65mn hardness

[davewilsonsr]

i'm a bit of a newbie when it comes to blade steels. I've read several reviews of 65mn steel suggesting that it is a decent steel for swords, machetes, etc. These review say that 6mn is fairly hard with and very tough. But the rockwell hardness ranges from 28 to 34. So my questions is how 65mn can be considered fairly hard with such a low rockwell hardness. I have found nothing calling 65mn a "soft" steel. Someone help me out on this.

 

[dirc]

that must be the un-quenched hardness...

65mn should be able to get in the low 50s easily with a decent heat treatment - if anyone tested a blade and it came back 28-34, they got something without any heat treatment basically

it's similar to 1070 simple carbon steel, with slight additions of chrome & silicon

Composition Comparison Graph For The Knife Steels AISI 1070, GB 65Mn Version 4.36

 

[PMQ]

Because different people have different opinions on how hard is hard.
For some, 65HRC is the mininum
For some, 60HRC is the perfect balance point
I've met people saying that knife steel should not be any harder than 55HRC.

 

[davewilsonsr]

that must be the un-quenched hardness...

65mn should be able to get in the low 50s easily with a decent heat treatment - if anyone tested a blade and it came back 28-34, they got something without any heat treatment basically

it's similar to 1070 simple carbon steel, with slight additions of chrome & silicon

Composition Comparison Graph For The Knife Steels AISI 1070, GB 65Mn Version 4.36

Thank you. Its just weird that when you google rockwell hardness of common blade steels, they all come in between 55 and 62 yet 65mn comes in at 28-34. Doesn't make sense unless what you are saying is true. Thanks for the reply.

 

[PMQ]

I just Google 65Mn composition, it has 0.62-0.70% Carbon, this means that it could be hardened to the low 50s, not excellent but usable.

 

[Cobalt]

i'm a bit of a newbie when it comes to blade steels. I've read several reviews of 65mn steel suggesting that it is a decent steel for swords, machetes, etc. These review say that 6mn is fairly hard with and very tough. But the rockwell hardness ranges from 28 to 34. So my questions is how 65mn can be considered fairly hard with such a low rockwell hardness. I have found nothing calling 65mn a "soft" steel. Someone help me out on this.

It can't at 28 to 34. It's basically structural steel at that point. Nothing more. Maybe the spine is 34 and the edge is higher. Could be a diff HT.

 

[soc_monki]

I just Google 65Mn composition, it has 0.62-0.70% Carbon, this means that it could be hardened to the low 50s, not excellent but usable.

Excellent for a sword! Swords need to be able to flex and not snap. Edge retention isn't as high a priority as it is in smaller cutlery.

 

[jbmonkey]

hes seeing Google results on the hardness on blogish type sites like knifeuser and knifeguides...seems low to me. id think low 50s hrc at the minimum...but im no metallurgist.....wouldn't it be great if we had one that participated here and even did a website full of info on steels used in cutlery.....and..........we are lucky enough that we do have a great one who educates us.....

Larrin

your thoughts Sir? thank you.

 

[Larrin]

With ~0.65C you could harden to at least 64 Rc if you wanted, though more likely it would be tempered lower of course.

 

[OrangeBlueOrangeBlue]

According to Zknives, it's equivalent to AISI 1066 or SAE G15660 steel, which harden into the 54-59 HRC range.
I think the low HRC numbers that are quoted various places are based on manufacturer's specs for use as a spring steel (e.g., https://www.otaisteel.com/products/65mn-spring-steel/ , which appears to be a steel manufacturer or distributor, lists the hardness as 28-34 HRC).

 

[Larrin]

According to Zknives, it's equivalent to AISI 1066 or SAE G15660 steel, which harden into the 54-59 HRC range.
I think the low HRC numbers that are quoted various places are based on manufacturer's specs for use as a spring steel (e.g., https://www.otaisteel.com/products/65mn-spring-steel/ , which appears to be a steel manufacturer or distributor, lists the hardness as 28-34 HRC).

I think that’s just misinformation. If the target was 28-34 Rc you would want a steel with less carbon.

 

[jbmonkey]

With ~0.65C you could harden to at least 64 Rc if you wanted, though more likely it would be tempered lower of course.

thank you Sir. appreciate your input on the topic.

 

[dirc]

I think that’s just misinformation. If the target was 28-34 Rc you would want a steel with less carbon.

I think you did yourself a disservice not to mention your excellent write up on carbides - going into the deep dive ->
basically, under the eutectoid point - you are not getting carbides, which is a great way to ensure steel has high toughness
(which was my point earlier, and why so many machete makers choose 1070 or 1075 - it is tough because it guarantees no carbide)

read about it on Larrin website

Carbide Types in Knife Steels - Knife Steel Nerds

A description of the major carbide types in steels, how they form, why they are there, and how carbides contribute to different properties of steel.

knifesteelnerds.com