【摘要】 利用Formastor-D全自动热膨胀记录仪测定了三种改进型 9%Cr- 1%Mo耐热钢焊缝金属的连续冷却组织转变相图 ,并用光学显微镜和透射电镜分析了各种冷却条件下的组织转变特点。结果表明 ,在很大的冷却范围内 ,三种焊缝金属的奥氏体均只发生马氏体转变 ,只有当冷速足够慢时才发生先共析铁素体转变和共析转变。其中 ,含合金元素较少的 2号焊缝金属具有最快的先共析铁素体形成冷速。研究发现 ,三种焊缝金属的奥氏体均形成板条马氏体并具有高位错密度的亚结构 ,马氏体中含有自回火产生的Fe3 C沉淀相 ,马氏体板条间有残余奥氏体的存在。先共析铁素体沿原始奥氏体晶粒边界生长 ,形成网状结构。珠光体中的碳化物为粗大的颗粒状M2 3 C6沉淀物。更多还原

【Abstract】 Formastor D autodiatomtry was used to determine the continuous cooling transformation diagram of three types of 9%Cr 1%Mo weld metals.Optical microscopy and Transmission electron microscopy were employed to observe the characters of the microsturcture transformation at different cooling rates.The results showed that the austenite of all three weld metals transformed to martensite at a very wide range of cooling rate.It could transform to pre eutectoid ferrite only at a quite slow cooling rate.Among those weld metals,the austenite of No.2 weld metal had the fastest cooling rate for pre eutectoid transformation.It was found that the martensite in three weld metals was lath martensite with high density of dislocations.Auto tempered cementite (Fe 3C) and residual austenite could also be found in martensite.The pre eutectoid ferrite transformation initiated at the original austenite grain boundaries and formed a net structure.In pearlite,the carbide was coarse spherical M 23 C 6.更多还原