Another simple weld that worked.

That same welder is what cost me a spare tire, the mount and my pride.....
Glad you only used it on something small......
Gunner

Is that a tie point for just attaching a tarp, or for holding heavy things? If it is the latter, I would personally redo it without a chain link.
i

I was wondering, along the same lines.
Let us take it the person and set-up gives a well-fused weld. (though I gather you are questioning that in this case with the Horrible Fright "Crapomatic 35" welding machine)
What's the rules for welding chain-links?
They are always quench-hardenable alloy (?) So one thinks of issues like high HAZ hardness and cracking.
I too have reflected that chain-links are just the right shape and readily available for quite a number of tasks. But should you really use them?
So how does this really pan-out?
Richard Smith

Gunner, if it wasn't for hitting that freeway exit sign, I bet that spare would still be rolling.
And for chain attachment, a keyhole is nice. Pass chain through, and put a bolt with nylock on under side. Removable, and may be a little bit safer and stronger than a weld. But Bob, I wouldn't put a lot of pressure on there, or trust it to hold anything heavy. Ask Gunner. ;-)
Steve

I wonder about that. Tons of trailers and older flatbed trucks out there with welded on hooks. I highly doubt they did anything other than bend a piece of rod and weld it on. We had hooks like that on my dad's old flatbed, and we hauled as much as 10K of grain sacks on it for years and years (over 20) lashed in place with 1/2" nylon rope. Never had a hook fail. Never even considered the possibility. I do have bolt through hooks on some things, and I have had some of those fail. Particularly those with the spring and pivot mechanism. Not an issue with this trailer anyway. 1500 pounds would break it.

I used to hate it, but since I added a cooling fan and learned to take my time and flow in to one piece and then the other with a nice overlapping puddle pattern I kinda like it for small stuff. I still can't weld more than 4-5 inches before it starts throwing crappy welds, but I couldn't weld more than 2 before.

My little Weldpak 100 has been getting a workout lately . I've been making lock boxes to weld to A/C condenser unit cages and welding them on on-site . Went back to fluxcore , since the wind makes using shield gas pretty much a waste ... and while it's a lot dirtier than solid wire/gas , it actually makes a pretty damn good weld ! I wouldn't use it to weld up a battleship , but the little portable 110v units are pretty useful within their limits .

Spend some time looking at the various supplier sites, there are tons of weld-on rated hooks and loops made for exactly that purpose. Those parts are made with appropriate materials and in appropriate thickness to not loose strength/temper/ductility from the welding heat and are also not plated.

Yes, those hooks are made from low carbon steel, are not heat treated, and are not screwed up by welding.
i

Right. The OP was talking about using a piece of CHAIN as a hook. Mild steel - yes, link of chain - no.
Bob

Weld on hooks are available, and have lots of meat along the edges you weld.
Steve

I've been thinking about this (I know - I should think BEFORE I post, not after ). Is chain really made out of anything other that mild steel? If so, why? After all, it's only ultimate strength that counts, not the yield strength, or not?
Puzzled and seeing an opportunity to learn something, Bob

jsw

Shit, now I'm even more confused, as if that were possible .
Jim's link has higher carbon steels used in higher grade chains. 'Cause it has higher "ultimate breaking strength".
Now, what I'm confused about is that I thought all steels had about the same ultimate strength and the difference between mild and "carbon steel" was the yield strength. Is that wrong? If so, what parameter is it that's about the same for all steels?
Thanks, Bob

The (Young's) Modulus of Elasticity is about the same for all, 29E6 (or call it 30). A 29 million pound pull would stretch a 1" square piece to twice its length, if it didn't break first.
Yield strength is the parameter that matters most. It's how hard you can pull without permanently deforming the part. It's generally proportional to hardness. Reasonable values for common steels are 36KSI (36 * 1000PSI) for hot-rolled, 60KSI for cold-rolled, 100-125KSI for Grade 5 bolts, 150KSI for Grade 8. Fine wire can approach 500KSI. My textbooks suggest not assuming over 2/3 of those values and in some critical cases designing at 1/3 of it. .
Ultimate strength is where it snaps, so normally you don't want to be there. One rule of thumb states that steel repeatedly loaded above half its ultimate strength will eventually fail by fatigue.
When you compare the Modulus to the Yield you see that most steel can stretch only a fraction of 1% of its length without damage.
Needs further work, but explains the terms: hth, ttfn, jsw

