Welding Cutting Demo

8/10/2019 Welding Cutting Demo

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Welding, Cutting and Brazing

Research and Created by:

V. Menchavez

JWPS Journeyman Welding &

Piping Services


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Training Objectives

Three Specific Types of Welding Modules

Methods of Arc Welding

Welding HazardsSafe Work Practices

Fire Protection & Prevention

Proper Ventilation for WeldingWelding Operators Protection

Copyright Journeyman Welding & Piping Services Permission required for reproduction or display.


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Three Specific Types of Welding

Modules

In this Welding, Cutting, and Brazing

module, three specific types of welding are

covered. These are listed below:

Oxygen-fuel gas welding and cutting

Arc welding and cutting

Resistance welding



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Oxygen-fuel gas welding & Cutting

The elements of Oxygen-fuel gas welding

and cutting:

General Requirements

Cylinders

Service Pipe Systems

Pipe System Protection



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General Requirements

Focuses on using Acetylene Safely Flammable

Unstable

Cannot be adjusted above 15 psi

Safe Work Practices

Blow out cylinder valve

Turn on cylinder valve first and

then adjust the regulator pressure screw. Never stand in front or behind

a regulator when opening the cylinder valve

Open cylinder valve slowly

The pressure adjusting screw:

Turning clockwise allows the gas

allows to flow.

Turning counterclockwise

reduces or stop the gas flow.



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General Requirements Cont.:

Safe Work Practices

Purge oxygen and acetylene passages

Light the acetylene Never use oil or grease

Do not use oxygen as a substitute for air

Keep your work area clean


Copyright Journeyman Welding & Piping Services Permission required for reproductio

n or display.


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Cylinders

Cylinder approval and marking marked for the purpose of identifying the gas content,

with either the chemical or trade name of the gas

Storage of cylinders

Storage area must be well ventilated Cylinders must be at least 20 feet from combustibles

Valves must be closed

Valve protection must be in place

Inside storage must be limited to 2,000 cubic feet.

Cylinders must be stored in upright position

Oxygen must be at least 20 feet from fuel gas

or 5 feet with a 1/2 hour fire barrier

Separate oxygen from fuel gas




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Cylinders Cont.:

Operating Procedures

Operation must emphasize the absence

of oily or greasy substances. Follow these

rules of operation:

Cylinders, cylinder valves, couplings,

regulators, hose, and apparatus shall be kept

free from oily or greasy substances.

Oxygen cylinders or apparatus shall not be

handled with oily hands or gloves.A jet of oxygen must never be permitted to

strike an oily surface, greasy clothes, or enter

a fuel oil or other storage tank.




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Service Pipe Systems

There are special requirements for service

pipe systems when using oxygen or

acetylene. Oxygen

Acetylene or Acetylene Compounds




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Pipe System Protection

The entire service pipe system must be

protected against build-up of excessive

pressure and leaks. This protection isaccomplished with:

Protective equipment

Regulators

Proper hose and hose connections.




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Pipe System Protection Cont.: Protective equipment is divided into the two

categories listed here:

Pressure Relief Devices

The pressure relief device should discharge upwards to

a safe location.

Pressure relief valves are required in fuel-gas piping

systems to prevent excessive pressure build up within

the system.




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Pipe System Protection Cont.:

Approved protective equipment shall be

installed in fuel-gas piping to prevent:

Backflow of oxygen into the fuel-gas supply

system

Passage of a flash back into the fuel-gas

supply system Excessive back pressure of oxygen in the

fuel-gas supply system.




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Arc Welding and Cutting

Definition:A fusion process wherein the coalescence of

the metals is achieved from the heat of an

electric arc formed between an electrode and

the work. Application

Installation

Operation & Maintenance



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ApplicationApplies to a large and varied group of

processes that use an electric arc as the

source of heat to melt and join metals.

Installation

Arc welding requires proper installation of

equipment.

A critical part of installation is ensuring thatproper grounding is completed.

Arc Welding & Cutting



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Operation & Maintenance

All connections to the machine shall be checkedto make certain that they are properly made.

The work lead shall be firmly attached to the

work. Magnetic work clamps shall be free from

adherent metal particles of spatter on contact

surfaces.

Coiled welding cable shall bespread out before use to avoid

serious overheating and

damage to insulation.Copyright Journeyman Welding & Piping Services Permission required for reproduction or display.


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Operation and Maintenance Cont.:

During welding operations, cables with spliceswithin 10 feet (3m) of the holder shall not beused.

Welders should not coil or loop weldingelectrode cable around parts of their body.

Cables with damaged insulation or exposedbare conductors shall be replaced.

Joining lengths of work and electrode cablesshall be done by the use of connecting means

specifically intended for that purpose. The connecting means shall have insulation

adequate for the service conditions.




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Definition: This is a group of fusion welding processes

that use heat and pressure to make the

coalescence.

The heat comes from electrical resistance tocurrent flow at the site of the weld.

The processes include:

Spot Welding

Projection Welding

Seam Welding

Resistance Welding

Note: FP&M only does spot welding.



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Spot Welding A process typically used in high-volume, rapidwelding applications.

The pieces to be joined are clamped between two electrodesunder force, and an electrical current is sent through them.

The advantages of spot welding are many andinclude the fact that it is: An economical process

Adaptable to a wide variety of materials including low carbonsteel, coated steels, stainless steel, aluminum, nickel,titanium, and copper alloys

Applicable to a variety of thicknesses A process with short cycle times

A robust process

Tolerant to fit-up variations

Resistance Welding



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Welding/Cutting Hazards

Potential Hazards

Firesmay start by hot materials igniting

nearby combustibles.

Burnsto the operator may occur if unprotected

skin comes into contact with the extremely hotwork.

