Fujiwara Kanenaga, anti-rust steel and "real hamon".

[Bruno]

Hi everyone,

 

I have been told that one smith Fujiwara Kanenaga succeed to produce a "real hamon" on stainless steel kaigunto. By real hamon I mean oil quenched not due to polishing effect.

 

I also have been told the contrary, that on stainless steel it is impossible to have any real hamon due to the presence of chrome.

 

Fujiwara Kanenaga was a metalurgist so he had probably a good knowledge with steels.

 

I have seen a couple of his swords and must say that all of them looked to have hamon made with stones.

 

So my question are:

 

Do all these Kanenaga's anti-rust steel swords have fake hamon?

 

Do some have fake hamon and others real? Maybe in some cases the composition of the steel was change to allow a real hamon (oil quenched)? I do not know.

 

I would be happy to read what you guys know about the subject.

 

http://www.h4.dion.ne.jp/~t-ohmura/gunto_121.htm

 

Thanks

[Bruno]

To those who own such a sword, you are welcome to post photos and share also your opinions.

[Bruno]

Finally, does one know if all these swords are sunobeto or if they have shingane?

[sanjuro]

As far as I know stainless steel does not have the ability to accept differential hardening nor does it have a 'grain' as does normal steel. It cannot therefore have a true hamon or indeed hada such as we see in true nihonto.

 

Having said as much, I or at least my words, will probably be torn to shreds by the metallurgists among us. I do however have broad shoulders and can bear the 'slings and arrows' of adverse opinion whilst perhaps learning something.

[Bruno]

Thanks Keith for your words. I am not a metalurgist neitheir!

 

In fact, according to the same person, it seems anti-rust steel and stainless steel are two different steels, which I did not know ten minutes ago. I thought they were the same thing.

 

The hamon seems to have be issued on anti-rust steel not stainless steel.

[cabowen]

Stainless steel is steel with more than a certain percentage of chromium. I do not know if the steel used in these WWII era swords has enough chromium to meet the modern definition, or simply enough chromium to be anti-rust....

 

It seems that folklore says that Kanenaga was able to get something similar to a hamon on these swords. I have never seen one that looked like anything more than an etched or stoned on hamon. They were not forged as I understand it, from several pieces laminated together.

[John A Stuart]

Martensitic stainless steels are hardened by austenitising, quenching and tempering much like low alloy steels. Austenitising temperatures normally are 980 to 1010°C, well above the critical temperature. As-quenched hardness increases with austenitising temperature to about 980°C and then decreases due to retention of austenite. For some grades the optimum austenitising temperature may depend on the subsequent tempering temperature.

 

Preheating before austenitising is recommended to prevent cracking in high-carbon types and in intricate sections of low-carbon types. Preheating at 790°C, and then heating to the austenitising temperature is the most common practice.

Martensitic stainless steels have high hardenability because of their high alloy content. Air cooling from the austenitising temperature is usually adequate to produce full hardness, but oil quenching is sometimes used, particularly for larger sections. Parts should be tempered as soon as they have cooled to room temperature, particularly if oil quenching has been used, to avoid delayed cracking. Parts sometimes are frozen to approximately -75°C before tempering to transform retained austenite, particularly where dimensional stability is important, such as in gauge blocks made of grade 440C. Tempering at temperatures above 510°C should be followed by relatively rapid cooling to below 400°C to avoid "475°C" embrittlement.

 

Some precipitation-hardening stainless steels require more complicated heat treatments than standard martensitic types. For instance, a semi-austenitic precipitation-hardening type may require annealing, trigger annealing (to condition austenite for transformation on cooling to room temperature), sub-zero cooling (to complete the transformation of austenite) and aging (to fully harden the alloy). On the other hand, martensitic precipitation-hardening types (such as Grade 630) often require nothing more than a simple aging treatment. John

[runagmc]

As far as I know stainless steel does not have the ability to accept differential hardening nor does it have a 'grain' as does normal steel. It cannot therefore have a true hamon or indeed hada such as we see in true nihonto. Having said as much, I or at least my words, will probably be torn to shreds by the metallurgists among us. I do however have broad shoulders and can bear the 'slings and arrows' of adverse opinion whilst perhaps learning something.

