f2 Hnet _ Л f 2 H

A.. =

Q

J/s.

Heat required for melting in Joules/mm3 E = voltage supplied in volts.

I = current consumed in Amp. v = welding speed in mm/s

Aw = (Am + Ar) in mm2

A, = A if no filler metal is added

Q =

and

where Aw = (Am + Ar)

f1 = heat transfer efficiency from electrode to plate f2 = melting efficiency

Heat required to melt the joint Net heat supplied H, = Net heat available at the weld

Example 1. An arc weld pass is made on steel under the following conditions :

E = 20 V I = 200 Av = 5 mm/s

f1 = 0.9 f2 = 0.3 Q = 10 J/mm3.

Estimate the cross-sectional area of the weld pass.

Solution.

A = (0.9)(0.3)(20)(200) = mm[4]. Ans.

w (5)(10)