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Re: MISC - Mill Certification/Higher Yield Stress

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There is no reason to specify "dual certified" steel on any project 
and there are several reasons not to.  Dual certified steel is a 
marketing invention introduced by one mill about 6 years ago.  This 
mill used electric arc furnaces, charged principally by scrap metal, 
as opposed to the more traditional processes that used pig iron as an 
input material.  The scrap based steel generally has a higher yield 
strength than does steel produced by the older process.  This 
manufacturer that his product could meet the requirements of both the 
A36 and A572 specifications and decide to certify it as meeting both. 
 This was advantageous for the mill, in that they did not have to 
sort steel, depending on what the customer ordered and could use the 
same piece of steel regardless of what the customer asked for.  Then 
the mill decided to advertise this "bright" idea and create the 
impression that dual-certified steel was somehow superior. 

The fact is, dual certified steel is neither superior or inferior, it 
merely conforms to both specificaitons.  If all that is required for 
a design is A36 material, that is what should be specified.  If a 
mill wants to supply dual-cert material - that meets the 
specification.  If a mill wants to supply single cert A-36, that will 
also meet the spec.  Since not all mills supply dual-cert material, 
specifying dual certified steel will cut down on the number of 
potential suppliers, possibly increasing cost and lengthening 
delivery times.


Ronald O. Hamburger, SE
Regional Manager
EQE International, Inc.
San Francisco, California