Wouldn't the lack of hada on a stainless steel sword be due to the lack of any forge welding/folding? If a billet of stainless steel was folded and forge welded before being drawn to length, wouldn't it have a hada just like any other folded-steel sword?

[Bruno]

This one is said to be oil quenched, just for example:

 

http://www.ebay.com/itm/140739899714?ss ... 1423.l2649

[kusunokimasahige]

I think one should not forget the fact that polishing stones leave their microparticles on any form of metal...

 

Try using Jizuya and Hazuya on many types of metal. You will very soon make it (to the untrained eye) look like there is Hamon present.

 

There are self-taught polishers out there who make swords look like they have very nice Hamon, most of which do not even follow the real Hamon if at all present.....

 

KM

[Bruno]

KM

 

Actually the boshi gives it away - look for the difference in the colour of steel. Interesting that there's no patination on the nakago, though theresome dark patches. There's what looks like the result of a very small bit of corrosion on one patch of the blade (plus a fingerprint). Don't think it is stainless maybe anti rust steel with less chrome that allows formation of hamon?

 

Well I do not know a lot that is why I asked here.

[kusunokimasahige]

I am not sure about what you say last about less chromium inside the steel causing rust, but I can tell you that my so called stainless steel diving knive after three days in the sea was rusted like i never seen rust before

 

KM

[Bruno]

What I meant us as far as I understand, there is :

 

stainless steel : with enough chrome not to allow a visible oil quenched hamon

 

and

 

anti rust steel : with chrome but less than with stainless steel that allow a visible oil quenched hamon

 

Both steels are very similar for the eyes so hard to tell which on is it.

[GregD]

That all said........there is a reference in Fuller and Gregorys in reference to stainless steel :"They successfully this new steel called Taiseiko(or Fuseiko) for millitary sword making managing to bring out the hamon.I have seen two of these swords.Having a metal working background,alot of that having to do with heat treatment of steel,I can assure you that these blades were seletively heat treated.My only regret is not buying them when I had the oportunity.

Greg

[ROKUJURO]

....Wouldn't the lack of hada on a stainless steel sword be due to the lack of any forge welding/folding? If a billet of stainless steel was folded and forge welded before being drawn to length, wouldn't it have a hada just like any other folded-steel sword?

You cannot fold and weld stainless steel because of it's chromium content. When heated, these steels produce a fine layer of chromium oxide on their surfaces acting like a separating coating preventing any welding. Technically, you could forge-weld such steels only under vacuum conditions or with absence of oxygen.

 

So-called stainless tool steel is likely to rust under favourable (or unfavourable, if you like) conditions as long as it contains carbon. As far as I know there is no tool steel that is absolutely rust-proof, but these steels oxidise very slowly.

 

On the other hand, stainless steel for household use (e.g. sinks and some kitchen tools) lacks a carbon content and thus cannot be hardenend and used for cutting instruments.

[Lance]

I don't have any pictures to back it up (I'll have to keep an eye out for pics online to add or local small gun shows) but in the past I've had 2 Kanenaga anti-rust swords. Both were in high quality shin gunto mounts instead of naval mounts, one with a removeable leather cover over steel saya with 2 hangers, the other had higher quality mounts with pierced tsuba and gloss brown metal saya with a single hanger.. Both had real hamon with a thin controlled noiguchi in suguha, and had more in common with what you'd see on a traditionally made sword, not at all like the thick indistinct oil hardened hamon or the fake brushed on hamon usually seen on "stainless" navy swords, and the lower quality swords in late war 1944 gunto mounts with tan metal saya. One was in excellent polish, appeared to have hada, but that could have been similar to mantetsu blades that are said to not be real grain. Anti rust swords wouldn't be considered gendaito but probably belong in the same quality level as Mantetsu and Murata-to above the usual Seki/Showato.

Regards,

Lance

[Bruno]

I don't have any pictures to back it up (I'll have to keep an eye out for pics online to add or local small gun shows) but in the past I've had 2 Kanenaga anti-rust swords. Both were in high quality shin gunto mounts instead of naval mounts, one with a removeable leather cover over steel saya with 2 hangers, the other had higher quality mounts with pierced tsuba and gloss brown metal saya with a single hanger.. Both had real hamon with a thin controlled noiguchi in suguha, and had more in common with what you'd see on a traditionally made sword, not at all like the thick indistinct oil hardened hamon or the fake brushed on hamon usually seen on "stainless" navy swords, and the lower quality swords in late war 1944 gunto mounts with tan metal saya. One was in excellent polish, appeared to have hada, but that could have been similar to mantetsu blades that are said to not be real grain. Anti rust swords wouldn't be considered gendaito but probably belong in the same quality level as Mantetsu and Murata-to above the usual Seki/Showato.

