【作者】 马跃进；

【导师】 李午申；

【作者基本信息】 天津大学 ， 材料加工工程， 2009， 博士

【摘要】 轧辊作为轧机的关键部件,在轧钢过程中消耗量极大。堆焊技术近年来在轧辊修复中得到广泛应用。经过堆焊修复的轧辊具有寿命长、使用效果好等特点,可使废旧轧辊重新利用,节约生产成本。但是堆焊产生的残余应力严重影响了修复轧辊的使用性能,使轧辊易产生剥落、裂纹等失效形式。随焊锤击工艺可以有效消除修复轧辊中的残余应力,提高轧辊表面疲劳强度,减少轧辊表面冷硬层材质不均匀和微型缺陷,从而提高修复轧辊的使用性能。电磁锤装置是实现随焊锤击工艺的关键部件,分参数检测模块、锤击参数控制电路、执行机构等三个部分。选用两种不同焊丝和堆焊试件进行试验,采用小孔法测量残余应力。首先,通过单因素试验分析了锤击力、锤击温度、锤击频率和锤头面积对残余应力的影响;其次,通过光学显微镜和扫描电镜对未锤击试件和锤击试件的显微组织进行分析和对比;利用正交试验法对随焊锤击工艺参数进行优化;最后,采用最优锤击参数,针对轧辊材料进行随焊锤击试验。研究工作及结论如下:(1)研制了针对轧辊堆焊的电磁式随焊锤击系统,试验表明运行良好。(2)经过不同规范的锤击处理,焊缝及附近的残余应力得到了不同程度的降低,在焊缝处应力降低的幅值最大,距离焊缝越远,应力降低的幅值越小。(3)焊缝金相组织分析表明:锤击处理可以细化晶粒,增加焊缝的强韧性,提高焊缝的硬度。(4)通过正交试验的极差分析得出了电磁锤随焊锤击工艺的最优方案;通过多元一次回归分析得出了残余应力与锤击参数之间的数学模型。(5)针对轧辊材料的随焊锤击试验表明,随焊锤击工艺可显著降低堆焊焊道的残余应力,改善其金相组织。更多还原

【Abstract】 As a key part of mill, roll has been consumpted significantly in the process of rolling. Surfacing welding technology has been widely used to repair roll in recent years. The roll has a long life and more effective characteristics after repair, so that through the repair of used roller, saving the cost of production. But the welding residual stress had made a serious impact on the performance of repaired roll, the form of failures include spalling and crack. The craft of weling with trailing peening can improve the performance of roll repairing by: effectively eliminate the existence of residual stress in roll, improve fatigue strength of roll surface chilled layer and reduce non-uniform and micro-defects in the material of roll surface chilled layer.Electromagnetic hammer device is the key component which to achieve with hammering, including parameter detection module, hammering parameters control circuit, implementation part.Different welding wire and specimen are selected in the test, orifice method is adopted to measure stress value. First of all, single factor analysis of hammering force, hammering temperature, hammering frequency and size of hammer on the impact of residual stress; followed by Microstructure analysis and comparison of test samples by optical microscope and scanning electron microscopy; Finally, the use of orthogonal test to the welding with trailing peening process parameters were optimized.Through the test concluded that: (1) Electromagnetic trailing peening system for welding roll is developed, experiments show that a good run. (2) In the different norms to deal with the hammer, the weld residual stress has been reduced to varying degrees, the largest amplitude is found on welding seam, the farther away from welding seam, to reduce the stress of the smaller amplitude. (3) From the weld structure can be seen: hammer can be refined grains and increase the weld strength of the weld and to improve hardness. (4) Through range analysis of orthogonal test The optimal program of welding with trailing peening process is obtained; through a multiple regression analysis to verify that resulted in residual stress and a mathematical model is built between residual stress and peening parameters. (5) The test with the optimal program on the material of roll concluded that welding with trailing peening process can be essential to reduce the surfacing weld residual stress significantly and improve its microstructure.更多还原