The (Young's) Modulus of Elasticity is about the same for all, 29E6 (or call it 30). A 29 million pound pull would stretch a 1" square piece to twice its length, if it didn't break first.
Yield strength is the parameter that matters most. It's how hard you can pull without permanently deforming the part. It's generally proportional to hardness. Reasonable values for common steels are 36KSI (36 * 1000PSI) for hot-rolled, 60KSI for cold-rolled, 100-125KSI for Grade 5 bolts, 150KSI for Grade 8. Fine wire can approach 500KSI. My textbooks suggest not assuming over 2/3 of those values and in some critical cases designing at 1/3 of it. .
Ultimate strength is where it snaps, so normally you don't want to be there. One rule of thumb states that steel repeatedly loaded above half its ultimate strength will eventually fail by fatigue.
When you compare the Modulus to the Yield you see that most steel can stretch only a fraction of 1% of its length without damage.
Needs further work, but explains the terms: hth, ttfn, jsw
Odd, but since you brought it up, I don't recall any chains in the oilfield, except holding down loads. All lifting was done with wire rope slings. And plain 1" manila rope. Yeah, I know, it's against regs and all, but at times, there's just no other way. As lifting planking when it's scattered all over a boat that's bobbing in six foot seas. Throw a timber hitch on there and go.
Didn't know that fact about failure on repeated use exceeding 50%.
Steve

The converse is that steel should last forever if the loading is kept below that, but metal fatigue is complex and sometimes unpredictable.
I heard that from an engineer who had just redesigned a failed part (not for a Rolls-Royce jet engine).
jsw

Bob - no, that's not the case - when you raise yield strength you invariably raise ultimate tensile strength.
But you are probably less wrong than the impression this gives.
Talking over a few beers with pipeline engineers:
They are not happy when the gap between yield strength and UTS gets small. Especially when there is reference to geological faults in the area, other serious aggravations the structure must survive, etc, etc. In these low-carbon no/low-alloy steels, yes, you tend to raise the yield by a lot but the UTS by not a lot.
If there is a big gap between yield strength and UTS, you tend to have a pretty widely deformed structure before failure. Which is generally good news. It put up a fight and absorbed a lot of energy before it gave out.
So if you are doing pipelines and structures, you are in a practical sense not so far off.
As I've said - conversation over beers.
I've got a lot to learn myself in this direction.
Getting into alloy steels including chains, etc - you are moving all properties a long way - but realistically speaking these are expensive (to buy and process) exotic materials compared to the vast tonnages of steel-mill steels.
Rich Smith

Wire rope has a phenomenal tensile strength. Way above that of chains. And it gets better. One link fails in a chain and the chain is broken. One strand in a wire rope snaps and the rope is still just fine. And you get warning - if there are lots of snapped strands sticking out of a wire rope, you have an readily observable warning well before failure.
Yeah - don't we know it! At the site of the emergency, tell Mr white-collar-man to stick his new "safety rule" prohibiting rope where the sun don't shine - seeing as the centuries-old tried-and-tested rope method is way way safer than a falling-out-of-its-sling inappropriate "new method" lift.
Just used timber hitches - had timber to move! - this summer. Is good - but this is another conversation!
The way you order the words is worrying. Can we do a check on what you understand?
If you repeatedly load steel above about 50% of its yield you will always eventually get a fatigue failure. Will take a lot of cycles if you otherwise have designed things right...
Below about 50% of yield - certainly below 40% of yield, a steel will never fatigue, ever, ever, ever. Some physical rule stops it happening.
(Ally doesn't behave like this - it will eventually fatigue at any stress - though the number of stress cycles to cause it makes it a theoretical point)
Hope this is all helpful and I haven't blundered too much beyond my practical experience.