摘要
利用H13棒材镦粗作为模具坯料,对镦粗后的模具坯料超声波探伤检测时发现部分坯料心部存在超标缺陷,不同部位钢材镦粗后缺陷大小有所差异。为查明缺陷原因,分别对原棒材及镦粗有缺陷坯料取样分析,利用金相显微镜、扫描电镜、电子探针显微分析仪等设备进行观察。结果表明密集粗大的一次碳化物是引起镦粗后心部缺陷的主要原因;钢锭冒口端钢材(冒口端)比非冒口端钢材(非冒口端)心部一次碳化物更密集、粗大,因此仅冒口端经镦粗后心部出现缺陷;冶炼时采用合理工艺参数是防止产生一次碳化物的主要手段;一旦出现一次碳化物,采用多次镦拔工艺成材可改善钢材心部质量。
Center defect has been found by ultrasonic testing on bars after upsetting, and defects in different parts havesome difference. In order to identify the defects, the morphology of the defect from the bars was observed by optical mi-croscopy, scanning electron microscopy and electron probe microanalysis （EPMA） before and after upsetting. The resultshows that the defect was caused by the intensive coarse primary carbides. Primary carbides in the ingot head were moreintensive and coarser than that in the ingot tail, so center defect was only found in the ingot head. Reasonable parameterscan be used to prevent primary carbides while smelting, repeated upsetting and drawing-out can be used to improve thecenter quality as the primary carbide appeared.
出处
《物理测试》
CAS
2014年第5期40-43,共4页
Physics Examination and Testing
关键词
模具钢
镦粗
超声波探伤
一次碳化物
die steel
upsetting
ultrasonic testing
primary carbide
