Oxidation-resistant heat-resistant alloy and preparing method

Abstract

The present disclosure relates to an oxidation-resistant heat-resistant alloy and a preparing method. The oxidation-resistant heat-resistant alloy of the present disclosure, by mass percentage, includes: 2.5%-6% of Al, 24%-30% of Cr, 0.3%-0.55% of C, 30%-50% of Ni, 2%-8% of W, 0.01%-0.2% of Ti, 0.01%-0.2% of Zr, 0.01%-0.4% of Hf, 0.01%-0.2% of Y, 0.01%-0.2% of V, N<0.05%, O<0.003%, S<0.003%, and Si<0.5%, the balance being Fe and inevitable impurities; wherein merely one of Ti and V is comprised. The method for preparing the oxidation-resistant heat-resistant alloy includes: smelting with inactive element materials→refining→adding mixed rare earth→adding slag→alloying active elements.

What is claimed is: 
     
         1 . A method for preparing an oxidation-resistant heat-resistant alloy comprising the following steps:
 Step 1: melting carbon and the inactive elements, to obtain a molten steel after being completely molten;   Step 2: heating up the molten steel, and refining;   Step 3: adding a mixed rare earth;   Step 4: adding a molten slag; and   Step 5: introducing an inert gas into a casting runner, placing active elements such as aluminum, hafnium, titanium, zirconium and yttrium in the casting runner, heating up, pouring the molten steel into the casting runner, and introducing the molten steel into a tundish to cast;   wherein the oxidation-resistant heat-resistant alloy, by mass percentage, consisting of: 2.5%-6% of Al, 24%-30% of Cr, 0.3%-0.55% of C, 30%-50% of Ni, 2%-8% of W, 0.01%-0.2% of Ti, 0.01%-0.2% of Zr, 0.01%-0.4% of Hf, 0.01%-0.2% of Y, and 0.01%-0.2% of V; wherein merely one of Ti and V is comprised;   wherein the alloy comprises: N<0.05%, O<0.003%, S<0.003%, and Si<0.5%, the balance being Fe and inevitable impurities;   wherein in an oxidizing atmosphere of 1000-1200° C., no less than 90% of an area of an oxidation film that is formed at a surface of the alloy is an Al 2 O 3  film.   
     
     
         2 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the addition amount of the mixed rare earth is 0.05%-0.25% of the mass of the molten steel. 
     
     
         3 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the slag contains CaO. 
     
     
         4 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the method further comprises casting after Step 5, and the speed from the steel tapping to the completion of the casting is 60-100 kg/minute. 
     
     
         5 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the alloy comprises: 3.3%-5.5% of Al, and 34%-46% of Ni. 
     
     
         6 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the alloy comprises: 3%-6% of W. 
     
     
         7 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein the alloy comprises: 0.01%-0.06% of Y. 
     
     
         8 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein a temperature of the refining in Step 2 is not less than 1640° C. 
     
     
         9 . The method for preparing an oxidation-resistant heat-resistant alloy according to  claim 1 , wherein part of the carbon is firstly added in Step 1, and remaining carbon is then added in Step 2 when the molten steel has been heated to no less than 1640° C.