Introduction to Welding Mr. Byron All images acquired from weldingteacher.com.

Introduction to WeldingMr. Byron

All images acquired from weldingteacher.com

Welding

• Welding joins two pieces of metal by the use of heat, pressure, or both

• Brazing or soldering involves a filler metal which has a lower melting point than the metal pieces to be joined

• Metal cutting is done by heating the metal with a flame and directing a stream of pure oxygen along the line to be cut

Coalescence: to cause to unite into one mass

Weld

• A homogeneous bond between 2 pieces of metal

• The strength of the welded joint exceeds or equals the strength of the original base metal

Types of Welding

• Arc Welding• Shielded Metal Arc Welding (SMAW)• Metal Inert Gas (MIG)• Tungsten Inert Gas (TIG)• Plaza Arc Welding (PAW)• Submerged Arc Welding (SAW)• And Many More…..more than 80 in all

The Weldment

Welding Safety

All information acquired from Sheridan College

Health Hazards

• Gases and Fumes…

• Welding “Smoke” is a mixture of very fine particles called fumes and gases

• Welding “Smoke” contains fumes and gases including…• Chromium, nickel, arsenic, asbestos, manganese, silica, beryllium, cadmium,

nitrogen oxides, phosgene, acrolein, fluorine compounds, carbon monoxide, cobalt, copper, lead, ozone, selenium, and zinc

Gases and Fumes

• Generally, gases and fumes come from…• Base material & filler material• Coatings & paints• Shielding gases & chemical reactions• Process & consumables used• Contaminants in the air

• It is difficult to list all the health effects of welding exposures because the fumes may contain so many different substances that are known to be harmful

• The individual components of welding “smoke” can affect just about any part of the body, including the lungs, heart, kidneys, & central nervous system

Exposure to welding “smoke” may have…

• Short-term effects…• Effects happen at or very soon after exposure

• Long-term effects• Effects may happen after repeated overexposures or an extended time after

the exposure

Short-term Exposures

• Exposure to zinc, magnesium, copper and copper oxide can cause Metal Fume Fever

• Symptoms of metal fume fever may occur 4 to 12 hours after exposure

• Symptoms include…• Chills, thirst, fever, muscle ache, chest soreness, coughing, wheezing, fatigue,

nausea, and metallic taste in mouth

Short-term Exposures

• Welding “smoke” can irritate the eyes, nose, chest and respiratory tract

• Welding “smoke” can cause coughing, wheezing, shortness of breath, bronchitis, pulmonary edema, and pneumonitis

• Welding “smoke” can cause nausea, loss of appetite, vomiting, cramps, and slow digestion

Short-term Exposures

• Exposure to cadmium can be fatal in a short time

• Ultraviolet radiation can react with oxygen and nitrogen to form ozone and nitrogen oxides

• These gases are deadly at high concentrations and can also cause irritation of nose and throat and cause serious lung disease

Short-term Exposures

• Ultraviolet rays given off by welding can react with hydrocarbon solvents such as…• Trichloroethylene; 1,1,1-trichloroethane; methylene chloride; &

perchloroethylene to form phosgene gas

• Even a very small amount of phosgene gas may be deadly• Early symptoms include dizziness, chills, and cough and usually take 5 – 6

hours to appear

Short-term Exposures

• Arc welding should never be performed within 200 feet of degreasing equipment or solvents

Long-term Exposures

• Studies of welders, flame cutters, and burners have shown that welders have an increased risk of lung cancer…• and…possibly cancer of the larynx and urinary tract

• Remember… welding “smoke” can include cancer causing agents such as…cadmium, nickel, beryllium, chromium, and arsenic

Long-term Exposures

• Welders may experience a variety of chronic respiratory problems, including…• Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased

lung capacity, silicosis, and siderosis

Long-term Exposures

• Other health problems…• Heart disease, skin diseases, hearing loss, chronic gastritis, gastroduodentis,

and ulcers of the stomach and small intestine• Reproductive risks

Other Health Risks

• Heat exposure…• Heat stress, heat stroke

• Burns, eye injuries from hot slag, metal chips, sparks, and hot electrodes

Other Health Risks

• Visible light, and ultraviolet and infrared radiation• Intense light can cause damage to retina• Infrared radiation may damage the cornea and result in cataracts

• Invisible UV light can cause “arc eye” or “welders’ flash”• May include sandy or gritty eye, blurred vision, intense pain, tearing, burning

and headache

Health Risks cont.

