Pre and Post weld treatments for multistory structures

[thedoug10]

On a general basis, what is the percentage of time, cost and resources needed for the various welding processes for pre and postweld treatments compared to entire welding process used in multistory construction of A992 steel? It will obviousily depend of numerous factors, but how much of these resources used for the welding process are needed for pre and postweld treatment?

The welding processes are SMAW, FCAW, GMAW and SAW.

 

[connectegr]

Too many factors.

Shop welding or field welding?
Geographically where is the structure?
When will the construction happen, seasonally?
What method of pre-heat do you prefer? rose-bud? heaters? thermal blankets?
How thick is the material?
What types of field welding is required? fillets? CJP?

???

Depending on your ambient temperatures postweld heat treatments may not be necessary. Pre-heat and interpass temperature will be the primary concerns.

http://www.FerrellEngineering.com

 

[metengr]

If you review the material specification for A992, the carbon equivalent of 0.47% is low enough because the specified carbon content is 0.23% max, where post weld heat treatment should not be required. For base metal thickness greater than 1" at ambient temperature, I would recommend a local preheat of 150 deg F minimum for this base material regardless of the mentioned welding processes.

What does all this mean relative to cost and time for welding? My guess is preheat would be less than 20% of the total cost of welding, and even less then this in comparison to welding time.

 

[thedoug10]

Too many factors.

Shop welding or field welding?
Geographically where is the structure?
When will the construction happen, seasonally?
What method of pre-heat do you prefer? rose-bud? heaters? thermal blankets?
How thick is the material?
What types of field welding is required? fillets? CJP?

???

Depending on your ambient temperatures postweld heat treatments may not be necessary. Pre-heat and interpass temperature will be the primary concerns.

I will try to answer the questions but again this is a general question so in reality of the answers are simply "it may depend". I appreciate the effort in answering such a general question though .

field welding
temperate climates, mid-atlantic/Southern US regions, West coast....really just depends
fall, temps 55-75 F......same, really just depends
rose-bud
.5" - 1" a992 steel
CJP weld


Thanks in advance

 

[connectegr]

thedoug10,
My intent was to explain that the labor and time required to achieve minimum preheat and interpass temperatures are dependent on the work environment and the method of heating. In an extremely cold environment, the cost may be 30-40% or more, of the total welding cost.

Metengr is also correct for A992, post-weld treatments do not apply. Except where necessary to avoid rapid cooling in extremely cold environments.

At the other end of the spectrum, with the ambient temperatures you mention 50-75 *F, there may be no preheat required. AWS D1.1 prescribes a minimum preheat/interpass of 50* for A992 material up to 1 1/2" thick. This would result in a minimal percentage of your welding cost.

Hope this helps.

PS For welding on the West Coast there may be some additional welding cost, based on the filler metal requirements (D1.8). This applies to Demand Critical welds for seismic applications, anywhere in the country. But, this was not part of your question.

http://www.FerrellEngineering.com