440 steel

[WD45]

question about 440 steel.. with the different types what is good and what is trash? Some knives say 440C some just say 440 or 440 stainless.
It would probably make a good sticky to post the different types of knife steels used from best to junk

[ctrout]

It really depends on what you plan on using the knife for and what your expectations are.  There are many properties in steel that must be considered when choosing a knife.  Some steels have better wear resistance for slicing while others have better edge stability for chopping, and still others have better rust resistance for working in an acidic environment. 

440C is considered the top of the 440 stainless scale.  If a manufacturer is using 440C, he will most likely advertise that fact by including the C after the 440.  If it only says 440 or 440 stainless, odds are that it is not 440C.  Some of the "lower grades" of steel can actually perform very well too.  Heat treat can make a big difference.  If a 440C knife has poor heat treatment, it may not perform as well as a 420HC or 440A steel that has better heat treat.  Stepping up from 440C would be 154CM which is merely a slightly modified version of 440C.

For more detail on different steel and their properties, follow this link http://www.knifeforums.com/forums/showtopic.php?tid/809833/  and start reading about half way down the page.

[Joel]

If it just says 440, then it's probably 440A; not that much 440B around.  440A has a good reputation for toughness, but is not the best edge holding steel around.  Here's the chart I use; I printed it out and keep a copy in my shop:  There are ALL kinds of steel around these days.
http://www.agrussell.com/Steel_Guide/a/73/

[WD45]

Thanks gents.. some good info on both of those sites. So where in the realm of numbers does the so called surgical stainless fall ?
Joel, is that chart listed from lowest to highest grade or is it a general composition chart ?

[Joel]

Surgical stainless generally refers to one of the 10 types of 420 steel.  This does not include 420HC,which is different.  Surgical steel refers to one that does not cause an allergic reaction to humans(or animals) and therefore is used in scalpel manufacture.  Since most of these scalpels are one time use, the quality of the steel doesn't have to be that high. Many scalpels these days are ceramic.  Of the 10 types of 420, I believe(without looking it up) that 4 don't have enough carbon to heat treat, 5 have minimal carbon and the last one is heat treatable. I've no idea which one the manufacturers use. That chart is just a general chart.