to 5.50% of Cr, 1.60 to 1.80% of Mo, 0.40 to 0.60% of V, not larger than 0.015% of P, not larger than 0.005% of S, not larger than 0.25% of Cu, not larger than 0.25% of Ni, not larger than 2ppm of [H], not larger than 20 ppm of [O], not larger than 120 ppm of[N] and the balance Fe and inevitable impurities. The forge piece impact toughness reaches above 20 J after component adjusting according to the above range from the common forge piece V port impactsmaller than 14 J, meanwhile, the early cracking resistance is greatly improved, a made mold is adjusted to reach above 10 times from the original time being short of 50000 times, in the preparing process, the water cooling superrefining treatment is adopted, the grain structure of the large-specification mold is obviously improved, the ASTM comparison method is used for measuring, the grain sizereaches above 6 stages, and the spheroidized structure reaches above AS5 stage in the North American die casting association standard NADCA#207 chart.

Description

technical field [0001] The invention belongs to the technical field of special steel forgings and heat treatment, and in particular relates to a low-cost electroslag remelting hot work die steel material and a preparation method thereof. Background technique [0002] Hot work die steel mainly refers to the alloy tool steel used in the mold for thermal deformation processing of metals, such as hot forging dies, hot extrusion dies, die-casting dies, hot heading dies, etc. Since the hot work mold works under high temperature and high pressure conditions for a long time, the mold material is required to have high strength, hardness and thermal stability, especially high thermal strength, thermal fatigue, toughness and other properties. [0003] At present, the ordinary hot work die steel provided in the domestic market generally has coarse core grains, low impact toughness, and poor early crack resistance, while the Swedish ASSAB brand ASSAB8407 die steel and the later developed...

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Problems solved by technology

[0003] At present, the ordinary hot work die steel provided in the domestic market generally has coarse core grains, low impact toughness, and poor early crack resistance, while the Swedish ASSAB brand ASSAB8407 die steel and the later developed brand DIEVAR die Although steel has improved impact toughness and other aspects, it is less economical and expensive

In addition, the currently prevailing ultra-fine treatment in China is mainly air-cooled or fog-cooled, which has a certain effect on hot work die steel with thinner specifications. However, with the development of the market, mold manufacturers have more and more demands for large-sized molds. Therefore, the air-cooling or fog-cooling ultra-fine process can no longer meet the performance requirements of large-scale molds

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