Tuesday, May 17, 2011

Re: [MW:11073] thickness

Hai Gents,
 
Advantages of Preheat
1.Slow down the cooling, which reduce the risk of hardening.
2. Allows obsorbed Hydrogen a better opportunity of duffusing out, there by reducing the risk of cracking.
3.Removes moisture from the material being welded
4.Improve overall fusion charateristics
5.Lower stresses between the weld metal and parent material by ensuring a more uniform expansion and contraction.
 
Preheat temperature are arrived by taking in to consideration the following
 
1.Carbon Equivqlent (C.E %)
2.Heat Input
3.Combined Material Thickness
 
With Regards,
Mohamed Ismail
KSA
 


 
On Mon, May 16, 2011 at 3:20 PM, Matee Toor <matee.toor@gmail.com> wrote:
dears

pleas tell me why preheat treatment is nessesry in welding and also tell
for what composition
what thickness


thands

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[MW:34820] RE: 34813] Clarification in Rate of heating and cooling.

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