Amounts of gas holes（shrinkage holes）were generated in SAF2507 super duplex stainless steel DN1200 body produced by alkaline phenolic resin sand

resulting in the scrap as a result of not be welded from microstructure porosity.Based on analyzing the material characteristics

through adopting the middle-gating system and the high-performance heat riser to improve the surface temperature to postpone solidification time

the gas holes（porosities） in the valve body can be decreased greatly as a result of the complete exhaustion of gas in the liquid steel

obviously improving the quality of the valve body.