HR3C钢高温时效过程中的析出相  

PRECIPITATES IN HR3C STEEL AGED AT HIGH TEMPERATURE

作　　者：方园园[1] 赵杰[1] 李晓娜[1,2] 

机构地区：[1]大连理工大学材料科学与工程学院,大连116085 [2]大连理工大学三束材料改性教育部重点实验室,大连116085

出　　处：《金属学报》2010年第7期844-849,共6页Acta Metallurgica Sinica

基　　金：国家高技术研究发展计划资助项目2006AA04Z421~~

摘　　要：本文研究了HR3C钢在750℃下时效500 h前后的显微组织变化和第二相的种类.研究结果表明,时效后HR3C钢中的析出物主要为形状各异的M_(23)C_6和NbCrN,其中M_(23)C_6在晶界和晶内均有析出,NbCrN以极其细微的尺寸大量弥散分布于晶内;时效过程中弥散析出的M_(23)C_6和极其细微的NbCrN提高了HR3C钢的硬度.晶内及晶界析出的M_(23)C_6晶格常数均为基体的3倍,并与基体保持完全共格的关系,晶界处部分M_(23)C_6转变成了高Cr的σ相.HR3C steel（Fe-25Cr-20Ni-Nb-N）is a new type of austenitic heat-resistant steel which has been widely used for super-heater and re-heater tubes in the ultra supercritical pressure （USC）boiler.The mechanical properties of HR3C steel were dependent on the stability of the microstructure, particularly the large amount of precipitates formed during service.This work was focused on the change of microstructure and the precipitations of HR3C steel after thermal aging for 500 h at 750℃.The results indicated that the major precipitates were variform M_（23）C_6 carbides and NbCrN nitrides.M_（23）C_6 carbides precipitated on grain boundaries and in intragranular.Fine and dispersed NbCrN nitrides were found to precipitate in intragranular.The hardness of HR3C steel had been improved through dispersed M_（23）C_6 and fine NbCrN precipitates after thermal aging for 500 h at 750℃.All the M_（23）C_6 carbides,with lattice parameter of three times of the austenite matrix,grown in a cube to cube orientation relationship with the matrix.Some of the M_（23）C_6 carbides which precipitated on grain boundaries were transformed intoσphase.

关 键 词：HR3C钢 时效 析出 显微组织 

分 类 号：TG132.33[一般工业技术—材料科学与工程]