"Welding"

Brief History

•     Prior to the 19th Century

Welding consisted of forge welding, heating and hammering, which is rigorous manual labor .

•     Late 19th Century

Scientist and engineers apply advances in electricity to heat and join metals.

•     Early 20th Century

Prior to WWI welding was not trusted as a method to join two metals due to cracking.

•     1930’s and 1940’s

Industrial welding gains acceptance and is used    extensively in the war effort to build tanks, aircraft,  ships, etc.

•     Modern Welding

Nuclear and space age technology helps bring  welding from an art to a science.

Oxyacetylene Welding

•     Flame formed by burning a mix of acetylene and oxygen.

•     Fusion of metal is achieved by passing the inner cone of the flame over the metal.

•     Oxyacetylene can also be used for cutting metals.

Weld Defects

•     Inclusions

Impurities or foreign substances which are forced into the weld puddle during the welding process.  Has the same effect as a crack. Prevented by proper technique/cleanliness.

•     Segregation

Condition where some regions of the metal are enriched with an alloy ingredient and others aren’t.  Can be prevented by proper heat treatment and cooling.

•     Porosity

The formation of tiny pinholes generated by atmospheric contamination.  Prevented by keeping a protective shield over the molten weld puddle.

Dangers

•   Burns!

•   Electric Shock!

•   Eye Damage!

•   Poisonous fumes!

•   Overexposure to UV light!

Unusual Conditions

•   Open Air (Outdoors)

•   Underwater

   Using ARC welding, inserts gases into weld for protection.

•   Outer Space

   Uses laser welding.