高强度接头螺栓感应亚温淬火及自回火工艺的研究

Study on Technique of Intercritical Hardening by Medium Frequency Induction and Self Tempering for High Strength Bolts

对高强度接头螺栓进行了中频加热感应亚温淬火及自回火工艺研究。结果表明，送料节拍由原来的１２个／ｍｉｎ提高到２０个／ｍｉｎ；在回火马氏体基体上保留有少量小块状铁素体，保证了螺栓的高强度和高塑性的良好配合。螺栓感应加热后在水中停留时间控制在５．４０～７．５０ｓ范围内，利用淬火余热进行回火，取消原工艺中的低温回火过程，提高了生产率并减少了能源消耗。新工艺处理后的螺栓性能符合ＧＢ５０９８—８５规定的１０．９级标准。在生产实际中取得了良好的经济效益。

The investigation was conducted on the technique of intercritical hardening by medium frequency induction and self tempering for the high strength bolts.The results showed that if the feeding pace was increased to 20 pieces per minute from original 12 pieces per minute and some small granular ferrites was remained on the tempered martensite matrix,a good match of high strength and high plasticity of bolts can be obtained.After medium frequency induction heated,bolts were quenched into water for 5 4～7 5 seconds,then themself tempered by remnant heat after quenching to replace low temperature tempering in the former process,which increased productivity and decreased energy consumption.The properties of bolts treated by the new process corresponded with the 10.9 grade of national standard GB 5098—85,and a great benifit has been gained in the practical production.