Method of producing a cold drawn wire

Abstract

Method of producing a cold drawn wire from a particle metallurgy steel includes the following steps:-preparation of a bulk of molten metal including in weight %: C 0.03-0.15, Si 0.01-1.2, Mn 0.1-1.5, Cr 15-20, Ni 540, Al 0.5-1.5, optionally max 2 of elements chosen from the group of N, P, S, Cu, Co, W, Mo, Nb, Ti, Zr, Ta, B, Be, Bi, Se, Mg, Ca, Hf, V, and REM, and, using electro slag refining and atomising to provide a metal powder; filling and sealing a capsule with the metal powder; compacting the capsule to provide a full density billet; hot working the billet and finishing by wire rolling; cold drawing the annealed wire with at least 30% area reduction.

1 . Method of producing a cold drawn wire from a particle metallurgy steel, comprising the following steps:
 preparation of a bulk of molten metal comprising in weight %:   C 0.03-0.15,   Si 0.01-1.2,   Mn 0.1-1.5,   Cr 15-20,   Ni 5-10,   Al 0.5-1.5, and, balance Fe apart from impurities;   casting the prepared molten metal to the shape of ingots, or, preferably to a strand which is cut up;   electro slag refining, so called ESR remelting, of said ingot or cut-up strand, preferably after hot working to the shape of electrodes, providing an ESR melt or for the formation of ESR ingots and remelting the ESR ingots;   atomising the ESR melt and thereby providing a metal powder;   filling a capsule with the metal powder;   sealing the capsule;   compacting the capsule in a hot isostatic press to provide a full density billet;   hot working the billet and finishing by wire rolling;   descaling the resulting rolled wire;   annealing the descaled wire; and   cold drawing the annealed wire with at least 30% area reduction.   
     
     
         2 . The method according to  claim 1 , wherein the bulk of molten metal comprises in weight %:
 N 0.005-0.15,   
     
     
         3 . The method according to  claim 1 , wherein the bulk of molten metal comprises in %:
 P<0.05,   s<0.1,   Cu<0.5,   Co<0.5,   W<0.1,   Mo<0.5,   Nb<0.1,   Ti<0.2,   Zr<0.1,   Ta<0.1,   B<0.1,   Be<0.1,   Bi<0.1,   Se<0.1,   Mg<0.1,   Ca<0.1,   Hf<0.1,   V<0.1, and   REM<0.2.   
     
     
         4 . The method according to  claim 1 , wherein the bulk of molten metal comprises at least one of the following elements:
 Ti 0.01-0.1;   Nb 0.01-0.1;   V 0.01-0.1;   and fulfilling the condition   Ti+Nb+V 0.01-0.2.   
     
     
         5 . Method according to  claim 1 , wherein the method further comprises
 atomising the ESR melt in an atomising chamber beneath an ESR furnace.   
     
     
         6 . The method according to  claim 1 , wherein the method further comprises:
 protecting the remelted ESR ingots in an inert gas, vacuum;   atomising the remelted ESR ingots by draining the liquid metal through a drain in the bottom of a furnace containing the melt to an atomising chamber.   
     
     
         7 . Method for producing springs comprising the steps of:
 producing a cold drawn wire according to  claim 1 ;   spinning springs from the cold drawn wire;   precipitation hardening the springs.   
     
     
         8 . The method of  claim 1 , wherein the bulk of molten elements is selected from the group consisting of a maximum of 2 elements chosen from the group of N, P, S, Cu, Co, W, Mo,Nb, Ti,Zr, Ta, B, Be, Bi, Se, Mg, Ca, Hf, V, and REM. 
     
     
         9 . The method of  claim 1 , wherein the step of casting the prepared molten metal comprises forming a strand that is cut up. 
     
     
         10 . The method of  claim 1 , further comprising:
 compacting said capsule in a cold isostatic press; and   preheating said capsule.   
     
     
         11 . The method of  claim 2 , wherein the bulk of molten metal comprises in weight %:
 N 0.01-0.15.