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Well, we thanked Ken for opening this topic up in our first post here and encouraged comment so thank you all very much. We are bouncing in here because a post by Jan touched on an area that we have regarded as one of the possible explanations for the part of the edge improvement phenomena that we have attributed to Sharp Pad and work hardening. When working with common stainless kitchen knives in the HRC55 hardness range we see burr formations that behave nothing like "brittle" or hardened steel but very much like soft steel. Very much the same process used to "work and bend" a paperclip into two pieces is required to "work and bend" the burr away from the edge. Is this definitive evidence in support of the hypothesis? Of course not. It does cause us to wonder though if the steel that composes the burr has been transformed in some manner. There are other possibilities as well but there is no need to speculate. As mentioned in our original post we will be testing for the efficacy of this process. If the tests indicate significant edge improvement we will work backward and try to understand why. So please don't go away! EOU will soon be dining on duck or eating crow. Possibly something in between - cruck?
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(03-18-2017, 01:22 PM)EOU Wrote: Well, we thanked Ken for opening this topic up in our first post here and encouraged comment so thank you all very much. We are bouncing in here because a post by Jan touched on an area that we have regarded as one of the possible explanations for the part of the edge improvement phenomena that we have attributed to Sharp Pad and work hardening. When working with common stainless kitchen knives in the HRC55 hardness range we see burr formations that behave nothing like "brittle" or hardened steel but very much like soft steel. Very much the same process used to "work and bend" a paperclip into two pieces is required to "work and bend" the burr away from the edge. Is this definitive evidence in support of the hypothesis? Of course not. It does cause us to wonder though if the steel that composes the burr has been transformed in some manner. There are other possibilities as well but there is no need to speculate. As mentioned in our original post we will be testing for the efficacy of this process. If the tests indicate significant edge improvement we will work backward and try to understand why. So please don't go away! EOU will soon be dining on duck or eating crow. Possibly something in between - cruck?
EOU, your promising statement is appreciated. Thank you for dropping hints concerning the burr formation and its behaviour. Good luck in hypothesis testing. Keep us posted, please. 
Jan
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Thank you Jan for your well measured response to our previous post. Without a doubt, this is a head spinner with or without a degree in metallurgy. Work hardening, plastic deformation, stress hardening, stress fracturing and metal fatigue seem to all be interrelated and sometimes interchangeable terms depending on whether we are speaking to the virtues and benefits or the detriments of work hardening. To question whether hardened and tempered steels can be work hardened might seem to question whether those same steels are subject to stress fracturing and metal fatigue but of course we know that they are. Evidence of plastic deformation, a hallmark of work hardening, is common with well tempered knife blades. Who hasn't put a permanent bend in the tip or blade of a knife? None of this is proof, one way or the other, and that is what we will be seeking over the next few months. Our Exchange master will close this thread after this post and it will be reopened when our tests are complete. We look forward to that day and once again to Ken, Thanks for bringing it up!
