Nb对2000 MPa级桥索钢热变形行为的影响  

Effects of Nb on Thermal Deformation Behavior of 2000 MPa Grade Bridge Cable Steel

作　　者：黄世伟 Huang Shiwei(Tong Yuan Design Group Co.,Ltd.)

机构地区：[1]同圆设计集团股份有限公司

出　　处：《宽厚板》2025年第1期6-11,共6页Wide and Heavy Plate

摘　　要：对含Nb和无Nb两种高碳桥索钢进行连续冷却相变与等温相变试验,通过光学显微镜、扫描电子显微镜和宏观硬度计等手段分析相变试样。连续冷却相变试验结果表明:随着冷却速度的加快,高碳桥索钢的硬度增加,同时马氏体组织增多,Nb元素通过抑制碳元素的扩散并细化晶粒,延缓相变过程,导致CCT曲线右移;此外,由于Nb元素的固溶作用可强化材料的晶格结构,因此导致马氏体相变点的提高。等温相变试验结果表明:随着终冷温度的提升,马氏体含量增多,导致材料的硬度增大,但无Nb钢的硬度大于含Nb钢;同时,Nb的加入降低珠光体相变点,通过增大高碳桥索钢过冷度,使珠光体的片层间距减小。The tests of continuous cooling transformation and isothermal transformation are carried out on the two types of high carbon steel for bridge cable with and without Nb element,the transformation specimens are analyzed by means of optical microscope,scanning electron microscope and macrohardness tester.The results of the continuous cool-ing transformation test show that with the increase of the cooling rate,the hardness and martensite of the high carbon steel for bridge cable increase,Nb element delays the phase transformation process by inhibiting the diffusion of carbon elements and refining grains,resulting in the right shift of CCT curve In addition,due to the solid solution functioning of Nb element,the lattice structure of the material is strengthened,so the martensitic phase transformation point is in-creased.The results of the isothermal transformation test show that with the increase of final cooling temperature,the hardness of the material increases due to the increase of martensite content,but the hardness of Nb-free steel is greater than that of Nb steel.At the same time,the addition of Nb reduces the phase transformation point of pearlite,and de-creases the lamellar spacing of pearlite by increasing the degree of supercooling of the high-carbon steel for bridge ca-ble.

关 键 词：高碳桥索钢 连续冷却相变 等温相变 

分 类 号：TG1[金属学及工艺—金属学]