發(fā)布時間：2018-03-12 07:04

  本文選題：齒輪鋼　切入點(diǎn)：化學(xué)成分　出處：《北京交通大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文以20Cr2Ni4重載傳動齒輪鋼為研究對象,主要采用頂端淬透性、熱膨脹、力學(xué)性能及滲碳變形等實(shí)驗(yàn),研究了化學(xué)成分波動對其淬透性、相變組織、力學(xué)性能及滲碳熱處理變形的影響規(guī)律,可得出以下結(jié)論:淬透性實(shí)驗(yàn)表明,碳元素對實(shí)驗(yàn)鋼淬透性的影響最大,隨著碳含量增加,硬度值增加,淬透性增大,淬透性曲線開始下降點(diǎn)向右移動;合金元素對淬透性的影響主要是通過對端淬特性值Eb的影響來實(shí)現(xiàn),隨著合金元素含量增加,淬透性曲線拐點(diǎn)位置右移。考慮合金元素交互作用而獲得的適用于實(shí)驗(yàn)鋼種的淬透性預(yù)報(bào)模型具有較高的精度。過冷奧氏體連續(xù)冷卻轉(zhuǎn)變實(shí)驗(yàn)結(jié)果表明,隨著碳元素和合金元素含量的增加,CCT曲線右移,馬氏體轉(zhuǎn)變區(qū)域增大,貝氏體轉(zhuǎn)變右移,珠光體轉(zhuǎn)變區(qū)域消失。馬氏體轉(zhuǎn)變的臨界冷卻速度約為4.3 ℃/s;在冷卻速度降低到0.86 ℃/s時,開始出現(xiàn)少量針狀貝氏體,當(dāng)冷卻速度增大時以貝氏體/馬氏體復(fù)相組織為主。滲碳熱處理變形實(shí)驗(yàn)結(jié)果表明,隨著C、Cr、Ni元素含量的增加,滲碳熱處理變形增大,其中以C元素的影響最大。淬透性和馬氏體轉(zhuǎn)變點(diǎn)是影響滲碳熱處理變形的主要因素,即隨著淬透性的提高和Ms點(diǎn)的降低,滲碳熱處理變形量和變形率均增大。
[Abstract]:In this paper, 20Cr2Ni4 heavy-duty transmission gear steel is used as the research object. The hardenability, thermal expansion, mechanical properties and Carburizing deformation of 20Cr2Ni4 heavy-duty transmission gear steel are studied, and the hardenability and phase transformation structure of 20Cr2Ni4 heavy duty transmission gear steel are studied. The effects of mechanical properties and Carburizing heat treatment deformation on the hardenability of experimental steel are as follows: the hardenability experiment shows that the hardenability of experimental steel is most affected by carbon element. With the increase of carbon content, hardness increases and hardenability increases. The hardenability curve began to move to the right, and the effect of alloy elements on hardenability was mainly realized by the effect of end quenching characteristic value E _ b, with the increase of alloy element content. The hardenability curve inflection point is shifted to the right. The prediction model for hardenability of experimental steels, which takes account of the interaction of alloying elements, has a high accuracy. The experimental results of continuous cooling transformation of undercooled austenite show that the model can be used to predict the hardenability of experimental steels. With the increase of carbon element and alloy element content, the CCT curve shifts to the right, the martensite transformation region increases, and the bainite transformation shifts to the right. The critical cooling rate of martensite transformation is about 4.3 鈩，

本文編號：1600489