A knife from 1045

G L Drew

G L Drew

Knifemaker / Craftsman / Service Provider
Joined
Feb 3, 2005
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I was at a blacksmith meeting last week when one of the smiths handed me a round bar of 1045 asking "can you make a knife from this?. I said let's give it a try thinking it would never harden enough. I hammered out a small crude knife, normalized and quenched it in water and didn't think it would need to be drawn back. I took it to a belt sander and gave it a quick finish and sharpened. The smith took the knife to work with him the next day (he is a machinist) and did a Rockwell test. It came out to a RC 70.

I have forged tomahawks from 1045 quenching them in water with good results but I never dreamed they could come out that hard. I have ordered a small piece of 1045 to experiment with wondering if maybe the small bar the smith gave me was something other type of steel. He claims it came from a reputable supplier and was indeed 1045.

Anyone had any experience with 1045 for knives? Would it test softer if quenched in oil? Would it have enough toughness to be a good knife?
 
I think he had the hardness tester set for the wrong scale. 1095 won't get that hard, let alone 1045. No steel I know of will get that hard just from a normalize in a blacksmith's fire and water quench with no temper. Also, if you did have a steel that would get that hard at all, you'd have figured it out during forging. Those steels don't want to move much, even at high temperature. The maximum published attainable hardness range for 1045, which is somewhere in the 59-60 range on the Rockwell C scale, is in the 70ish range in the Rockwell D scale. It's an easy enough mistake to make, since both scales use the same diamond indenter. I spent a few minutes trying to figure out how O1 that measured 64 HRc the day before suddenly jumped to 74 just sitting in the lab overnight.

I have no direct experience with 1045, but Bob Engnath (RIP) used to make his japanese style blades from it. It would likely be slightly softer if quenched in oil, but it depends on the exact oil. If used for knives, it will have very good toughness, but the lack of hardness and wear resistance might make it fall short of your edge holding goals, depending on how high your standards are. If you have the steel on order, it's definately worth a try. I'm thinking large chopper or smaller very rough use blade that can be repaired by the user with just files, stones, and sandpaper, but that's just me.
 
"High Carbon" railroad spikes have around 40 points of carbon. Not the greatest blade steel, but they cut :)
 
One can sharpen a common nail to cut. But how long do you think the edge would last? The tests I have read on HC RR spikes give from .30 carbon to .35 at the most.
 
My water quench of 1045 gives a file-test (yes I know not very accurate) of 59-60, but it is close to what google gave me too! (I water quenched and file tested the piece weeks before sending the sample for analysis... didn't know it was 1045 until after)
 
1045 is interesting stuff. You could maybe get it through hard in a very thin cross section but I don't think it is possible to get no pearlite.
 
i think it has enough manganese to through-harden fairly thick, my sample was 1/2", Austenitized @ 1550 though I'd have to check notes to be sure. After a stress relieving temper it would be hard enough for some people for a knife (sometimes for me too) but I was using it for breaching tools.

Still, it's cheap to buy knife steel... unless the supply of 1045 is consistent and nearly free I find it hard to see usefulness for it... unless like me you can't help hoarding every chunk of steel that comes your way!
 
imo, there are 2 possiblities might cause this 70 hardness. 1) using the wrong scale. 2) did HV test and hit some hard carbide. then attempt translante that into RC.

1045 is one of the most common used steel over here. we call it #45, most of our hand hammer is made of this steel. the hardness as quenched might go as high as 59~61hrc.
 
hammerfall said:
1045 is one of the most common used steel over here. we call it #45, most of our hand hammer is made of this steel. the hardness as quenched might go as high as 59~61hrc.
Click to expand...

thank you very much for this information. I would love to hear more about the stuff you guys use over there for tools!
 
My thought was using 1045 in a one day basic knifemaking class that I teach to save the two hour down time for tempering that is necessary with other knife steels. I was hoping to quench and grind making an acceptable knife without the delay to draw a blade back.

I just have to try it in my shop first.
 
You could probably cut it down to an hour, and save some time by quenching in water afterwards. I think even an as quenched steel at ~60 HRc will be fairly brittle, but give it a test and let us know. I've recently been interested in some 0.40%-0.50% steel myself.
 
Does your water have any additives in it. I just read a paper where 1015 was hardened to a reported 42 HRc in brine (15%) plus dishwashing detergent. This was tested at 1 mm depth (surface grind). I'd guess 1045 might harden up more then expected if your cooling rate is fast enough.
 
20°C 5%~15% NaCl water solution is the demanded quenching solution for 1045 to get "full" matensite. this is a very commonly used steel over here, hand hammers, axe, and most of peasants farming tool are made from this steel. its cheap, easy to buy and can be very simply heat treated. in south they used to mass product katana with 1045.
 
Best option if you need to save that time Gerry is to draw the temper manually in the forge or with a torch. Even 1045 needs to be tempered, regardless of RC. But as everyone else here is mentioning, 70 doesn't seem likely with 1045 on C scale.

I think I remember you mentioning you have access to one, but if not, I've got a hardness tester (Thanks Chris!), you're welcome to use anytime, if you want to test some 1045.

Ironically I spent the weekend making hammers and other tools from 1045 with Brian Brazael, and the numbers are in the expected ranges.
 
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