| 高洁净度齿轮钢中非金属夹杂物的检测方法 |
| |
| 作者姓名： | 肖娜 惠卫军 张永健 赵晓丽 陈鹰 |
| |
| 作者单位： | 1.北京交通大学机械与电子控制工程学院，北京 100044 |
| |
| 摘 要： | 研究了一种方便可靠的夹杂物评估方法:利用合适电化学充氢后的拉伸试样获取夹杂物并与极值统计法相结合估算不同体积钢中非金属夹杂物的最大尺寸并预测疲劳强度。研究选用工业生产的高洁净度20Cr2Ni4A齿轮钢，将淬火+低温回火态的标准拉伸试样进行电化学充氢，使拉伸断口由于氢脆现象存在一些以粗大非金属夹杂物为中心的脆性平台，从而可方便快捷地在扫描电子显微镜下对夹杂物的类型、尺寸和分布进行检测，并利用极值统计法对钢中的最大夹杂物尺寸进行评估。为了验证该方法的准确性，采用传统金相法和旋转弯曲疲劳试验对钢中非金属夹杂物进行了检测，结果表明，使用本文所提出的夹杂物评估方法预测的钢中最大夹杂物尺寸及疲劳强度与疲劳试验结果相吻合。因此，该方法有望成为预测高洁净度高强度钢中最大夹杂物尺寸及其疲劳强度的一种有效方法。
|
| 关 键 词： | 最大夹杂物尺寸评估 氢脆 极值统计法 齿轮钢 高洁净度钢 |
| 收稿时间： | 2019-07-15 |
Detection of nonmetallic inclusion in high-strength gear steel with high cleanliness |
| |
| Affiliation: | 1.School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China2.Central Laboratory, Central Iron and Steel Research Institute, Beijing 100081, China |
| |
| Abstract: | It is well known that large-sized nonmetallic inclusion seriously affects the mechanical properties of high-strength steels, particularly the fatigue properties. Therefore, significant efforts have been made to enhance the fatigue properties of gear steels by improving the cleanliness and, thus, reducing the size and the number of inclusions in steels. However, an effective inclusion inspection method is particularly important because of the relatively low-rate emergence of large-sized inclusions in highly clean steels. Herein, a new inclusion inspection strategy was proposed using a properly hydrogen-charged tensile specimen combined with the application of the statistics of extreme value (SEV) method, which can be used to conveniently and reliably estimate the maximum inclusion size in any volume of high-strength steel and its fatigue strength. A commercial heat of 20Cr2Ni4A gear steel with high cleanliness was used to verify the proposed method. Standard tensile specimens were quenched, tempered at low-temperature, and then properly charged with electrochemical hydrogen. It is found that there were many embrittled platforms, generally with large inclusions on the fracture surfaces of the specimens after normal tensile testing because of the trapping of the charged hydrogen around inclusion and the occurrence of hydrogen embrittlement. The size, composition, and distribution of these inclusions can be analyzed using a scanning electron microscopy, thus, the maximum inclusion size can be predicted using the SEV method. To verify the accuracy of the proposed method, additional inclusion rating methods of conventional optical metallographic observation and high-cycle fatigue testing were conducted. Using the proposed method, it was confirmed that the predicted maximum inclusion size and fatigue strength are consistent with that obtained via the rotating bending fatigue test. Therefore, the proposed method is a promising, efficient, and reliable for use in high-strength steels with high cleanliness to inspect the maximum size inclusion and predict fatigue strength. |
| |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《》浏览原始摘要信息 |
|
点击此处可从《》下载全文 |
|
