Hi Guy's

Iv'e been diggin' around on the internet off and on for a couple of days and can't seem to find out what the nose (Time to Quench) is on 5160. The reason I'm asking is I'm tring to do an edge quench on a hunter blade about 4.5" long. Iv'e done it on the same blade 3 times and only about the first inch or so of the tip gets file skating hard. :( I'm quenching from 1525 in Canola oil heated to 120 deg. I'm not wasting any time getting the blade from the oven to the quench. I hold the tip in the quench for about 2 seconds and then lower the rest of the edge into the quench and hold it until it stops smoking (about 10 seconds or so) and then submerge the hole thing until it cools to about 150 to 130.

I hope someone can help.

Jerry

The time to get from austenitizing heat to below Ar1, as well as any bainite formation appears to be around 5 seconds, but I doubt this is your issue. I would focus on your quench sequences.

First off, it is significantly harder to achieve maximum hardness using the edge quenching technique, Thermal extraction rates are really messed up by the shallow quenchant and the residual heating from the spine. I will not even go into the canola oil as it is none of my business.

I have had to deal with the sequence issues many times while teaching at the ABS school. Put the edge in first, as it is the largest thermal mass to get cool, and then tip the point down into the oil. Do not do either too fast or the hardness will suffer. Put the edge in and count off "1000- one" then lift to sumberge the point, then back down with the edge. do the 1 second counts on the rocking until the spine is entirely black, then full quench.

Do not be concerned about the delay in getting the tip. Cooling the major mass of the blade will over come this and allow the minor portion of the tip to catch up. As long as you are above Ar1 the time limits do not really count. But when you begin cooling you will quickly drop into transformation ranges and then you need to be quick. That is why a well timed quench medium can be very import. Not only does it have to cool things, it has to cool things at the correct rate at the right times ;) . Good luck, I hope this helps.

Thanks Kevin. It does help. Something new to try with the sequence. I appreciate your taking the time to answer
Jerry