Metal-base alloy product and methods for producing the same

Abstract

A metal base alloy and methods for producing the alloy. The metal base alloy product includes the formula Me base T a Si b Cr c Mnj V e Cf, wherein—Me base is a metal base selected from the group having Fe, Co and Ni, in an amount ranging from about 45-75 w %. The metal base alloy product contains a substantially homogenous dispersion of separate precipitated carbide particles in an amount ranging from 10-65 percentages by volume and the precipitate carbide particles have an average diameter of 0.01-5 micrometers.

1 . A metal base alloy product consisting of the formula Me base  T a  Si b  Cr c  Mn d  V e  C f , wherein
 Me base  is a metal base selected from the group consisting of Fe, Co and Ni, in an amount ranging from about 45-75 w %,   T a  is an alloying material selected from the group consisting of Mo, Nb and Ta in an amount a ranging from about 5-10 w %,   Si b  is a further alloying member in an amount b ranging from about 4-10 w %,   Cr c  is a further alloying member in an amount c ranging from about 8-30 w %,   Mn d  is a further alloying member in an amount d ranging from about 0-10 w %   V e  is a further alloying member in an amount e ranging from about 0-10 w %, and   C f  is a further alloying member in an amount f ranging from about 2-4 w %, wherein   
       said metal base alloy product contains a substantially homogenous dispersion of separate precipitated carbide particles in an amount ranging from 10-65 percentages by volume and said precipitate carbide particles have an average diameter of 0.01-5 micrometer. 
     
     
         2 . Metal base alloy product according to  claim 1  wherein said precipitated carbide particles are substantially spherical carbides having an average diameter of 0.1-5 micrometer. 
     
     
         3 . Metal base alloy according to  claim 1 , wherein said precipitated carbide particles are a mixture of substantially spherical carbides having an average diameter of 0.5-5 micrometer and of nano-crystalline carbides having an average size of 0.01-0.5 micrometer. 
     
     
         4 . Metal base alloy according to  claim 1 , wherein said precipitated carbide particles are surrounded by a matrix of ferrite and/or austenite. 
     
     
         5 . Metal base alloy according to  claim 1 , wherein said alloy has a tensile strength of at least about 800 MPa. 
     
     
         6 . A metal base alloy according to  claim 1 , wherein the Me base  is Fe present in an amount from about 45-75 w %. 
     
     
         7 . A metal base alloy according to  claim 1 , wherein the T a  is Mo present in an amount from about 5-10 w %. 
     
     
         8 . A method to produce a metal base alloy product consisting of the formula Me base  T a  Si b  Cr c  Mn d  V e  C f , wherein
 Me base  is a metal base selected from the group consisting of Fe, Co and NI, in an amount ranging from about 45-75 w %,   T a  is an alloying material selected from the group consisting of Mo, Nb and Ta in an amount a ranging from about 5-10 w %,   Si b  is a further alloying member in an amount b ranging from about 4-10 w %,   Cr c  is a further alloying member in an amount c ranging from about 8-30 w %,   Mn d  is a further alloying member in an amount d ranging from about 0-10 w %   V e  is a further alloying member in an amount e ranging from about 0-10 w %, and   C f  is a further alloying member in an amount f ranging from about 2-4 w %, wherein the method comprises the steps of:   melting said metal base together with chosen alloying components using different melting processes such as high frequency or arc melting,   casting said alloy providing segregation free solidification conditions forming a featureless structure of said alloy,   controlling the cooling conditions of said alloy after casting transferring the featureless structure to carbides and austenite or ferrite, and   heat treating said alloy in at least a first heat treatment step to further control the dispersion of a substantially homogenous separate precipitated carbide particles in an amount ranging from 10-65 percentages by volume and said precipitate carbide particles have an average diameter of 0.01-5 micrometer.   
     
     
         9 . Method according to  claim 8 , wherein the step of casting said alloy is performed in a mould, which mould is kept at a constant temperature from about 20 (room temperature) to 800 degrees Celsius to control the decomposition of the featureless structure. 
     
     
         10 . Method according to  claim 8 , wherein said first heat treatment step is performed in an inert atmosphere or under vacuum at 800-1000 degrees Celsius for 0.1-50 hours wherein said precipitate carbide particles are controlled or further precipitated to form substantially rounded carbides having an average diameter of 0.5-5 micrometer in a matrix of austenite. 
     
     
         11 . Method according to  claim 8 , wherein said first heat treatment step is performed in an inert atmosphere or under vacuum at 650-800 degrees Celsius for 1-30 hours wherein said precipitate carbide particles are controlled or further precipitated to be substantially rounded carbides having an average diameter of 0.1-5 micrometer in a matrix of ferrite. 
     
     
         12 . Method according to  claim 8 , wherein the step of heat treating said alloy comprises a second heat treatment at 200-600 degrees Celsius for 1-30 hours wherein said precipitate carbide particles are formed as nano- crystalline carbides having an average diameter of 0.01-0.5 micrometer. 
     
     
         13 . Method according to  claims 9 , wherein the method comprises a further step of:
 quenching said alloy rapidly at the end of a heat treatment.   
     
     
         14 . A method to produce a metal base alloy product according to  claim 1 , wherein the method comprises the steps of:
 melting said metal base together with chosen alloying components using different melting processes such as high frequency or arc melting   powder processing of said alloy to produce powder with a particle size of 0.1-40 pm size, and   heating said powder to control the transformation of featureless structure to carbides and austenite/ferrite,   keeping said powder at a constant temperature during said heating to ensure that the carbides become small and rounded   pressing said obtained powder using high isostatic pressing (HIP) at a pressure of 60-150 MPa at a temperature of 800-1050° C.,   cooling said product rapidly to approximately room temperature (20° C.), and -heat treating said alloy in an inert atmosphere or under vacuum wherein said precipitate carbide particles are formed as nano-crystalline carbides having an average diameter of 0.01-5 micrometer.