High tensile strength steel wire

Abstract

A high tensile strength steel wire having as steel composition: a carbon content ranging from 0.20 weight percent to 1.00 weight percent, e.g. from 0.3 weight percent to 0.85 weight percent, e.g. from 0.4 weight percent to 0.7 weight percent, e.g. from 0.5 weight percent to 0.6 weight percent, a silicon content ranging from 0.05 weight percent to 2.0 weight percent, e.g. from 0.2 weight percent to 1.8 weight percent, e.g. from 1.2 weight percent to 1.6 weight percent, a manganese content ranging from 0.40 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.9 weight percent, a chromium content ranging from 0.0 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.8 weight percent, a sulfur and phosphor content being individually limited to 0.05 weight percent, e.g. limited to 0.025 weight percent, contents of nickel, vanadium, aluminum, copper or other micro-alloying elements all being individually limited to 0.5 weight percent, e.g. limited to 0.2 weight percent, e.g. limited to 0.08 weight percent, the remainder being iron, said steel wire having martensitic structure, wherein at least 10 volume percent of martensite are oriented.

1 . A high tensile strength steel wire having as steel composition:
 a carbon content ranging from 0.20 weight percent to 1.00 weight percent, e.g. from 0.3 weight percent to 0.85 weight percent, e.g. from 0.4 weight percent to 0.7 weight percent, e.g. from 0.5 weight percent to 0.6 weight percent,   a silicon content ranging from 0.05 weight percent to 2.0 weight percent, e.g. from 0.2 weight percent to 1.8 weight percent, e.g. from 1.2 weight percent to 1.6 weight percent,   a manganese content ranging from 0.40 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.9 weight percent,   a chromium content ranging from 0.0 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.8 weight percent,   a sulfur and phosphor content being individually limited to 0.05 weight percent, e.g. limited to 0.025 weight percent,   contents of nickel, vanadium, aluminum, copper or other micro-alloying elements all being individually limited to 0.5 weight percent, e.g. limited to 0.2 weight percent, e.g. limited to 0.08 weight percent,   
       the remainder being iron, 
       said steel wire having martensitic structure, 
       wherein at least 10 volume percent of martensite are oriented. 
     
     
         2 . A high tensile strength steel wire according to  claim 1 , wherein at least 20 volume percent of martensite are oriented. 
     
     
         3 . A high tensile strength steel wire according to  claim 1 , wherein at least 40 volume percent of martensite are oriented. 
     
     
         4 . A high tensile strength steel wire according to  claim 1 , wherein said steel wire has a yield strength Rp0.2 which is at least 80 percent of the tensile strength Rm. 
     
     
         5 . A high tensile strength steel wire according to  claim 1 , wherein said steel wire has a corrosion resistance coating. 
     
     
         6 . A high tensile strength steel wire according to  claim 5 , wherein said corrosion resistance coating is selected from any one of zinc, nickel, silver and copper, or their alloys. 
     
     
         7 . A high tensile strength steel wire according to  claim 1 , said steel wire being in a cold-drawn state and having a round cross-section. 
     
     
         8 . A high tensile strength steel wire according to  claim 1 , wherein said steel wire has a tensile strength R m  of at least 2000 MPa for wire diameter above 5.0 mm, at least 2100 MPa for wire diameter above 3.0 mm and at least 2200 MPa for wire diameters above 0.5 mm. 
     
     
         9 . A high tensile strength steel wire according to  claim 1 , wherein said steel wire has a reduction in area after fracture of at least 45%. 
     
     
         10 . A high tensile strength steel wire according to  claim 1 , wherein said steel wire has a reduction in area after fracture of at least 50%. 
     
     
         11 . Use of a high tensile strength steel wire according to  claim 1  as a spring wire or an element for producing a rope. 
     
     
         12 . A process of manufacturing a high tensile strength steel wire,
 said steel wire having as steel composition:
 a carbon content ranging from 0.20 weight percent to 1.00 weight percent, e.g. from 0.3 weight percent to 0.85 weight percent, e.g. from 0.4 weight percent to 0.7 weight percent, e.g. from 0.5 weight percent to 0.6 weight percent, 
 a silicon content ranging from 0.05 weight percent to 2.0 weight percent, e.g. from 0.2 weight percent to 1.8 weight percent, e.g. from 1.2 weight percent to 1.6 weight percent, 
 a manganese content ranging from 0.40 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.9 weight percent, 
 a chromium content ranging from 0.0 weight percent to 1.0 weight percent, e.g. from 0.5 weight percent to 0.8 weight percent, 
 a sulfur and phosphor content being individually limited to 0.05 weight percent, e.g. limited to 0.025 weight percent, 
 contents of nickel, vanadium, aluminum, copper or other micro-alloying elements all being individually limited to 0.5 weight percent, e.g. limited to 0.2 weight percent, e.g. limited to 0.08 weight percent, 
   the remainder being iron,   said steel having martensitic structure,   wherein at least 10 volume percent of martensite are oriented.   said process comprising the following steps in order:   a) austenitizing a steel wire rod or steel wire above Ac3 temperature during a period less than 120 seconds,   b) quenching said austenitized steel wire rod or steel wire below 100° C. during a period less than 60 seconds,   c) tempering said quenched steel wire rod or steel wire between 320° C. and 500° C. during a period ranging from 10 seconds to 600 seconds,   d) work hardening said quenched and tempered steel wire rod or steel wire.   
     
     
         13 . A process of manufacturing a high tensile strength steel wire according to  claim 12 , wherein said process is further followed by a step of:
 e) aging said work hardened steel wire at a temperature between 100° C. and 250° C.   
     
     
         14 . A process of manufacturing a high tensile strength steel wire according to  claim 12 , wherein said work hardening occurs at a temperature below 700° C. 
     
     
         15 . A process of manufacturing a high tensile strength steel wire according to  claim 12 , wherein said work hardening is cold drawing.