Abstract: The production flow sheet for test steel is 2 t medium frequency induction furnace-200 kg ESR (Φ180 mm) -annealing-upset forging to Φ325 mm-spheroidal annealing-quenching at 1050 ℃-tempering at 590 ℃，furnace cooling. The effect of 0 - 0.001 0% Mg on structure and mechanical properties of hot-working-die steel H13 (/% : 0.40-0.41C, 0.98-1.01Si, 0.29Mn, 4.95-5.08Cr, 1.21-1.22Mo, 0.91-0.93V, 0.023-0.027P, 0.006-0.007S) has been tested and studied. Results show that with increasing Mg content in steel from 0 to 0. 0010% , the average tensile strength and HRC value of test die steel H13 increases respectively from 1617.6 MPa and 45.7 to 1702.9 MPa and 47.8 ； Mg is available to increase the stability of tempered martensite in steel, in high temperature tempered die steel H13 containing Mg, a lot of tempering troostite occurs in structure and partial globular carbides with size less than 10 μm precipitate around Mg-Al inclusions, it is favourable to improvement of performance of steel.

Key words: Mg, Hot-Working Die Steel H13, Structure, Tensile Strength, Hardness

摘要： 试验钢的生产流程为2 t中频感应炉-200 kg电渣重熔(Φ180 mm)-退火-镦粗至Φ325 mm-球化退火-1050℃淬火-590℃回火,炉冷。试验研究了0~0.0010%Mg对热作模具钢H13(/%:0.40~0.41C、0.98~1.01Si、0.29Mn、4.95~5.08Cr、1.21~1.22Mo、0.91-0.93V、0.023~0.027P、0.006~0.007S)组织和力学性能的影响。结果表明,随钢中Mg含量由0提高至0.0010%时,试验模具钢H13的平均抗拉强度和HRC硬度值分别从1 617.6 MPa和45.7提高至1 702.9 MPa和47.8;Mg可以增加钢中回火马氏体的稳定性,高温回火后含Mg模具钢H13的组织中出现大量回火屈氏体,而且部分碳化物在Mg-Al夹杂物周围析出,成球形,尺寸小于10μm,有利于改善钢的性能。

关键词: Mg, 热作模具钢H13, 组织, 强度, 硬度