Welding Tips and Tricks

Cheers Steve. This was only a single pass, the spec was a 6mm (1\4") weld on 12mm (1\2") plate.
I'll have another go today, maybe go to the top settings on the spec and see if that gives me more pen.
Cheers
Andy

OK, so I thought I'd do a side bend on the butt weld, at least it didn't break lol

"LIKE"...

A side-bend pass is a good thing.

Steve S

Your side bend looks great!

After careful review I am beginning to think the lack of penetration on your T joints is your gun angle. Look carefully back at the pictures you posted. You can see your "nipple" is pointed toward and into your bottom plate. I believe you may be trying to hold a true 45* when you need to actually point a little more toward the vertical plate. I was going to break my piece today and see how it did but we used the other side to set a machine so I will try to get another in soon.

Another thing that concerns me is the last picture has a lot of "balls" laying on the horizontal plate. I am also wondering if either you have way touch push angle or you don't have enough wire and are in fact not at 260 amps. I am leaning toward the gun angle though.

These are just thoughts, let me know what you think.
-Jonathan

Thanks Steve and Jonathan.
I thought about torch angle too, as the bottom leg is longer than the vertical.
I took all my tests on Monday, cranked up the juice a bit, burnt my knuckles on my left hand through my gloves lol ( Jody needs to invent a tig knuckle lol)
I think I could have done better, but I'm always self critical.
Results will be in next week so fingers crossed.
I'll keep you posted.
Thanks again for all advice,
Cheers Andy

andygmac wrote:...I think I could have done better, but I'm always self critical...
Cheers Andy

Not the first time I've said it...

We like to call ourselves craftsmen, so we are always our own worst critics.

Steve S

Is there a pre-heat on those plates?

Nope, no pre heat, just ambient temperature which was around 28°c in the shop
Andy

andygmac wrote:Nope, no pre heat, just ambient temperature which was around 28°c in the shop
Andy

At the school I go to, 12mm (1/2 inch for us barbarians), is about the beginning of the range where we start to pre-heat. Not sure if your spec allows for it or not. Is there a interpass temp you have to maintain?

We also slow cool by burying the parts in a bucket of sand, again, entirely up to spec.

I got the test results back today, passed the procedure test for multi run 20mm fillet, failed on procedure tests for, 12mm single fillet, and 12mm multi run v butt, both failed on "hardness in heat affected area" . so my weld shape, leg length, fusion, penetration, macro, and x-ray were fine, just failed on something that I can't check myself to improve on lol

So, I'm happy in a way that I passed one procedure test, (being the first tests I have ever attempted, and knowing procedure tests are scrutinised more than welder tests)
But gutted that I failed, not on my weld as such, but on the surrounding base metal , grrrrrrr.
Andy

Hardness in the HAZ is usually caused by too quick of a cooling cycle, and is extremely common in MIG/GMAW and on thicker material. As I mentioned before, a pre/post heat, and slow as possible post-weld cool down will reduce the possibility of that happening.

Read up on cold cracking and hydrogen diffusion.

Hobart has an easy to understand article on it.
http://www.hobartbrothers.com/index.php ... turnid=523

andygmac wrote:I got the test results back today, passed the procedure test for multi run 20mm fillet, failed on procedure tests for, 12mm single fillet, and 12mm multi run v butt, both failed on "hardness in heat affected area" . so my weld shape, leg length, fusion, penetration, macro, and x-ray were fine, just failed on something that I can't check myself to improve on lol

So, I'm happy in a way that I passed one procedure test, (being the first tests I have ever attempted, and knowing procedure tests are scrutinised more than welder tests)
But gutted that I failed, not on my weld as such, but on the surrounding base metal , grrrrrrr.
Andy

That's the story of a welder's life. If you meet a man who's never busted a test, you've met a liar.

