Nd:YAG雷射對不銹鋼鑽孔時重鑄層特性之探討

An Investigation on the Characteristics of Recast Layer in Drilling Stainless Steel by Using Nd:YAG Laser

王志文(Wang Chih-Wen)

指導教授 ： 簡文通

國立屏東科技大學/工學院/機械工程系所/碩士(2010年)

https://doi.org/10.6346/NPUST.2010.00242

摘要

本研究是利用Nd:YAG雷射對厚度1.0mm 430不銹鋼進行循圓鑽孔，探討雷射加工參數對雷射入口端之工件表面重鑄層及微裂縫等之影響特性。選定雷射加工參數包括之尖峰功率、脈衝頻率、循圓速率和氣體壓力等4項，並根據先期實驗各選定不同的數值，在搭配後進行一系列的循圓鑽孔實驗，鑽孔的孔徑為2.0 mm。當完成一次鑽孔操作後，對工件的雷射入口面進行重鑄層等之觀察、成份鑑定及量測。結果顯示雷射加工選定的參數範圍內高尖峰功率及高氣體壓力會減少熔渣之噴濺量，且熔渣型態呈葉片狀。經研磨及拋光後，於背向電子觀察及能量散佈分析儀分析雷射入口端均可發現未被氣化之重鑄層會熔附於氧化層上，且最大重鑄層厚度為8.67μm，外觀幾何型態均無固定型式。重鑄層中亦未有微裂縫之產生，僅有氧化層上出現微裂縫，此微裂縫最大長度為22.70μm，當高尖峰功率及高氣體壓力下氧化層之厚度及其上微裂縫長度，而重鑄層也亦會隨之呈遞減之趨勢。本研究的成果可提供給雷射對不銹鋼鑽孔時之相關研究及產業界應用時之參考。

關鍵字

雷射鑽孔 ； 重鑄層 ； 微裂縫 ； 氧化層

並列摘要

In this research the characteristics of recast layers and microcracks on the entrance surface influenced of each laser parameter are investigated for a trepan drilling 430 stainless steel with 1.0 mm thickness by using Nd:YAG laser. The selected laser parameters include the peak power, pulse frequency , trepanning speed and gas pressure. A 2.0 mm hole diameter used for a series of drilling experiments are conducted. After each drilling operation , an observation , components indentification and measurement of recast layers are performed . It is shown that slag amount reduces and shows leaf-like pattern with a higher peak power and a higher gas pressure . When a grinding and a polishing processes have been conducted , a recast layer without evapored and a maximum thickness 8.67 μm can be found on the laser entrance surface by using EDS analysis of a back-electron observation. It shows that no microcrack has been found on recast layers ； however , some microcracks are appeared on the oxided layers and the maximum value is 22.70μm . It also can be seen that a higher peak power and higher gas pressure would cause more oxided layer thickness and microcracks , while recast layer has a decreasing trend . The results of this research can be applied to related study or practical usage in laser drilling stainless steel.

並列關鍵字

Laser drillng ； Recast layer ； Microcrack ； Oxide layer

參考文獻

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