Cunha Ângela, Bartolomeu Flávio, Silva Filipe, Trindade Bruno, Carvalho Óscar
CMEMS-Center for Microelectromechanical Systems, University of Minho, 4800-058 Guimarães, Portugal.
LABBELS-Associate Laboratory, Braga/Guimarães, Portugal.
Materials (Basel). 2022 Dec 15;15(24):8979. doi: 10.3390/ma15248979.
AISI 420 martensitic stainless steel is widely used in the mould industry due to its high tensile strength, hardness, and corrosion properties. Another requirement concerning any material used for this type of application is high thermal conductivity to minimise the time between consecutive injection cycles. The surfaces of some parts of the mould may be textured and reinforced with a material with higher thermal conductivity to achieve this aim. The results of a detailed study on the texturing of annealed 420 stainless steel using a Nd:YVO fibre laser are presented in this work. The influence of the laser's processing parameters (laser power, scanning speed, number of passes, and line spacing) on the dimensions of the track, microstructure, and hardness of the modified surfaces was studied. Based on the continuity and dimensions of the machined grooves, several promising textures could be produced with laser power values from 5 to 30 W, scanning speeds of 500 to 2000 mm/s, 8 passes or more, and line spacings of 40 and 50 µm. High laser powers were responsible for the dissolution of chromium carbides in the laser tracks, the incorporation of chromium in austenite, and the consequent hardening of the microstructure.
AISI 420马氏体不锈钢因其高抗拉强度、硬度和耐腐蚀性能而在模具行业中得到广泛应用。对于用于此类应用的任何材料的另一项要求是高导热性，以尽量减少连续注射周期之间的时间。模具某些部件的表面可以用具有更高导热性的材料进行纹理化和强化，以实现这一目标。本文介绍了使用Nd:YVO光纤激光器对退火420不锈钢进行纹理化的详细研究结果。研究了激光加工参数（激光功率、扫描速度、扫描次数和线间距）对改性表面的轨迹尺寸、微观结构和硬度的影响。基于加工凹槽的连续性和尺寸，在激光功率值为5至30W、扫描速度为500至2000mm/s、8次或更多扫描次数以及线间距为40和50µm的情况下，可以产生几种有前景的纹理。高激光功率导致激光轨迹中的碳化铬溶解、铬在奥氏体中的掺入以及微观结构的随之硬化。
