[AT] Heat treating tractor parts

[Grant Weir]

Hi Dean,

   I think Brett has the right idea here - use material that is already 
heat-treated.  Our shop uses the stuff all the time instead of spending 
money on small batch heat-treating.  The common designation is 4140 HTSR or 
4340 HTSR.  The "HTSR" stands for "Heat Treated and Stress Relieved".   4340 
is a little tougher than 4140 but close enough not to matter.  Ask for 
"HTSR".  I don't think you want Case Hardening as it only hardens the outer 
0.03" or so and leaves the center soft.  This is fine for a wear surface but 
does little to improve strength.

   Also, if you use 4140 or 4340 you can tell your customers that the parts 
are made from "billet chrome-moly steel dude!".  As soon as you say "billet" 
or "chrome moly" everyone will think you really know what your talking about 
and want to buy your stuff.  No kidding!

Grant Weir
Saskatoon, SK.
Canada


>From: "Brett Phillips" <bphillip at shentel.net>
>Reply-To: Antique tractor email discussion group 
><at at lists.antique-tractor.com>
>To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
>Subject: RE: [AT] Heat treating tractor parts
>Date: Thu, 17 Mar 2005 09:33:32 -0500
>
>Dean:
>
>	Jim has some good questions regarding the design of the shaft.  The nature
>of the load may also have some bearing on the material selection.  Is this
>an impact load, or more of a constant load?  For an impact type load, you
>should look for something that will remain ductile and tough, even after
>heat treating (which can be done many ways according to the desired 
>result).
>	If you're looking for something more economical than a custom heat
>treatment, you might consider something like an AISI 4142 pre-heat-treated
>steel.  This material is a 4140 steel alloy which has been stress relieved,
>and then heat treated to 28-32 on the Rockwell "C" scale.  This leaves you
>with a tough material that can still be machined with common practices, yet
>it has a tensile strength of about 150,000 psi, and very good impact
>properties.  Compare this with something like AISI C1018 (plain ole cold
>rolled squeal, er steel) at about 80,000 psi tensile, or cold rolled 4140 
>at
>~100,000 psi.
>Just another option.
>
>Regards,
>Brett Phillips
>
>
>-----Original Message-----
>From: at-bounces at lists.antique-tractor.com
>[mailto:at-bounces at lists.antique-tractor.com]On Behalf Of Jim and Lyn
>Evans
>Sent: Thursday, March 17, 2005 6:36 AM
>To: 'Antique tractor email discussion group'
>Subject: RE: [AT] Heat treating tractor parts
>
>
>How much load does the shaft have to take?  Are there any grooves or
>shoulders (other than the threads) that might cause some stress risers?
>
>Jim
>
>-----Original Message-----
>From: at-bounces at lists.antique-tractor.com
>[mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Dean VP
>Sent: Wednesday, March 16, 2005 8:20 PM
>To: at at lists.antique-tractor.com
>Subject: [AT] Heat treating tractor parts
>
>I would like some help from experienced metal fabricators.  I would like to
>know how much increased durability/strength "heat treating" a 1" round 
>steel
>shaft, threaded at both ends would offer.  The shaft is primarily under
>tensile forces only but the forces are severe in actual application. The
>threaded ends of the rods are RH and LH threads and are inserted into
>threaded cast forks at each end. Kind of like a turnbuckle.
>
>I am trying to have these fabricated at a local machine shop however, in
>order to heat treat economically they need to be heat treated in batches of
>50 each which is a larger quantity than what I would like to produce at one
>time. If not done in a relatively large batch the heat treating becomes a
>too significant part of the overall manufacturing cost.
>
>What am I gaining in this application by heat treating or what am I losing
>by not doing so?
>
>I have been advised to use 4340 steel, heat treated RC40 or 1018 steel not
>heat treated.  Help, I'm not a metallurgist. These would be for resale so
>there is an inherent responsibility to do it right.
>
>Any help is appreciated.
>
>Dean A. Van Peursem
>Snohomish, WA 98290
>
>I'm a walking storeroom of facts..... I've just lost the key to the
>storeroom door
>
>
>www.deerelegacy.com
>
>http://members.cox.net/classicweb/email.htm
>
>
>
>
>
>
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