Discoloration after HT?

[LightningSharp]

Greetings,
After taking my first knives from the oven and sanding them with 180, I've noticed some splotches that are not sanding out. Could the coloring difference be that the temper is different?

My D2 recipe:

heat to 1100 hold 5min
heat to 1500 hold 5 min
heat to 1860 hold 20 min (should this be longer?)
Plate quench....
heat to 450 hold 2hrs
cool
heat to 450 hold 2hrs
cool
RC 58-60

Does anyone see any problems?

Lee Haag

 

[EdCaffreyMS]

Often a splotchy appearance will happen if the soak wasn't long enough..... any heat treat recipe you find for any steel is only a starting point...often times you will have to experiment to get the exact results you seek. What many don't realize/understand is that the vast majority of industry heat treat data available is based on a 1" cube (1'x1"x1") of the specified material, and although using the recommended data will get you "close", it still requires you to "break a few eggs" to get optimal results for a specific item....in this case a knife blade.

That's not to say its your exact issue here (there are a number of possibilities), but I've had similar things occur with CPM154, and after experimenting with increased soak times my issues disappeared.