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Chapter 11: Gas Tungsten Arc Welding (GTAW)

A welder in a leather welding jacket GTA Welding a butt joint using a fixture..
GTAW with a Purge Block / Photo Credit: Mass Communication Specialist 2nd Class Jason T. Poplin, PD

Overview

Whether you are welding a root pass on high-pressure piping, the intake on a Boeing 747, or building a bicycle frame, you want maximum control to ensure you produce as flawless of a weld as possible. This is where gas tungsten arc welding (GTAW) comes in. This process lets you manipulate the molten weld puddle from the palm of one hand with a high degree of accuracy using a non-consumable tungsten electrode (meaning the tungsten does not become part of the weld). Increasing and decreasing the amperage/current as you are welding also gives the welder a unique amount of control.

GTAW is also known as tungsten inert gas (TIG) welding, and some welders may still use the term “Heliarc” welding for the process’ use of helium. Argon and helium are used as shielding gasses to protect the molten weld puddle from contaminants in the air. These gasses can be used separately (100% argon or 100% helium) or as a mixture.

This chapter covers the many variables of GTAW, including the process, how it is used in the industry, and how to develop your skills using it. Most importantly, we will review how to maintain a safe working environment while using this process.

Objectives

After completing this chapter, students will be able to:

  • List the uses of the GTAW process in industry.
  • Identify equipment associated with GTAW.
  • Comprehend GTAW-specific safety concerns.
  • Recall settings and techniques for using GTAW.
  • Classify electrodes, filler metals, and shielding gasses used for GTAW.

Key Terms

  • Autogenous weld
  • Distortion
  • Inert gas
  • Laminar flow
Person wearing a protective welding jacket and welding hood, welding a practice piece vertically using GTAW
Figure 11.1. Vertical Welding With GTAW / Photo Credit: Master Sgt. Matt Hecht, PD

Attributions

  1. Chapter opening image: SIGONELLA, Sicily (July 15, 2009) Aviation Support Equipment Technician Airman Anthony Hammond, from Ft. Washington, Md. assigned to the aircraft intermediate maintenance department at Naval Air Station Sigonella, performs tungsten inert gas welding during a training evolution. by Mass Communication Specialist 2nd Class Jason T. Poplin in the Public Domain; United States government work
  2. Figure 11.1: Tungsten Arc Welding by Master Sgt. Matt Hecht in the Public Domain; United States government work

License

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Introduction to Welding Copyright © by Washington State Board for Community and Technical Colleges is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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