# Welding heat input

#### chandran

In a welding process,i am welding two plates. The welding current is 110A and welding voltage is 20V. Suppose 100% of this electric energy is
converted to heat then the heat energy generated is 110x20. i.e., 2.2KJ/sec.
Suppose the length of the plate is 2 metres, How can i calculate what is the heat input into the welded joint at each point? I have one more data
that welding speed is 1metre/minute.

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#### Gokul43201

Staff Emeritus
Gold Member
(assuming no losses) power generated / welding speed = heat input per unit length

#### chandran

if the welder weld faster then heat will be less thereby producing a good
less,residual stress weld?

#### FredGarvin

chandran said:
if the welder weld faster then heat will be less thereby producing a good
less,residual stress weld?
Perhaps. Any weld is going to create stresses. The increased speed would have to be balanced by the fact that a certain percentage of the weld penetration would be sacrificed. Most welds are stress relieved after the process.

#### PerennialII

Gold Member
Yeah, if you require the weld to penetrate (well, you usually do) I think you can't really gain much residual stress wise by decreasing heat input (material properties are a different matter of course). Typically heat input affects the residual stress gradient at line of fusion towards the base material, where there is a square root dependency between the yielded zone and arc power, which again has a linear relationship with the extension of the residual stress field - but this leaves the weld metal residual stresses still as is, higher arc powers widen the volume under residual stresses. Would go with post-weld heat treatment.

#### brewnog

Gold Member
Power beam welding processes (e-beam, laser welding) tend to be better in applications where residual stress is a concern. The power density is much higher, although the net heat input is often lower than electric arc welding techniques. As a result, the heat affected zone tends to be a lot smaller. (Pretty much what Perennial said...). I don't think a simple increase of welding speed is going to solve any problems.

#### patelam

Hello, How to input heat source in welding simulation ( ANSYS ).By heat flux or heat genaration or heat flow etc..........?.How to calculate if effic=60%,V=16, I=80,weld speed=1 m/min.

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