Dan Maragni Intro / 1095-1075 Switch
26Apr,2022

Dan Maragni Intro / 1095-1075 Switch

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26 comments

1075 and 1095 Comparison

 

INTRODUCTION

 

My name is Dan Maragni and I am responsible for the change from 1095 steel to 1075 steel at Ontario Knife Company and here is the story and reasoning behind the decision.

 

I have been an independent contractor working at Ontario Knife Company since 2007 and work as a technical consultant specializing in heat treatment, knife design and training.  I was responsible for updating their heat treatment facility with digitally controlled salt pots, designing their impeller agitated quench tank and monitoring the heat treatment processes.

 

I have have been a dedicated student of the blade all my life and began my career as a bladesmith in the mid-1970s working with an extremely knowledgable and talented artist and smith named Phillip Baldwin who I met in high school.  Phill introduced me to the use of W-1 for a blade steel and everything I ever learned about smithing blades I learned from him (Phill made his first “Damascus”/folded steel blade in 1969).  Phill and I began working together while we were attending college over the summer and winter breaks. Phill and I had a complimentary roles in our work together- he was the bladesmith and smithing teacher and I was the researcher although there was little research material available on bladesmithing at the time.

 

I became a full time bladesmith in 1980.

 

PHYSICAL TESTING

 

In about 1979 I met Jimmy Fikes at a course Phill and I were teaching at Peter’s Valley Crafts and he introduced me to Don Fogg and Jim Schmidt.  I was unbelievably lucky to be exposed to the ideas and work of these incredible bladesmiths especially this early in my career.  In 1980 Jimmy invited me to speak at the first “Ashokan Hammer-In” on heat treatment which resulted in a long, boring lecture on my part.  As bladesmiths making functional tools at the time we were understandably interested in how our blades would perform and needed to come up with a way to determine how functional our blades were.  Ultimately we came up with a series of cutting and strength tests involving manila rope (especially tough on brittle edges with large carbides), hard and soft wood and flexing blades often with “cheater bars”.  Not only did this show us how our blades performed but if our blades were improving over time.  For the first few years we were all bringing blades to the Ashokan Seminar and testing them often to their limits and the performance of the blades increased in leaps and bounds (I remember piles of rope fragments and wood chips strewn all over).  Although it may seem obvious I have always felt that you learn more about a blade when cutting with it than not cutting with it. I also started looking at other steels which might improve my blades and my research ultimately led me to W-2, a slightly tweaked version of W-1 which had benefits in heat treating.  Remember, at this time we were all heat treating our blades in coal forges judging temperatures by eye and I felt that I needed every advantage I could get (Phill and I had also figured out a way to create a hamon on our blades which showed if our edges got completely hard and was a great quality control technique).

 

CARBON V

 

In the late 1980s I met Lynn Thompson at the Costa Mesa Knife Show in California and he noticed that I made knives from “Damascus Steel”.  “Damascus Steel” at the time had a reputation in the literature as being the highest performance steel available although mine and others testing was showing that the high carbon steels out performed them quite consistently.  (“Damascus Steel” is not really a steel but rather a technique and varied greatly from smith to smith depending on the choice of steels and the ability of the smith.). Lynn was determined to make the best performing knives and I suggested making them of carbon steel which was more consistent and readily available.  He bought into the idea and sometime in the early 1990s I was overseeing the domestic production of what was ultimately to become the Trailmaster.  The first thing I did was take samples of some blades to a metallurgist and he did some micros and I did some physical testing.  We both found that the performance of the blades could be improved and I had the heat treatment tweaked (changed the austenitizing temperature, soak time and tempering temperature).  I then selected the heat treatment that produced the microstructure that resulted in the best cutting and toughest blades.  I continued to work for Cold Steel as a technical consultant and supervisor of domestic production until 2006 when Camillus Cutlery Company closed.

 

1075 and 1095

 

In the mid 1990s I modernized my shop getting digitally controlled kilns and building an impeller agitated quench tank with a “J-Tube” to concentrate and direct the flow of the oil.  I was interested in making longer blades and my research into metallurgy and the metallurgy of ancient swords was revealing that I should be looking at other steels to maximize the toughness of the blades.  I began experimenting with steels that would develop more tough lath martensite than brittle plate martensite (1060, 1075, 5160 and 6150) and using the same procedures  I developed for Carbon V were used to maximize the heat treatment of these steels. One of the findings which surprised me the most was that these lower carbon and alloy steels cut as well or slightly better than than steels with carbon contents at 0.95-1.00%.  I was aware that the literature always said that the excess carbon in steel which had over 0.6% would produce more carbides which increased abrasion resistance and resulted in better edge retention. But the literature was not focussed on the metallurgy of blades (unlike what is available today) and the edges of most tools have a very different configuration and is subject to very different stresses than the edge of a knife.

 

For me the worst of all failures for a blade is for it to break. Once a blade breaks it is rendered pretty much unusable.  My research into ancient swords confirmed this bias of the ancient smiths and a great example of this is the Japanese sword (laminations, differential heat treatment, creating compressive stresses along the edge). Yoshindo Yoshihara the traditional Japanese swordsmith whose uses a kobuse laminate for his blade construction prefers steel with a carbon content of 0.7% for the outside/edge steel.  Sword edges must be very tough and the choice of 0.7% C (his brother prefers 0.6% C) is revealing.

