Post on 27-Jan-2016
description
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)