Got problem with Spectrumwear and XHP HT in the same batch.

S

shqxk

Joined
Mar 26, 2012
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Last week I have finished HTing 4 blades made out of two steel which are Zwear and XHP using Evenheat kiln.

I wrap all of the blades in 309 stainless foils. Since both steel seems to share similar austenitizing temp so I HT them in the same time.

Here is the recipe I used.

Preheat the kiln to 1500F, put the blades in and wait till the temp returned and soak for 10 min

Full ramp to 1950F and soak for 35 min

Plate quench till hand ward > dry ice/acetone subzero for 2 hours then air warm to room temp

The XHP blades temper at 400F in electric oven for 1 hour 2 times.
Spectrumwear I use the Evenheat kiln to temper at 1000F 3 times 2 hours each.

I just got the HRC test yesterday. I got 61.9RC on XHP but only 58RC for Spectrumwear

Im not sure why the HRC is much lower than expected on the later steel. Any suggestion?
 
That's odd. I have Rc63.5 with 1975f, cryo, and 1000f x3. With foil, decarb shouldn't be much of an issue.
 
Willie71 said:
That's odd. I have Rc63.5 with 1975f, cryo, and 1000f x3. With foil, decarb shouldn't be much of an issue.
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Could it be the problem of the kiln that is overheat at lower temp? This is a brand new kiln that has been use very few times. But I think this isn't the problem at austenitizing stage since the XHP got great result.
 
Yeah, that's possible. I find steels like this tend to come out pretty much as expected. They're usually pretty consistent. I think z-wear is my new favourite steel. It's good stuff.

You're sure the steel wasn't mislabeled?
 
I would guess a heat gradient or inconsistency in the kiln at the tempering temp caused it.
 
Hey bright I have an extra thermocouple if you want to try a different one, I can send to you to test. It's shielded and good up to 800c so it wouldn't work for austenitizing temperatures but for a tempering oven would work no problem


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Thanks you Nick for your offer! for now I have to give up on any steel require secondary hardening tempering. Hope we can meet up soon on the next year. Happy New Year anyway!
 
I just did a skinner with 1975 austenitize, plate quench, sub zero, then three 1000f 2h tempers. I got Rc61/62. I didn't get the extra 2Rc points I got with cryo as part of the quench.
 
Willie71 said:
I just did a skinner with 1975 austenitize, plate quench, sub zero, then three 1000f 2h tempers. I got Rc61/62. I didn't get the extra 2Rc points I got with cryo as part of the quench.
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Wow didn't expect that the different between LN2 cryo vs dry ice subzero is that much even for high tempering steel! I may need to get some good dewar soon :P
 
shqxk said:
Wow didn't expect that the different between LN2 cryo vs dry ice subzero is that much even for high tempering steel! I may need to get some good dewar soon :P
Click to expand...

Let me duplicate those results before you spend that much money.
 
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