Ralph W.Yates of 147 Lynnwood Ave.;Belle Vernon;died Thursday;April 11;1968;at 10:30 a.m.in Allegheny General Hospital;Pittsburgh;after an extended illness.  Born in St.Helens;England;Mr.Yates had lived in Monessen most of his life;moving to Belle Vernon in 1944.  He was a retired metallurgist of the Monessen plant of Pittsburgh Steel Co.  Surviving are his widow;Anne;a daughter;Mrs.Robert (Doris) Gibson of Monessen;three grandchildren;and  a brother;Peter of Charleroi.  Friends will be received after 7 p.m. on April 13;at the Robert A.Billick Funeral Home;Monessen.   Service there Monday;April 15;1968;with the Rev.Joseph C.Rial;Jr.;pastor of Monessen’s First Methodist Church;officiating.  Interment;Belle Vernon Cemetery.  Robert A.Billick is funeral director.