Noel, have you given it a clean up grinding? It is possible that you have some decarburization. So try a clean up grind and do the hardness test with a file. If it still does not pass then you can re do the heat treat. I would only bring it to 1500 once, then slow cool. Then go through your heat treating again. You did not say what oil you were using.

Brion

Thanks Brion! My apologies, I was using parks 50 heated to 108 degrees plus or minus a degree or two. It is still too soft under the cleaned up outer layer so I think redoing the heat treat is whats needed. Thank you for the advice!! By a slow cooling do you mean not a full anneal but slower then an air cooling?

Noel the air cool should be fine. The parks is good. I would shoot for 1475 and you need a soak time with W2 of 5-10 minutes with it. If you are using a forge to bring up to temp, turn it as low as you can and take your time bringing it up to temp.

Brion

Are we certain it is W-2? Do we have a chemistry? If so we can better plan a course around the problem since W-2 can technically have anywhere from .75% to 1.2% carbon and still be called W-2. This can make it tough to navigate the problems since that carbon range actually spans the two phase categories of eutectoid and hypereutectoid.

If it is above .8% in carbon there are two things that will make matters worse, slow cooling from above non-magnetic (by slow I mean anything slower than an air cool) and excessive low temperature cycling.

If we are using a device that will allow us to work with actual temperature numbers then we can isolate the operations much better. If the C content is above .8% then 1475F is the magic number. That is where you will be hardening from. If all of the parameters are optimum for the quenching then we focus on the heating, or the solution. In order for steel to harden you need two things- sufficient carbon in solution and sufficient cooling speed to trap that carbon in solution. The most common instinct is to look to the quench first, but that is rarely the actual problem, however with W-2 it cannot be ruled out.

More commonly the problem is sufficient carbon in solution. If the carbide is in a condition that is readily soluble 1475F with a short soak will do the trick. If the carbide is locked up tight in large collections, or in the grain boundaries, it is going to take a significant soak or a bit more temperature to peel off the needed carbon and put it into solution. Never cool a hypereutectoid slower than air cooling from above nonmagnetic, or you will be heating and soaking that steel to death to get things into solution and still have embrittling carbide networks.

For this blade an easy stress relieving, heat to 1,200-1,250F and air cool, should get you ready to quench again, if you think it was the quench. But if it was an austenite solution issue then you will want to heat it to above 1500F, maybe even 1600F, perhaps a couple of times and then air cool, and then proceed with the a heat to 1475F and quench.

If we are not working with tools that will allow exact temperatures then we need to condition the steel to behave more like a simple carbon/iron alloy that forges work best with. For this you want the carbide and ferrite structures as fine as possible, so that the need for soaking is minimal to none. Fine pearlite is probably your best bet without the ability to go for upper bainite. Fine pearlite is easy enough, just air cool with everything. Heat to forging heat- air cool, heat to above nonmagnetic- air cool, heat to just when the magnet lets go and quench until the blade is black but is still hot enough dry itself of any oil very quickly (do not flash your Parks #50, that will ruin this oil). Then go for non-magnetic and your actual quench to harden the steel. This process will first dissolve all the heavy carbides and coarse structures and then keep new ones from forming from unwanted slow cooling. Follow up heats will refine the grain as wells as further refine the carbide. Then the intermediate quench will take the fine structures to partial solution and cool them so fast that they remain as is and rapidly reduce grain, but will not go all the way to martensite, and may even keep the newer fine austenite grains in solution so that on your next heat you do not have to dissolve what is already there. Then quench to harden.

If none of these measures work, it may require more serious efforts, I have been getting a larger volume of e-mail lately about these issues with W-2, so there may be a batch of heavily spheroidized or segregated steel going around right now.

Thank you Kevin. I noticed a number of people having these issues with an older batch of W2, from about three years ago.

Brion

Brion, I had those issue with that batch of W2. I waisted way to much time and money trying to figure it out. Now I don't even mess with W2. I have other options for whatever I am trying to get out of the forged blade to risk the lost time and money.

Chris

Thank you both so much!! Kevin I really appreciated the instructions for working without the temperature controlling devices. I followed them as closely as I was able and it worked like a charm! The way the file skated off the blade it might as well of been made of glass. Thank you! I was using a batch of W2 purchased from New Jersey Steel Barron in late June. Seems like their W2 is bought up fairly quickly so I imagine it wasn't made too long ago.

I had a similar issue with my W2 not getting hard. I had done 3 attempts of quenching, starting at 1485 and increasing about 10 degrees each time. I took a little piece I had cut off the tang that was about 1" long, stuck it in the forge and and quenched it in Parks 50 like I had done with the blade. I stuck it in a vice and it snapped crisply. A quick test showed it 63. Knowing that my process was not flawed I found this post in a search to get help. I decided to start at 1600 for several rounds of thermal cycling. I dropped 50 degrees each time down to 1300 and quenched one more time at 1495. The file bit very hard and I used my little tester on a spot, (the black circle) and it tested around 20. I was about 10 seconds away from sticking it in a vice and breaking it and then wondered if there was a hamon line. I did a quick clean up grind and did a quick dip. When I brought it out I could see lots of shiny spots and noticed my test of 20 was dead in the middle of one of those. I tested a spot that was darker, (red circle) and it was 62. I cleaned off the rest of the shiny scale and found the exposed steel was mostly around 62. Under the clay was barely above 40. What am i looking at as far as migration here. Something has come to the surface, and it was not hard.