关键词: M2髙速钢, 2 t电渣锭, Φ183 mm锻坯, 偏析, 过热, 针孔缺陷

Abstract: The Φ183 mm round billet of high speed steel M2 (/% ： 0. 86C, 0. 39Si, 0. 32Mn, 0. 015P, 0. 006S, 6. 00W, 4. 00Cr, 4. 80Mo, 1. 85V) is forged from 2. 0 t ESR ingot （Φ500 mm). The nondestructive detect defect ratio of forged billet of steel M2 is 33. 3% ~ 69.23% and the main defect is pinhole at center position of billet. Analysis results show that due to producing overheating of billet during heating and forging process the segregation of ingot forms pinhole defect. With process measures including decreasing the ESR current from 8 000 → 6 800 A to 7 000 → 6 000 A to decrease remelting speed, decreasing the beginning forging temperature from 1 070 ~ 1 090 °C to 1 030 ~ 1 060 °C and decreasing the end forging temperature from 960 〜980 °C to 900 〜950 °C to decrease the center temperature of forging billet, the nondestructive detective defect ratio of 0183 mm forged billet of steel M2 decreases from 50% to 5. 71% .

Key words: High Speed Steel M2, 2 t ESR Ingot, Φ183 mm Forged Billet, , Segregation, , Overheating, Pinhole Defect