Soften Hardened Steel

Need help on making hardened steel soft enough to drill through. What I am making is purely cosmetic, so no structural problems to worry about.

 

get it real hot and let it cool slowly.

 

Red hot, let cool slowly. That's all I got.

 

Bury it in dry sand, that will prolong the cooling.

 

What they said works most of the time. Bury it in the sand will help slow the process as long as there isn't much moisture in the sand. We used Mica in the factory.
If it happens to be air hard tool steel, you're in trouble.

 

speedy dry works real good as insulation when slowing the cooling rate.

 

I had a guy ask me this before...I told him to soak it in water over night and it would soften it...he came back a few days later saying it didn't work to well...


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This is a used farming disc, if that helps. Last night I heated one spot red hot and tried to drill it, "tried" is the word, tough stuff.

 

get it cherry red with a rosebud

 

been successful with a carbide bit, what size hole

 

Ultra slow drill press that can press hard.

Also, if you custom grind the drillbit, it can help.

Hard to explain without pictures, but a normal bit is sharpened to be like a snowplow blade, that digs under... if you make the bit edge like a flat push, almost 90 degrees to the thing you are drilling.

Lots of cut oil, real slow, lots of pressure.

 

7/16, slowest speed on the press,approx 300, a lot of cutting fluid, one hole went like normal steel, the other two ate up bits.

 

I use masonry drill bits to drill hardened tool steel with. Run your drill at about the same speed that you would drill mild steel at. Don't spray coolant ohe drill bit or part that you are drilling the cold shock from the coolant it will shatter the carbide tipped drill bit,a steady blast of air works good,don't get the drill bit to hot but some heat seems to help when drilling hard steel
It is also a good idea to clamp a piece of mild steel under your part,other wise your bit will most likely shatter when the tip of the drill breaks through the hardened steel and have everything clamped solid to your drill press table.

 

I would heat it up cherry red and slowly back the torch away letting the color go to dull red then blue then grey. Let it slowly cool to room temperature from there. Why not torch the holes?

 

Yessss....torching the holes is an option, but I need to ummm "seat" them for lack of a better term.
So I will heat the disc ( where the shanked (?) ) where the bolt will go to make it flush with the disc.
Does that make any sence???

 

What about torching bigger holes, welding in nuts and "seating" them in the nuts?

 

Trying to keep the top of the counter sunk bolts flush with the top of the disc.....They will bolt to a rim....Moon disc style.

 

Please tell me this is an art project.

 

Those discs are pretty damn heavy if this is going on a car to actually drive

 

Won't it make your car tend to plow into the corners?

 

I worked at a heat treating shop for many years. I suspect the disc is a case hardened 1040 or similar material. A disc has to be very hard or the abrasive soil will quickly wear it out. Annealing it will require a 1600 f and controlled slow cooling. If your wifes not home heat it with a torch and throw it in the oven at its highest setting. Shut the oven off and let it cool off. Cheaper than taking it to the local heat treating shop.

 

I agree that its probably case-hardened. The base steel is a relatively softer steel, so bringing it up to 1600 F may render it as soft as dog-poo.

I would drill it with cobalt or Ti coated drills, using a water soluble coolant in a spray bottle (if you have it). Motor oil will work too with a brush. If you are using a drill press, hold the part in a vise or clamp it to the table.

Using a conservative cutting speed of 60, yout max RPM for the final drilling is around 540. I would spot the hole with a spotting drill or center drill, make the spot a little bigger than your finish size of .437.

Start with a smaller drill (~ .250) and work up in steps to the final size. Run the .250 drill at around 900 RPMs. I have a shitload of drill around, so I'd step it at .250, .343, .406 and .437 diameters.

Bob

 

What about hitting it with a torch until cherry red and then quickly putting the drill to it while it's still glowing?

I have no clue what the results may be, but my curiosity may overcome me enough to try it myself just to see what happens.

 

If this is a on a disc it is a good steel, do the oven trick.

 

Rickybop, that's a good one --- plow into the corners!!!!! I've used the wife's oven many times for my shop projects to slow the cooling process, but, never when she's home.

 

There probably is not enough carbon in the base steel to get any advantage out of a heating process. And if you're not sure of the alloy, be conservative with what you do. The actual depth of case hardening goes around .040-.062.

Years back, I had made a tool with what was supposed to be vega (A2) tool steel. After heat treat, we ran a quick Rockwell test on it prior to annealing, it was down to around a Rc of 28, expected hardness should have been in the Rc 52-56 range.

So if you want to go with the oven processing, toss in a couple of sheets of cookies to the exercise won't be totally futile.

Bob

 

Will dull the drill bit PRONTO.

 

This shit is HARD! Heated to red hot, cooled - no luck. Tried to drill it red hot - no luck. Red hot, let cool a coupla times - no luck. Want a nicer hole then what the torch will do.

 

Find a waterjet shop to make the hole. It'll probably be cheaper than you think.

 

Go with the water jet, you have something more than case-hardened.

Did you run a file across an edge of it? That is the best and fastest indication of how hard a material is. If it digs in a lot, you have soft material. If the file skates off it and makes a minimal mark, you have very hard material.

Bob