Author Topic: oil quench and tempering  (Read 3404 times)

Offline LRB

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Re: oil quench and tempering
« Reply #25 on: September 22, 2018, 04:11:38 PM »
  You won't correct mushy with heat treat, assuming the spring did not take a set bend. If a V spring, heat to red and spread the arms a tad, then re-heat treat. If that doesn't work, you just have to replace the spring with one of thicker steel. Steel flexibility is controlled by it thickness. Example: 1/4" thick Bowie knife vs 1/16" butcher knife, both of the same profile, steel, and heat treat.

Offline Dan Fruth

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Re: oil quench and tempering
« Reply #26 on: September 22, 2018, 05:11:25 PM »
Jack Haugh made all springs from 1095 and tempered them with burning sperm whale oil. It worked for him. I use lead and a thermometer (thanks Jerry H ) and the results are always great...But make sure the spring is hard when you start.
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Offline LRB

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Re: oil quench and tempering
« Reply #27 on: September 22, 2018, 07:18:26 PM »
  1095 offers a small but not insignificant challenge as to getting it to it's potential maximum hardness. It's critical heat is from 1475° to 1500°, with it being best to stay closer to the lower temp. From critical, it requires less than one second in temp drop to under 900° to get it to it's max hardness. A brine quench is about the only quench that will achieve this goal, but a quench in Canola oil warmed to about 130° is close enough for most practical purposes. There are of course commercial oils that are better, but expensive. It is a good practice to heat cycle whatever part you make from this this or other steels. Heat cycling reduces the grain size giving your part a stronger structure. Do 3 cycles total starting at about 1600°, down to about 1500°, and the last at about non-magnetic. Let each cycle air cool until you can handle the part, then harden and temper. Using a steel with less carbon than 1095 makes for a better degree of success. 1075, 1080, 1084, 5160, and some others are much more forgiving in their heat treat results and in use.
« Last Edit: September 22, 2018, 07:30:26 PM by LRB »