Chemically milling stainless steel - to obtain dull defect-free wire for fasteners prodn

摘要

The milling bath is an aqs. bath contng. (by vol.) 3-15% H2SO4, 3-15% HCl, 2-6 HNO3 and 0.1-5% extract of Acacia Mollissima bark (A). The bath is for stainless steels and Ni alloys and is used at 175-195 degrees F. for 5-30 mins. pref. in a wooden tank or vat. The bath gives the desired dull, defect-free finish without intergranular attack, pitting etc. The inhibitor (A) increases the life of the bath C.F. prior art baths which contain quinordine, and provides a foam blanket which retains heat, prevents evaporation and keeps spray and odours down.