选区激光熔化成型30CrMnSi钢组织和性能研究

Microstructure and Properties of 30CrMnSi Steel Manufactured by Selective Laser Melting

利用选区激光熔化(SLM)成型工艺制备了30CrMnSi合金试样,并采用金相显微镜对微观组织进行了表征,采用洛氏硬度计、材料试验机等仪器进行了性能测试,采用SEM扫描电镜分析了试样断口形貌,研究了粉末层厚对SLM成型试样的显微组织和力学性能的影响。结果表明,当激光功率为270 W,扫描间隔为0.16 mm,扫描速度为900mm/s,层厚在0.01~0.03 mm范围内变化时,30CrMnSi合金钢SLM试样内部组织为片状马氏体,并且由于Cr元素的存在,试样内部存在一部分FeCr相组织,马氏体组织随着层厚的不同,其均匀性也有差异;随着层厚的增大,试样的致密度会逐渐降低,而硬度和抗拉强度会出现先升高后降低的现象,当铺粉层厚设置为0.02 mm时,试样具有较好的综合力学性能,致密度达到86.42%,抗拉强度和硬度达到最大,分别为1931 MPa和39.12 HRC。

30CrMnSi alloy parts were prepared by selective laser melting(SLM) forming technology. The microstructure, hardness and tensile strength of the SLM samples were systematically studied by means of metallographic microscope, Rockwell tester and material testing machine. The effects of powder layer thickness on the microstructure and mechanical properties of SLM forming samples were investigated. The results show that when the laser power is 270 W,the scanning interval is 0.16 mm, the scanning speed is 900 mm/s and the layer thickness varies in the range of 0.01-0.03 mm, the internal structure of 30 CrMnSi alloy steel is flaky martensite, and a part of FeCr phase structure exists in the samples due to the presence of Cr element, and the martensite structure has different uniformity with different layer thickness. With the thickness of the layer increasing, the density of the sample gradually decreases, while the hardness and tensile strength increase first and then decrease. When the layer thickness is 0.02 mm, the sample has good comprehensive mechanical properties, the density reaches 86.42%, the tensile strength and hardness reaches the maximum of 1931 MPa and 39.12 HRC, respectively.