Killed steel vs. Cast WCB 1

DRE111,

A216 WCB does have Mn and Si limits of 1.0 and 0.6 wt. %, respectively. The general answer to your other questions is "no".

There are both metallurgical and cost considerations for each kind of deoxidation melt practices. Rimmed vs. fully killed are on the opposite ends of the melt practice with capped and semi-killed in between. There is also vacuum degassing to achieve high purity alloys, but this method is not usually used for carbon steel, except in special circumstances or product forms.

In a rimmed casting, the continuous reaction of carbon and and oxygen evolves CO/CO2 gas which forms minor and useful porosity which counters the effect of thermal shrinkage in the mold. On the other hand, a rimmed product generally needs more careful melt practices, slag control and pouring temperature since you don't want to pour the casting while the melt is in a vigorous carbon/oxygen boil, which could cause blow holes threw the casting.

Castings, unlike forgings, contain shrinkage, porosity, segregation and non-uniform grain structures. Killing the steel would not overcome these negative attributes. So you have a little extra porosity, no big deal. The rimmed product does produce a high quality surface which is important in the cast product.

Normally customer request for killed steel because the quality of casting is more better compare to non-killed steel.
Killed-steel means already fully deoxidation. Where if not done this method can cause porosity,highly inclusion etc.
In modern technology, normaly deoxdidation process is compulsary especially for the continous casting process.

Thanks to both Metalmeister and Zulsaid.
Seems that the bottom line is the term "killed" does not really apply to castings.

Everything I've read says "Killing" is strictly deoxidation through chemistry manipulation.

I also, see now that ASME B16.34 shows A516, Gr. 70 as an equlivalent plate form of A216, Gr. WCB

If it's strictly chemistry, then I can see why the grades are equivalent.

Seems that the bottom line is the term "killed" does not really apply to castings.

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This is not entirely correct. You can specify fully killed castings under this specification under a specific melting and refining process. It is up to the purchaser, read ASME SA 703.