0.5% Carbon steel knives/opinions

[petrochemicals]

hello,

Was wondering if anyone has opinions on knives made from 0.5%c steel, now I know there are lots of variables so lets go for industry standard, I believe its classed as Low Alloy Steel. I dont know of knives that are made from it or a particular grade of steel.

I thought a knife made from this may be able to be made thinner profile wise, and the actual cutting edge shallower, to still be sharpened by hand. Is this right or wrong.

Its not for cutting anything harder than dry wood

Hope to hear soon.

Thanks, pete.

 

[ged]

Low carbon steels will in general be more flexible than steels with higher carbon contents so yes, you're probably thinking along the right lines for a thin blade that might not snap so easily. And you can get one from France for a fiver.

A carbon content in the region of 0.5% tends to be used more in machinery than in knife blades, although a lot of kitchen knives and I believe the famous Opinel carbon blades use steel with about 0.4% carbon.

But there's a lot more to using a steel than knowing how much carbon is in it.

The presence or absebce of elements like chromium, copper, molybdenum, nickel and vanadium are especially important, as can be the absence of elements like nitrogen, sulphur and (shudder) hydrogen.

Depending on the application, phosphorous can be a very good thing in very small quantites and a very bad thing in less small (but still small) quantites. Some applications can forgive much larger quantities of elements like aluminium, lead and silicon.

The steels used in knife blades are invariably heat treated, and this treatment is often much more important than the precise composition of the blade.

All steels corrode. Some corrode a lot more quickly in some conditions than other steels will do in the same conditions.

Steels can be work-hardened. That may be a good thing or it may not, and the composition may encourage or discourage it.

There are many steels which are available very cheaply (and even for nothing) which will make excellent knives. I have some really lovely parangs which were made in Malaysia from old truck springs, but if you don't get the contact quite right with a big chopping move they don't half give the palm of your hand a slap!

A lot of people who make knives rarely use anything but O1 tool steel, it's a time-honoured and well-known material. A number of my blades are made from O1, which is cheap compared with the various stainless steels in most of my smaller blades. I don't mind hacking firewood that might have the odd surprise in it with a cheap blade, about the worst that can happen is that I'll have to grind a ding out of it.

A lot of people pick up old files at car boot sales. Anybody's guess what they're made of half the time, but some have made lovely-looking and apparently perfectly serviceable knives with them. Again, heat treatment is the key.

Do you have a big pile of steel sitting somewhere and you're wondering what to do with it?

 

[Dave Budd]

a 0.5% carbon steel isn't what makes it a low alloy steel. 1095 (0.9%C) is a low alloy steel. The lack of many other alloying elements is what make it a low alloy steel 0.5% or there abouts are known industrially as medium carbon or spring steels.

If you are after toughness rather than edge retention, then a hypoeutectic steel (0.8% or less) is what you would normally seek out, but other alloying elements such as nickel, silicon and manganese are often added for various properties that they imbue.

If hardness and abrasion resistance is what you are after then a hypereutectic steel (above 0.8%) is what you are after, this is the territory of high carbon and tool steels. 1095/cs100 are high carbon, low alloy steels and and are oddly known as spring steels rather than tool steels due to their usual industrial applications: as springs. Again, other alloying elements will effect these properties, notably, tungston, chromium, molybdenum and vanadium

O1 is a (just) hypereutectic, low alloy tool steel. The reason it is so popular in UK knifemaking isn't just because it is a good blade steel, but because it is pretty much all you can find easily and in small quantities of precision ground flat bar! Many spring steels are available here, but only if you buy it by the sheet (or have a specialist laser cutter sell you pieces cut from a sheet)

once you decide whether toughness or abrasion resistance is your main criteria, the heat treating will make or break any alloy used for your knife.

Not many knives will be made from a plain 0'5% carbon steel, but some are made from other steels with 0.5 or 0.6% carbon and other things added to increase the hardenability of the steel. EN45 is 0.5C with a bunch of silicon and manganese added and as well as being tough as old balls, it does hold a pretty decent edge. Also 5160 that the Americans love so much is only 0.6%, but has a load of chromium and silicon to increase wear resistance. Many Japanese swords will also be in this region of carbon because it will allow you to water quench and get a hamon without breaking the blade

 

[Jared]

Cold Steel make a lot of their big blade/machete type stuff out of 1055 which is ~0.5-0.6% range. Also thin and easy to sharpen with just a file.

 

[Shinken]

I think 0.5% plain carbon steel is fine for a knife. Its not the best but can make a fine knife Imo