 

Hi Lance,

 

Interesting. However I have a question regarding the two Kanenaga swords that you said to be anti rust steel with real hamon. Did the inscriptions "made with anti rust steel" (sometimes present on these kind of nakago) are present on both nakago or did you assume they were made of anti rust steel because of the particular colour of the steel?

[Lance]

Hi Bruno,

Both swords were signed as being made from anti-rust steel. I attached a page with some information from one of the Fuller & Gregory's Oshigata books, (104 Unusual, Rare, and Interesting Oshigata from Japanese Sword Blades)

Both were nearly identical to the example here, if I remember correctly the ones I had might have used Noshu or Mino in the signature. Hope this is useful.

Regards,

Lance

[Bruno]

Thanks Lance, that is very interesting. Fuller & Gregory is a reliable source so one can assume real hamon could be produced on some Kanenaga anti-rust steel swords.

 

Does one if these particular swords were most likely water or oil quenched, and if they had a core steel like Mantetsuto or were sunobeto?

[Lance]

I assumed they were water quenched because the hamon was so unlike what you'd see on oil quenched Seki/Showato, I think the only way to know for sure what the full construction medthods used would be if a news or research article written back then existed and turned up?

Regards,

Lance

[Bruno]

I assumed they were water quenched because the hamon was so unlike what you'd see on oil quenched Seki/Showato,

 

Water quenched hamon, that is interesting...It would be nice to see some good shots of these blades. Not so easy I guess.

 

I think the only way to know for sure what the full construction medthods used would be if a news or research article written back then existed and turned up?

 

I haven't seen any till today. :?

[runagmc]

You cannot fold and weld stainless steel because of it's chromium content. When heated, these steels produce a fine layer of chromium oxide on their surfaces acting like a separating coating preventing any welding. Technically, you could forge-weld such steels only under vacuum conditions or with absence of oxygen.

Thanks Jean, I didn't know that...

[runagmc]

Funny, I just happened to run into a reference talking about forge welded 300 series stainless steel... so I'm a little confused. Would this have been done in the absence of oxygen somehow, or might there be a way to stop the oxidation during forging (mabey some kind of flux)?

 

Here's the web page, http://www.taganearts.com/modernavailable.html

 

Edit, After reading a little on the web it seems that forge-welding stainless steels is possible. It's apparently done fairly commonly using several different techniques. However, I didn't see anything about it ever being done in Japanese swords... other than mabey some modern "Japanese style" blades.

[ROKUJURO]

Funny, I just happened to run into a reference talking about forge welded 300 series stainless steel... so I'm a little confused. Would this have been done in the absence of oxygen somehow, or might there be a way to stop the oxidation during forging (maybe some kind of flux)?.....

Edit, after reading a little on the web it seems that forge-welding stainless steels is possible. It's apparently done fairly commonly using several different techniques......

As I said, it is possible under special circumstances, and it works only when oxygen can be kept away from the heated surfaces. As the artist on TAGANEARTS explains:...Classical techniques were never meant to work material like this......

 

In making stainless MOKUME GANE or damascus steel, you only need to pile up the sheet metal and seal-weld it (electrically) from the sides so no air can reach the steel inside. Then you can weld the billet in the forge, but you have to grind the surfaces clean before folding again, and you have to repeat the electrical welding every time you make a new fold. It is a slow and labourious technique!

 

I admire the artistic performance shown but I would not buy stainless steel KODOGU.

[Lindus]

Great range of knowledge out there as usual so my Halfpenny worth may not add much.

 

 

 

When working on the Jones wet magnetic seperator many years ago we used a product "Stainless Iron", this allowed minerals to pass through an electro magnetic force via these grooved plates. The plates resisted rust while also allowing them to become magnets.....

Long time ago but unlike short term memory failures this seems pretty accurate.

Roy