Gas Tungsten Arc Welding (GTAW) / Tungsten Inert-Gas (TIG)

Introduction Input Pre-requisites Production Batch Output Co-requisites Duration

	Facility: Free	Material: Charge / Free (*)	Mould / Pattern: N/A	Digital data: N/A
	Location: W001 Sheet Metal / Welding Workshop Contact: H.M. Leung Office: Room W105 Telephone: (852)2766 7605 Facsimile: (852)2334 4634 E-mail: ichml@polyu.edu.hk * Depends on production volume, please consult responsible staff beforehand

Introduction:

For gas tungsten arc welding, a tungsten electrode is positioned in a special holder through which inert gas flows to provide a protective shield around both the arc and the pool of molten metal. As the tungsten is not consumed at the temperatures of the arc, a separate welding rod is sometimes used to provide filler metal. Besides, the arc length remains constant so the arc is stable and easy to maintain. Good welding surface is then resulted.

In IC, gas tungsten arc welding torch can be run on a track. Constant, stable and smooth weld joint is then resulted.	For GTAW, the torch is fixed and the filler metal is automatically fed. This set up can give smooth straight welding.

Input:

Gas tungsten arc welding can be used to join similar metal. This metal includes-

• Steel
• Wrought and Cast Iron
• Aluminum Alloy
• Titanium

But it cannot be used to weld the following materials:

• Zinc Alloy
• Copper Alloy

The material to be weld must be thicker than 1 mm.

Pre-requisites:

top

The base material for welding can be produced by the following methods-

Cast Metal can be formed by-

• Die Casting
• Investment Casting
• Sand Casting
• Spin Casting

Sheet Metal can be formed by-

• Nibbling
• Notching
• Shearing

All material for welding must be free from paint, grease or rust. The following processes are usually followed by gas tungsten arc welding-

• Cleaning
• Filing (Aluminum Oxide removal)
• Joint Preparation

Production Batch:

top

Number of Product at a time: 1

Time for each run: Several minute

Output:

top

Permanently joined similar metal with a bead of solid metal at the joint. Gas tungsten arc welding forms strong bonding between metals so the joint is able to withstand large forces. The surface finish of gas weld is good. Further finishing of weld joint might not be required.

Co-requisites:

top

Duration:

top

Gas tungsten arc welding is a fast process, more time is spent on planning and joint preparation than the gas welding process. Depends on the size and geometry of the product, it usually takes less than half day to finish.