Nd:YAG雷射銲接Ti-6Al-4V薄板之製程參數最佳化分析

An Investigation on the Optimum Parameters in Nd:YAG Laser Weld Ti-6Al-4V Thin Plates

蔡永豐(Yung-Feng Tsai)

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(2009年)

https://doi.org/10.6346/NPUST.2009.00071

摘要

本研究之目的在探討Ti-6Al-4V薄板雷射銲接處之抗拉強度與硬度，及其間的關係，並分析實驗參數之影響性。首先利用田口法直交表規劃實驗參數的配置，以銲接後之抗拉強度及銲道硬度分別為銲接品質之兩個單一目標函數。藉由田口法對此二目標函數分別進行銲接參數最佳化分析，並探討雷射加工參數對目標函數的影響趨勢。相關實驗數據並用做為分析抗拉強度與硬度之關係。整體實驗規劃分為三部分，第一部分經由前置實驗結果選定影響雷射銲接品質較為重要的八個參數，分別為氣體種類、尖峰功率、脈衝頻率、脈衝寬度、銲接速度、聚焦位置、脈衝重覆率及氣體壓力，依照田口法直交表L18（21×37）配置雷射銲接參數進行實驗。第二部份則是利用最佳化參數進行確認實驗做為分析抗拉強度與硬度之關係。第三部分則是探討最重要參數因子對銲接品質之影響趨勢。經抗拉強度與銲道硬度關係圖比對，結果顯示銲道硬度在32.8到33.1之間，銲接後的抗拉強度可以達到母材的65%到66%之間；銲道硬度在33.5到34之間，抗拉強度在母材的63.5%到64%之間。且當銲道硬度越高則銲道的抗拉強度也隨之降低。至於影響Ti-6Al-4V銲接品質較重要的參數則分別為脈衝頻率及氣體種類。本研究的過程及結果對於雷射銲接Ti-6Al-4V薄板之加工品質可提供實質上的協助及參考。

關鍵字

雷射銲接 ； Ti-6Al-4V薄板 ； 最佳化參數 ； 田口法

並列摘要

The purpose of this study is to investigate the tensile strength and hardness and their relationship at the welded portion in laser welding Ti-6Al-4V thin plates. The experiments are arranged with an orthogonal array of Taguchi method and used to explore for the objective of tensile strength and the objective of hardness respectively. The analytic procedure of Taguchi method is used to find the welding optimiged parameters combination for these two objectives separately, and the influence of each parameter on the objective was also discussed simultaneously. The overall experimental procedure is divided into three parts. In the first part, according to the preliminary tests there are eight laser welding parameters that showed stronger influence on welding quality have been selected, namely, gas type, peak power, pulse frequency, pulse width, welding speed, focus position, pulse repetition rate and gas pressure. The experiments were conducted based on the arrangement of laser welding parameters by an L18(21×37) orthogonal array of Taguchi method. In the second part, a confirmed test is carried on by using the optimiged parameters combination and the relationship between tensile strength and hardness has been conducted. In the third part, the discussion on the most important parameter affecting the weld quality tendency is investigated. Finally, the relational graph between the tensile strength and hardness has been introduced that shows the welded tensile strength achieves 65% to 66% of the parent material when hardness is HRC 32.8 to 33.1; while tensile strength achieves 63.5% to 64% as hardness is HRC 33.5 to 34. Furthermore the tensile strength of welded portion decreases as the hardness increases. The most important laser parameters affecting welding quality are pulse frequency and gas type. The developed process and obtained results in this study can provide a substantial assistance and reference for laser welding Ti-6Al-4V thin plates.

並列關鍵字

Laser Welding ； Ti-6Al-4V Thin Plate ； Optimiged Parameter ； Taguchi Method

參考文獻

[16] 程昭榮，2008，「Nd：YAG雷射銲接鎂合金最佳化參數及預測模式之探討」，碩士論文，屏東科技大學，屏東。

[35] 賴廷鏤，1999，鋁合金6061-T6銑削加工表面粗糙度最佳化切削參數研究，碩士論文，元智大學。

[43] Capello E., Chiarello P., Previtali B., and Vedani M., 2003, “Laser welding and surface treatment of a 22Cr-5Ni-3Mo duplex stainless steel,” Materials Science and Engineering, Vol. A351, pp. 334-343.

[44] Chen C. B., Lin C. T., Chang C. W., and Ho C. P., 2000, “Grey Relation for Solving Multi-Quality characteristics Problems of Taguchi Methods,” Journal of Technology, Vol. 15, No.1, pp. 25-33.

[46] Li S., 1997, “Laser welding techniques for titanium alloy sheet” Journal of Materials Processing Technology, Vol. 65, pp. 203-208.