我厂生产出口玛钢件已十多年了，用冲天炉熔炼，室式煤粉炉退火，退火后的超硬件达１２％左右，严重影响正常生产和工厂的效益。多年实践证明，常规热处理（见图１）后，出现超硬件的主要原因是废钢带入强碳化物形成元素铬超过规定（应≤０．０６％［１］）所致。生产中往... Our factory has been exporting Masteel for more than ten years, with cupola smelting, room-type pulverized coal furnace annealing and superhardware after annealing reaching about 12%, seriously affecting the normal production and the benefit of the factory. Years of practice have shown that the main reason for the appearance of superhard hardware after conventional heat treatment (see Figure 1) is that the scrap is brought into the form of a strong carbide forming element, chromium, exceeding the specification (≤0.06% [1]). Production to ...