Φ300mm S53马氏体时效强化钢环状花样低倍组织分析及工艺改进

Analysis on Ring Pattern Macrostructure of Φ300 mm S53 Ageing Strengthening Martensitic Steel and Process Improvement

6 t真空自耗炉冶炼的S53钢在Φ300 mm锻材低倍组织检测时发现了环状花样组织,组织及扫描电镜能谱分析表明:Cr、Mo等元素的偏析是造成环状花样组织的原因。通过调整真空自耗熔炼参数,熔滴短路时间由平均0.8 s降低到0.3 s,电压值由平均26 V降低到25 V,熔速由平均6 kg/min降低到4.8 kg/min,电流值由平均11500 A降低到7500 A,氦气压力由平均600 Pa降低到300 Pa,消除了S53钢环状花样组织。

A ring-shaped pattern macro-structure inΦ300 mm forged bar of S53 steel melting by a 6 t vacuum consumable enectrode furnace is found,analysis by structure and SEM shows that segregation of Cr,Mo and other elements is the cause of ring pattern formation.By vacuum consumable smelting parameters adjusted,the droplet short circuit time reducing from 0.8 s to 0.3 s on average,the voltage value decreasing from an average of 26 V to 25 V,the melting rate decreasing from an average of 6 kg/min to 4.8 kg/min,the current value decreasing from an average of 11500 A to 7500 A,helium pressure reducing from an average of 600 Pa to 300 Pa,the ring pattern structure of S53 steel is eliminated.