激光重熔功率对不锈钢改性层性能影响研究

Study on the Effect of Laser Remelting Power on the Microstructure of Stainless Steel Modified Layer

为研究激光功率对316L不锈钢改性层微观组织结构和耐腐蚀性能的影响,采用纳秒脉冲激光对不锈钢表面进行重熔试验。建立激光重熔不锈钢瞬态非线性温度场模型,研究过程中的温度分布及变化规律,并通过试验探究激光功率对改性层微观形貌、元素分布及耐腐蚀性等影响规律。结果表明:不锈钢表面经过激光重熔生成了一层铬和铁氧化物,基体相由α-Fe向γ-Fe转变;当激光功率为5 W时,重熔生成的改性层微观形貌最佳、耐腐蚀性能最强。在激光作用下,不锈钢的微观组织结构致密化,晶核变大、晶粒细化,不锈钢表面的Cr、Mn等元素固溶于奥氏体中,产生微观组织较为致密且耐腐蚀元素含量较多的改性层。

In order to investigate the effect of laser power on the microstructure and corrosion resistance of 316L stainless steel modified layer,nanosecond pulse laser remelting experiments were conducted on the surface of stainless steel.The transient nonlinear temperature field model of laser remelting stainless steel was established to study the temperature distribution and variation rule during the remelting process.The influence of laser power on the micro morphology,element distribution and corrosion resistance of the modified layer was explored through experiments.The result indicated that a layer of metal oxide including chromium and iron was formed on the surface of stainless steel after laser remelting,and the substrate was transformed fromα-Fe toγ-Fe phase.When the laser power is 5 W,the microstructure of the modified layer and its corrosion resistance is the best.Under laser action,the microstructure of stainless steel becomes denser with larger crystal nuclei and finer grains.Elements such as chromium and manganese on the surface of stainless steel are solidly dissolved in austenite,resulting in a modified layer with a denser microstructure and a higher content of corrosion-resistant elements.