Magnetic fields could easilydestroy/disrupt electroniccomponents, stored data ifnot careful.



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Welding/Cutting Hazards

Potential Hazards Cont.:

Metal fumesfrom vaporizing of the work with theextremely hot arcs may be inhaled into the workers

lungs.

Certain metals and metal oxide fumes, including zinc,

cadmium and beryllium, produce serious illnesseswhen inhaled.

Fluxes used with welding to create inert atmospheres

at the point of the weld also present inhalation

hazards. All welding and cutting must have adequate

ventilationto protect the person doing the welding

and those working around the welding area.



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Methods of Arc Welding

Three Types of Welding Methods:

Tungsten Inert Gas Welding (TIG)

Gas Metal Arc Welding (MIG)

Shielded Metal Arc Welding (SMAW)/ Stick

Welding



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Tungsten Inert Gas Welding (TIG) Definition:

TIG welding is an arc that is formedbetween a non-consumable tungstenelectrode and the metal being welded.

Gas is fed through the torch to shield theelectrode and molten weld pool.

Benefits:

Welds with or without filler metal

Precise control of weldingvariables (heat)

Low distortion

Shielding Gases:Argon

2 to 5 Hydrogen

w/Helium



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Applications Most commonly used for aluminum and

stainless steel

For steel Slower and more costly than consumablewelding

Except for thin sections or where very high

quality is needed

Tungsten Inert Gas Welding (TIG)



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Gas Metal Arc Welding (MIG) Definition:

The heat source is formed by creating anelectric arc between the work piece and a wire,

which is fed continuously into the weld pool.

Benefits:

Long welds can be made

without starts and stops

Minimal skill required

Minimal cleaning of

surface before weld

Allows welding in all

positionsCopyright Journeyman Welding & Piping Services Permission required for reproduction or display.


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Shielding Gases:

Inert

Argon, Helium

Used for aluminum alloys and stainless steels.

Active

1 to 5% Oxygen, 3 to 25% CO2

Used for low and medium carbon steels

Applications

Gas Metal Arc Welding (MIG) is used to weld all

commercially important metals, including steel,

aluminum, copper, and stainless steel.

Gas Metal Arc Welding (MIG) Cont.



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Shielded Metal Arc Welding

(SMAW)/Stick Welding

Definition: Consumable electrode coated with

chemicals that provide flux and shielding

The filler metal (here the consumableelectrode) is usually very

close in composition to

the metal being welded.



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Benefits

Simple, portable,& inexpensive

Self flux provided by electrode

Provides all position flexibility

Shielding Gases

No shield gases added

Lower sensitivity to Wind


(SMAW)/Stick Welding



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Applications

Construction, pipelines, shipbuilding,

fabrication job shops.

Used for: Steels, stainless steels, cast irons.

Not used for aluminum and its alloys, or

copper and its alloys (energy density is too

high).


(SMAW)/Stick Welding Cont.:



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UW-Eau ClaireFacilities Planning & Management

Definition: A stream of oxygen is directed against a piece of

heated metal, causing the metal to oxidize or burnaway.

Making a Cut

Mark a line as a guide. Turn on acetylene as for welding and light.

Turn on oxygen adjusting flame to neutral.

Make sure the oxygen lever flame remains neutral.

Place metal on the cutting table so metal will fallclear.

Flame Types:

Cutting



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Brazing

Definition: A process which a filler metal is placed at or between

the faying surfaces, the temperature is raised high

enough to melt the filler metal but not the base metal. The molten metal fills the spaces by capillary attraction.

Torch Brazing

Oxy-fuel torch with a carburizing flame

First heat the joint then add the filler metal



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Safe Work Practices

Electric & Gas WeldingSafety Check:

Ensure electrical cord, electrode holder

and cables are free from defectsNo cable splices within 10 feet of electrode holder.

Ensure welding unit is properly grounded.

This helps to avoid over heating.

All defective equipment shall be repaired

or replaced before using.



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Safe Work Practices

Electric & Gas Welding Cont.:

Safety Check:

Inspect hoses for cuts and frayed areas.

Set gauges to desired PSI. Ensure that sufficient PPE is madeavailable.

Locate welding screens to protect

employees ONTblock your exit. Ensure that adequate ventilation and

lighting are in place.



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Fire Protection & Prevention

Fire hazards must be removed, or Guards installed, or

Welding/cutting must NOT take place

Hot work permit should be used

outside designated areas to ensurethat all fire hazards are controlled

Use of fire watch

1/2 hour after operation ceases



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Proper Ventilation for Welding

Ventilation

Proper ventilation can be obtained either naturally or

mechanically.

Natural Ventilationis considered sufficient for welding and

brazing operations if the present work area meets these

requirements: Space of more than 10,000 square feet is provided per welder

A ceiling height of more than 16 feet.

Mechanical ventilationoptions generally fall into two basic

categories.

Low vacuum system which takes large volumes of air at lowvelocities.

High vacuum system that are captured and extracted fumes as

near to the work as possible.



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Proper Ventilation for Welding

Ensure protection from fumes

and gases by one or a

combination of the following:

Good general ventilation.

Use of a booth.

Local exhaust ventilation

on the hand piece.

Air supply to the helmet.



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Welding Operators Protection

Welding involves specialized personal

protection that must be worn every time

you perform welding operations. The

following is a list of basic PPE: Fire-resistant gloves

Aprons

Safety shoes

Helmet Ultraviolet radiation filter plate (arc welding)

Goggles with filter lenses



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Summary Major hazards include:

Fire

Burns Shock

Toxic Exposure

Follow proper procedures to prevent fires

Use appropriate engineering controls

Wear appropriate PPE



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Documents

Welding Cutting Demo