steel strength
steel strength
(OP)
Hi guys
Is it possible a steel to withstand 1600MPa in bending, because i'm a witness of that by applying 260Nm (90kg x 0.3m)bending moment of a shaft Ø12,
It withstood it even without crook.
According to the formula σ = (32.M)/(π.D^3) = 1532MPa
Is that true or I'm wrong in the calculation.
Thanks in advance for your opinion
Is it possible a steel to withstand 1600MPa in bending, because i'm a witness of that by applying 260Nm (90kg x 0.3m)bending moment of a shaft Ø12,
It withstood it even without crook.
According to the formula σ = (32.M)/(π.D^3) = 1532MPa
Is that true or I'm wrong in the calculation.
Thanks in advance for your opinion





RE: steel strength
If one end is fixed (in a collar or similar) then you have to change things a bit.
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P.E. Metallurgy, Plymouth Tube
RE: steel strength
(264.87Nm x 32)/(π x 1.2cm ^3)= 1561MPa. If add the shear and contact stress it must've exceed 1600MPa
I did that experiment in order to check the hardened steel strength myself as the information I found differs too much.
But if my result is correct why there is no such amount of strength in any of the steel properties lists.
But I prefer to believe rather on my eyes then the lists
Am I going to make a revolution in the engineering science?
RE: steel strength
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: steel strength
Did the end deflect about 40mm?
Are you sure that there was no permanent deformation?
I am sorry but unless this is some very special grade of steel I cannot imagine a 1/2" bar, 12" long, taking a 200lb end load without some set.
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P.E. Metallurgy, Plymouth Tube
RE: steel strength
Today I tried with another metals and the results was also amazing.
-Drive shaft from a car Φ22 in bending 1600Mpa (my weight 90kg at 1.8m + weight of the lever)and probably more as I did not dare to broke it, because it can injure me
at the same way I obtained
-piece of concrete rebar Φ14, in bending - 1400MPa starts to deform.
-Threaded dowel (plain carbon steel) M14 in bending 800Mpa starts to deform
and
-Threaded dowel M8 (Φ6 inner) in tensile about 800Mpa tears (23000N force - my weight through a lever)
So I feel a bit confused, considering the difference with values of strength I've known
Who don't believe can try, it's pretty simple
RE: steel strength
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P.E. Metallurgy, Plymouth Tube
RE: steel strength
Shafts OK but what about the low carbon steel shouldn't its ultimate strength be about 350Mpa(51ksi) not 800MPa (116ksi)
RE: steel strength
Automotive shafts for driveline and transmission applications are either surface hardened by induction heat treatment, or by case carburizing. Typical surface hardness is 59 HRC minimum, which means that a surface bending stress under maximum load should be less than ~ 2200 MPa. The strength of the part varies from the surface to the core depending on the steel grade and the details of the heat treatment.
RE: steel strength
And in conclusion I accept it's normal automotive shafts to withstand 1500+ Mpa.
But I wonder what is the predetermined stress in the design of high strength auto parts like drive shafts ets