JCB Welding

[Delgado]

Might be common, but today I saw some 8mm ish strengthening plates (factory) welded onto the arm of a JCB telescopic fork lift which caught my eye.

The plates were lap welded along the top and bottom, but the weld carried on from the corner of the plate about 100mm along the arm and into nothing (almost like the welder got destracted by a pretty bird or something).

They were the same on all 4 corners on both sides, so I'd guess that it was done purposefully to stop stress risers at the end of the weld?

What would be the advantages to doing this, as opposed to just welding around the corner say about 20mm?

 

[Omniata]

Could be as you've said to spread the HAZ (Heat Affected Zone) into a wider area rather than focussing it at a narrow point

 

[Drains]

Yes, it's to avoid stress risers. It's not the HAZ that's an issue, just the geometry of the weld/plate interface. The end of the weld is a stress raiser, particularly on a lap welded plate like the one you're talking about (but far less on a fillet tee joint). By extending the weld away from the plate, the stress is also moved away so cracking is less likely to start at the end of the plate. Taking the weld around the corner would be an improvement, but extending the weld into the middle of nowhere is better.

 

[Delgado]

Thanks for clearing that up, makes more sense now.

Maybe I'll use that method myself if the situation ever arises.

 

[pedrobedro]

I used to use it as an excuse for running over before I got a decent screen I'd seen the same on machines and never thought about why they did it.

 

[Delgado]

I used to use it as an excuse for running over before I got a decent screen

Not overly impressed by the standard of welding on some of their plant that I've seen, but here's a photo to illustrate what I was refering to...

 

[Tino]

I do this quite a lot, as said its to try to control the stress, sort of blend one plate into the other. I use a piece of 10mm thick copper, its important not to hit the copper with the arc because that would put lots of copper in the weld and it would crack as it cooled (defeats the object) just keep the arc on the steel and let the weld sit on the copper. I then feather the weld out with the grinder.

 

[Welderpaul]

Not seen it done like that before, looks a neat way of finishing off.
Smart fillets as well.

New job doing similar sort of work?

 

[Tino]

Yep. Feel a lot more relaxed not having to keep an eye out for my ex boss trying to kill himself or somebody else. The pics are from the old place but I'm doing the same stuff.

 

[Delgado]

Thanks for posting the photos Tino, always nice to see how others do things. I also haven't ever seen multipass fillets finished in that way, and it looks like that copper's certainly seen some action

Nice welding!

 

[Drains]

Tino, put up a picture of your Kromer would you? I want to see the holes.

 

[Tino]

My Kromer isn't to bad, just very grubby. T-shirt, jeans, other clothes and overalls don't seem to fair as well

 

[snowcat]

I'm guessing 1.6 solid in the 30Vs some ware for that hairless forearm and permermatan look?

nice little trick on the coper BTW, who you working for now or is that secret squirrel stuff?

 

[Tino]

Hi, Snowcat, “hairless forearm and permermatan look” made me smile. 1.6 is a bit brutal.
No secret, working for J.J. Bullen (Plant &Equipment) Ltd.

 

[TechnicAl]

nothing JCB does syrprises me anymore. that continuation is doing absoluteky nothing. it should go arpund the corner. someone will have set up the robot incorrectly or done the prototype wrong. if theres a wrong way they will do it but the parts are so massiveky over engineered that it doesnt matter.
i cant see inos wekds proprly as ive only got the phone

 

[Tino]

that continuation is doing absoluteky nothing.

To be honest I dont think my tails are doing much. If anything at all... Apart from looking fancy.

 

[TechnicAl]

To be honest I dont think my tails are doing much. If anything at all... Apart from looking fancy.

They look good and they avoid sharp edges so they are technically good as well.

The JCB weld is, if anything, introducing a stress raiser as there is a "notch" between the elongated weld and the plate. If it ended at the end of the plate the stresses would spread and not concentrate on that one spot.

And there are lots of welds made onto copper backing bars so it is common practice and you would need to be pretty brutal to pick up enough copper to cause cracking (hot shortness). There are some steels that contain 0.5%. Just saying so you dont get too concerned about using the copper bar.