冷却速率对MX246A合金组织和持久性能的影响.pdfVIP

学兔兔 Apr．2010 铸 造 VOI．59 N0．4 FOUNDRY ·355· 冷却速率对MX246A合金组织和持久性能的影响 王建涛，骆合力，李尚平，曹 栩，张喜娥 (钢铁研究总院高温所，北京 100081) 摘要：研究了浇注后不同的冷却速率对MX246A合金组织和持久性能的影响。结果表明，组织特征只受该组织形成时 的冷速影响。冷速从3O℃／min降到8℃／min时，晶粒增大，共晶 的体积分数从1．86％减少到0．86％，尺寸从30 m增大 至50 m；冷速从30℃／min降到4~C／min时，枝晶干^y 尺寸由0．93 Ixm增大至3．09 m，边界由平直转为圆滑，碳化物颗 粒变大，数量减少；枝晶干 和碳化物的尺寸和形貌对高温持久性能影响较大。当冷速为30℃／min时，获得较小尺寸、 边界平直的枝晶干_y 和细小弥散分布的碳化物，持久性能较好。 关键词：Ni l；冷却速率；微观组织；持久性能 中图分类号：TG132．3+2；TGI13．12 文献标识码：A 文章编号：1001—4977(2010)04—0355—03 Effect of Cooling Rate on Microstructure and Stress Rupture Property of MX246A Alloy WANG Jian—tao，LUO He—li，LI Shang—ping，CAO Xu，ZHANG Xi-e (High Temperature Materials Department of Central Iron and Steel Research Institute， Beijing 100081，China) Abstract： Effects of different cooling rates after pouring on micrOstructures and stress rupture properties of MX246A alloy have been studied．The results show that microstructures of MX246A alloy are influenced only by the cooling rate at the certain time when the microstructures are formed．With the reduction of cooling rate frOm 30℃／min tO 8℃／mIn。size of grains becomes Iager．volume percent of primary y decreases frOm 1．86％tO 0．86％and size of primary y increases fr0m 30 U m tO 5O um： when cooling rate reduces fr0m 30℃，min tO 4℃／min，size of dendrite stem y changes frOm 0．93 um tO 3．09 um with its morphology frOm rectangular to cellular．It iS concluded that size and morphology of dendrite stem y and carbides are the most important contributions to high temperature stress rupture property；when the cooling rate iS 30℃／min，stress rupture pr