Material selection and heat treatment of pins

[gibsoni]

Hi All,

FIrst timer here, great site!

I am after your suggestions on what steel to make 25mm pins out of for a large tractor mulcher. The pins are 25mm round with a head on one end and a split pin in the other. The old pins are case hardened I think (or flame etc) as a pin punch doesnt touch them, yet the core is much softer as expected.

At my disposal is a standard machine shop and a small furnace.

Is 4140 or 1045 suitable for this? Is the supplied hardened and tempered state sufficient for maximum strength? I would then attempt to flame harden this by hand with a oxy acetylene torch with a water jet attached. Workable?

If not - I would greatly appreciate your suggestions. The old pins were breaking (clean breaks, rather than bending)

Kind Regards, Iain.

 

[Metalguy]

Are they loaded in shear? Was wear present? Fatigue evidence? Any photos?

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[gibsoni]

Hi,

Thanks so much for your reply. I will take a photo and post it this evening or tomorrow morning (pin is not here at present). The pin is loaded in shear. There is some wear evident from the blades (will show in photo).

Regards, Iain.

 

[gibsoni]

Hi,

Photos below show the broken pin. To avoid confusion, there is actually 1 and a half pins I have photographed - more than 2 halves, so if they dont match up, its the wrong mate.

 

[gibsoni]

Additional photos

http://files.engineering.com/getfil...15c0-46b9-b700-0275dc52822b&file=IMG_2396.jpg

http://files.engineering.com/getfil...d7ac-4f88-9867-1176cd23ccac&file=IMG_2395.jpg

http://files.engineering.com/getfil...0011-4ee3-98a7-f260f98f2324&file=IMG_2394.jpg

http://files.engineering.com/getfil...aacf-460e-9a78-1fffb6af79de&file=IMG_2391.jpg