喷射成形H13钢的组织与力学性能  

MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SPRAY FORMED H13 TOOL STEEL

作　　者：张金祥[1] 黄进峰[1] 王和斌[1] 卢林[1] 崔华[2] 张济山[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《金属学报》2014年第7期787-794,共8页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展计划资助项目2011CB606303~~

摘　　要：分别采用传统铸造与喷射成形工艺制备了H13钢并对其进行了锻造和传统热处理.利用OM,SEM和XRD研究了铸造与喷射成形H13钢在不同工艺状态下组织的差异,并且在相同的热处理制度下测试了两者的常温与高温力学性能.结果表明:与传统铸造H13钢相比,喷射成形H13钢具有更好的回火稳定性、更高的室温与高温拉伸强度,室温冲击韧性提高了2倍,并且消除了带状偏析,提高了组织的等向性.喷射成形H13钢力学性能的提高主要归因于沉积态H13钢组织均匀细小,消除了宏观偏析,更没有粗大的一次碳化物,这使得淬火后基体含有更多的合金元素,分布也更均匀,从而在回火时析出的二次碳化物更弥散并且晶粒也更细.H13 steel is well-established for hot-work applications in different parts of the world, combining good hot strength, plasticity, toughness, oxidation resistance and thermal fatigue resistance due to its reasonable design of alloying elements. However, the alloying elements segregation and coarse primary carbides are serious and unavoidable in traditional cast H13 steel, which develops into band structure after the subsequent hot-working process, causing a poor isotropy, and finally reduces the service life of tool. Spray forming, as one of the rapid solidification technologies, fills the gap between casting and powder metallurgy, combining advantages of rapid solidification, and gaining a fine grained microstructure without macro-segregations. H13 steel was prepared by traditional casting and spray forming respectively, subsequently forged and conventional heat treated. The microstructures of as-cast and spray-formed H 13 steels at various stages of processing were studied by OM, SEM and XRD. Mechanical properties were tested at ambient and elevated temperatures for both steels under the same heat treatment processes. The microstructure of as-cast H13 steel is characterized by coarse dendritic structure and primary carbides, while spray forming resulted in a much refined equiaxed grain structure without segregation of carbides. Meanwhile, the as-deposited H 13 steel contains higher volume of austenite than that of the as-cast H13 steel, induced by the high cooling rate during the atomization process in spray forming. The density of the spray-formed H13 billet before and after hot-forging process are 98.2% and 99.7% respectively, indicating pores are completely eliminated. Compared to the as-cast H13, the spray-formed H13 has better temper resistance, higher room temperature tensile strength and hot strength. Moreover, the spray-formed H13 increases the room temperature impact toughness two times than that of the as-cast H13. The band structure which is obvious in the cast H13 steel can hardly be seen in the spra

关 键 词：喷射成形 H13钢 组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]