440 clarification
Posted: Wed Jan 30, 2008 4:47 pm
I would like something clarified about 440 steel. I have seen "440 stainless" and "high carbon 440". are they the same or is there a difference?
Thanks
Gene
Thanks
Gene
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440 clarification
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Posted: Wed Jan 30, 2008 5:27 pm
AISI 440 if memory doesn't trick me, is a stainless steel, it contain Cr, I don't remember the C % . Usually crappy wallhanger come in AISI440
Posted: Wed Jan 30, 2008 6:11 pm
440 is a range of stainless steels that have different carbon content. Without know *which* 440 is being used you basically know nothing and the presumption is they are using the WRONG alloy as they would be telling you if they used the right one, yes?
Knifemakes often use 440C which tends to be a bit brittle for swordblades.
Of course the second part of the equation is how good a heat treat are they doing, doesn't matter how great an alloy they are using if the head treat is a cheap botch and pretty much nobody will tell you the details on the heat treat to let you make an informed decision.
Thomas
Knifemakes often use 440C which tends to be a bit brittle for swordblades.
Of course the second part of the equation is how good a heat treat are they doing, doesn't matter how great an alloy they are using if the head treat is a cheap botch and pretty much nobody will tell you the details on the heat treat to let you make an informed decision.
Thomas
Posted: Wed Jan 30, 2008 11:37 pm
Chromium content of 440-series IIRC is about 15-17%, all through 440A, 440B and 440C. 440A runs 70 points of Carbon (or 0.70% C), 440C upwards of 100. The steels had their origin as steels for gas turbine blades, and for surgical instruments.
So just saying 440 stainless is vagueness. This seems less trustworthy than a more exact description. And it doesn't suit sword blades. These are too highly stressed and need a very springy steel. The straight simple carbon steels or else low-alloy steels, 1095 or 5160 respectively, suit swords far better.
Take levered stress out of the picture and 440 steels really start to shine, with their edgeholding ability plus their corrosion resistance. I think the edgeholding depends entirely upon the heat treat. Given that, it makes excellent knives. Cutco Cutlery, of Olean NY, uses nothing else. And those guys know their cutlery, as they insist on building the best knives you can have anywhere.
So just saying 440 stainless is vagueness. This seems less trustworthy than a more exact description. And it doesn't suit sword blades. These are too highly stressed and need a very springy steel. The straight simple carbon steels or else low-alloy steels, 1095 or 5160 respectively, suit swords far better.
Take levered stress out of the picture and 440 steels really start to shine, with their edgeholding ability plus their corrosion resistance. I think the edgeholding depends entirely upon the heat treat. Given that, it makes excellent knives. Cutco Cutlery, of Olean NY, uses nothing else. And those guys know their cutlery, as they insist on building the best knives you can have anywhere.