Welding Experiments

TEACHDRM · Mon Jan 08, 2018 10:18 pm

Looking for some interesting welding experiments. We know about the 6010/7018 and mineral oil one, but are there any other interesting welding experiments out there?

Lightning · Tue Jan 09, 2018 8:37 am

TEACHDRM wrote:We know about the 6010/7018 and mineral oil one

What is that?

One demonstration our instructor used was, he got a long bar of steel and welded two pieces of steel coming off the bar with "T" joints. One of the pieces he welded with 7018 and the other with hard surfacing rod. Then he broke them off with a hammer to show the difference between hardness and strength/ductility.

Farmwelding · Tue Jan 09, 2018 9:58 am

I always enjoy scratching a 6010 on some plate and then polishing and bending it to see how devastating arc strikes can be. Or tacking a piece of angle iron to a table a foot in and then putting a tack on it and putting all my weight on it and then simply lift it up and break the tack to show how important weld placement is.

TEACHDRM · Tue Jan 09, 2018 9:17 pm

Lightning wrote:
TEACHDRM wrote:We know about the 6010/7018 and mineral oil one
What is that?

One demonstration our instructor used was, he got a long bar of steel and welded two pieces of steel coming off the bar with "T" joints. One of the pieces he welded with 7018 and the other with hard surfacing rod. Then he broke them off with a hammer to show the difference between hardness and strength/ductility.

Yes, If you take 3 identical plates and weld one 6010, the other 7018 rod left out of the oven (the longer the rod is left out the better results) and 7018 directly from the oven and place them in container of mineral oil you can see the hydrogen gas bubbles coming out of the welds. This shows why proper storage of rod is important. There is a youtube video that shows a really nice example.
https://youtu.be/H4aSkugbcaA

Lightning · Wed Jan 10, 2018 9:38 am

TEACHDRM wrote: Yes, If you take 3 identical plates and weld one 6010, the other 7018 rod left out of the oven (the longer the rod is left out the better results) and 7018 directly from the oven and place them in container of mineral oil you can see the hydrogen gas bubbles coming out of the welds. This shows why proper storage of rod is important. There is a youtube video that shows a really nice example.
https://youtu.be/H4aSkugbcaA

Huh. Never saw anything like that before. I'm surprised the hydrogen isn't "dissolved" in the weld deposit, and thus "trapped forever" in the steel. I don't understand how it's getting out to bubble through the oil. (Or maybe that's just the hydrogen trapped at the very edge, the very top surface layer, of the weld deposit? Or is the weld deposit "honeycombed" at a microscopic level with microscopic, interconnected porosity that lets the hydrogen escape?)

MinnesotaDave · Wed Jan 10, 2018 3:11 pm

Lightning wrote:
TEACHDRM wrote: Yes, If you take 3 identical plates and weld one 6010, the other 7018 rod left out of the oven (the longer the rod is left out the better results) and 7018 directly from the oven and place them in container of mineral oil you can see the hydrogen gas bubbles coming out of the welds. This shows why proper storage of rod is important. There is a youtube video that shows a really nice example.
https://youtu.be/H4aSkugbcaA
Huh. Never saw anything like that before. I'm surprised the hydrogen isn't "dissolved" in the weld deposit, and thus "trapped forever" in the steel. I don't understand how it's getting out to bubble through the oil. (Or maybe that's just the hydrogen trapped at the very edge, the very top surface layer, of the weld deposit? Or is the weld deposit "honeycombed" at a microscopic level with microscopic, interconnected porosity that lets the hydrogen escape?)

This paper could clear it up for you. I think it's pretty well written. http://www.jwri.osaka-u.ac.jp/publicati ... 421-07.pdf

Artie F. Emm · Wed Jan 10, 2018 4:51 pm

One of Jody's videos features a 7014 rod in a stinger, no human touch involved, balanced so the weld end of the electrode is held by gravity against the workpiece. The arc strikes and the electrode feeds itself into the weld.

Not really an "experiment" but possibly good for a demo, or a lesson in holding a tight arc.

Farmwelding · Wed Jan 10, 2018 6:45 pm

Artie F. Emm wrote:One of Jody's videos features a 7014 rod in a stinger, no human touch involved, balanced so the weld end of the electrode is held by gravity against the workpiece. The arc strikes and the electrode feeds itself into the weld.

Not really an "experiment" but possibly good for a demo, or a lesson in holding a tight arc.

And showin how forgiving the 7014 is

Lightning · Wed Jan 10, 2018 8:33 pm

MinnesotaDave wrote:This paper could clear it up for you. I think it's pretty well written. http://www.jwri.osaka-u.ac.jp/publicati ... 421-07.pdf

Thanks, MinnesotaDave. I'm somewhat familiar with the concept of hydrogen embrittlement, and why 7018 used for code work needs to be kept dry in an oven, but I never saw the demonstration with the hydrogen bubbling out of the steel. I just kind of scanned the article...does it explain how the hydrogen is (apparently) getting out of the weld deposit?

aland · Thu Jan 11, 2018 2:10 am

Lightning wrote:
MinnesotaDave wrote:This paper could clear it up for you. I think it's pretty well written. http://www.jwri.osaka-u.ac.jp/publicati ... 421-07.pdf
Thanks, MinnesotaDave. I'm somewhat familiar with the concept of hydrogen embrittlement, and why 7018 used for code work needs to be kept dry in an oven, but I never saw the demonstration with the hydrogen bubbling out of the steel. I just kind of scanned the article...does it explain how the hydrogen is (apparently) getting out of the weld deposit?

You want him to read it for you also?