热处理工艺对热轧包层钢筋界面结合性能的影响

Influence of heat treatment process on bonding interface property of hot rolled clad bar

采用热轧法制备不锈钢/铁屑包层钢筋,通过不同扩散退火工艺处理试件,应用光学显微镜和显微硬度仪对结合界面复合情况及复合界面附近显微硬度进行了分析。通过剪切实验测试了两金属间的复合强度,并应用SEM分析了剪切断面的微观形貌。运用扩散理论研究了不同退火工艺对Cr元素扩散的影响,应用EDS测得Cr元素的分布情况。结果表明:通过热轧制备的不锈钢/铁屑包层钢筋复合界面附近仍存在一些微小孔洞,通过扩散退火处理可以减少孔洞数量,提高复合界面剪切强度,提高温度增加保温时间可以使剪切断裂面上的剪切韧窝变得更加细密,均匀。在退火温度900℃,保温90 min,剪切强度可以达到441 MPa,同时提高退火温度增加保温时间可以增加Cr元素的扩散距离,提高复合界面的结合强度。

Influence of heat treatment process on bonding interface structure and properties of the stainless steel/iron chips clad bar prepared by hot rolling was investigated by using OM, SEM, shearing test and microhardness test. The influence of heat treatment on the diffusion of Cr was investigated based on the diffusion theory, the distribution of Cr element in the interface zone was measured by using EDS analysis. The results indicate that some small voids still exist near the bonding interface of the stainless steel/iron chips clad bar prepared by hot rolling, after the diffusion annealing treatment, the voids are reduced and the shearing strength increases. The higher the annealing temperature and the longer the holding time is, the smoother and more uniform of the shearing dimples on the shearing fracture surfaces is. With the diffusion annealing temperature of 900 ℃ and heat holding time of 90 min, the shearing strength can reach 441 MPa. Raising the annealing temperature and heat holding time, the diffusion distance of Cr and the bonding strength of the interface is increased.