Elongated steel element comprising a ternary or quaternary brass alloy coating and corresponding method

Abstract

An elongated steel element adapted for the reinforcement of rubber products is covered with a ternary or quaternary alloy coating of copper-M-zinc. M is one or two metals selected from the group consisting of cobalt, nickel, tin, indium, manganese, iron, bismuth and molybdenum. The copper content inside the coating ranges from 58 weight percent to 75 weight percent, the content of said one or two metals inside the coating ranges from 0.5 weight percent to 10 weight percent, the remainder is zinc and unavoidable impurities. The one or two metals are present throughout the coating. The phosphorus is present on and/or in the coating in an amount ranging from 0.3 milligram per square meter to 1 milligram per square meter of the coating. The coating further lacks triazole residues. Good results for under cure adhesion have been obtained. Furthermore, a corresponding method for manufacturing such an elongated steel element is disclosed.

1 . An elongated steel element adapted for the reinforcement of rubber products, said elongated steel element being covered with coating of a ternary or quaternary alloy coating of copper-M-zinc,
 where M is one or two metals selected from the group consisting of cobalt, nickel, tin, indium, manganese, iron, bismuth and molybdenum,   the copper content inside said coating ranging from 58 weight percent to 75 weight percent,   the content of said one or two metals inside said coating ranging from 0.5 weight percent to 10 weight percent,   the remainder being zinc and unavoidable impurities,   said one or two metals being present throughout said coating,   phosphorus being present on and/or in said coating in an amount ranging from 0.3 milligram per square meter to 1 milligram per square meter of said coating, said phosphorus amount being measured by means of an Inductively Coupled Plasma technique,   said coating further lacking residues of compounds which complex with copper in the coating to form an insoluble film, as measured by a ToF-SIMS technique.   
     
     
         2 . The elongated steel element according to  claim 1 , the copper content ranging from 61 weight percent to 70 weight percent. 
     
     
         3 . The elongated steel element according to  claim 2 , the content of said one or two metals ranging from 2 weight percent to 8 weight percent. 
     
     
         4 . The elongated steel element according to  claim 1 , said elongated steel element being a steel wire or a steel cord. 
     
     
         5 . A process for manufacturing an elongated steel element adapted for the reinforcement of rubber products, said process comprising the following steps:
 a. coating an elongated steel element with a ternary alloy of copper-M-zinc, M being one or two metals selected from the group consisting of cobalt, nickel, tin, indium, manganese, iron, bismuth and molybdenum, the copper content inside said coating ranging from 58 weight percent to 75 weight percent, the content of said one or two metals inside said coating ranging from 0.5 weight percent to 10 weight percent, the remainder being zinc and unavoidable impurities, said one or two metals being present throughout said coating;   b. drawing said coated elongated steel element in an aqueous lubricant containing a phosphorus compound, the amount of phosphorus compound being such that phosphorus is present on and/or in said coating in an amount ranging from 0.3 milligram per square meter to 1 milligram per square meter of said coating, said phosphorus amount being measured by means of an Inductively Coupled Plasma technique,   said lubricant further lacking compounds which complex with the copper in the coating to form an insoluble film, such that said coating lacks residues of said compounds as measured by a ToF-SIMS technique.   
     
     
         6 . A process according to  claim 5 , said process further comprising a step of twisting two or more of said elongated steel elements. 
     
     
         7 . A reinforced rubber article comprising a rubber compound and an elongated steel element wherein said elongated steel element is an elongated steel element according to  claim 4 .