Patent ID: 7829820

Claim:
A process for forming a weld bead with reduced gas tracking using a cored electrode comprising a metal sheath and a fill composition, comprising the steps of: (a) providing a cored electrode for use in gas shielded flux-cored arc welding which comprises a sheath and a fill composition: (i) said sheath comprising iron; (ii) said fill composition comprising: (A) about 15-80 wt. % slag forming agent based on said fill composition, said slag forming agent further comprising: (I) a titanium dioxide; (II) at least one potassium silico-titanate compound and sodium silico-titanate; (III) a metal oxide selected from the group consisting of aluminum oxide, boron oxide, calcium oxide, chromium oxide, iron oxide, magnesium oxide, niobium oxide, potassium oxide, silicon dioxide, sodium oxide, tin oxide, vanadium oxide, zirconium oxide and mixtures thereof; (IV) over 50 weight percent of said slag forming agent comprising titanium dioxide and said at least one silico-titanate compound; (V) said slag forming composition comprising: 10-35% titanium dioxide; 15-45% silico-titanate compound; 0-10% Al 2 O 3 ; and 0-10% silica or silica compound; (B) about 0.5-20 wt. % of at least one fluorine containing compound based on said fill composition; (C) a wt. % ratio of said metal oxide to said fluorine containing compound ranging from about 1.1/1-20/1; and (b) at least partially melting said cored electrode by an electric current to cause said melted portion of said cored electrode to be deposited on said workpiece; (i) said combination of said titanium dioxide, said at least one silico-titanate compound and said metal oxide in said slag forming agent lowering a melting point of a slag formed with the addition of said at least one silico-titanate compound, to allow said slag to remain molten for a longer period of time for gases to evolve from said molten weld and dissolve in said slag; and (ii) said fluorine containing compound promoting a formation of hydrogen fluoride which decreases a partial pressure of hydrogen in said weld bead thereby further reducing said gas tracking, said fluorine containing compound releasing at least some fluorine gas to shield said molten weld bead from surrounding moisture and other hydrogen sources.