 

CHEMISTRY

 

Lath martensite forms in carbon steel at carbon contents at 0.6% and below, plate martensite forms at carbon contents of 1.0% and above and in between these carbon contents the martensite is a mixture of the two types.  When quenched carbon steels will pretty much reach “full” hardness with a carbon content of 0.6% and the remaining carbon will form carbides.  1075 is less likely to form as much retained austenite as 1095 as the Mf (martensite finish temperature) decreases with increasing carbon content (the Mf is below room temperature for steels containing more than 0.8% carbon).  If the steel does not reach the Mf temperature when quenched the austenite will not transform to martensite and remains “soft” and there is the possibility the austenite will ultimately  transform to untempered martensite. 1095 also exhibits micro cracking when quenched due to the greater amount of expansion in the martensitic transformation which is typical of higher carbon content steels (as carbon content increases above 0.75% so does the amount of micro cracking).  1075 also has a higher manganese content than 1095 which results in a slower critical cooling rate and minimizes the chance that you will clip the nose of the pearlite curve in the quench and wind up with a mixture of martensite and pearlite in the finished blade. The finished structure of a blade should be tempered martensite and having a mix with retained austenite and pearlite is not an optimal structure.

 

HEAT TREATMENT

 

As we all know even the best steel can be compromised by a poor heat treatment and heat treating can only allow you to optimize the performance characteristics of the steel. 1075 is a lot less sensitive than 1095 in heat treatment (slower critical cooling rate) and resultant structure has less micro cracks and retained austenite than 1095 which results in a stronger blade.

 

 

SUMMARY

 

By replacing 1095 with 1075 Ontario has selected a steel that is readily available, responds better to heat treatment resulting in a blade with less retained austenite and less micro cracking. The physical testing also shows the blades in 1075 are tougher and hold an edge as well or better than 1095.

 

Toshishiro Obata, the Japanese tameshigiri champion, was known to say that a sword should have these characteristics

 

                           “Be Strong, Be Sharp, Be Beautiful”

 

While the third characteristic is determined by an aesthetic sense and is not so easily defined the goal at Ontario is to create blades that are a combination of the first two.

26 comments

Author

Dan Maragni

Feb 04, 2023 at 14:45

Mr. Carlos- OKC changed steel five years ago after analyzing performance characteristics between 1095 and 1075 and found the 1075 to be superior. We stand by that change and cannot comment on what products you have as we don’t know when you purchased them or from whom. We do appreciate your business and believe you have purchased superior knives in 1075 steel. Thank you for writing and expressing your views and for your confidence and loyalty to OKC.

Author

Carlos

Dec 02, 2022 at 17:24

Hello. After reading the post, I have realized that I have bought three Ontario knives thinking both were made out of 5160 steel and the other one in 1095 (as advertised at the shop) and, finally I have three knives made out of 1075 steel. One of them is the SP53 Bolo and the other the RTAK II. I am very disappointed since I was looking for 5160 steel, not for 1075 instead. I can‘t understand the game played by Ontario on the steel of their blades, It is a mystery to know which one has been used for your knife. When I bought the Sp10 Marine Raider Bowie I was told that It was made out of 1095 steel but surprise, It is in 1075 again but, well, It’s Ok. Mr. Dan Maragni is talking and talking about the 1075 steel‘s virtues just to convince customers on the advantages of changing from the 1095 and 5160 to the cheaper 1075 steel. I have no problems with the 1075 steel but if I buy a knife in this steel is my choice not being cheated with wrong product info. Do not tell me the supply chain problems and so on…I have the Tops Operator 7 in 1075 steel and It is nice but I had all the info available to make my decision, Tops is not playing disinformation on the specs of the knives they produce.
Now I know I have three knives in 1075 from Ontario. I will give them as a birthday gift to some friends of mine. Good gift at least, and for free.
Regards.

Author

Dan Maragni

Nov 09, 2022 at 13:12

Mr. King-Thank you for your kind words regarding the SP 53 and for your appreciation of knife’s performance characteristics. “Cutting like an Axe” was what I was going for while I was designing it. The 5160 Gen II blades were laser etched “5160 OKC-USA” on the blade, all the others would be made from 1075 steel. Both steels are good choices for the knife’s application but the lower carbon content and additional alloys in the 5160 steel would produce a tougher blade. If you have any other questions or comments please feel free to post again and I will try to respond a bit more promptly.

Author

Paul King

Oct 17, 2022 at 15:54

I recently bought a SOG made with Chinese steel. It was the SOG survival knife. After just a few hacks on some camp wood the blade edge broke and even bent around the break. I returned it and bought the Gen ll Spec 53 bolo knife. It has performed beautifully both chopping and batoning. It is amazingly sturdy. I love the knife. When I bought it, it was advertised as 5160 steel. I understand OKC has gone to 1075. Whichever it is it cuts like an axe. I bought it on Amazon about two months ago. Is it possible it is a slightly older 5160 model? I know 1075 is used in axes and I believe it was this year the switch was made. Just curious about the steel. The proof of its quality has been borne out in its performance. Blade sharpens plenty easy. Thanks Dan. I look forward to your response. Best regards,
Paul

Author

Dan Maragni

Oct 03, 2022 at 12:32

Steve- I found out that the orange handled SPAXs were discontinued a couple of years ago so it is very possible that there are 1095 versions floating around.

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