轮带是回转窑中的关键部件,铸钢毛坯单件重达40～60 t.热处理后要求外圆表面硬度达到HB 185以上.一般的正火回火工艺,由于空冷速度不够,处理后工件的硬度只能达到HB150～170.通过工艺分析,设计了用于此轮带的大流量喷雾装置.此装置结构简单,制作成本低,在一般企业都容易实现.通过使用这种自制的大流量喷雾喷枪,采用喷雾正火处理,常规回火工艺,外圆表面硬度均在HB185～220,稳定达到图纸技术条件要求.由于喷雾正火可以细化组织,经超声波探伤检查,所有的部件均没有出现晶粒粗大的缺陷.经过多次现场实践,此工艺方法稳定,而且经济效益显著.%Tyre casting in cast steel is a key part for rotary kiln.A single-piece blank weight is the range of 40-60tons.It is required that the surface hardness of the outer rings is more than HB 185.If conventional normalizing and tempering procedure is applied,the tyre's surface hardness can only be HB 150-170 due to slow air cooling rate.Through process analysis,we developed a large flow spray device with simple structure and low manufacturing cost.By using of the homemade device,the surface hardness of the outer rings for all tyres after spray normalizing treatment and routing tempering process are all at HB 180-220,reaching the requirements of technical specification.And because high efficiency cooling spray can refine structure,the ultrasonic inspection did not show grain coarse defect as well.On-site operations of many times show that the process is stable and economic benefit is dramatic.
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