In this article, we will talk about the ff:
-Â types of joints
– types of welds,
– how to interpret weld symbols
Welding is the process of joining two or more pieces of metal by applying heat and/or pressure with or without filler metal, to produce a union through localized fusion of the substrates and solidification across the interface
- Simple joint design
- Reduce the amount of materials and work sequence
- Reduce the weight of components
- High joint efficiency
- Well air tightening
- No limitation for joint thickness
- Less noise during work
- Distortion due to the local heating/cooling by welding
- Residual stress
- Changes in metallurgical or mechanical property of the base metal
- Propagation of the cracks
- Difficult to dismantle
Types of Joints
Types of Welds
Other Types of Welds
Plug or Slot Weld â€“ are welds which partially or entirely fill the holes.
Side Seam Weld
Spot Weld â€“ is typically used when welding particular types of sheet metal by application of heat.
Stud Weld â€“ is a form of spot welding where a bolt or specially formed nut is welded on to another metal part. The bolts may be automatically fed into the spot welder. Weld nuts generally have a flange with small nubs that melt to form the weld. Studs have a necked down, unthreaded area for the same purpose.
- Groove radius
- Root opening (groove weld) is the space between the pieces before welding
- Root face
- Groove angle
Significance of Arrow
Fillet Weld Symbol
Square Groove Weld Symbol
Bevel Groove Weld Symbol
V-Groove Weld Symbol
J-Groove Weld Symbol
U-Groove Weld Symbol
Flare-Bevel Groove Weld Symbol
Flare-V Groove Weld Symbol
Plug or Slot Weld Symbol
Stud Weld Symbol
Spot Weld Symbol
Basic and Supplementary Weld Symbols
Back or Backing Weld
Back or backing weld symbols are used to indicate bead-type back or backing welds deposited at the back of single-groove welds to assure complete root penetration.
The back weld is made after the groove weld.
The backing weld is made before the groove weld.
Surfacing is the deposition of filler metal on a metal surface to obtain desired properties or dimensions.
Field welds are welds not made in the shop or at the place of initial construction.
Small black flag symbol is placed above and at right angles to the reference line.
All Around Weld
Welds extending completely around a joint is indicated by a weld-all-around symbol placed at the intersection of the reference line and the arrow.
It is not required for welds extending around the circumference of a pipe.
- Welding symbols can be combined
- Multiple reference lines can be used to indicate sequencing
– Â Line closest to the arrow is first
- Cranked arrow line points to the member to be prepared
- Application of Break in Arrow Symbol
Photo credit to bugphaiÂ of freedigitalphotos.net