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02-23-2015, 02:49 PM
(This post was last modified: 02-23-2015, 03:16 PM by jawnn.)
I have been wanting to build a stainless steel bicycle for many years. And now I have found a good source of tubing.
But people keep telling me that stainless steel is to heavy for a bicycle. How does it compare to 4130 air plane steel?
ok the stainless is a bit heavier 0.6576 pounds as apposed to 4130 being 6491lb per foot 1x.065 in wall.
How much does a good two layer baked on powder coat weigh?
And maybe the stainless is not as flexible????
Well for a cargo bike it would be worth the extra weight.
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There is no practical difference in the density of the steel so for a given tube diameter and wall thickness the weight will be the same. But there can be a difference in the strength of the stainless tube compared to the 4130 tube due their respective mechanical properties due to forming methods or heat treatment.
Per my Ryerson catalog the 300 series stainless steels have about half the yield strength of hot rolled or cold drawn 4130 steel. Also the 400 series stainless steels can be ordered with very high yield and tensile strengths (three to four times higher than 4130).
You will need to look at the mechanical properties of the different tubing you want to use to see if the cost to benefit is worth it or not. Personally, I would like to see you make a stainless steel frame bicycle if you can afford it!
JScott, proud to be a member of MetalworkingFun Forum since Mar 2014.
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02-23-2015, 03:23 PM
(This post was last modified: 02-23-2015, 03:30 PM by jawnn.)
would heat hardening it do any good??
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(02-23-2015, 03:23 PM)jawnn Wrote: would heat hardening it do any good??
Per my book the 300 series stainless steels are only hardened by cold working so heat treatment won't work. So to make the 316L stainless tubing work you will need to use a thicker, heavier tube than 4130.
JScott, proud to be a member of MetalworkingFun Forum since Mar 2014.
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What JScott is saying is absolutely true. The basic molecular weight of the two materials is so close it's not a factor. Tensile and yield strength, Young's Modulus are all completely different for the two materials. Heat treatment of the material really doesn't make it much better in you application, it only adds wear resistance. 4130 tubing is plenty stiff.
This also why when bike frames are made out of aluminum they tend to be huge diameter and relatively thick wall. It is hard to achieve the strength of a good chrome-molybdenum steel for the price and weight. There's one piece of "old school tech" that you can't beat at an economical price.
