{"title":"用超声后向散射法测定具有软硬度梯度的淬火钢和淬火钢的深度","authors":"Paul Graja, N. Meyendorf","doi":"10.1115/qnde2021-74995","DOIUrl":null,"url":null,"abstract":"\n Heat treatment of steel is a common industrial procedure to alter the microstructure of a component locally. Often, only the surface of a component is heat-treated to a certain thickness such that it benefits from the high durability provided by a hardened microstructure, while the core microstructure remains ductile. The nondestructive determination of this thickness, the case-hardened depth, can be performed by evaluating the slight differences of the ultrasonic backscatter from the grains of changing size in different layers. However, current methods require a small transition zone from the hardened to the core microstructure for accurate results. In this work, a different approach for the determination of the case-hardened depth of components with a large transition zone is described. This approach utilizes ultrasonic frequencies about 20 MHz in contact technique. The ultrasound is introduced in an oblique setup with a wedge and is mode converted to the transverse mode. The statistical evaluation of the backscattering shows promising results for the determination of the case-hardened depth of hardened components with a smooth decrease of the hardness over the depth.","PeriodicalId":189764,"journal":{"name":"2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation","volume":"116 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Determination of the Case Depth by Ultrasonic Backscatter of Case and Induction Hardened Steel With a Soft Hardness Gradient\",\"authors\":\"Paul Graja, N. Meyendorf\",\"doi\":\"10.1115/qnde2021-74995\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\n Heat treatment of steel is a common industrial procedure to alter the microstructure of a component locally. Often, only the surface of a component is heat-treated to a certain thickness such that it benefits from the high durability provided by a hardened microstructure, while the core microstructure remains ductile. The nondestructive determination of this thickness, the case-hardened depth, can be performed by evaluating the slight differences of the ultrasonic backscatter from the grains of changing size in different layers. However, current methods require a small transition zone from the hardened to the core microstructure for accurate results. In this work, a different approach for the determination of the case-hardened depth of components with a large transition zone is described. This approach utilizes ultrasonic frequencies about 20 MHz in contact technique. The ultrasound is introduced in an oblique setup with a wedge and is mode converted to the transverse mode. The statistical evaluation of the backscattering shows promising results for the determination of the case-hardened depth of hardened components with a smooth decrease of the hardness over the depth.\",\"PeriodicalId\":189764,\"journal\":{\"name\":\"2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation\",\"volume\":\"116 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2021-07-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1115/qnde2021-74995\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1115/qnde2021-74995","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Determination of the Case Depth by Ultrasonic Backscatter of Case and Induction Hardened Steel With a Soft Hardness Gradient
Heat treatment of steel is a common industrial procedure to alter the microstructure of a component locally. Often, only the surface of a component is heat-treated to a certain thickness such that it benefits from the high durability provided by a hardened microstructure, while the core microstructure remains ductile. The nondestructive determination of this thickness, the case-hardened depth, can be performed by evaluating the slight differences of the ultrasonic backscatter from the grains of changing size in different layers. However, current methods require a small transition zone from the hardened to the core microstructure for accurate results. In this work, a different approach for the determination of the case-hardened depth of components with a large transition zone is described. This approach utilizes ultrasonic frequencies about 20 MHz in contact technique. The ultrasound is introduced in an oblique setup with a wedge and is mode converted to the transverse mode. The statistical evaluation of the backscattering shows promising results for the determination of the case-hardened depth of hardened components with a smooth decrease of the hardness over the depth.