Compacted steel strand with cladded core

Abstract

A steel strand ( 10 ) comprises a steel core wire ( 12 ). This steel core wire ( 12 ) is surrounded by steel layer wires ( 14 ) that are twisted around the steel core wire ( 12 ). The steel core wire ( 12 ) is covered with a thick corrosion resistant core coating ( 16 ) provided by strip cladding or by metal extrusion. The steel layer wires ( 14 ) are covered with a thin corrosion resistant layer coating ( 18 ) provided by a hot dip operation or by an electroplating or chemical plating process. The steel strand ( 10 ) is compacted so that said steel layer wires ( 14 ) have a non-circular cross-section and that the thick corrosion resistant core coating fills the interstices between the steel core wire ( 12 ) and the steel layer wires ( 14 ) in order to give the steel strand ( 10 ) an improved corrosion resistance and increased lifetime.

1 . A steel strand comprising
 a steel core wire,   said steel core wire surrounded by steel layer wires that are twisted around said steel core wire,   said steel core wire covered with a corrosion resistant core coating provided by strip cladding or by metal extrusion,   said steel layer wires covered with a corrosion resistant layer coating provided by a hot dip operation or by an electroplating or chemical plating process,   said steel strand being compacted so that said steel layer wires have a non-circular cross-section and that said corrosion resistant core coating fills the interstices between the steel core wire and the steel layer wires.   
     
     
         2 . The steel strand according to  claim 1 ,
 wherein said corrosion resistant core coating is of aluminium or an aluminium alloy.   
     
     
         3 . The steel strand according to  claim 1 ,
 where said corrosion resistant core coating has a weight ranging from 400 g/m 2  to 2500 g/m 2 .   
     
     
         4 . The steel strand according to  claim 1 ,
 wherein said corrosion resistant layer coating is of zinc or a zinc alloy.   
     
     
         5 . The steel strand according to  claim 4 ,
 wherein said corrosion resistant layer coating has a weight ranging from 150 g/m 2  to 450 g/m 2 .   
     
     
         6 . The steel strand according to  claim 4 ,
 wherein said corrosion resistant layer coating is a zinc aluminium alloy.   
     
     
         7 . The steel strand according to  claim 6 ,
 wherein said corrosion resistant layer coating is a zinc aluminium magnesium alloy.   
     
     
         8 . The steel strand according to  claim 1 ,
 wherein said steel strand has an outer diameter ranging from 10.0 mm to 30.0 mm.   
     
     
         9 . The steel strand according to  claim 1 ,
 wherein said steel strand is in a stress-relieved state.   
     
     
         10 . Use of the steel strand according to  claim 1  as a pre-tensioned strand. 
     
     
         11 . Use of the steel strand according to  claim 1  as a post-tensioned strand.