Question about tempering....

[Tony_A]

If 2 knives are identical (shape and type of steel,) but each is tempered by 2 different maker's individual heat-treatment process, but both end up say, exactly 59RC for the entire blade, will both knives perfom the same? In other words, If 2 knives have the exact same hardness, shape, and type of steel, but both go through different heat treatment processes (while ending up the SAME RC), will the knives exhibit different characteristics? (edge holding, ease of re-shapening, tensile strength, etc) For arguments sake, assume both are ground out of the same slab of 440C.

 

[Hair]

They will perform different and have different characteristics.

However, I think the biggest difference will be that they will not be 59RC over the whole knife, and that the two knives will be harder/softer in different places.

Heat treating is VERY important and rockwell hardness is no way to judge a heat treat, it is just one variable.

 

[Cobalt]

ok, so rame Rc throughout, Same Steel, different heat treatment.

The blades could be similar in performance or they could be completely different, depending on how the HT's are. For example, lets say that the steel one maker used was HT'd a certain way and during Quenching and tempering the process was not done correctly, internal stresses may still exist, these internal stresses can cause stress risers and premature failure of the steel, especialy at the edge where it is thinner. The more complex the steel (alloy) the more complex the HT. That is why simple carbon steels are favorites, because they are easier to HT.

I would rather get a knife from a maker that specializes in only one or two different steels, than from one that will make anything, because he obviously cannot know all about every steel and farms it out.

Good example of HT is 1095. Ontario knives can be really good or bad depending on the batch. HT gone bad sometimes. TOP's version of 1095 is really good. When you break a knife you can tell a lot about it's HT.

but you may have been better off asking this question in the knifemaker forums.

 

[Cliff Stamp]

There are different ways to get to the same hardness, it would not tell you the blades are the same aside from the fact they are equally hard.

-Cliff