|
I had a spring break on a piece of yard equipment. Since it was just the curved tip on the end that broke off, I figured I could just heat up the end, and bend it around to form a new curve. It worked, at least until I put it in place. Once tension was applied, it broke again right at the spot where I had formed the curve. This happened twice. Now I'm wondering what I did to the metal to make it so brittle. Could dipping it in water after heating and bending it have caused the problem?
- DC
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
|
|
|
|
|
Yes - springs are usually a medium carbon steel (less carbon than edged tools, more than structural items). If you let it air cool after bending it will be soft (due to large rounded crystals forming during the cooling process), while if you quench it immediately after bending (when it is still quite hot, not necessarily visibly red) the crystals will be needle-shaped and quite brittle. If you find an introductory book on blacksmithing it should have material on how to properly work with springs.
I used to be a blacksmith for a while, when I needed a break from the programming industry. However, I'm a far better smith than salesman, so I went back to programming since I'd gotten used to eating.
|
|
|
|
|
Bummer - needing to eat.
Dave.
|
|
|
|
|
Heating and rapid cooling will make metal stronger but more brittle.
It is called Quenching.
It is how Japanese swords are made.
They allow the main part of the blade to cool slowly, but quench the cutting edge.
The main body remains more maleable and less likely to break whilst the hardness of the edge allows for sharper edging.
---------------------------------
Obscurum per obscurius.
Ad astra per alas porci.
Quidquid latine dictum sit, altum videtur .
|
|
|
|
|
Dipping it in water could have hardened it more depending on how the metal is made up and thus makeing it more brittle.
In a welding school we had to use a piece of "Tempered Steel" and retemper it by reheating and dipping it in water.
If it rang when we droped it it was correct and we passed.
You may try a slow cool and see if that helps.I have had to stick stuff in clean dry sand to slow the cool before.
Springs can be tricky,they end up being to hard(break) or to soft (bend)
I found an article that most everyone just recomends replacing the spring because of the dificulty getting it to the correct temper. They also suggest it may already be work fatigued.
http://www.homesteadingtoday.com/country-living-forums/shop-talk/489272-if-how-re-temper-coil-spring-end.html[^]
|
|
|
|
|
DavidCrow wrote: Could dipping it in water after heating and bending it have caused the problem?
Absolutely! That quenching causes steel to become brittle, which is odd considering that quenching non-ferrous metals anneals them instead. You'll have better luck letting it cool slowly, but you may still find it's fragile near the interface of the heated part and the still springy tension coils. If you had the means, holding the hook you've made at about 500F for a few minutes would allow grain growth and remove the brittleness, then you could let it air cool. But while doing this you'd need to keep the spring body cool to keep it strong. It's an art, and it's probably easier to just replace the whole spring. 
Will Rogers never met me.
|
|
|
|
|
Roger Wright wrote: It's an art, and it's probably easier to just replace the whole spring.
Which is what I did. It was only a $4 part. Due to shipping, the downside is I have to wait until next weekend to finish the garden.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
|
|
|
|
|
DavidCrow wrote: the downside is I have to wait until next weekend to finish the garden.
Darn the bad luck.. Maybe a few beers will help to pass the time. ![Beer | [beer]](https://www.codeproject.com/script/Forums/Images/beer.gif)
Will Rogers never met me.
|
|
|
|
|
I believe you may need to use oil instead of water - read up on it (and be very careful)...
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
|
|
|
|
|
As others have said, yep - that'd do it.
Aside from quenching in oil, you may also get some mileage from quenching in methylated spirits. Yes really!
Years ago as a jeweller, we'd quench in metho to make the metal as soft as butter. Since it's got such a poor heat capacity, it can't carry the heat away anywhere near as fast as water does, so it would make the metal even softer than if it was heated then allowed to air-cool. Depending on the size of the article, this may be a very dangerous proposition - we would always submerge the metal in enough liquid to well and truly cover it. I.e we'd use about 20 or 30 times the volume of the hot metal.
Red-hot copper/gold/silver wire/bar quenched in metho ended up considerably softer and more ductile than quenching in water.
|
|
|
|
|
At first I thought you were complaining that you had to spend you Spring Break on a riding lawn mower. Bummer of a holiday, that.
|
|
|
|
|
kdmote wrote: At first I thought you were complaining that you had to spend you Spring Break on a riding lawn mower.
I did...three acres worth. I then started tilling the garden.
kdmote wrote: Bummer of a holiday, that.
Quite the opposite, in my book.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
|
|
|
|
|
DavidCrow wrote: Could dipping it in water after heating and bending it have caused the problem
Yep. WHat you need to do it get it red hot, the dip it in water, then reheat it to blue, then dip it. That way you will make 'spring steel' and hopefully maintain a nice blue colour.
"The whole idea that carbon dioxide is the main cause of the recent global warming is based on a guess that was proved false by empirical evidence during the 1990s." climate-models-go-cold
|
|
|
|
|
Not really relevant now that you have replaced the spring, but another aspect of dealing with forming spring steel is hydrogen embrittlement http://en.wikipedia.org/wiki/Hydrogen_embrittlement[^]. I have experienced this problem in aircraft production - took a lab analysis to discover the cause of the sudden fractures and a vendor change to solve it.
|
|
|
|
|
In welding class we had to peen our welds - hitting them while still red-hot with the rounded end of a ball-peen hammer. It was to relieve the stresses caused by the differential cooling the two pieces as they cooled at the very-localized, very-dramatic heat differential of the weld line. Something about carbon, crystals, and brittleness was mentioned too.
According to Wikipedia's article on peening, " in 1930, a few engineers at Buick noticed that "shot blasting" (as it was originally termed) made springs resistant to fatigue. " I always tend to peen my welds -habit more than necessity since everything I weld tends to be over-engineered.
Peening the new bend as it cooled should have made it "tougher", but YMMV.
-Bob
|
|
|
|
|
Shot peening is normally used to put the surface layers into compression which improves fatigue life through fewer stress reversals.
Peening of welds is generally frowned upon due to inducing localized brittleness which may induce cracking.
http://en.wikipedia.org/wiki/Peening[^]
|
|
|
|
|
Interesting - perhaps that's why we were taught to peen while our welds and surrounding metal were still red hot - relieves differential cooling induced stresses. Compare with the cold-metal shot-peening that induces surface compressive stresses.
-Bob
|
|
|
|
|
There are a variety of quenching processes. In general the faster, the more hard and more brittle the metal. In really rare metals, this quenching starts in a 540 degree oven that you spend a couple of weeks getting it down to 150 degrees where you can then air cool it. I haven't looked at this since the 70's when I was studying to be a Mechanical Engineer.
|
|
|
|
|
My youngest is doing well in all of her classes with the exception of 'Walking'.
She has a 'D' in that class.
Maybe I should stop buying her gum...
|
|
|
|
|
She sells Gum?
---------------------------------
Obscurum per obscurius.
Ad astra per alas porci.
Quidquid latine dictum sit, altum videtur .
|
|
|
|
|
Yes - to caricature Yorkshiremen, over the internet. Her site is called eBayGum.
|
|
|
|
|
I thought it was GumBucket?
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
|
|
|
|
|
Two Girls and a Piece of Gum?
djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.
|
|
|
|
|
I am sooooo not going there.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
