Thread: Grain size / work hardening

Hi All,
Bruno has posted an excellent shot to show that grain refinement from forging. However, {please correct me if i am wrong} i have always been under the impression that when the steel goes through the heat treating processes the grain refinement from forging is undone. The soak times produce an even grain size. This can be adressed in two ways - differential hardening {controlled edge quench with depth in quenchant or clay coating} or edge packing can be re-done in a cold forging process after heat treat, {popular with Japanese smiths} which works on knives, but as a razor has such a thin cross section i probably would not try cold forging that....
Like i said - i could be wrong. There are many ways to get great results, and many many more to get less than great.
Love having my mind stretched and no where better than here with so many knowledgeable fellers.
Respectfully,
Adam

If I have some time this weekend, I'll follow up with more break tests after various stages of working to see how the forging and annealing process changes the grain, starting from factory annealed stock.

Adam, I don't know the precise answer to your question. If I get to do more tests, it will probably be visible in the break results.

I know this is an old thread but...

The main reason there is grain growth to this magnitude is due to forging at welding temperature. When steels are heated to a this level grain growth starts to set in. Welding temperatures are to high for regular forging of tool steels and can lead the this problem. If you forge at temperatures of no higher than 1100 Celsius you will have a smaller forging window, but an increased level of grain refinement and better edge retention.