Clandia Sim22/7/2016Heriot-Watt University

Types of Arc Welding

• SMAW – Shielded metal arc welding

• GTAW – Gas tungsten arc welding

• GMAW – Gas metal arc welding

• SAW – Submerged arc welding

Background

• Rod keep melting

• Covered electrode creates shield

• Avoid oxidation which contaminate the weld

• Spray of metal transfer to the joint >> spatter

SMAW – Sheilded / stick

SMAW – Sheilded / stick

• AWS Electrode E6011

• E – electrode

• 60 – 60,000 psi tensile strength of deposited weld metal

• Digit 1 – welding position suitable for use (all position)

• Digit 1 – covering type and current type (greater number, better shielding)

• Other examples: 6010, 6013, 7018, 7024

SMAW – Sheilded / stick

• Tungsten electrode, not consumable

• Argon or helium mixture shielding

• With or without filler metal (similar to base metal) depend on thickness

GTAW – Tungsten / TIG

GTAW - Tungsten

• MIG / MAG welding

• Arc melts continuously as wire fed automatically

• Sheilded gas: argon, helium, CO2 or gas mixtures

GMAW – Gas metal / MIG

• 3 ways of metal transfer:

GMAW – Gas metal / MIG

1. Short-circuit

• Low heat input

2. Globular

• High heat input• Hard to control the droplets

size

3. Axial Spray

• High heat input• Flat horizontal position

• Highly control axial spray is called pulsed spray transfer (GMAW-P)

GMAW – Gas metal / MIG

GMAW – Gas metal / MIG

• Examples on AWS Class and Product Name

SAW - Submerged

• Arc and molten metal are covered by a layer of powder through chute

• Prevent sparks, spatter, intensive UV radiation and fumes

• Flux is part of the powder, thermal insulator

• Allow deep penetration of heat

• Flat, horizontal position due to the powder

• Circular welds on pipe possible if they rotated

SAW - Submerged

• Consumable electrode wire fed automatically

• 1.5 – 10 mm diameter

• Unfused powder can be recovered, treated and refused

• High speed, productivity, high quality welds

• Shipbuilding, pressure vessels

SAW - Submerged

Thank you very muchAny questions? Just comment