Welding formula question for preheat
Welding formula question for preheat
(OP)
I recently learned that there are more than one carbon equivalent (C.E.) formulas out there. The formulas I am interested in understanding are the AWS and the ASTM versions. If the formula is not met, then welders have to exercise precautions for preheating when welding.
The AWS version includes a term Si/6. The ASTM version includes a term V/5. Can anyone explain the difference? I noticed that ASTM A709 steels contain up to 0.40% Si (some grades even more). The Vanadium content is limited to a much smaller level, typically 0.06% for example. If the silicon content of steel is frequently higher than the limit for Vanadium, then the AWS formula appears more strict.
Is this warranted? If it is, then why would the ASTM folks not think it wise also?
The AWS version includes a term Si/6. The ASTM version includes a term V/5. Can anyone explain the difference? I noticed that ASTM A709 steels contain up to 0.40% Si (some grades even more). The Vanadium content is limited to a much smaller level, typically 0.06% for example. If the silicon content of steel is frequently higher than the limit for Vanadium, then the AWS formula appears more strict.
Is this warranted? If it is, then why would the ASTM folks not think it wise also?
RE: Welding formula question for preheat
As you can see, the affect of vanadium is greater than that of silicon, which is commonly used to deoxidize (or kill) steel.
Yes, the AWS CE formula is more restrictive and widely used for carbon and some low alloy steels.
RE: Welding formula question for preheat
FAQ330-1077
RE: Welding formula question for preheat
Most of what we do with the AWS is fabrication of A709 Steel and I am assuming by your comment that the AWS formula for C.E. is valid for that family of steel.
I guess the question becomes, which other steels are valid for the C.E. formula in the AWS with the Si/6 term? And, which steels are suitable for the C.E. formula in ASTM?
RE: Welding formula question for preheat
RE: Welding formula question for preheat
Hg
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