informative link and yet more questions

[scdub]

Hi All,

Came accross a great article (IMHO). Deals with the metallurgy of heat treating steel in some depth but in fairly simple terms. Great for me as a new maker. Check it out and let me know what you think:

http://www.iforgeiron.com/blueprints-000-100/bp0078-the-metallurgy-of-heat-treating.html

No surprisingly, after reading the article I've found a few more questions.

1) The article suggests that quenching multiple times, while improving toughness, can also induce breaks through multiple thermal shocks. Thoughts?

2) The article also says you should increase the heat of multiple temperings each time you temper. I temper 5160 at 450F twice for 2 hours each (for high lateral strength). Should I increase my second temper to 475?

3) Anyone use tempil sticks to determine exact temp of steel? Do they work well?

Last - most important question: Is there a device I can make to allow for more uniform heating of my knives when using an old coal forge? It seems I've heard of people using a section of pipe or something of that sort. Any links, etc.?

Thanks so much!

 

[scdub]

I didn't break some rule did I?

Anyone have an idea for my last Q at least? Device to assist in uniform heating in a coal forge?

Thanks...

SCDUB

 

[David Wesner]

Good Morning SC

multiple quench:
I am not sure of what "multiple quenchs" means in this article. A technique I use when clay coating is 3 count in the quenchant, 3 count out, 3 count in...... while agitating lengthwise. I haven't had one break yet but I primarily use oil as my quenchant.

increase the heat of multiple temperings each time you temper:
I do that but it is so that I can zero in on the RC hardness I'm after. I start a bit lower than the advised temperature on the first temper cycle, check it then adjust my temp accordingly.

Anyone use tempil sticks to determine exact temp of steel?
I have a small botle of 1450* tempilaq that I picked up many years ago prior to getting a pyrometer and kiln. I used a magnet though rather than the tempilaq so I can't speak for it. I've heard that it works well.

Is there a device I can make to allow for more uniform heating of my knives when using an old coal forge?

Yes, the length of pipe you mentioned is the standard not only in a coal forge but gas also. That is what I use and it works well :thumbup:

Thanks for the link, it was an informative article

 

[IronWolf]

The tempil sticks and tempilaq work better than a magnet for judging temperatures. I have used them quite often, When you use them, don't look for a color change, look for them to melt.

When using a pipe, try to get a thick walled pipe, such as sch 80, and cap one end. the thicker the walls the more even you will be able to keep the chamber. a bit of charcoal, or wood chips will also help reduce the oxygen in the pipe and help you control scale.

Ken

 

[scdub]

Thanks guys.

I just found the post from the 18th about using a pipe for HT too. Sorry for the repeat on the question...