Help selecting proper in-house HT procedure for 8620
Help selecting proper in-house HT procedure for 8620
(OP)
We are wanting to bring a case hardening process in house for some parts we are making. We are primarily looking at 8620 as the material. These are auto transmission parts. We would like to buy the material in the pre-hard condition (125ksi), machine the parts, then apply a surface hardening technique with a kiln. We are primarily looking at nitriding with Ammonia gas because it seems the safest and most practical but wondering if that process is ideal for 8620 with it's Chromium and Moly content to acheive our target hardness of HRC 60-62 with .010" thickness.
Also, would it be typical to apply a tempering technique after the surface hardening?
If nitriding is not idea for this material, are there other materials that work better with gas nitriding or possibly other surface hardening techniques that would work for a small in-house situation? ie, Cyanide gas, Methane gas in a hot oven, etc do not sound safe enough for some rookie heat treaters like us.
I have not checked as of yet but wondering if Ammonia gas is even available without special licensing.
Also, would it be typical to apply a tempering technique after the surface hardening?
If nitriding is not idea for this material, are there other materials that work better with gas nitriding or possibly other surface hardening techniques that would work for a small in-house situation? ie, Cyanide gas, Methane gas in a hot oven, etc do not sound safe enough for some rookie heat treaters like us.
I have not checked as of yet but wondering if Ammonia gas is even available without special licensing.





RE: Help selecting proper in-house HT procedure for 8620
What is the intended service or application of the part(s) that would exclude other surface treatment options, like carburizing?
RE: Help selecting proper in-house HT procedure for 8620
gas nitriding was also appealing because it does not require a quench. I am certainly open to other ideas though.
We have pretty much wrote off nickel or chrome plating due to cost and our materials are more than capable of obtaining our target hardness on their own.
RE: Help selecting proper in-house HT procedure for 8620
You may need to look closer at the differences between nitriding and carburizing in terms of case performance, and not just cost. This is a well researched subject area with information to guide you on the advantages and disadvantages of both surface treatment options based on intended service conditions.
RE: Help selecting proper in-house HT procedure for 8620
RE: Help selecting proper in-house HT procedure for 8620
RE: Help selecting proper in-house HT procedure for 8620
RE: Help selecting proper in-house HT procedure for 8620
Based on your case depth requirement I would go with carbonitriding or cyaniding. I would also recommend contacting the Metal Treating Institute for a capable experienced heat treater because of the safety requirements and furnace and atmosphere controls required.
RE: Help selecting proper in-house HT procedure for 8620
I guess we can get Ammonia but still not sure if that procedure is right for this shop. The last thing I need is a safety concern in the shop..
RE: Help selecting proper in-house HT procedure for 8620
http://www.nitromet.com/
RE: Help selecting proper in-house HT procedure for 8620
RE: Help selecting proper in-house HT procedure for 8620
besides all the good sugestions
Nitraloy 135(Best) or 4340M or 4330M Steel for Gas/Ion Nitriding
4340M induction harden to 50-55 Hrc
9310 or 8620 for Edothermic/Vacuum Carburize.
it is better farm this job out."for testing"
there would have to be a million parts to justify
up starting a dedicated heat treat shop.
plus the experience to run it.
for minimal distortion Nitride is best bet.
RE: Help selecting proper in-house HT procedure for 8620