Subject: Re: WaSKIP/NEWSGROUPrping Steel

From: [email-masked]
Date: 4 Aug 93 09:14:10 CDT

In article <[email-masked]>, [email-masked] (Joe Landau) writes:
> Gary writes:
>  
>>I just purchased about 500 pounds of steel ( 1018 ) in various sizes
>>from 3/8 square to 1 inch X 4 inch. When we mill the surface of the the
>>steel, it machines fine but. When we take the stock out of the vise it
>>immediatly bows ( worps)  this happens even when we only take 30
>>thousands off the surface. The same situation happens when we use a fly
>>cutter and a milling cutter. The larger the cut the more worpage.
>>My question is: Is this normal with 1018 steel? Is there a better steel
>>that will not worp when machining?

> 
> I have read (but do not know firsthand) that crs is stressed by the forming
> process, and when you machine it the stresses are unevenly relieved, so the
> steel warps.  The cure is said to be annealing before machining.  
> 
I'm no expert but thought I'd throw in my $.02 worth.

I've heard that during the cold rolling process the structural matrix near
surface of the steel is deformed, giving rise to stresses.  You might try
stress relieving but playing a torch over the area.  HRS may cool slowly
to avoid stresses (I see no indication whether you bought hot rolled or 
cold rolled). You also might try using a piece of steel that is somewhat
thicker than your final dimension, milling off about .030 from one surface,
milling another .030 from the opposite surface, going back to the first
surface, etc.  Unless the steel is quite thick surface grinding won't
help because the magnetic vise pulls the piece flat and the warp comes
back when you remove the magnetism.

I believe that leaded crs is easily machineable and minimizes warp.
For really precise work you can get precision ground low carbon
cs for an industrial supplier.

I'm less certain that the stresses from cold forming may go as deep
as 0.10".