could this be for the new baby dmax eng [4.5] ?,and what wrong with CGI?

 

I think this order is only for the big 6.6 Duramax as they are closing the ironproduction i Defiance

If the Baby Duramax is coming at last, I think the blocks will be poured by Tupy or Teksid and they are in both Mexico and Brazil. In CGI as the original spec is.
Both foundrys have recently made more installations for volume production of High Quality CGI.

 

and doesn't the GM ls eng use a powered metal cracked rod,so maybe the cge/metal thing is good

 

Until now GM is using a induction hardened grey iron in the blocks.

"The use of induction hardening is a common technology in metallurgy that can be applied to all types of cast irons and steels. Induction hardening heats the surface of the iron for a few seconds and then allows the surface to cool. This rapid heating and cooling increases the hardness on the surface of the material, to a depth of approximately 0.2 mm. Induction hardening can be included as an extra step in the manufacturing process to improve wear resistance – it does not provide any strength benefits to the material or to the component. Induction hardening is commonly used in the valve seats of grey iron cylinder heads to minimise valve seat wear, and for many other wear components. In the absence of detailed information, it can be assumed that the induction hardening in the Duramax engine was applied in the ring reversal area at the top of the cylinder bores (a span of approximately 25 mm, approximately 25 mm below the top surface of the cylinder bores). CGI is harder than grey iron and also has superior wear resistance (this also explains why the machining of CGI is more difficult than grey iron). None of the current production CGI cylinder blocks require induction hardening."

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