PREVENTING METHOD FOR SULFURIZATION OF CAST STEEL CASTING

摘要

PURPOSE:To prevent the sulfurization phenomenon that occurs near the surface of a cast steel casting during production of said casting by coating an aq. soln. of a mold coating material having affinity to sulfur contents on the surface of a self-curing mold using an org. sulfonic acid catalyst then coating a known mold coating material thereon. CONSTITUTION:In the case of using, for example, a furan mold as the above- mentioned mold, the furan molding sand mixed with a furan resin and an org. acid is molded to make a furan mold 2. Next, a mold coating material 3 for prevention of sulfurization consisting of an aq. soln. consisting basically of a material having affinity to sulfur (e.g. NaOH) is coated on the surface of the mold 2, and is dried with a burner or the like. Next, a conventional mold coating material (e.g. a commercially marketed basic mold coating material) 4 is coated on the interface part of the dried material 3 in contact with molten metal. The sulfide type gases produced when molten metal 1 is charged into this mold 2 is absorbed by the material having affinity to sulfur of the material 3, whereby the carburization phenomenon near the casting surface is prevented or reduced considerably.