New austenitic alloy

Abstract

The invention relates to an austenitic alloy comprising the following elements in weight %: C ≤0.03; Si ≤1.0; 5 Mn ≤1.5; S ≤0.03; P ≤0.03; Cr 25.0 to 33.0; Ni 42.0 to 52.0; 10 Mo 6.0 to 9.0; N 0.07-0.11; Cu ≤0.4; Balance Fe and unavoidable impurities; and characterized in that the austenitic alloy fulfills the following condition: E Ni >1.864*E Cr −19.92 wherein E Cr =[wt % Cr]+[wt % Mo]+1.5*[wt % Si] and E Ni =[wt % Ni]+30*[wt % C]+30*[wt % N]+0.5*[wt % Mn]+0.5*[wt % Cu]. The invention also relates to a manufacturing method and an object comprising said alloy. The alloy and objects made thereof have less than 0.3% intermetallic phases after solidification.

1 . An austenitic alloy comprising the following elements in weight %:
 C ≤0.03;   Si ≤1.0;   Mn ≤1.5;   S ≤0.03;   P ≤0.03;   Cr 25.0 to 33.0;   Ni 42.0 to 52.0;   Mo 6.0 to 9.0;   N 0.07 to 0.11;   Cu 0.4;   Balance Fe and unavoidable impurities;   wherein the austenitic alloy fulfills the following condition:
     E   Ni >1.864 *E   Cr −19.92
 
   wherein 
     E   Cr =[wt % Cr]+[wt % Mo]+1.5*[wt % Si] and 
     E   Ni =[wt % Ni]+30*[wt % C]+30*[wt % N]+0.5*[wt % Mn]+0.5*[wt % Cu]. 
   
     
     
         2 . The austenitic alloy according to  claim 1 , wherein the Cu content is ≤0.25 wt %. 
     
     
         3 . The austenitic alloy according to  claim 1 , wherein the Mn content is ≤1.2 wt %. 
     
     
         4 . The austenitic alloy according to  claim 1 , wherein the Si content is ≤0.5 wt %. 
     
     
         5 . The austenitic alloy according to  claim 1 , wherein the Cr content is between 25.5 to 32.0 wt %. 
     
     
         6 . The austenitic alloy according to  claim 1 , wherein the Mo content is between 6.1 to 9.0 wt %. 
     
     
         7 . The austenitic alloy according to  claim 1 , wherein the Ni content is between 43.0 to 51.0 wt %. 
     
     
         8 . The austenitic alloy according to  claim 1 , wherein the austenitic alloy has a CPT which is greater than 88° C. (ASTM G150 with 3 M MgCl 2  as electrolyte). 
     
     
         9 . A method for manufacturing an austenitic alloy having a composition of the following elements in weight %:
 C ≤0.03;   Si ≤1.0;   Mn ≤1.5;   S ≤0.03;   P ≤0.03;   Cr 25.0 to 33.0;   Ni 42.0 to 52.0;   Mo 6.0 to 9.0;   N 0.07 to 0.11;   Cu ≤0.4;   Balance Fe and unavoidable impurities,   wherein the austenitic alloy has an intermetallic content of less than 0.3% after solidification, the method comprising the steps of:
 providing a melt; 
 analyzing the melt to obtain the weight % of the elements contained therein; 
 inserting obtained values from the melt in the following equation:
     E   Ni >1.864 *E   Cr −19.92
 
   wherein 
     E   Cr =[wt % Cr]+[wt % Mo]+1.5*[wt % Si] and 
     E   Ni =[wt % Ni]+30*[wt % C]+30*[wt % N]+0.5*[wt % Mn]+0.5*[wt % Cu] 
 
   optionally adding alloying element to the melt until the equation is fulfilled; and
 solidifying the melt. 
   
     
     
         10 . The process according to  claim 9 , wherein the solidifying method is casting. 
     
     
         11 . The process according to  claim 9 , wherein said process also comprises at least one hot working step. 
     
     
         12 . The process according to  claim 9 , wherein said process also comprises at least one cold working step. 
     
     
         13 . The process according to  claim 9 , wherein said process also comprises at least one heat treatment step. 
     
     
         14 . The process according to  claim 9 , wherein said process also comprises at least one hot working step, at least one cold working step, and at least one heat treatment step. 
     
     
         15 . The austenitic alloy according to  claim 1 , wherein the Mo content is 6.4 to 9.0 wt % 
     
     
         16 . The austenitic alloy according to  claim 1 , wherein the Ni content is 43.0 to 51.0 wt %. 
     
     
         17 . The austenitic alloy according to  claim 1 , wherein the austenitic alloy comprises the following elements in weight %:
 C ≤0.02;   Si 0.01 to 0.3;   Mn 0.01 to 1.2;   S ≤0.03;   P ≤0.03;   Cr 25.5 to 32.0;   Ni 44.0 to 51.0;   Mo 6.4 to 8.0;   N 0.07 to 0.11;   Cu 0.01 to 0.25;   Balance Fe and unavoidable impurities.   
     
     
         18 . The austenitic alloy according to  claim 17 , wherein the austenitic alloy further comprises one or more of Al, Mg, Ca, Ce, and B having a total content of ≤1.0 wt %.