Question

1. Rank in order of total heat input (Note: don’t confuse with heat input RATE) and overall size of heat affected zone: GTAW, SMAW, Oxyfuel, laser beam welding

2. What are the advantages of reducing total heat input in a weld?

Answer 1

First of all let's know what is the relationship between Total heat input and the Heat Affected Zone (HAZ).

Here it is seen that higher the heat input in a welding process higher the size of heat affected zone.

Here Oxyfuel welding has a high heat input resulting in high more of HAZ.and laser beam welding has low heat input resulting in less size of HAZ.The arc welding lies between these two extremes with less heat input for Gas Tungsten Arc Welding (GTAW) and more for Sheild Metal Arc Welding (SMAW).

Therefore Ranking (in increasing order) of these welding methods :-

1)Based on Total heat input:-

i)Oxyfuel welding ii)SMAW iii)GTAW. iv)Laser beam welding.

2)Based on overall size of HAZ:-

i)Oxyfuel welding ii)SMAW iii)GTAW. iv)Laser beam welding.

Advantages of reducing total heat input in welding:-

i)It helps to reduce the changes in the mechanical properties of the base material.

ii)It helps to increase the tensile strength of the weld area.

iii)Various changes in the grain properties can be minimized.

Hope you have understood. Wish A great career ahead. Convey your feedback...