Bohler says at least three tempers and cryo in between.
We are dealing with M390 after all.
Yet it is easy to spot that the great majority of production knives fail even before in the way that they are not austenized at > than 1150°C. This is the very first step to avoid precipitation of big chunks of Cr carbides. As this way we achieve the best possible Cr carbide dissolution to start with. This means more Cr in solid solution for stain resistance, more C for hardness (say edge stability)
Molten salt bath it the best quenching media.
IMHO stopping quenching at more than 70-80°C ain't properly the best practice.
But in production world I'd be glad even with 5bar gas quenching (instead of Molten salt bath).
And Bohler endorses my thought.
I eagerly wait for the very first production M390 knife heat treated this way.
We are dealing with M390 after all.
Yet it is easy to spot that the great majority of production knives fail even before in the way that they are not austenized at > than 1150°C. This is the very first step to avoid precipitation of big chunks of Cr carbides. As this way we achieve the best possible Cr carbide dissolution to start with. This means more Cr in solid solution for stain resistance, more C for hardness (say edge stability)
Molten salt bath it the best quenching media.
IMHO stopping quenching at more than 70-80°C ain't properly the best practice.
But in production world I'd be glad even with 5bar gas quenching (instead of Molten salt bath).
And Bohler endorses my thought.
I eagerly wait for the very first production M390 knife heat treated this way.
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