View source for Engineering:Autogenous welding

{{Short description|Form of welding where no additional filler material is added}}
'''Autogenous welding''' is a form of [[Chemistry:Welding|welding]] in which the filler material is either supplied by melting the base material or is of identical composition.<ref name="Copper, 29" /> The weld may be formed entirely by melting parts of the base metal, and no additional filler rod is used. 

There is some variation in the use of this term. Those bodies concerned with teaching the craft skill of welding tend to define it as using no filler rod, i.e. the technique is based purely on the base metal. Those concerned with the welded joint's [[Chemistry:Metallurgy|metallurgy]] may make no distinction between a filler rod and the base metal, provided that the final metallurgy is identical.<ref name="Copper, 29" />

Most welding processes may be either autogenous or use additional filler. Some are characteristically autogenous and avoid filler. Some [[Physics:Arc welding|arc welding]] processes, including such major process such as manual metal arc (stick) welding and [[Physics:Gas metal arc welding|MAGS]] (wire-feed) welding, cannot be used autogenously, as they rely on the consumption of a filler rod to provide the arc.

Some processes are typically autogenous. These include some gas welding processes such as [[Chemistry:Lead burning|lead burning]] (although fillers may optionally be used) and [[Engineering:Oxy-acetylene welding|oxy-acetylene welding]] in some positions, such as seam welding the edges of two overlapping sheets. Resistance welding, both [[Engineering:Spot welding|spot welding]] and seam welding, is inherently autogenous, as there is no convenient way to apply a filler. [[Engineering:Friction welding|Friction]] and laser welding have similar restrictions.

Some alloys are prone to changing their composition when heated, particularly a loss of [[Chemistry:Zinc|zinc]] from [[Chemistry:Brass|brass]] by its evaporation as vapour. In these cases, an excess of 2–3% extra zinc may be provided in the filler rod to compensate.{{sfnp|Welding, Brazing and Soldering of Copper and its Alloys|1952|pages=83–84}} Silicon may also be used as an additive to reduce this loss.{{sfnp|Welding, Brazing and Soldering of Copper and its Alloys|1952|pages=83–84}}

A few materials, such as the [[Chemistry:HY-80#Weldability|HY-80]] series of high-strength steels, require a non-autogenous process to control their metallurgy.<ref name="Roepke, 2009" /> However, advanced processes, such as [[Physics:Laser-hybrid welding|hybrid laser arc welding]], have been used to achieve the same effect autogenously.<ref name="Roepke, 2009" />

== References ==
{{Reflist|refs=

<ref name="Copper, 29" >{{Cite book
  |title=The Welding, Brazing and Soldering of Copper and its Alloys
  |publisher=Copper Development Association  |location=England
  |id=CDA Publication Nº47
  |origyear=1952
  |edition=4th
  |year=1956
  |ref={{harvid| Welding, Brazing and Soldering of Copper and its Alloys|1952}}
  |page=29
}}</ref>

<ref name="Roepke, 2009" >{{Cite journal
  |last=Roepke|first=C
  |date=August 2009
  |title=Hybrid Laser Arc Welding of HY-80 Steel
  |url=https://app.aws.org/wj/supplement/wj0809-159.pdf
  |journal=Supplement to Weld. J.
  |volume=88
  |pages=159–167
}}</ref>

}}

[[Category:Welding]]

{{Sourceattribution|Autogenous welding}}