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How to forge stainless steel? Forging a 14C28N chef knife

How to forge stainless steel? Forging a 14C28N chef knife

I really enjoy forging, and have ended up making mostly just chef knives.

I like that I get to use them more often than I would an outdoor style knife.

What I am not a fan of, is giving away a knife and having to explain about carbon steel in the kitchen..

It will not rust, just keep it dry. But it will patina.. it will develop a cloudy, grey patina with use from cutting acidic food stuffs. If you cut a lemon and leave it on the bench, you will shortly have a big blue or brown ring on the blade.

Like everyone else I have also done stock removal from stainless steel. It is awesome being able to grind out a blade, and grinding bevels from square stock is easier than grinding on a forged blade where nothing is ever flat and parallell :)

So I wanted to forge stainless steel, getting the best of both worlds!

I have done it a few times now, had one or two break and what seems to work for me, is to forge at a lower temperature than the steel will harden at.

If this is the optimal way to do this, I do not know. I have read you are "not supposed" to forge stainless steel, so I am keen to learn how this one works over time in our kitchen. Will it be less corrosion-resistant? Will it hold an edge as long as our other 14C28N chef knives?

14C28N is a Swedish stainless steel, the next generation of 12C27, made by the same manufacturer.

Very popular with knife makers due to ease of heat treatment and having a bunch of it at the workshop, it has been the stainless I have experimented with when forging.

Forging Stainless Steel 14C28N

  • Forge from 995 C, staying low and away from heat treatment temp 1050-1090 C
  • Stop forging when no longer red
  • Forge in small increments, expect the steel to move much slower than carbon steel
  • The steel dents more than drawing out so expect to spend more heats per process
  • I "normalised" by heating to 1000 C and leaving to air cool without the stress of being hammered on x 3 ... no idea if this does anything to stainless steel, but thought it would not hurt

Hardening 14C28N:

  • Sandvik says hold time of 5 min for 2.5 mm thickness, 12 mins for 4 mm 
  • I held at 12 mins, thinking spine thickness and not edge thickness mattered
  • Quenched from 1060 C into medium-speed quench oil for 5-10 sec
  • Wiped with paper, into plate quench to help harden flat and true
  • Cleaned up profile on grinder and rough grind to see tempering colours
  • Kitchen freezer -20 C for 30 mins
  • Tempered at 175 C for 2 hours x 2
  • Estimated 60 HRC according to the Sandvik heat treatment recipe

Here is a video I made from my process, including making the handle.

What do you think of the sound of the steel, does it sound any different than hammering carbon steel to you?

18th Aug 2022 Bjorn J

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