Search results

Darrin, There is no twisting, you simple seem to not be able to understand that tempering of steel happens even at room temperature, I noted not only the exact temperatures but the actual materials reference to the published data which is in a peer reviewed materials journal. There are carbon...

Chris, I knew I had read this before, very low tempering but it took awhile to track it down. I got the temperatures a bit mixed up, what Ed is sering is most likely not transition carbide but something else. I blame the fact I mixed it up as the original citation used the Kelvin's scale. It...

They are part of tempering and they form at very low temperatures as they are diffusion based. The diffusion of carbon is one of the reasons why austenite stabilizes for example at room temperature and why if you want minimum retained austenite you have to do a continuous quench. Diffusion of...

Darrin, Please read what I wrote specifically, I was not saying that tempering, as in reduction of hardness was happening. The softening happens in the second and third stage of tempering which becomes significant above 200C. Above that temperature the transition carbide is replaced by...

With all due respect Ed, do you really want people to accept anything you say regardless of its content? Would you not want people to actually think about what you say and see if it makes sense? Do you not want people to not only question what you say but demand that you have justification for...

To clarify, this is the procedure I was responding to based on the question that me2 raised : "As a base line I also sent a blade of 5160 that had been single quenched, and then immediatly tempered (not allowed to cool in the oil)" Now a few things need to be understand, I am simplifying some...

While these reactions can happen, they are more to do with the temperature used vs the number of tempering cycles. The only reason that multiple tempers can have a different effect is that there is more than just tempering, there is the quenching after the temper. For example if during the...

In order to get the properties it was designed for, hardness/corrosion resistance it needs to be soaked. It has, depending on the soak temperature, <5% chromium carbides by volume and they are very small, on the order of ~micron. It can reach a hardness of 64/65 HRC after tempering and has high...

If the blade is allowed to cool then the heat in the oil could be auto tempering it vs letting it cool more rapidly if you take it out of the hot oil. The very low temperature tempering for martensite produces transitional carbides, this is stage I tempering. If this is happening then these...

The problem is at that low a temperature the chromium put in solution will be lowered significantly, hence why the retained austenite is low. If you check isothermals, that temperature has about 9-10% Cr in solution which is going to compromise the corrosion resistance significantly. If you are...

The thing I don't understand about this idea, which I have heard many times, is how/why is sharpness defined in such a way that it is high but the knife can't cut a tomato? If the knife was sharpened in a way which would cut the tomato then would it make sense to say it was less sharp? In...

This is one of those things that comes up often and is based in reality but is a little distorted. A lot of people get frustrated with sharpening and resort to using high powered sharpening equipment, pull through grinders or high speed wheels or even angle grinders. Take a knife and press hard...

Think of this very simple fact, before hardening, there is much more carbide in the steel than after. The soaking removes a large portion of the carbide from the steel and ideally the quenching doesn't add it. However the blade gets much harder in the as-quenched state compared to after...

The reason why extended quenches are used is because when steels get a very high alloy dissolved into the austenite it lowers the Mf point and thus at the end of a traditional quench, which is at most room temperature, there is still a lot of retained austenite which is soft/weak. A cryogenic...

Credit has to be given to people like Farid for working with new materials and seeing how they work for knives. However when we see demonstrations like that we always have to ask is what we are seeing due to the steel or something else? People who have used the knife Farid demonstrated with have...