San Mai cladding steel: 410 vs 416

jdm61

jdm61

itinerant metal pounder
Joined
Aug 12, 2005
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I have been using 416 for guards, fittings etc for like 8 + years. Like many others. I love it because it machines, sands and polishes easily. 410, which I have had to use on occasion because thin 416 stock like 1/8 got kind of, well, thin on the ground a few years back is not so easy to machine, cut, etc. I know that people use 416 for san mai cladding for field knives, but most of the Japanese san am kitchen knives seem to use 410 or some other variant of that recipe. My understanding is that 416 is more "free machining" because it has like 5 times as much sulphur as 410. My question is will that sulphur also have the effect of making the cladding more reactive to food acids and possibly give off a stinky sulphur smell? I have heard that mentioned with other steels. My other problem is that while 416 is readily available in thickness up to 3/8 or even 1/32 inch, 410 seems to only come thin. Any thoughts or suggestions?
 
410 is available in thick stock. I've seen 1" bar stock.

The reason big companies use 410 for san-mail is because it is available in sheet. 416 is only available in bar stock and is very difficult (impossible) to find in .125" or thinner from the mill. Some companies have been taking thicker 416 and blanchard grinding it down to thinner sizes.

Chuck
 
In the making of San Mai with stainless, the added sulfur, which is what makes machining more friendly in 416, is not your friend.
Literally, the sulfur makes the steel 'come apart' easily.
During forging this is called 'hot shorting'.
I buy a lot of larger round stock 416 to forge down for my fittings. If you take a piece of 416 that's 1 1/4" and forge it too fast, that little bitch will crack right now.
That's the sulfur.
I use 3/8" 1095 and .270 420SS in my San Mai to avoid the sulfur and any possibility of hot shorting during thickness reduction.
I did see all kinds of 416 in flat stock at Blade last weekend. Most of it in the .125" range.
But as far as the sulfur reacting to food acids and smelling, etc., I guess only time will tell.
I do know that stainless will etch. And some folks use vinegar and fruit juices to etch.
So it could be a problem.
 
Thanks, guys.
Karl, how hard does the 420 get and where do you get the stuff? are you using the lower carbon "regular" 420 and not the 420 HC like Buck uses for blades? As for the stank, supposedly some carbon steels are more "reactive" than others when it comes to getting a patina, but also in giving funky tastes to foods and even discoloring high acid foods like onions.
Thanks
 
Chuck, I believe that you were the first guy that told me that the previously available thinner sizes of 416 were pretty much a thing of the past a few years back. the majority of the 416 that I have bought over the last 8 or so years came from you. I just recently saw some of the gourd 1/8 stock you spoke of and that is the fist time in years I have seen it offered.
Alpha Knife Supply said:
410 is available in thick stock. I've seen 1" bar stock.

The reason big companies use 410 for san-mail is because it is available in sheet. 416 is only available in bar stock and is very difficult (impossible) to find in .125" or thinner from the mill. Some companies have been taking thicker 416 and blanchard grinding it down to thinner sizes.

Chuck
Click to expand...
 
Joe, Sheffield had a large variety of 416 flat stock in Atlanta.
I use the 420 that is actually more like '415' in carbon, because it ranges somewhere between 410 and 420.
You don't have to worry about it getting hard at 1500 degrees austenizing temps for carbon.
 
Do you use three separate pieces of steel? If so, do you have to clay the spine?
Karl B. Andersen said:
Joe, Sheffield had a large variety of 416 flat stock in Atlanta.
I use the 420 that is actually more like '415' in carbon, because it ranges somewhere between 410 and 420.
You don't have to worry about it getting hard at 1500 degrees austenizing temps for carbon.
Click to expand...
 
I use a 1095 core and 1 piece of 420 on each side = 3.
Don't know why one would clay the spine. I never clay a spine - ever.



 
Karl, Burt Foster may have told me that he did that with 52100 to keep if from going crazy and delaminating in the quench. I'm getting a bit fuzzy in my old age......wait...That is ear hair. :D Where do you get your 420SS? BTW, that blade is NICE!!! Love that diffusion line.
Karl B. Andersen said:
I use a 1095 core and 1 piece of 420 on each side = 3.
Don't know why one would clay the spine. I never clay a spine - ever.



Click to expand...
 
If your San Mai delaminates, then you didn't spend enough time at welding heat and need to rethink your process.
The biggest threat is not delaminating but splitting apart down the center, like pulling a sandwich apart. It will literally rip the core steel in two.
I do clay my ricasso, where the stainless is the thickest. That's where the big differential takes place. It can rip right at the front edge of the choil and carry into the blade.
I get my 420 where we all get our steel - Aldo.
 
Ah. That may be what Burt was talking about. Thanks for the heads up as Aldo does not have the 420 listed on his website. As for me, the only time that I have tried it , I couldn't get 416 to stick to CruForgeV. :D
Karl B. Andersen said:
If your San Mai delaminates, then you didn't spend enough time at welding heat and need to rethink your process.
The biggest threat is not delaminating but splitting apart down the center, like pulling a sandwich apart. It will literally rip the core steel in two.
I do clay my ricasso, where the stainless is the thickest. That's where the big differential takes place. It can rip right at the front edge of the choil and carry into the blade.
I get my 420 where we all get our steel - Aldo.
Click to expand...
 
Karl, do you have a theory on what's going on that would pull it apart like that? Is it the different cooling rates of the 420 vs the 1095?
 
Now that I think about, I recently saw a picture where the Hitachi white #2 steel core on a straight razor made from a piece of suminagashi laminate did that.
 
elementfe said:
Karl, do you have a theory on what's going on that would pull it apart like that? Is it the different cooling rates of the 420 vs the 1095?
Click to expand...

If you austenize the core under full thickness SS, like it will be in the ricasso area, the martensite conversion in the core wants to move some, but is restricted by the differential. So it just rips itself apart.
 
Karl, what do you think the clay does in this case, "a" or "b"?
a) prevent the core to get to full austenitization in the ricasso/ avoiding the nose in case of full aust., during the quench
b) Keeping the ss cladding hot enough for a while to move some together with the core at the clay area during conversion at the quench
 
Do you weld up the seams? Also, Chuck, I must point out to the audience that you have some SERIOUS machinery in your shop than allows you to stick titanium and other strange and exotic materials together so our milage my vary....a lot! . :D
Alpha Knife Supply said:
We laminated 410 & CruForgeV. We did not use flux.

Chuck
Click to expand...
 
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