tire hammer dies : I am in process of building a tire hammer a la Clay spencer. I am wondering about the procedure for making the dies. The plans call for 4140 welded to mild steel plate. Heating to 1200 F ,soaking for 15 min rise to 1575 and soak for 10 min Then quenching in warm oil. Can I do this in my little nc propane just using heat colors to guestimate temp? or should I find a heat treating service which won't be less than an hours drive away,if they will do it.

4140 (or 42CrMo4) is a pretty undemanding steel. Just heat up to 820-880°C (light red), soak for 10-15 min and quench in water or oil. Don't forget to stop the quenching at 70°C and to temper immediately. 400°C is pretty hard to tell by annealing colors. I made some tolls of 4140 by quenching in water an annealing in the kitchen oven at full power. It worked really good. As i said the steel is really undemanding and pardons a lot of mistreatment. 

An IR temperature gun will cost less than your trip to the heat treaters. They have recently come down in price for the higher temperature ones, a few years ago they were in the thousands of pounds. 

I bought one which goes between -50˚C and 1600˚C for £120 UK pounds from an Amazon UK link last year.

Professional Infrared Thermometer - CEM-8859

...they had reduced it to to £60 a few months later gggrrrr. At least it meant a couple of friends were able to get them at that rate a month or so ago...

Alan

1 hour ago, Alan Evans said:

Professional Infrared Thermometer - CEM-8859

nice hint, unfortunately not available, neither at amazon UK nor amazon DE.

11 minutes ago, c.baum said:

nice hint, unfortunately not available, neither at amazon UK nor amazon DE.

Do a search on here then. Ianinsa gave a lead to a company in China who would supply them below £100. Maybe not CEM but an equivalent temperature range. They are available nowadays at this sort of figure just need to find the source.

Alan

On 2016-11-08 at 5:33 AM, c.baum said:

4140 (or 42CrMo4) is a pretty undemanding steel. Just heat up to 820-880°C (light red), soak for 10-15 min and quench in water or oil. Don't forget to stop the quenching at 70°C and to temper immediately. 400°C is pretty hard to tell by annealing colors. I made some tolls of 4140 by quenching in water an annealing in the kitchen oven at full power. It worked really good. As i said the steel is really undemanding and pardons a lot of mistreatment. 

If you were tempering in the kitchen oven it is unlikely you were at 400 C (750F) Perhaps you meant tempering at 400F or 200C ? I think I can see giving it a try . By the time my little one burner has it up to temp it will have more or less soaked at 1200 and if I can throttle it a bit or open the door to avoid going too high can get a soak at light red. Thanks all for input.

I think that tempering at 400C would be in the blue enbrittlement area anyway....

Good ol boys color chart.. 

(. POSSUM EAR BLUE )  works every time

 

12 hours ago, canada goose said:

If you were tempering in the kitchen oven it is unlikely you were at 400 C (750F) Perhaps you meant tempering at 400F or 200C

of course the kitchen oven didn't reach 400°C/752°F (looking at the color something about 300°C/572°F). I just wanted to say that this worked though (165 lb power hammer dies). That's what i meant saying that this steel pardons a lot of mistreatment. 

 

9 hours ago, Steve Sells said:

 

I think that tempering at 400C would be in the blue enbrittlement area anyway....

 

400°C/752°F is what the steel data sheet says to be the minimum temp.

I thought that tempering is at 200C or 400F ... ?

see the tempering diagram below

I think there is some confusion around the word "tempering" To temper is to soften steel after it has been hardened by heating past the transition point(approx. non magnetic) and quenched. Tempering typically done from 400- 650 F with 400 or so being typical for hammers. I appreciate your point about 4140 not being a technically fussy steel . I would like to not screw this up as each die will have about 50$  Cdn. worth of steel . Thanks for all input.

On 08/11/2016 at 11:53 AM, c.baum said:

nice hint, unfortunately not available, neither at amazon UK nor amazon DE.

CEM DT-8859  is listed on eBay,  presumably the DT stands for digital thermometer or similar...I found some around the £200 now.

The company I bought mine from may have just bought a box full and was pricing them low to be rid.

Look for Ianinsa's information on IFI though.

Alan

15 hours ago, canada goose said:

To temper is to soften steel after it has been hardened by heating past the transition point(approx. non magnetic) and quenched

That's exactly what i meant. But you can't say that every steel has to bee hardened slightly over Curie temperature and tempered at 200°C/400°F. The temps differ among the steel types and also depend on what you want to use it for. So the steel data sheet always should be consulted. E.g. spring steels become pretty hard when tempered at 200°C, usable for rough working-knives. But if you want to use it for a spring you need a much more complex tempering.

On ‎11‎/‎9‎/‎2016 at 3:19 PM, Jim Coke said:

Good ol boys color chart.. 

(. POSSUM EAR BLUE )  works every time

 

Thanks Jim, consider that quote stole & then some. 

possom ear blue, thats a tough one for us .Would that be close to the well known iceberg blue?

51 minutes ago, canada goose said:

possom ear blue, thats a tough one for us .Would that be close to the well known iceberg blue?

I would call it more of a baboon butt blue

23 hours ago, Steve Sells said:

I would call it more of a baboon butt blue

Now, it's gonna be hard to get THAT picture out of my mind next time I temper something.........thanks a lot, Steve 

the good teacher find ways for the student to remember the course material,

the students remembers that even good teachers can get board and need some amusement at times.

Good Morning,

I think you must be careful with "Blue Embrittlement" of 4140 and 4340.

For the Tire Hammer, I would not Heat Treat. Leave the Dies softer than Harder!! You are working "HOT" material.

I make my Dies for the Kuhn with T-1, un-Heat Treated. I have been using them for over 15 years, No Problem.

The worst you will have to do, in quite a few years, is touch them up with a Grinder.

Better than getting a Bullet in your Body or someone else's Body when the dies explode because "You" did your own Heat Treating.

Neil

T1 is quite a different steel from 4140 . With that amount of Cr is it surprising that it is hard and tough even untreated? Would 4140 perform the same ?