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[[File:Symboles soudure V.svg|300px|thumb|right|The symbolic representation of a V weld of chamfered plates in a technical drawing]]
*[[Welding]] is process of joining similar or dissimilar metals by the application of heat and sometimes pressure.
The '''symbols and conventions used in [[welding]] documentation''' are specified in national and international standards such as [[International Organization for Standardization|ISO]] 2553 ''Welded, brazed and soldered joints -- Symbolic representation on drawings'' and ISO 4063 ''Welding and allied processes -- Nomenclature of processes and reference numbers''. The US standard symbols are outlined by the [[American National Standards Institute]] and the [[American Welding Society]] and are noted as "ANSI/AWS".<ref name=greg>{{cite book|author1=E. N. Gregory|author2=Ann A. Armstrong|title=Welding symbols on drawings|url=https://books.google.com/books?id=X9cxdD6GfdIC&pg=PR7|accessdate=10 October 2011|date=20 April 2005|publisher=CRC Press|isbn=978-0-8493-3591-4|pages=7–8}}</ref> Due in part to the growth of the oil industry, this symbol set was used during the 1990s in about 50% of the world's welding operations.<ref name=greg/> An ISO committee sought to establish a global standard during this decade.<ref name=greg/>
Welding process has become popular in recent decades for joining of metal parts with each other. Many techniques and methods have been available for general as well as specific purposes.
For simplicity,it is necessary to have Symbolic Representation and conventions.
[[File:SMAW weld area.svg|thumb|Welding]]
# Square butt joint
# Single V preparation joint
# Lap joint
# T-joint.
[[File:Common joint types.png|thumb|Welding]]
==Types of symbols==
Various categories of welded joint are represented by symbols which are similar to the shape of welds to be made. These symbols are categorised as:
*Elementary symbols
*Supplementary symbols
*Combination of elementary and supplementary symbols
*Combination of elementary symbols
==Elementary Welding Symbols==
The elementary symbols are as follows:
==Supplementary Welding Symbols==
These symbols are used with elementary symbols to show the finishing of the weld joint. Such as flatness, convexity, concavity etc.
==Conventional Signs==


In [[engineering drawing]]s, each weld is conventionally identified by an arrow which points to the joint to be welded. The arrow is annotated with letters, numbers and symbols which indicate the exact specification of the weld. In complex applications, such as those involving [[alloy]]s other than [[Carbon steel|mild steel]], more information may be called for than can comfortably be indicated using the symbols alone.<ref name=greg/> Annotations are used in these cases.<ref name=greg/>
*'''Bureau Of Indian Standards (BIS'''):
According to this standard the welding all around the joint is represented by
# using a hallow circle
# using a filled-in circle
at the elbow (connecting corner of the arrow and reference line).
*'''International Standards Organization(ISO)''':
This convention indicates the process of welding used.To represent this the 90°V is formed at the tail end of the arrow and the name of process is written in that.
<ref>MACHINE DRAWING BOOK BY NEW AGE PUBLICATION</ref>


==Location of welds==
==Component elements==
The location of welds is specified by the following:
[[File:Elements of a welding symbol.PNG|thumb|right|350px|The location of the elements of a welding symbol when following US conventions.]]
In the US, the component elements of the weld specification are:<ref name=TC9237>{{citation |title=Welding Theory and Application |publisher=Department of the Army |date=7 May 1993 |number=Training Circular 9–237 |url=https://armypubs.us.army.mil/doctrine/DR_pubs/dr_aa/pdf/tc9_237.pdf}}</ref>
# Position of the arrow line
# The reference line - the body of the arrow which is the baseline for the specification.
# position of the reference line
# The arrow tip which goes at an angle to the reference line, pointing to the joint to be welded.
# position of the symbol
# The tail which goes at the other end of the reference line.
# The basic welding symbol which goes on the reference line to indicate the shape of the weld such as a fillet or plug. The symbol is placed on the arrow side or other side of the line to indicate which side of the joint the weld goes.
# The dimensions and other numbers such as the length of the weld or number of spot welds go above and below the reference line.
# Supplementary symbols go at the junction of the reference line and the arrow tip. One such symbol is a circle to indicate an all-around weld, which goes on every side of the joint.
# Finish symbols go above the reference line to indicate the surface contour or finish of the weld such as flush, convex or concave.
# Letters indicating the welding process are placed at the tail end, such as AHW for [[atomic hydrogen welding]]. Further examples include:
==Abbreviations for welding processes==
{{Main|List of welding processes}}
If a particular welding process needs to be indicated in addition to the symbols, the following abbreviations are commonly used in North America:<ref>"Welding Inspection Handbook", 3rd edition, [[American Welding Society]], {{ISBN|0-87171-560-0}}, Miami, FL, pp. 10-11 (2000)</ref><ref name=TC9237/>


