铸造低合金钢回火焊道技术适用性判别分析

Discriminant Analysis on the Applicability of the Temper Bead Welding for Casting Low Alloy Steel

回火焊道技术是通过第二层焊道的热循环来改善第一层焊道的组织和性能的焊接技术,但目前尚无明确标准规定其适用范围。以A217 WC6和A217 WC9钢为对象,采用Gleeble热模拟试验判断二次回火对两种铸造低合金钢性能的影响规律,进而用回火焊道技术制造焊接试样,进行焊态、热处理态下的组织和性能对比试验。试验结果表明,A217 WC6钢在一次高温热循环后,冲击功从70 J提升至126 J,硬度值从154 HV10增至375 HV10。二次热循环后,A217 WC6钢的硬度整体降低,回火峰值温度对其性能有显著影响。相比之下,A217 WC9钢的冲击功从77 J降至52 J,硬度值从182 HV10增至364 HV10,二次热循环对其性能影响不显著。焊接试样的性能和硬度变化趋势与Gleeble热模拟试验一致。由此得到结论:Gleeble热模拟试验可以判断钢种是否适用于回火焊道技术;A217 WC6钢较A217 WC9钢更适合采用回火焊道技术进行修复。

To investigate the applicability of temper bead welding technology in the repair of cast low-alloy steels,Gleeble thermal simulation tests were employed to assess the influence of secondary tempering on the performance of A217 WC6 and A217 WC9,two types of cast low-alloy steels.Subsequently,welding samples were fabricated using temper bead welding technology,and the microstructure and performance under as-welded and heat-treated conditions were compared.The results indicated that after a single high-temperature thermal cycle,the impact energy of A217 WC6 steel increased from 70 J to 126 J,and the hardness value rose from 154 HV10 to 375 HV10.Following the second thermal cycle,the hardness of A217 WC6 steel decreased overall,with the tempering peak temperature significantly affecting its performance.In contrast,the impact energy of A217 WC9 steel dropped from 77 J to 52 J,and the hardness value decreased from 182 HV10 to 364 HV10,with the second thermal cycle having an insignificant effect on its performance.The trends in performance and hardness changes of the welding samples were consistent with those of the Gleeble thermal simulation tests.It is concluded that Gleeble thermal simulation tests can determine the suitability of steel for temper bead welding;A217 WC6 steel is suitable for repair using temper bead welding technology,while A217 WC9 steel is not as suitable.