STAINLESS STEEL PRODUCT CONTAINING B AND METHOD FOR PRODUCTION THEREOF

A stainless steel slab containing B, wherein a protecting material is joined onto at least two faces across the bloom from each other in a stainless steel bloom containing B of 0.3 - 2.5 mass %, being integrated into one-piece by forming a weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by following formulas (1) - (4), and a method to produce a steel product by rolling said slab. Further, it is preferable to interpose an insert material between above stainless steel bloom and above protecting material in bonding process. 15