General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
Farmwelding
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We just did liquid nitrogen day at school and I asked my shop teacher who was running the show if I could weld something real hot and then dunk it. He thought it would be cool but was wary due to safety. So what would something like liquid nitrogen do the the strength of a weld. Dunking welds in water makes them weaker/makes them break differently but how extreme would the damage to weld integrity be at like -300 degrees? Or would the weld just kind of snap or break off?
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Nick
Poland308
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Depends entirely on the temp of the part when you dunk it. I've welded steel and done brazed copper for process liquid nitrogen lines.
I have more questions than answers

Josh
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It's not the temperature difference so much as heat transfer rate. Liquid Nitrogen transfers heat slower than water because the lower vapor pressure forms a skin of vapor over the hot spots. Ever see the guy on "Outrageous Acts of Science" dump the bucket of LN2 on his head? That's why it didn't hurt him. The vapor still transfers heat, and you will quench the weld, but what you proposed to the teacher is no more dangerous than putting a room-temperature part in LN2.

I regularly "cold-shock" stainless steel welds in LN2 for the abrupt temperature change to prove the weld won't crack, and I also put hardened carbon steel in LN2 when installing bearing races in semi-trailer hubs.

I've never actually put a fresh glowing weldment in LN2, but it would be interesting. Low-carbon steels will not harden much at all, just as quenching in water. I rarely weld harder steels.

Steve
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Otto Nobedder wrote:It's not the temperature difference so much as heat transfer rate. Liquid Nitrogen transfers heat slower than water because the lower vapor pressure forms a skin of vapor over the hot spots. Ever see the guy on "Outrageous Acts of Science" dump the bucket of LN2 on his head? That's why it didn't hurt him. The vapor still transfers heat, and you will quench the weld, but what you proposed to the teacher is no more dangerous than putting a room-temperature part in LN2.

I regularly "cold-shock" stainless steel welds in LN2 for the abrupt temperature change to prove the weld won't crack, and I also put hardened carbon steel in LN2 when installing bearing races in semi-trailer hubs.

I've never actually put a fresh glowing weldment in LN2, but it would be interesting. Low-carbon steels will not harden much at all, just as quenching in water. I rarely weld harder steels.

Steve
I use LN2 to make frozen margaritas...you guys are way overthinking this shit :lol:
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exnailpounder wrote: I use LN2 to make frozen margaritas...you guys are way overthinking this shit :lol:
I want to see a video of this... :lol:
Richard
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