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When Using Hot Rolled Steel Girders

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Round in circles

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#1
When using hot rolled steel girders etc cut up as needed into billets of steel as a way of not having to purchase expensive quality thick steels do be aware that where the steel thickens into the web of an " H " girder or at the corner webs of a " U " channel etc the steel will be very very much stress loaded & have lots of hard spots to get through .

So if like me you try turning it in your four jaw chuck or on the face plate to get cheap flat plate don't be surprised if you start to hit rather hard patches at the change of direction points in the metal .


Tonight it took me five resharpens of the facing tool before I realised that it was these hard & stressed points that were taking the cutting edges off the HSS hand ground cutters in a matter of a few seconds .

I spent ages resetting all the gibs , checking the flatness of the tool post mount , security of the tools in the tool post etc, etc . & run out of the lathe , for I couldn't understand why the flat piece I was turning kept measuring up like a section of round cheese some 0.08 mm out towards one corner .

It was the hard zones allowing the tool & tool post to be forced to the tail stock fraction every time it passed the hard zone area . I should have worked it out after the third resharpening session .

In the end I dug out some old heavy 3/4 inch TCT tools , put on a different tool post on that would take it and got cracking .. even then the TCT had to be resharpened once & there is still a slight hill 0.06 mm in the worst corner .
 

carlquib

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#3
Not sure where you are at, but a trick I often use for material like that is to throw it in my woodstove with a fresh load of wood. It will heat it to a lovely red and then cool it slowly, as the fire burns down, which effectively aneals it for you. A little messy to clean the scale off but very effective to make steel soft and easy to machine.

Hello, my name is Brian and I'm a toolaholic
 

george wilson

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#5
I have used the wood stove to anneal large pieces of tool steel also. I put in 2 or 3 pieces of tool steel about 3 or 4" wide,x 1 1/8" thick(over 1" thick by 1/8"),and about 12" long. I loaded the stove with oak,and when it got burning good,closed the damper down so just a little air could get in. That makes the stove get very hot. After leaving the stove overnight,the steel was fully annealed.

The first time I tried it,I had doubts that such massive billets of hardened steel could be gotten hot enough. But,it really worked perfectly .
 

Downunder Bob

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#7
Not sure where you are at, but a trick I often use for material like that is to throw it in my woodstove with a fresh load of wood. It will heat it to a lovely red and then cool it slowly, as the fire burns down, which effectively aneals it for you. A little messy to clean the scale off but very effective to make steel soft and easy to machine.

Hello, my name is Brian and I'm a toolaholic
Yes that will work, but only appropriate in the winter. or for a smaller piece heat it up with an oxy torch or even a propane torch or sit it on the top of a gas stove, shouldn't have to be red hot if you can make a small polished spot take it up through straw to blue/ black and then cool it slowly, turn the flame down low for awhile before turning it off. I have found the problem is usually worse when the metal has been oxy cut and it's bad near the cut. Also near a weld will often have hard spots, especially if it has been cooled quickly.
 

Wreck™Wreck

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#8
Use a carbide roughing tool such as a WNMG shape, these work a charm in such applications, both facing and turning in steel and cast iron, also excellent tools for interrupted cuts as they are very tough.
 
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