Welded Joints

Welding is a process of joining metallic parts by heating to a suitable temperature with or without application

Advantages of Welded Joints:

(a) It does not require an additional cover plate, gaskets, straps, or clip angle; thus, the welding assembly results in lightweight construction.

(b) Design of welded assemblies can be easily and economically modified.

(c) Welded joints are tight and leak-proof as compared to riveted joints and also their production time is less.

(d) Strength of weld metal is high, even higher than parent metal.

Disadvantages of Welded Joints:

(a) Vibration damping capacity of welded structure is very poor.

(b) It result in thermal-distortion of the parts, thus inducing residual stress.

(c) Quality and strength of the weld depends upon the skill of the welder.

Methods of Stress Relieving:

• Preheating of the weld area to retard cooling of the metal in the vicinity of the joint.
• Stress relieving of the weld area by using proper heat treatment, such as normalizing and annealing, in a temperature range of 550°C to 675°C.
• Shot peening by hammering the weld along the length when the joint is hot. It also increases the fatigue strength of the joint.