Low alloyed steel powder

Abstract

A water atomized pre-alloyed iron-based steel powder which includes by weight-%: 0.4-2.0 Cr, 0.1-0.8 Mn, less than 0.1 V, less than 0.1 Mo, less than 0.1 Ni, less than 0.2 Cu, less than 0.1 C, less than 0.25 O, less than 0.5 of unavoidable impurities, and the balance being iron.

1 . A water atomized pre-alloyed iron-based steel powder which comprises by weight-%:
 0.4-2.0 Cr,   0.1-0.8 Mn,   less than 0.1 V,   less than 0.1 Mo,   less than 0.1 Ni,   less than 0.2 Cu,   less than 0.1 C,   less than 0.25 O,   less than 0.5 of unavoidable impurities, and   the balance being iron.   
     
     
         2 . A powder according to  claim 1 , wherein the content of Cr is at most 1.8 weight-%, preferably at most 1.5 weight-%. 
     
     
         3 . A powder according to  claim 1 , wherein the content of Cr is at least 0.5 weight-%. 
     
     
         4 . A powder according to  claim 1 , wherein the content of Mn is at least 0.2 weight-%, preferably at least 0.3 weight-%. 
     
     
         5 . A powder according to  claim 1 , wherein the content of Mn is at most 0.7 weight-%, preferably at most 0.6 weight-%. 
     
     
         6 . A powder according to  claim 1 , wherein the sum of the chromium and manganese content is less than 2.5 wt %, preferably less than 2.3 wt % and most preferably less than 1.9% by weight. 
     
     
         7 . A powder according to  claim 1 , wherein the content of Cr is 0.4-0.6 weight-%, and the content of Mn is 0.6-0.8 weight-%, preferably the content of Mn is 0.7-0.8 weight-%. 
     
     
         8 . A powder according to  claim 1 , wherein the content of Cr is at least 0.7 weight-%, and the content of Mn is at most 0.5 weight-%. 
     
     
         9 . A powder according to  claim 1 , wherein the content of Cr is at least 1.0 weight-%, and the content of Mn is at most 0.4 weight-%, preferably at most 0.3 weight-%. 
     
     
         10 . An iron-based powder composition comprising a steel powder according to  claim 1  mixed with 0.35-1% by weight of the composition of graphite, 0.05-2% by weight of the composition of lubricants and optionally copper in an amount up to 3%, and optionally hard phase materials and machinability enhancing agents. 
     
     
         11 . A method of producing a sintered component comprising the steps of:
 a) preparing an iron-based steel powder mixture having the composition claimed in  claim 10 ,   b) subjecting the composition to compaction between 400 and 2000 MPa,   c) sintering the obtained green component in a reducing atmosphere at temperature between 1000-1400° C.,   d) optionally forging the heated component at a temperature above 500° C. or subjecting the obtained sintered component to a heat treatment or hardening step.   
     
     
         12 . A sintered component produced from the powder composition according to  claim 10  having a pearlitic/ferritic microstructure.