American Welding Society Forum
What is the differences between melt through and blow through?
Melt through is defined in AWS A3.0:"Visible root reinforcement in a joint welded from one side."
But I could not find the definiation of blow through in that specification.
This is only personal opinion but melt through is when you put excessive heat into a second run on a pipe (usually in the vertical and flat positions) and the heat causes the root to "push" through but it still stays smooth.
Blow through or burn through is where the second run actually penetrates the first run (eg. An SMAW run over a GTAW run where the SMAW "blows through" the GTAW)
Hope that helps,
It is a matter of terminology.
If you are going to adopt AWS terminology then this is a synopsis of the difference between the two terms (no I didn't take the time to look it up):
Melt-through: The visible root reinforcement on the root side of a complete joint penetration groove weld deposited from one side.
Burn-through: a hole melted through the root face and left unfilled. Whether it occurs during the root pass, the second or third pass is of no consequence.
Blow-through: nonstandard term for burn-through.
Another point to remember when defining terms is who the source is: AWS, API, ASME, etc. There are many terms that differ between D1.1 and API 1104. They differ either/or in formal definition and then as to application.
So, when trying to define any terms I always start with A3.0 but then take the job into consideration to see if I need to be looking up another organization's glossary.
I say that because I already see two different perspectives here, at least I believe I do. Al is looking at your request from a structural application with D1.1 & A3.0 being the go to sources. Shane was commenting from a pipe welding perspective and thus taking pipe applications and definitions into account.
From your OP, I'm not sure we can precisely answer your query as we don't know the specifics of your job.
Have a Great Day, Brent
Another definition comes to mind that I almost forgot. Thanks to Brent for reminding me.
Blow through: something that happens when she inadvertently coughs too hard. It's what happens when she blows a hole right through the facial tissue; yuck, icky, sticky, and gooey! I just hate those head colds.
Thanks a lot, Brent an Al. I think I understood now.
Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill