D2 Hardening 1

[mikeymate]

Hi all,
We have been, for a few years now, hardnening the replacement parts on our customers tools by a very basic hardening method of using an industrial oven to heat up to 960c and then heating the part until it glows red (about an hour), then simply dumping it straight in quenching oil.
Could anyone hazzrd a guess at the kind of rockwell we should be achieving ? we are replacing parts that were 58-60 Rockwell, so would like to reach those figures. The metal we use and replace are both D2. The parts are cylindrical and can vary in size from 10mm wide to 30mm wide, and 50-160mm dia. If anyone could attempt to let me know the correct method and timings in oven and oil e.t.c. would be great too..
Thanks in Advance

 

[unclesyd]

First off D2 is an air hardening tool steel, do not oil quench. There is no telling what you are getting metallurgically wise by your present heat treatment.

Hardening:
Heat to 1850°F in a protective atmosphere for 30 minutes per inch of thickness. Remove form furnace and air coll in still air until cool to touch.
Tempering:
Heat to 1000°F hold for 2 hrs and coll in still air.
This material should have two tempers for optimum results.

Can you come back with the end use for your product.

 

[ajack1]

This should help

http://www.westyorkssteel.com/D2.html

 

[mikeymate]

The tools are used in the printing and converting trade. They are called magnetic cylinders, and look like this..

http://www.rotometrics.com/roto/Web...D58AE7057C86257444006FC592?opendocument&dl=en

The replacement parts are the beaeres either side of the magnetic body, these wear down over time, and go out of working tolerances, and need to be replaced, and cylindrically ground back to correct spec within 2 microns. So the harder they are the longer they last. And they do millions of revolutions.

 

[redpicker]

For maximum wear resistance, D2 should be in the 58/60 HRC range.

D2 is a high carbon tool steel, so you will need to protect against decarburizationn with a protective atmsophere, as mentioned above, or in vacuum or a salt bath. Also, a double temper is recommended, perhaps a cryogenic treatment in between tempers.

You might consider a nitriding surface treatment. If it is wear on the ID surface that you are concerned about, you should consider ion-nitriding to get good results on the ID.

rp

 

[ajack1]

If you are thinking about nitriding the surface you need to consider the tempering more carefully, some “coating” processes require triple tempering and most if not all require the tempering to be at a greater heat than the coating.