7 Most Common Defects In Welding and its causes
Different Types of Welding Defects
- poor ductility of base metal,
- high sulpher and carbon contents,
- high arc travel speeds i.e. fast cooling rates,
- too concave or convex weld bead
- high hydrogen contents in the weld metal.
2. Distortion/ Imperfect Shape
- Lamellar tearing is a type of welding defect that occurs in rolled steel plates that have been welded together due to shrinkage forces perpendicular to the faces of the plates.
- Lamellar tearing is caused mainly by sulfurous inclusions in the material. Other causes include an excess of hydrogen in the alloy. This defect can be mitigated by keeping the amount of sulfur in the steel alloy below 0.005%
- Modifying the construction process to use casted or forged parts in place of welded parts can eliminate this problem, as Lamellar tearing only occurs in welded parts.
Undercutting is when the weld reduces the cross-sectional thickness of the base metal and which reduces the strength of the weld and workpieces. One reason for this type of defect is excessive current, causing the edges of the joint to melt and drain into the weld; this leaves a drain-like impression along the length of the weld. Another reason is if a poor technique is used that does not deposit enough filler metal along the edges of the weld. A third reason is using an incorrect filler metal, because it will create greater temperature gradients between the center of the weld and the edges
Read More Related to welding :
Welding process l Advantages and Disadvantages of welding Connections
Selection Of Welding Processes and Application Of welding Process
Classification Of Welding Processes and allied Processes
Introduction To Spot Welding -Working Principle of Projection welding
Pressure Vessels - Parts, Design, Application, Types, Material, Diagram
Introduction to Pressure Vessels Vessels, tanks, and pipelines that carry, store, or receive fluids are called pressure vessels. A pressure vessel is defined as a container with a pressure...
Knuckle Joint - Parts, Diagram, Design Calcuation, Applications
Knuckle Joint A knuckle joint is used to connect two rods which are under the action of tensile loads. However, if the joint is guided, the rods may support a compressive load. A knuckle joint...