Recent advance in research for keyhole behavior during laser deep penetration welding process

Recent advance in both experimental and numerical research for keyhole dynamics during laser deep penetration welding are reviewed.X-ray observation of keyhole behavior with aid of high speed CCD imaging is the most effective method to reveal keyhole dynamics.Split beam techniques,hybrid laser welding techniques and assisting gas are usually employed to improve stability of laser welding process.Typical keyhole model includes the hole drilling model,the transient keyhole model using VOF to trace vapor/liquid interface and the transient model that based on Level Set method.The most promising of numerical models for keyhole dynamics as a class are those utilizing accurate tracking method to trace the movement of vapor/liquid interface during welding.