A Conversation for Mohs Scale of Hardness

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Post 1

Smudger879n

How about the HAZ, Heat Affected Zone of a weld. We used to take the Brunel hardness test across this area of a weld, and found it varied dramatically depending on how much "heat input" per Kj the actual welding procedure called for.
We found that by "Temper Beading" the capping runs, (finishing layer of the weld) this vastly reduced the chance of stress cracking due to high H/V (hardness values) Temper Beading, was a way of placing the very last run of the cap a set distance away from the edge of the weld, this vastly reduced the H/V.
We also to take take "v" Notch Charpie tests at -20c when I first started in the oil industry, but this went up to -40c after new procedures for making steel were used.
This meant that we could make supporting structures from far thinner steel, but we had to really tighten the Heat Input to get these welding procedures through the required machanical values.
Then of course along came new steel alloys like, Duplex & Super Duplex, which were even harder to weld. So the welding procedure was tightened up even more.
smiley - cheersSmudger,


Heat Affected Zone

Post 2

BigAl Keeper of the Glowing Pickle and Monobrows

smiley - ta for that Smudger. Obviously, it's beyond the scope of my Entry, but your observations may be of interest to other readers of this thread.

smiley - cheers

smiley - biggrin


Heat Affected Zone

Post 3

Smudger879n

Hi! It was just to add how much importance is placed on Hardness Values when it comes to welding different materials.
As you say, it may of interest to someone reading this threadsmiley - oksmiley - cool
smiley - cheersSmudger,


Heat Affected Zone

Post 4

flyingtwinkle

hi smudger what exactly is it that makes something more har than others?


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