This is the third knife I made. I've given it several different finishes the first finish was hand rubbed then polished then a couple patina finishes and now an 800 grit cork belt with green compound followed by a coffee treatment (I was treating another blade) under a three hour soak. I usually don't consider coffee to be much of an etchant, but I think there is some banding from one side to the other. The blade was stock removal 52100 from 2013 with no cycles before heat treat.
IMO that banding is because of the method used to finish it. Those lines (bands) appear to be from the belt edges, OR are leftover scratches that you missed during the process.
I would also advise to not, in any way, buff a blade prior to any etching process (that's basically what you did with the belt and compound), but rather hand finish to a smooth, even 600 grit or finer prior to etching. Generally if I etch straight steels, I go to 800 grit, and for damascus, the finer the pattern, the higher the grit finished to.
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
Yep, classic banding for something like 52100. It could be erased by a normalization treatment before the final hardening heat. It may be irritating to look at, but shouldn't offer too much functional issues. You have a little too much undissolved carbide, probably spheroidal in nature, bunched up in the heavily chromium rich zones of the steel.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
Are we seeing something different? I see the alloy banding, but what jumped out and me, were the 45 degree "streaks" which appear to be a result of belt edges.
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
I see plenty of lengthwise banding, I was just sort of ignoring the 45° lines which could be streaks or scratches that appear to be accentuated by the angle of lighting in the photo, but I was focused on the banding.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
