{"title":"Cr - Mn - C - N钢铸态变形与断裂","authors":"E. E. Deryugin, N. Narkevich, Yu. F. Gomorova","doi":"10.17073/0368-0797-2022-12-879-886","DOIUrl":null,"url":null,"abstract":"The paper studies the influence of boundary conditions and the loading rate on the strain behavior and fracture of Cr – Mn – C – N austenitic steel in the cast state without additional heat treatment. Regularities of steel strain and fracture were analyzed on the basis of three-point bending test data of square-section samples with and without a notch, placed with a rib on supports. In addition to the initial stage of the steel elastic strain, this unconventional arrangement of the sample on supports enabled the detection of two more stages of strain development under the effect of an external applied force: the stage of nonlinear strain and the stage of discontinuous strain preceding the moment of sample failure. As the loading rate increases, it was demonstrated that the fracture resistance and the extent of the nonlin-ear strain stage of the sample with a notch increases, and the extent of the discontinuous strain stage decreases. The sample without a notch has a prolonged nonlinear strain stage and exhibits maximum strength in the absence of the discontinuous stage. The end of the nonlinear strain stage corresponds to the moment of sample failure. A characteristic property of cast steel under the given loading conditions is that the fracture of the sample is brittle, despite the prolonged stage of non-linear strain. Structural metallographic and diffractometric studies have shown that in all tests the steel fracture is brittle with-out traces of plastic yield. The nonlinear strain stage of steel is determined not by dislocation plastic yield, but by the mechanism of γ → αʹ transformation in austenitic interlayers between nitride and car-bide particles under the effect of an external applied force. The discontinuous strain stage of steel is associated with the process of stable crack propagation across the sample.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Deformation and fracture of Cr – Mn – C – N steel in as-cast condition\",\"authors\":\"E. E. Deryugin, N. Narkevich, Yu. F. Gomorova\",\"doi\":\"10.17073/0368-0797-2022-12-879-886\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The paper studies the influence of boundary conditions and the loading rate on the strain behavior and fracture of Cr – Mn – C – N austenitic steel in the cast state without additional heat treatment. Regularities of steel strain and fracture were analyzed on the basis of three-point bending test data of square-section samples with and without a notch, placed with a rib on supports. In addition to the initial stage of the steel elastic strain, this unconventional arrangement of the sample on supports enabled the detection of two more stages of strain development under the effect of an external applied force: the stage of nonlinear strain and the stage of discontinuous strain preceding the moment of sample failure. As the loading rate increases, it was demonstrated that the fracture resistance and the extent of the nonlin-ear strain stage of the sample with a notch increases, and the extent of the discontinuous strain stage decreases. The sample without a notch has a prolonged nonlinear strain stage and exhibits maximum strength in the absence of the discontinuous stage. The end of the nonlinear strain stage corresponds to the moment of sample failure. A characteristic property of cast steel under the given loading conditions is that the fracture of the sample is brittle, despite the prolonged stage of non-linear strain. Structural metallographic and diffractometric studies have shown that in all tests the steel fracture is brittle with-out traces of plastic yield. The nonlinear strain stage of steel is determined not by dislocation plastic yield, but by the mechanism of γ → αʹ transformation in austenitic interlayers between nitride and car-bide particles under the effect of an external applied force. The discontinuous strain stage of steel is associated with the process of stable crack propagation across the sample.\",\"PeriodicalId\":14630,\"journal\":{\"name\":\"Izvestiya. Ferrous Metallurgy\",\"volume\":\"27 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2022-12-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Izvestiya. 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引用次数: 0
摘要
研究了边界条件和加载速率对铸态Cr - Mn - C - N奥氏体钢应变行为和断口的影响。根据带肋支承的带缺口和不带缺口的方形截面试样三点弯曲试验数据,分析了钢的应变和断裂规律。除了钢弹性应变的初始阶段外,这种非传统的支撑试样排列方式还可以检测到在外力作用下的另外两个应变发展阶段:非线性应变阶段和试样失效前的不连续应变阶段。结果表明,随着加载速率的增加,带缺口试样的断裂抗力和非线性穗应变阶段增大,不连续应变阶段减小;没有缺口的试样具有延长的非线性应变阶段,在没有不连续阶段时表现出最大的强度。非线性应变阶段的结束对应于试样的破坏时刻。在给定的加载条件下,铸钢的一个特征是试样的断裂是脆性的,尽管非线性应变阶段延长了。组织金相和衍射研究表明,在所有的测试中,钢的断裂是脆的,没有塑性屈服的痕迹。钢的非线性应变阶段不是由位错塑性屈服决定的,而是由外力作用下氮化物与车相颗粒之间奥氏体层γ→α→相变机制决定的。钢的不连续应变阶段与裂纹在试样上的稳定扩展过程有关。
Deformation and fracture of Cr – Mn – C – N steel in as-cast condition
The paper studies the influence of boundary conditions and the loading rate on the strain behavior and fracture of Cr – Mn – C – N austenitic steel in the cast state without additional heat treatment. Regularities of steel strain and fracture were analyzed on the basis of three-point bending test data of square-section samples with and without a notch, placed with a rib on supports. In addition to the initial stage of the steel elastic strain, this unconventional arrangement of the sample on supports enabled the detection of two more stages of strain development under the effect of an external applied force: the stage of nonlinear strain and the stage of discontinuous strain preceding the moment of sample failure. As the loading rate increases, it was demonstrated that the fracture resistance and the extent of the nonlin-ear strain stage of the sample with a notch increases, and the extent of the discontinuous strain stage decreases. The sample without a notch has a prolonged nonlinear strain stage and exhibits maximum strength in the absence of the discontinuous stage. The end of the nonlinear strain stage corresponds to the moment of sample failure. A characteristic property of cast steel under the given loading conditions is that the fracture of the sample is brittle, despite the prolonged stage of non-linear strain. Structural metallographic and diffractometric studies have shown that in all tests the steel fracture is brittle with-out traces of plastic yield. The nonlinear strain stage of steel is determined not by dislocation plastic yield, but by the mechanism of γ → αʹ transformation in austenitic interlayers between nitride and car-bide particles under the effect of an external applied force. The discontinuous strain stage of steel is associated with the process of stable crack propagation across the sample.