IMPROVING MEASURES OF THE TRANSVERSE IMPACT ENERGY OF 1.2344 HOT WORKING DIE STEEL
The average unnotched impact energy is around 230J currently during the production process of high-end hot work mold steel in ZhangXuan Technology,which cannot meet the expected target of 300J from customer quality requirements.By analyzing the possible reasons for the low impact energy and a series of optimization measures was taken for improving impact performance.The triple EAF+LF+VOD process is employed in the electric furnace smelting to reduce the levels of harmful elements,O,N,H gases and detrimental non-metallic inclusions such as sulfides,nitrides and oxides in steel.This enhances the purity of molten steel by appropriately decreasing silicon and vanadium content which impact toughness,while further optimizing its composition.The forging stage utilizes multi-directional upsetting forging to effectively disrupt columnar dendrites within the ingot,achieving finer grain structure and improved material density.For heat treatment,water-cooled rapid cooling and ultra-fine mixing processes are adopted post-forging to minimize secondary network chain carbide precipitation due to improper cooling and stabilize grain boundary binding force.The process optimization effect is remarkable,the grain size in the steel is more uniform and fine,the band segregation basically disappears,the carbide distribution in the annealed structure is more uniform and dispersed,the number of impact fracture dimpled significantly increases,the impact energy is further increased,and the average value is more than 300 J.
hot work die steelimpact workrefining grainband segregationcarbidepurityforging deformation
万方数据
维普
