Relation between Heat Intensity and Time required to produce melting

[Nashanas]

Hello,

I have a theoretical question. In the ASM Handbook for welding it is written that:
Tm = (5000/HI)^2

Here HI = W/cm^2 (Heat intensity)
Tm = sec (Time required to produce melting on a surface)

I am unable to get seconds from this equation theoretically.

W = kg.m/s^3
W/cm^2 = 10000 kg/s^3
Tm =(5000/HI)^2 = (5000*s^3/10000kg)^2 = (0.5*s^3/kg)^2 = 0.25*s^6/kg^2

So this is not equal to seconds. Why have they listed this value as seconds? What am I missing here?

 

[EdStainless]

The units on the conversion factor 5000.
You do realize that this is a very rough approximation. And that it has little to do with meling the full material.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

What am I missing here?

A basic course in welding technology? No sarcasm intended.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Nashanas]

You are right, and I am self studying to get the fundamentals of welding technology. But here I am talking about simple conversion of units. Can you make LHS = RHS?

 

No, but that's because I am acronym-challenged.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[MintJulep]

I think what EdStainless was trying to explain is that the magic number 5000 in the formula hides whatever units are necessary to make the units on both sides of the equation match.