pits in 1095 after heat treat

D

dan416

Joined
Apr 7, 2010
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6
Hello, I get pits in 1095 after the heat treat. 1525 degree furnace, 6 min soak at temp. quench 125 deg ATF, some single pits, some in groups of 6-8. maybe .010-.015" across, and about the same depth, any thoughts? thanks, Dan
 
I got them using "turco"
I think it needs to be thinned?
 

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Dan, welcome to the forum .You should get some good responses here .
 
The furnace at 1525 is right at the top end for heat, if your furnace is reading a little low you might be over heating the steel. I do my 1095 blades at 1475 with a 7-8 minute soak and quench in parks 50. I get my 1095 from Jantz supply, might not be the cheapest place but I have had zero issues with the product which more than makes up for it.
 
dan this is the way i do mine and never have pits.

1095
slow heat to 1525 , soak for 4 to 5 min bigger blade , smaller blades 3 to 4 min.
Oil should be 130 to 140f. Park#50
Temp @450 2 times for 2 hours at a time, with cool-down between
vern
 
I put a chunk of lump wood charcoal in my kiln to absorb any stray oxygen with any heat treats, I do not use any coating, and I never have any problem. Be sure to leave a few thousandths for decarb

-Page

welcome to BF, fill out your profile
 
Don Hanson III said:
Always go back to the grinder after heat treating.
Click to expand...

Absolutely...!...not only to remove any decarb, but also to compensate for
any warpage.

I'd also recommend getting rid of the ATF...the fumes are bad news, and
there are better quenchants....like Parks #50, and Brownell's Tough Quench.
 
I agree with Russ and Don. I always grind after heat treat and it sounds that you are one the right track for heat treating. One thing that is REAL important with 1095 is quenchent oil speed. You want get it with ATF. Need Parks 50 or Mcmasters-Carr 11 second oil. Makes a hell of a difference in edge and hardness. Welcome to the forum.
 
Hi guys, thanks for the ideas. Where do I get Parks 50? I buy steel from Admiral. V -6 when do you put the blade in the oven? I did another blade today, cleaned w/alcohol first, 1500 for 4 min and it still pitted.
 
I let my kiln equilibrate for at least an hour before any blades go into it, my kiln has a layer of refractory between the elements and the chamber that way there is no direct radiant overheating of the surface ( radiant energy as the chamber is coming up to temp can seriously overheat blades) the blade and the lump of charcoal go in for 20-30 minutes, then immediately into the 130 degree oil that is directly below the kiln. When I have cut cross sections my decarb layer is only 15-30 microns thick (or less sometimes) I don't get pitting, and since I started putting my blades in stainless steel racks that hold them off of the floor of the kiln with the edge up I have gotten no warping unless I bump something on the way to the oil (disclaimer, most of my blades are 6 inches plus tang or less)

good luck

-Page
 
Basically the same here. 1500 for 4-5 minutes, quench in parks50, 450 for an hour two times. Actually are you using new ATF or used? It looks like your ATF may be contaminated with something, and always grind more after heat treating.
 
ATF is HORRIBLE stuff for quenching 1095. If you can't get proper oil, at least get olive oil or peanut oil (canola polymerizes into plastic)

ATF has horribly toxic smoke, it will give you vapor pocket cavitation, and is way too slow a quench for 1095 not to mention flaming at the surface when the blade enters

-Page
 
Hi all, I'm brand new to this forum.

This sounds similar to a problem I'm having except that I use a charcoal fired forge, and instead of pits I get raised bumps on 1095 that I heat treat. I doesn't show up on D2 for some reason.

I heat the blade until it is non magnetic (no soaking) and quench it in either cooking oil or water. It is very frustrating to put a smooth finish on a blade and have it coming out looking like there is a growth on it.

I've left it on some blades because I felt it added "character" to them. I often use the term "character" when talking about flaws in my work.;-)

What is this growth, what causes it, and how can I get rid of it without spending a lot of money?

Paul Meske
 
I think you will find that those bumps are just scale. Try soaking the blade in vinegar overnight. If you will go to the sticky concerning hypereutectoid steels, you will find that non-magnetic is not enough heat for 1095. You need 50°, to 75° more heat. Non-magnetic is only 1414°, you need from 1475° to 1500°, or you will not get it hard enough, and before you say it, the old file test will lie to you in this case.
 
Thanks LRB. I don't think it's a question of getting hot enough as I seem to have a knack for melting the tips of my blades during the hardening process. I have a couple of blades to harden in the next day or two and will try the vinegar idea.

The raised areas sure seem like metal and can take a shine. It doesn't come off when treated to 220 grit sandpaper. However I have no idea what scale or slag looks like or acts.

Any idea why D2 doesn't produce the same irregularities as 1095?

- Paul Meske
 
Scale can be very hard and tough, but is usually dark. It is hard to sand off.
 
lonepine said:
Any idea why D2 doesn't produce the same irregularities as 1095?

- Paul Meske
Click to expand...
Interested in how you are doing the D2. It needs to be around 1850f and a 1/2 hour soak to harden properly and is usually done in a foil envelope to prevent decarb at the higher temp. It also has 12% chrome which helps prevent the scale. But, if done in an envelope it will come out just as you put it in except for becoming a light gray color.
 
I treated three blades last week and again they have the "bumps" on the 1095 steel. I don't think it is scale because sand paper makes them shine like the rest of the metal. I soaked one in vinegar for an hour (after tempering) and other than removing the surface oxidation it did nothing to remove the bumps. I gotta figure how to post a picture.

I suspect I did the D2 all wrong. I treated it the same as the 1095, heat it until nonmagnetic and then a vegetable oil quench. No soaking. No foil envelope. Not hot enough, huh?

My "forge" is a coffee can filled with homemade charcoal and a blower from a hot water heater proving draft. If D2 is not able to be hardened with such a primitive (mostly cheap) apparatus them I will stop using D2. This is my second year of making knives with about a dozen finished. I do a lot of scrounging and spend money when I can't find what I need, like for good steel.

I find It to be very confusing reading these posts at times. For instance one person might say that 1095 shouldn't be quenched in water and another person will say just the opposite. I don't know what to believe. I suspect that they may BOTH be correct but only for their own particular circumstances.

Having vented a little bit (sorry for that) I appreciate your feedback, advice, etc. Learning to make knives has been an exciting learning experience for me, far more complicated than I thought it would be. I suppose anything is easy if you don't have to do it.

- Paul Meske
 
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