{| class="wikitable sortable" style="text-align:center; width:50%;"
|-
! Designation!! Welding process
|-
| CAW || [[Carbon-arc welding]]
|-
| DB || [[Dip brazing]]
|-
| FB || [[Furnace brazing]]
|-
| FW || [[Flash welding]]
|-
| GMAW || [[Gas metal arc welding|Gas metal-arc welding]]
|-
| GTAW || [[Gas tungsten-arc welding]]
|-
| IB || [[Induction brazing]]
|-
| OAW || [[Oxy-acetylene welding]]
|-
| OHW || [[Oxyhydrogen welding|Oxy-hydrogen welding]]
|-
| PGW || [[Pressure gas welding]]
|-
| RB || [[Brazing#Heating methods|Resistance brazing]]
|-
| SAW || [[Submerged arc welding]]
|-
| SMAW || [[Shielded metal arc welding]]
|-
| TB || [[Brazing#Heating methods|Torch brazing]]
|-
| UW || [[Upset welding]]
|}


==References==
{{reflist}}

==Further reading==
* {{Cite book
| author = K.L.Narayana,P.Kannaiah,K.Venkata Reddy
| year = 2008
| title = Machine Drawing
| publisher = New age International
| isbn =978-81-224-1917-7
}}
* {{Cite book
| author = N.D.Bhatt,V.M.Panchal
| year = 2003
| title = Machine Drawing
| publisher = Charotar Publishing House
| isbn = 81-85594-19-8
}}

==External links==
*[http://www.arcraftplasma.com/welding/AWS-welding-symbols.pdf Welding symbols] at Arcraft Plasma Ltd.
*[https://web.archive.org/web/20111109234545/http://www.metallicfusion.com/symbols_and_definitions.htm Welding symbols and definitions] at Metallic Fusion
*[http://www.engineersedge.com/weld_symbol.htm Standard welding symbols] at Engineer's Edge
*[http://www.download-it.org/free_files/filePages%20from%2026.%20Welding%20and%20welding%20symbols.pdf Extract from Chapter 26 – Welding and welding symbols] in ''Manual of Engineering Drawing'' by Colin H. Simmons and Dennis E. Maguire. Newnes (2004). {{ISBN|0-7506-5120-2}}


[[Category:Notation]]
[[Category:Standards]]
[[Category:Welding]]
[[Category:Welding]]

Revision as of 19:48, 10 June 2023

The symbolic representation of a V weld of chamfered plates in a technical drawing

The symbols and conventions used in welding documentation are specified in national and international standards such as ISO 2553 Welded, brazed and soldered joints -- Symbolic representation on drawings and ISO 4063 Welding and allied processes -- Nomenclature of processes and reference numbers. The US standard symbols are outlined by the American National Standards Institute and the American Welding Society and are noted as "ANSI/AWS".[1] Due in part to the growth of the oil industry, this symbol set was used during the 1990s in about 50% of the world's welding operations.[1] An ISO committee sought to establish a global standard during this decade.[1]

In engineering drawings, each weld is conventionally identified by an arrow which points to the joint to be welded. The arrow is annotated with letters, numbers and symbols which indicate the exact specification of the weld. In complex applications, such as those involving alloys other than mild steel, more information may be called for than can comfortably be indicated using the symbols alone.[1] Annotations are used in these cases.[1]

Component elements

The location of the elements of a welding symbol when following US conventions.

In the US, the component elements of the weld specification are:[2]

  1. The reference line - the body of the arrow which is the baseline for the specification.
  2. The arrow tip which goes at an angle to the reference line, pointing to the joint to be welded.
  3. The tail which goes at the other end of the reference line.
  4. The basic welding symbol which goes on the reference line to indicate the shape of the weld such as a fillet or plug. The symbol is placed on the arrow side or other side of the line to indicate which side of the joint the weld goes.
  5. The dimensions and other numbers such as the length of the weld or number of spot welds go above and below the reference line.
  6. Supplementary symbols go at the junction of the reference line and the arrow tip. One such symbol is a circle to indicate an all-around weld, which goes on every side of the joint.
  7. Finish symbols go above the reference line to indicate the surface contour or finish of the weld such as flush, convex or concave.
  8. Letters indicating the welding process are placed at the tail end, such as AHW for atomic hydrogen welding. Further examples include:

Abbreviations for welding processes

Main article: List of welding processes

If a particular welding process needs to be indicated in addition to the symbols, the following abbreviations are commonly used in North America:[3][2]

Designation Welding process
CAW Carbon-arc welding
DB Dip brazing
FB Furnace brazing
FW Flash welding
GMAW Gas metal-arc welding
GTAW Gas tungsten-arc welding
IB Induction brazing
OAW Oxy-acetylene welding
OHW Oxy-hydrogen welding
PGW Pressure gas welding
RB Resistance brazing
SAW Submerged arc welding
SMAW Shielded metal arc welding
TB Torch brazing
UW Upset welding

References

  1. ^ a b c d e E. N. Gregory; Ann A. Armstrong (20 April 2005). Welding symbols on drawings. CRC Press. pp. 7–8. ISBN 978-0-8493-3591-4. Retrieved 10 October 2011.
  2. ^ a b Welding Theory and Application (PDF), Department of the Army, 7 May 1993
  3. ^ "Welding Inspection Handbook", 3rd edition, American Welding Society, ISBN 0-87171-560-0, Miami, FL, pp. 10-11 (2000)

Further reading

  • K.L.Narayana,P.Kannaiah,K.Venkata Reddy (2008). Machine Drawing. New age International. ISBN 978-81-224-1917-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
  • N.D.Bhatt,V.M.Panchal (2003). Machine Drawing. Charotar Publishing House. ISBN 81-85594-19-8.
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