Metallurgy question
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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
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.
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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
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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
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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. :-D
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
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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:
Will Rogers never met me.
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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
DavidCrow wrote:
Could dipping it in water after heating and bending it have caused the problem
:doh: 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
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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
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.
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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
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
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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[^]
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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[^]
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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
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.
