Process for producing brass-coated steel wire for the tire cord applications

摘要

A process for producing steel wire for tire cord includes providing a brass coating on the wire containing from about 54 to about 65% copper and from about 46 to about 35% zinc. The weight of the coating is within the range of from about 2.5 to about 13.0 grams per kilogram of wire. The coated wire is heated at a temperature of at least about 650° F. for a time sufficient to reduce the hardness of the coating to a range of 40 to 70 Rockwell B. The heat treated wire is then cold reduced to final thickness. The wire subjected to this treatment has significantly improved drawability and greater coating continuity. In another aspect, an improved steel wire product for tire cord applications is provided when the brass coating contains from about 54 to about 62% copper and from about 46 to about 38% zinc and the coating weight is within the range of from about 7.0 to about 13.0 grams per kilogram of wire. The wire having these harder coatings is subjected to the aforementioned heat treatment to enable it to be drawn to final size. The wire having such coating exhibits a pull-out force of at least about 150 new tons when it is embedded in certain rubber formulations, cured and then subjected to a steam aging test for an exposure of 48-hours.