10CrNi3MoV船用钢热冲压成形表层渐变微观结构与抗冲击性能

采用电子显微镜（SEM）、力学性能测试等手段，分析了10CrNi3MoV船用钢热冲压成形前后微观结构变化，及热冲压成形后材料表层渐变微观结构和里层马氏体结构产生原因与变化规律。研究表明，在热冲压成形过程中，10CrNi3MoV船用钢受急剧的冷热交互作用及高温氧化脱碳等的影响，其表层由里到表依次形成以完全马氏体、马氏体与铁素体的混合组织、铁素体组成的渐变微观结构，里层则形成以均匀的板条状的马氏体组织为主的微观结构。10CrNi3MoV船用钢热冲压成形后其表层渐变微观结构，能有效的降低结构的峰值冲击力，保证了内层强度大的马氏体材料不至于过早失效，而材料较平缓的结构峰值力及逐层失效的特点性，使热冲压成形后的成形件保持较高的吸能能力和抗冲击性能。

Gradually Changing Surface Microstructure and Impact Resistance of Hot Stamping 10CrNi3MoV Marine Steel

Microstructural changes of 10CrNi3MoV marine steel before and after hot stamping were detected by testing devices such as scanning electron microscope(SEM) and mechanics, the formation causes and law of gradually changing surface microstructure of hot-formed material and those of the interior martensite structure were analyzed. The study shows that in the10CrNi3MoV marine steel hot and cold by sharp interaction and the influence of high temperature oxidation decarburization, etc, in the surface layer formed by the table to ferrite, ferrite and martensite in the hybrid organization, fully martensitic gradient of microstructure,the inner layer is formed isgiven priority to with uniform lath martensite organnization of microcosmic structure in hot stamping process.The gradually changing surface microstructure formed in 10CrNi3MoV marine steel after hot stamping makes the material hardness increases sharply from surface to interior within the 0-0.25mm surface depth scope, and the hardness is maintained at 40-45HRC after reaching the 0.25mm depth; the material malleability decreases evidently from surface to interior within the 0-0.25mm surface depth scope, with the change amplitude being great, and the decrease amplitude is obviously reduced at the 0.25-0.50mm depth scope, and becomes very small after the 0.50mm depth is reached; the role of its gradually changing surface microstructure and the display of large malleability characteristic by the soft outer layer prevent the interior high-strength martensite from premature failure in the impact process, and enable a gentle structural peak value, and the gentle impact level and the gradual failure of the material enable the structure to keep a high energy absorption capacity and impact resistance. This indicates that hot-formed 10CrNi3MoV marine steel combines the excellent properties of single-phase materials, and is suitable for structural members that should withstand impact and absorb energy.