• Permanent eye damage• Skin burns• Skin cancer• Noise• Can result in stress, increased blood pressure, may contribute to heart

disease, tiredness, nervousness, and irritability

Musculoskeletal Injuries

• Back injuries, shoulder pain, tendonitis, reduced muscle strength, carpal tunnel syndrome, white finger, and knee joint diseases

• Injuries may be caused by overhead work, vibration and heavy lifting

Electrical Hazards

• Even though welding generally uses low voltage, there is still a danger of electric shock

• Wet work areas, Cramped work spaces

• Falls, fractures and other accidents can result from electrical exposure

• Even small shock can cause brain damage• Death can occur from large shocks

Electrical Hazards

• Always use dry gloves• Always wear rubber soled shoes• Always use insulating layers• Protect yourself from surfaces that conduct electricity• When working on electrically powered machinery, make sure the frame

is grounded• Keep insulation on all welding equipment and components dry and in

good condition• Don’t change electrodes with bare hands, wet gloves or while standing

on wet or ungrounded surfaces

Fire and Explosion Hazards

• Intense heat and sparks can cause fires or explosions if in the vicinity of combustible or flammable materials

• Welding and cutting should only be performed in areas free of combustible materials such as trash, wood, paper, textiles, plastics, chemicals, and flammable dusts, liquids and gases

Fire and Explosion Hazards

• Never weld or cut on containers that have held a flammable or combustible material unless the container is thoroughly cleaned or filled with an inert gas

• A fire inspection should be performed prior to leaving a work area and for at least 30 minutes after the operation is completed

• Fire extinguishers should be nearby, of proper size, type and number for the hazards involved

Dangerous Machinery

• All machines in the area with moving parts must be guarded to prevent worker’s contact• Hair, clothing, fingers, etc.

• When repairing machinery by brazing and welding, power must be disconnected, locked out, and tagged so the machinery cannot be started up accidently

Trips and Falls

• To prevent trips and falls…• keep work areas clear of equipment, machines, cables, and hoses• Always properly maintain and use handrails• Always use and maintain safety lines, harnesses and lanyards• Always make sure that scaffolds are properly assembled and used

Welding Hazards

• Never weld or cut in explosive, flammable, combustible or other dangerous environments

• Always use all necessary Personal Protective Equipment (PPE), including, harness and lanyard, respiratory protection, eye protection, etc.

Compressed Gas Hazards

• Gas welding and cutting use a fuel gas and oxygen which are stored in high pressure cylinders

• Most fuel gases are explosive

• Pure oxygen will increase the flammability of any combustible/flammable material

Compressed Gas Hazards

• All cylinders should have caps or regulators• Pressure regulators must be designed for gas in use• Check all equipment and components prior to use• Cylinders must be stored upright and secured• Oxygen and fuel gas cylinders must be stored separately• Be aware of flashbacks and backfires• Close cylinder valves when work is completed or left unattended

during breaks, etc.

Protective Clothing

• Fire resistant gauntlet gloves• Head cap• High top hard toed shoes• Leather apron• Face shield• Flame retardant clothing• Safety Glasses

Hearing Protectors

• Ear plugs and/or muffs should be worn during noisy operations such as air arcing or grinding

Work Cited

Welding Teacher.com. N.p.. Web. 20 Aug 2014.

WY MSHA State Grant Program, . "Welding Safety.“ Sheridan College. N.p.. Web. 24 Aug 2014.