新闻资讯
FV520B不锈钢激光熔覆热影响区组织演变及其对力学性能的影响
发布人：上海艾荔艾金属材料有限公司www.shailiai.com
更新时间：2015-11-02
对FV520B不锈钢零件的激光熔覆热影响区进行了组织特征分析，结合过冷奥氏体连续冷却转变（CCT）实验、模拟热影响区拉伸及冲击实验，研究了热影响区组织及力学性能的演变规律和机理。
FV520B不锈钢激光熔覆热影响区组织演变及其对力学性能的影响HEAT-AFFECTED ZONE MICROSTRUCTURE EVOLUTION AND ITS EFFECTS ON MECHANICAL PROPERTES FOR LASER CLADDING FV520B STAINLESS STEEL
对FV520B不锈钢零件的激光熔覆热影响区进行了组织特征分析，结合过冷奥氏体连续冷却转变（CCT）实验、模拟热影响区拉伸及冲击实验，研究了热影响区组织及力学性能的演变规律和机理。结果表明：热影响区可以按照组织演化特点分为4个特征区域，半熔区(A区)、析出相溶解区(B区)，完全奥氏体化区(C区)，部分奥氏体化区(D区)。各区域均为马氏体组织，靠近界面区域的组织较为粗大，第二相发生溶解，硬度更高，固态相变点更低；距界面稍远区域回火马氏体增多，第二相未溶解，但有长大的趋势，硬度较低，固态相变点较高，接近原始材料。决定激光熔覆热影响区组织及力学性能的最主要因素是热循环的最高温度，最高温度越高，强度损失越大，固态相变点越低，相应硬度越高，延伸率及冲击功降低。
FV520B steel is a martensitic stainless steel developed by Firth-Vickers. With its good corrosion resistance and weldability, high strength and toughness. It has been widely used in heavy load and corrosion-resistant components such as compressor impeller, valves, fasteners and pump shafts, which are easy to be damaged because of severe service-environments. The production cycle of those expensive components are long. If we can repair and remanufacture these components, the accessional value of the products can be reserved. At the same time, it can save time, resources and funds, and reduce environmental pollutions. Laser cladding is an attractive green reconstruction technology, which is widely used for the remanufacturing of faulty metal parts. However, the heat-affected zone (HAZ) of remanufactured parts will experience cycles of heating and cooling during the cladding operation, its properties will change and may be extremely different than that of the unaffected area of the base material. Hence, the study of HAZ of FV520B steel is essential.
The laser cladding on FV520B stainless steel was conducted to investigate the microstructure and mechanical property development of HAZ. The microstructure of the HAZ was characterized by means of OM and SEM, and hardness distribution was measured. Thermo-simulation was carried out to analyze the continuous cooling transformation (CCT) diagram, which provides useful instructions to investigate the microstructure evolution of HAZ. Simulated HAZ specimens and its mechanical properties were obtained by Gleeble3500 thermal/mechanical simulator and MTS810 material testing system. The results indicate that, microstructures of the HAZ are martensite, the grain grows and second phase particles dissolve in the areas near the fusion zone. Meanwhile, its martensite start temperature lower, and hardness higher than that of the unaffected area of the base material. The maximum temperature of thermal cycle dominates the evolution of microstructure and property of HAZ. With the decrease of the maximum temperature, the solid-state transformation temperature, elongation and impact energy higher, and the hardness decrease. Thermal cycle have a little influence to the tensile strength of HAZ under the processing parameters in this study. It can be speculated that the reduction in impact toughness and elongation of the HAZ can be controlled by decreasing the scanning speed of cladding.
以上资料由上海艾荔艾金属材料有限公司提供，欢迎新老客户来电洽购。
本文来自上海艾荔艾金属材料有限公司http://www.shailiai.com，转载请注明出处。