Here's an article from Kobelco of Japan on the Carbon Equivalent formula used to calculate the minimum preheat temperature to use on carbon steels in order to avoid the potential for underbead cracking:
Here's a case history from the Army Corp of Engineers of a bridge in Pasco Washington which upon repeated repairs, parts of the bridge still kept cracking:
Wow thanks but is that my new nickname??? I kind of got used to being called an "old fart" but heck, "Information Czar" sounds pretty cool to me yet, please don't confuse that with knowing everything because I know I don't!!! ;)And I sure as heck wouldn't want to anyway because then life would be too darn boring knowing what was going to happen next, and man would all of those headaches from having all of that knowledge stuck in one's head!!! Sheeesh!! Not for me my friend - no, no!!! Not for me.;) I'd rather live by the K.I.S.S philosophy of living! ;) ;) ;) Thanks for the compliment nonetheless Swsweld!!! :) :) :)
under my current understanding, underbead cracking usually has a componenet of stress upon the cooled weld bead, which allows for micro tears or even variations in grain structure to accumulate the still diffusing hydrogen.
Now I've always been curious is this overall situation at all dependent on stress orientation relative to the weld bead, or grain structure. My thought would be that compressive loads are significantly less likely to open up internal defects as the force is acting to push the grains closer together.
also voids in the grain structure are most always going to be oriented based upon the slippage plains of the grain structure. If stress is acting perpendicular to the long axis of a grain boundary wouldn't that also act to close together any possible voids (then again hydrogen atoms are very small).
Anyone have any field experience or data on this subject. This is merely my (semi)logical guessing as I never have had to deal with hydrogen cracking in my work.
This explanation of HIC comes from the Corrosion Doctors (Remember to click the next page to complete the explanation which goes right into Hydrogen Embrittlement):
I'm not quite sure what you're asking but, perhaps this article may help some although I caution that it is quite long so be patient when reading this:
He asked for data so, I gave him some... He wasn't too specific with what type of base or filler metal he was referring to so, I decided to give him some articles dealing with different metals...
All in all, I don't think anyone in here could just give him one answer that would cover every type of metal, and as you know too well that different metals including their various alloyed cousins so to speak, behave quite differently and do not always follow one theory that would cover them all... Hopefully, I covered all of the bases where he could extract an answer that would suit his fancy! :) :) :)
I believe there are a few in the mix that should satisfy his curiosity and I sprinkled some other stuff in there to hopefully show some different perspectives also.
I guess I got carried away just a tad... ;) ;) ;) Oh well, My motto is to always remain teachable, and I hope that he embraces it also. ;)
Henry, you are the infomation czar. If there is a question asked on any subject, you have a link to a website that will address the question. I don't know how you find them and I'm not going to ask.
If you have a question, who you gonna call? Henry, that who!
Keep up the good work! You're a good man to have around and a good person to call a friend.
I'm just curious, does AWS get it's info from Henry?? LOL!! I don't think I know any one person with all the resources of information, or at least the knowledge of where to find it, as vast as Henry's. I wouldn't know where to keep it all. And even if I could begin, I wouldn't remember where to find it, even with my computer.
Thank you again Henry from someone who really appreciates all your efforts to help out the rest of us.