440C striations??

dhannon

dhannon

Joined
May 9, 2000
Messages
143
I have been using 440C for my blades and find that there is a maze of markings on the blade after polishing. These are not scratches, but seem to be part of the metallurgy? Has anyone run into this and know what this is? And how to eliminate this? After hand sanding it is quite pronounced (while looking for those 600 and 1500 grit scratches), but seem to blend in a little after a good polish.

Dan
Hannon Bearpaw Knives
 
What you may be seeing is the actual grain in the steel. If the steel is over buffed, this will tend to be more pronounced. What occurs is that there are hard and soft parts in the steel. When it is buffed to excess, this will tend to be more prevalent. I am not sure if this is actually what you are seeing but is my best guess.

C Wilkins

 
If you got the steel from Admiral Steel, it is not hot rolled strips but shear plate. They shear it into strips, and that seems to cause a crazing in the steel. It is visible even before you begin to polish and difficult or impossible to remove completely. I find that finishing with white compound on a loose buff at 3600rpm works pretty well.

I've gotten so I only use steel from Admiral if I intend to brush finish it.

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Jerry Hossom
www.hossom.com

[This message has been edited by GaKnife (edited 05-20-2000).]
 
i have noticed that when you get air hardening steels super hot when grinding before h/t that is sets up some kind of thing like what you are talking about in the steel.....

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http://www.mayoknives.com


 
DH, I've gotten the same thing in all my 440c and ats-34 that I've bought from Admiral Steel. Terry Sommers said it is their manufacturer that is the cause.
It has nothing to do with how you grind the steel or whether you get it hot. I ground a blade and dipped it after each pass and it still has it all the way thru the grind. The only way I've found to get rid of it completely is to blast it with ceramic beads.

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Always think of your fellow knife makers as partners in the search for the perfect blade, not as people trying to compete with you and your work!http://www.nebsnow.com/L6steel
Buzzards gotta eat, same as worms!!!
 
I've been using Admiral Steel also, with the same problem. Does anyone have another source thats better quality 440C?
Tom
 
Guys,
I've been using 440-c from Sheffields for 11 years with good results.
biggrin.gif


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Craig Blankenship
Blankenship Knives
http://www.blankenship-knives.com

[This message has been edited by knifemaker3 (edited 05-20-2000).]
 
The steels you get from any of the knifemakers supply houses are hot rolled strips and will not have this problem. Crucible Steel seems to cut theirs with a water jet (nice clean edge BTW) and this doesn't have the problem either. Their A2 and 154CM which I've used is very clean and polishes well.

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Jerry Hossom
www.hossom.com
 
can you buy the entire sheet and cut it yourself? that's what i wanna do. say 4ft. by 8ft. 1/8" thick? it would be easier for me to deal with entire sheets.
 
Sure, you can buy it directly from the manufacturer. They sell it by the pound. The only holdup, there is a minimum order.

There's a couple of folks that frequent this forum that have done just that. About the best situation would be to order something that you could split with some other folks to keep the price down per person.

C Wilkins
 
Wow, lots of experience here with this. Thought it was a silly question. I've seen the grain structure in certain steels show up like this, ie., 410 stainless will have stringers where the grain boundaries will line up and will show under a magnetic particle test. (410 ss used for compressor piston rods, not knives.)

I notice that the lines are harder to see after heat treat, but still not gone. I suppose I will have to start using better stuff after my last purchase is depleted. (You know, that limited budget thing for us hobbyists). Until then I'll start hand rubbing the finish (cuts better hand rubbed than mirror finished anyway).

Dan
Hannon Bearpaw Knives http://www.freeweb.pdq.net/dhannon/hannon.htm
 
buying in sheets would be easier, could i buy it from admiral in the sheet? do those striations affect the performance of the steel, if they do i'll switch to ats-34 completely.
 
I just finished polishing some 440C bird and trout knife blades made from steel I got from Koval. It is dead clean and has polished to a dark mirror finish with no imperfections. It has nothing to do with thickness or whether it is hot rolled or cold rolled, it seems to be related to how it is cut. Shearing appears to impart the crazing to the steel, whether it is hot or cold rolled, in any thickness. What the knifemaking supply companies sell is hot rolled as bars, not sheet, so it is only cut to length. I've never seen this problem with this source of steel. While Admiral sells their steels in bars, it is all cut from sheet.

I have found you can buy directly from Crucible Steel with no minimums, except on shipping charges. Their prices are excellent, but you may have to tell the guy you talk to there what knife steel is. They have the worst trained customer service people I've ever talked to. They will also insist on selling it by the pound, so weigh some of what you want to buy to figure out how much a pound is.

Their website lists their service centers.
http://www.crucibleservice.com/crumain2.htm

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Jerry Hossom
www.hossom.com
 
Magnum, Admiral's ATS-34 does the same thing. So far as I can tell the problem is only cosmetic and doesn't affect performance.

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Jerry Hossom
www.hossom.com
 
alright, i'll won't buy it from admiral, some one should tell them there cutting method is effecting the steel.
 
Hi if you want some good 440 with out all the problems uses are speaking of
give RwWilson a try he has great 440 and he
has all the other prices beat for he works in the steel mill were it is made
we web page is www.rwwilsonknives.com
 
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