Steve S

Axis wrote:Hardness in the HAZ is usually caused by too quick of a cooling cycle, and is extremely common in MIG/GMAW and on thicker material. As I mentioned before, a pre/post heat, and slow as possible post-weld cool down will reduce the possibility of that happening.

Read up on cold cracking and hydrogen diffusion.

Hobart has an easy to understand article on it.
http://www.hobartbrothers.com/index.php ... turnid=523

Cheers for that

Pre and post heat would be an option but we are trying to avoid this because if any heat is used in the procedure test, then it would have to be used in every weld thereafter which in our production would cost time and money lol

The strange thing with my fails were that they were both on the 12mm plate, one v butt multi pass (7passes), and one single pass fillet. The passed test was 20mm plate multi pass fillet. It was hot on the test day with the workshop having an ambient temp of around 30°c. All test pieces were allowed to cool on the bench, no quick cooling.
There were no cracks found in any of the welds, they were x rayed, mpi, cut, bent, etched, impact tested, and inspected under a microscope, and the fail was hardness in the haz.

A good workman always blames something else, so I'm blaming the 12mm plate he he he

You are right Steve my motto is " he who has never made a mistake, has never made anything"

andygmac wrote:

Axis wrote:Hardness in the HAZ is usually caused by too quick of a cooling cycle, and is extremely common in MIG/GMAW and on thicker material. As I mentioned before, a pre/post heat, and slow as possible post-weld cool down will reduce the possibility of that happening.

Read up on cold cracking and hydrogen diffusion.

Hobart has an easy to understand article on it.
http://www.hobartbrothers.com/index.php ... turnid=523

Cheers for that

Pre and post heat would be an option but we are trying to avoid this because if any heat is used in the procedure test, then it would have to be used in every weld thereafter which in our production would cost time and money lol

The strange thing with my fails were that they were both on the 12mm plate, one v butt multi pass (7passes), and one single pass fillet. The passed test was 20mm plate multi pass fillet. It was hot on the test day with the workshop having an ambient temp of around 30°c. All test pieces were allowed to cool on the bench, no quick cooling.
There were no cracks found in any of the welds, they were x rayed, mpi, cut, bent, etched, impact tested, and inspected under a microscope, and the fail was hardness in the haz.

A good workman always blames something else, so I'm blaming the 12mm plate he he he

You are right Steve my motto is " he who has never made a mistake, has never made anything"

First thought, you can put the test piece in a bucket is sand or wrap in fiberglass, this will allow for a slow cool and you might be able to get away with this. However, it is best to figure out why this is happpening and how to fix it. I would hate for you to have problems in the future.
Ok now define "hardness in the HAZ". What was acceptable and where did you fall? I will try to get a friend to help out with this one, hopefully.

Steve,
Took the words right out of my mouth!!
-Jonathan

Cheers Jonathan, I'm waiting for the paperwork to come back to me, the test lab is real busy at the moment so they just emailed my results to me, with the paperwork to follow, hopefully this will give me more of an idea what went wrong, I'm still blaming the 12mm plate lol
Cheers Andy

Andy,
Anxious for a update! What did you find out?
-Jonathan

Hi Jonathan, would you believe I only got the paperwork through today
My butt weld passed on every test bar the hardness test, it had 38 different "dots" where it was tested, from parent metal through haz, through weld, through haz on other side, and into parent metal . out of the 38 dots, 2 were over hard, gutted.
Much the same results for the single pass, and pipe to plate test.
The strange thing was, there was only hardness in the 12mm plate in all tests, there was no hardness in the pipe in the pipe to plate test , only the plate?
Another thing I noticed was the hardness of the actual unaffected parent metal, the 12mm plate was 11% harder than the 20mm plate, and 17% harder than the pipe, but they were all supposed to be the same grade, S355j2.
So the 12mm plate was harder to start with, if it had been 10% softer I may have passed?
Just got to get a new batch of steel, and get the inspector round again and give it a go again, at least I know I can weld to a standard, so bring it on lol

Cheers
Andy