Skip to content

Module 1: Welding Science Fundamentals

Overview

This module introduces the underlying science and mechanics of arc welding, with emphasis on the similarities and differences between GMAW and GTAW processes. Students will understand how the arc is initiated and sustained, how shielding gas protects the molten puddle and influences arc stability, the metallurgical changes that occur in the heat affected zone, weld joint design principles, and filler metal selection based on base metal properties.

Learning Objectives

  1. Explain arc physics in both GMAW and GTAW contexts
  2. Describe the role of shielding gas in arc stability and weld quality
  3. Understand heat affected zone (HAZ) metallurgy and its effects on mechanical properties
  4. Identify common weld joint types and their design advantages
  5. Explain filler metal classification systems (AWS A5.18, A5.10)
  6. Relate base metal properties to process and filler selection

Module Structure

  • Slide 1: Arc Physics in GMAW vs. GTAW
  • Slide 2: Shielding Gas Function & Selection
  • Slide 3: Heat Affected Zone & Metallurgy
  • Slide 4: Weld Joint Types & Design
  • Slide 5: Filler Metal Classification & Selection

Assessment

  • 10-question module quiz (arc physics, gas function, HAZ effects)
  • Activity: Weld joint identification and design analysis
  • Analysis: Match base metal to appropriate filler metal
  • Hands-on: Examine cross-section of welds showing HAZ

Time Allocation

  • Instructor Delivery: 4.5 hours
  • Guided Activities: 1.5 hours
  • Self-Study & Assessment: 1 hour
  • Total Module Time: 7 hours

Key Standards Referenced

  • AWS A3.0M: Standard Welding Terms and Definitions
  • AWS C1.1M: Specification for Welding Procedure and Performance Qualifications
  • ANSI Z49.1: Safety in Welding, Cutting, and Allied Processes

Prerequisites

  • Plasma Cutting Unit (Unit 05) is helpful but not required
  • Basic metallurgy and electricity fundamentals

Resources

  • OEM equipment manuals (power supply, torch, controls)
  • AWS A3.0 glossary
  • AWS A5.18 (MIG filler) and AWS A5.10 (TIG filler) specification sheets
  • Metallurgical cross-sections showing HAZ (carbon steel, stainless, aluminum)
  • Weld joint type reference diagrams
  • Video demonstrations of both processes

Module Version: 1.0 Created: 2026-03-15