Abbreviations, Terms, and Welding Symbols
It is useful to have an understanding of acronyms utilized within the world of welding and also welding inspection. Some commonly utilized ones are:
API: American Petroleum Institute
ASME: American Society of Mechanical Engineers BM: base metal
BS: British Standard
BSI: British Standards Institute
CVI: close visual inspection
DT: destructive testing
EN: European standard (Euro Norm)
GVI: general visual inspection
HAZ: heat affected zone
ISO: International Standards Organisation LCT: lower critical temperature
MT/MPI: magnetic testing/magnetic particle inspection NDE/NDT: non destructive examination/non-destructive testing
PQR: Procedure Qualiﬁcation Record PT/LPE: penetrant testing/liquid penetrant examination
PWHT: post-weld heat treatment RT/RAD: radiographic testing/radiography SWI: senior welding inspector
UCT: upper critical temperature
UT: ultrasonic testing
UTS: ultimate tensile strength
VI: visual inspection
VWI: visual welding inspector
WI: welding inspector
WM: weld metal
WPS: welding procedure speciﬁcation
Longitudinal direction: along the length of the weldment (parallel to the weld)
Transverse direction: along the width of the weldment (perpendicular to the weld) Short transverse direction: through the weldment thickness Weldment: the combined weld, HAZ, and base metal.
Fusion weld: a weld produced by joining materials in a molten state
Yield point: the point at which plastic deformation starts in a material
Prior to welding takes place the components to be joined need to be prepared as well as organized right into the required kind. One of the most typical forms of joint are butt (or groove) joints, T joints, and lap joints. Butt joint participants are ﬁtted edge to edge, T joints are ﬁtted edge to the surface area as well as lap joints are ﬁtted surface to the surface area
Sorts of weld used on the joints are butt (or groove) welds, ﬁllet welds, edge welds, plug welds, and also spot welds. The type
Abbreviations, Terminology, as well as Welding Symbols of the weld, will be determined by the joint set-up yet one of the most frequently used welds are butt or ﬁllet welds.
Full penetration butt welds are typically the best sort of weld with the strength included within the throat of the weld, The throat amounts to the thinnest of the parent materials to be signed up with.
Fillet welds likewise contain their stamina in the throat as well as the style throat dimension is generally (but not always) based on the leg size. In visual inspections, we can usually work out the layout throat dimension of a miter ﬁllet with equivalent leg lengths by increasing the leg size.
Buttweld joint prep work consists of preparing both edges and after that organizing them with each other to permit the needed deepness of weld infiltration to be accomplished. Full infiltration welds are the most common however numerous applications will only require partial infiltration if the bonded joint is either lightly packed or is simply a securing weld.
The main objective of the joint preparation is to allow the needed level of combination between the joint faces. The type of weld prep work used will for that reason be dependent upon the thickness of the material as well as the welding procedure to be utilized. Some normal butt weld joint preparations are shown in Fig.
Single-sided preparations enable welding to happen from one side whereas double-sided preparations need welding to be done from both sides. A major negative aspect of having accessibility to only one side is that the other side of the initial root run can not be accessed to execute the removal of welding- generated problems. An example of this would be where a large space was called for to allow blend throughout the whole cross-section of the weld yet too much infiltration then occurred. Good control and also the development of the origin weld should, as a result, be maintained at the time of welding, and this can be assisted by using the root control steps
- Non-fusible backing bars. These are always removed and also are normally made from copper (often water-cooled down) or ceramic as well as aid from the origin weld shape. It is very important to make certain that the copper bar does not melt and contaminate the weld as this might create weld steel cracking.
- Fusible backing strips. These are constructed from a material similar to the parent product and are tacked on to the mom and dad material. They are merged into the root and also are generally ground off, or occasionally left in place
- . Pre-placed ﬁller such as EB inserts. These are utilized on pipelines as well as welded making use of a TIG (tungsten inert gas) process. The EB represents Electric Boat as well as is the name of the firm that ﬁrst supplied them. The use of EB inserts is a specialist procedure made use of in professional applications such as the nuclear market.
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