Rockwell C & UTS 1

[HarleyE30]

Hi all,

I've undertaken a Rockwell C hardness test on a camshaft lobe & follower and both have returned a reading of 33 RC.

I've found a table which converts this to a UTS of 1048 MPa.

Now, I can only assume this relates to some sort of steel??

Thanks for any help

 

[metengr]

HarleyE30;
This is only an approximate conversion to ultimate tensile strength and is applicable to steel, in general (carbon and low alloy). To identify the steel requires different testing methods.

 

[HarleyE30]

I'm using a formula to work out the Hertzian stress at every degree around the lobe, and the formula requires a material constant, which varies for steel - on - steel, iron - on - iron, steel - on - iron etc etc...

the formula doesn't take into account which steel it is, just simply 'steel'. Can I safely assume the material is indeed steel?!

 

[redpicker]

In all likelyhood, yes. You can check it with a magnet as an additional test. There are few materials that are magnetic that would have a hardness of 33 HRC, and I'd guess that for most cam applications, it is probably steel. I would have expected a cam lobe to be much harder, though, more like 55-60 HRC, but that is making assumptions about the applications that are not evident in your post.

rp

 

[EdStainless]

You might want to do some superficial Rockwell's also.
Many cams are case hardened and with RC you may be punching through the surface.
Though RC33 does sound rather low for a cam lobe.

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