Welding Basics Manufacturing Technology HPEDSB. What is Welding? The process of joining two or more pieces of similar metals, through the application.

Welding Welding BasicsBasics

Manufacturing TechnologyManufacturing Technology

HPEDSBHPEDSB

What is Welding?What is Welding?

The process of joining two or more pieces of similar metals, The process of joining two or more pieces of similar metals, through the application of heat and sometimes filler material.through the application of heat and sometimes filler material.

Base MetalBase MetalPart 1Part 1

Base MetalBase MetalPart 2Part 2

The two pieces have been joined using a Butt JointThe two pieces have been joined using a Butt Joint

Overview of the WeldOverview of the Weld

The most important aspect of any weld is the amount of The most important aspect of any weld is the amount of penetration or the depth that the filler material fuses into the penetration or the depth that the filler material fuses into the original workpiece or parent metal.original workpiece or parent metal.

Penetration

Welding can be broken down into two sub-Welding can be broken down into two sub-categories.categories.

1. Fusion 2. Non-Fusion

Gas Welding (oxy-acetylene torch)

GMAW (Gas Metal Arc Welding)

SMAW (Shielded Metal Arc Welding)

GTAW (Gas Tungsten Arc Welding)

Brazing (oxy-acetylene torch)

Each sub-category can be broken into methods of Each sub-category can be broken into methods of weldingwelding

Any welding operation involving melting Any welding operation involving melting of the base or parent metal.of the base or parent metal.

The joining of metals without melting The joining of metals without melting the base or parent metal.the base or parent metal.

Fusion Welding # 1Fusion Welding # 1Gas WeldingGas Welding

Uses the heat created by a flame fueled by compressed acetylene gas Uses the heat created by a flame fueled by compressed acetylene gas and accelerated by compressed oxygenand accelerated by compressed oxygen

The flame is created and maintained at the end of the torch tip and The flame is created and maintained at the end of the torch tip and varied by controlling the line pressures as well as the valves for each varied by controlling the line pressures as well as the valves for each compressed gascompressed gas

Three main flame types known as:Three main flame types known as: Carburizing – too much acetylene in the mixtureCarburizing – too much acetylene in the mixture Neutral – correct mixture of acetylene and oxygen to be used for weldingNeutral – correct mixture of acetylene and oxygen to be used for welding Oxidizing – too much oxygen in the mixture, sometimes required for cuttingOxidizing – too much oxygen in the mixture, sometimes required for cutting

Oxygen TankAcetylene Tank

Oxygen Regulator Gauges

Acetylene Regulator Gauges

Torch

Friction Lighter

Shade 5 Goggles

Fusion Welding # 2Fusion Welding # 2GMAW (MIG Welding)GMAW (MIG Welding)

Gas Metal Arc WeldingGas Metal Arc Welding Metal Inert Gas WeldingMetal Inert Gas Welding Uses an electric arc to create heat for Uses an electric arc to create heat for

the welding processthe welding process Uses an automatically fed filler rod to Uses an automatically fed filler rod to

help join the pieces of metal togetherhelp join the pieces of metal together Uses shielding gas to prevent Uses shielding gas to prevent

contaminants from entering the weldcontaminants from entering the weld

Main Unit

GunGround Clamp

The circuit must be completed to The circuit must be completed to create an arc.create an arc.

Hose for Shielding Gas

1.

2.

3.

4.

5.

6.

7.

The parts of a MIG gun and the weld The parts of a MIG gun and the weld itselfitself

Direction of travelContact Tip (Copper)Wire Filler Rod

Shielding Gas / Fumes

Weld Pool

Solidified Weld

Parent or Base Metal

Fusion Welding # 3Fusion Welding # 3SMAW (Arc Welding)SMAW (Arc Welding)

Shielded Metal Arc WeldingShielded Metal Arc Welding Uses an electric arc to create the heat Uses an electric arc to create the heat

for the welding processfor the welding process Uses a consumable electrode that Uses a consumable electrode that

provides the filler material for the provides the filler material for the weldweld

Electrode can be coated to provide a Electrode can be coated to provide a shielding gas when burning off during shielding gas when burning off during the welding processthe welding process

Ground clamp

Electrode Holder

Main Unit

The circuit must be completed to The circuit must be completed to create an arc.create an arc.

Arc Welding Electrodes vary in size, Arc Welding Electrodes vary in size, type, positional use and strength. type, positional use and strength. The following example shows the The following example shows the meaning of the identifiers on a meaning of the identifiers on a common electrodecommon electrode

Electrode Tensile

strength of weld in thousands of pounds per square inch

Position

1 – All

2 – Horizontal

4 - Vertical

Power source (AC, DC or both), type of coating (low hydrogen, mineral, organic or rutile), type of arc (soft, medium or digging), penetration (light, medium or deep) and amount of iron powder in the coating.

Fusion Welding # 4Fusion Welding # 4GTAW (TIG Welding)GTAW (TIG Welding)

Gas Tungsten Arc WeldingGas Tungsten Arc Welding Tungsten Inert Gas WeldingTungsten Inert Gas Welding Uses an electric arc to create the heat Uses an electric arc to create the heat

required for the welding processrequired for the welding process Uses a torch with a tungsten electrode to Uses a torch with a tungsten electrode to

produce the heat for the weld – torch also produce the heat for the weld – torch also emits the shielding gas for the weldemits the shielding gas for the weld

Filler rod is fed in by hand which makes it Filler rod is fed in by hand which makes it a very controlled welda very controlled weld

Welding temperatures can be varied at Welding temperatures can be varied at any point during the weld via the foot any point during the weld via the foot pedal controlpedal control

The circuit must be completed to The circuit must be completed to create the arc.create the arc.

Non-Fusion Welding # 1Non-Fusion Welding # 1BrazingBrazing

Brazing is a method of joining metals together Brazing is a method of joining metals together without fasteners or by using a fusion welding without fasteners or by using a fusion welding processprocess

A filler rod (usually bronze) is heated by an A filler rod (usually bronze) is heated by an oxy-acetylene torch and melts at a lower oxy-acetylene torch and melts at a lower temperature than the materials being joined, temperature than the materials being joined, therefore allowing it to flow onto the materialtherefore allowing it to flow onto the material

When the bronze cools, it dries and forms a When the bronze cools, it dries and forms a surface bond that is quite strongsurface bond that is quite strong

Comparable to hot glue on wood productsComparable to hot glue on wood products

Welding Safety OverviewWelding Safety Overview

Proper eye protection must be worn at Proper eye protection must be worn at all timesall times Shade 10 for all Arc welding processesShade 10 for all Arc welding processes Shade 5 for brazing or gas weldingShade 5 for brazing or gas welding Welding curtains should always surround Welding curtains should always surround

you to protect the other people working in you to protect the other people working in your immediate areayour immediate area

Skin protection should also be worn Skin protection should also be worn including:including: Welding GlovesWelding Gloves Welding Apron or Welding CoatWelding Apron or Welding Coat

Prestart ChecksPrestart Checks

Dampness or water in welding areaDampness or water in welding area Leaks in gas tanks (check with soapy Leaks in gas tanks (check with soapy

water)water) Cable and hose condition (free of Cable and hose condition (free of

cracks, tears)cracks, tears) Flammable or combustible materials Flammable or combustible materials

in areain area Proper ventilation (is system turned Proper ventilation (is system turned

on)on)