Concerned about ambient air temperature...

Ron Raducanu

Ron Raducanu

Joined
Feb 10, 2021
Messages
4,792
I'm reading a lot on this site about the HT process and watched a bunch of YT videos and here's my concern.

It's winter here in the NE and my workshop is in my garage. I realize that I'm a beginner, and my blades won't be a piece of art or terribly functional at first. My concern is that when I go to HT the blade, the fact that my workshop is so cold will alter my results significantly. Is that a legitimate issue or am I just being my usual worry wart self? Thoughts?
 
As I keep saying. It depends...the devil is in the details
What steel are you heat treating and in a forge or furnace? How cold is your shop?
 
HSC /// said:
As I keep saying. It depends...
What steel are you heat treating and in a forge or furnace?
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Ack...I should have included all that in the OP. Apologies.

For now it's 1084, and I'm building a little insulated fire brick forge and using a torch. It's the one on Outdoor55's YT channel. I'll be using that to normalize and for the quenching process. I have Canola Oil for quenching. Then final HT in my home oven. My concern is that when normalizing, the temp of the steel will drop very quickly and also between the forge and the quench as well.
 
HSC /// said:
How about you use Use a radiant heater in the local area where you are working or a fan heater?
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I personally don't mind working in the cold, but if that will making a difference with the process, I certainly will!

It's also a 2 car garage, so I guess I'd have to position the heater right at the workstation. I wasn't sure that it would make a real difference. Mostly because of convection and how air moves around. Would spot heating like that work?
 
I remember living in NH as a kid. It would be 90+° in the afternoon and frost the next morning.

Let's say the temperature is 75° in the shop in June. The blade will quench from 1500°F to the quenchant temperature ( eg. 130° canola oil). You wouldn't worry about that at all.

Now, when the temperature is 30° in the garage during January. The difference from the warmer days is 45° - do you think the 1500° steel will not even notice the difference.

Here is why - while a quenchant will lower the temperature fairly fast, air is a lousy quenchant. it removes heat very slowly compared to a liquid. Your 1084 needs a reasonably fast drop in temperature to clear the pearlite nose at 1000°F, but the air it si exposed to between the forge/oven and the quench tank will not drop the 1500° blade significantly faster at 45° than at 70°.

More important is having the quenchant at the right temperature. Canola should be 120-130°F. In the winter warm it to 130° to allow for a little drop before the quench. Parks #50 is a room temperature oil, but in the cold time of year it should be warmed to around 70-80°.
 
I'm hoping others with metallurgical knowledge will chime in, because with thinner stock, I'm sure it can make some difference, but how much is the question...
HSC /// said:
How cold is your shop?
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I work in my outside shop regularly at temps down into the 40s, how much lower are you talking about? I can't imagine you're in the teens or much below freezing.
Also, don't forget that we're talking about temps in the 1475+ range, so I don't think a 20-30 degree change in ambient temp will matter that much.
Ron Raducanu said:
Would spot heating like that work?
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Sure, why not?

PS - Looks like Stacy beat me with a better answer:rolleyes:
 
Thank you all for the replies!

I've never really measured the temp in my garage, but I'm in there even when the temp outside is in the mid 20s. My garage is not insulated, neither are my garage doors. I'll get a space heater, in any case. Maybe my fingers won't get so cold, LOL.
 
Ron Raducanu said:
Maybe my fingers won't get so cold, LOL.
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This is actually something I was going to bring up. I don't know how old you are, but this is something to avoid. The effects of working in cold on the extremities (fingers and toes) are cumulative, long lasting and permanent. Now that I'm in my 50s, I'm starting to have problems with circulation in my fingers and toes now from my many years (in my 20s and 30s) both working as a snowboard instructor and salmon/steelhead fishing in the cold.
 
weo said:
This is actually something I was going to bring up. I don't know how old you are, but this is something to avoid. The effects of working in cold on the extremities (fingers and toes) are cumulative, long lasting and permanent. Now that I'm in my 50s, I'm starting to have problems with circulation in my fingers and toes now from my many years (in my 20s and 30s) both working as a snowboard instructor and salmon/steelhead fishing in the cold.
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I'm 48, and happily I've been very careful over the years avoiding extreme exposure. I grew up in Montreal, Quebec and was a competitive downhill skier. I'm used to the cold!
 
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