摘要
利用LSSK-009型数控激光熔覆机对45钢进行激光淬火,通过正交试验方法优化了激光淬火工艺参数,研究了离焦量、电流、扫描速度等工艺参数对45钢表面硬度的影响。结果表明:影响45钢表面硬度的主要因素是离焦量,其次是电流;最佳的激光淬火工艺参数为离焦量22.5 mm、电流210 A、扫描速度300 mm/min;45钢经最佳激光淬火工艺,搭接率为44%的多道扫描激光淬火处理后,由表及里依次为完全相变硬化层、热影响区和基体,其中完全相变硬化层的组织为针状马氏体和残留奥氏体,深度为0.48 mm,宽度为1.15 mm,硬度为842 HV0.2,比45钢整体淬火提高18%,热影响区的组织由完全马氏体逐渐转变为珠光体和铁素体组织,厚度为0.1~0.2 mm,硬度从823 HV0.2到438 HV0.2呈梯度分布;相邻道与道之间的表面硬度从842 HV0.2到450 HV0.2呈梯度分布,热影响区宽度为0.3 mm。
The laser quenching experiment was operated on 45 steel by LSSK-009 CNC laser cladding machine. Effects of process parameters （defocusing amount, current, scanning speed ） on the surface hardness of the steel were studied and the optimal process parameters were obtained by using orthogonal test. The results show that the main factor influencing the surface hardness of the steel is defocusing amount while the second is current ; the optimal process parameters are 22.5 mm × 210 A × 300 mm/min ; the structure of the surface is transformed into completely hardened layer, heat affected zone and base metal by overlapping quenching （22.5 mm× 210 A × 300 mm/min, overlapping ratio 44% ） ; the metallographic structure of completely hardened layer is composed of acicular martensite and retained austenite ; the depth and width of the hardened layer is 0.48 mm and 1.15 mm, respectively,and the microhardness is 842 HV0. 2 that is 18% higher than that of integral quenching; the metallographic structure of the heat affected zone is from martensite gradually transformed into pearlite and ferrite; the thickness is 0.1-0.2 mm and the microhardness is gradually reduced from 823 HV0.2 to 438 HVO. 2. The surface hardness between tracks of overlapping quenching is gradually reduced from 842 HV0. 2 to 450 HV0.2 ; the width of heat affected zone by overlapping quenching is 0.3 mm.
出处
《金属热处理》
CAS
CSCD
北大核心
2017年第1期154-158,共5页
Heat Treatment of Metals
关键词
激光淬火
正交试验
工艺参数优化
laser quenching
orthogonal test
optimization of process parameters
