High hardness, high corrosion resistance and high wear resistance alloy

Abstract

There are provided a high hardness, high corrosion resistance and high wear resistance alloy, wherein the alloy is an aging heat treated Cr(chromium)-Al(aluminum)-Ni(nickel)-base alloy, the proportion of a mixed phase of (α phase+γ′ phase+γ phase) precipitated at grain boundaries of γ phase grains in a metal structure in the cross section of the alloy is not less than 95% in terms of area ratio, and the intensity ratio as measured by X-ray diffractometry of the alloy is not less than 50% and not more than 200% in terms of Iα(110)/[Iγ(200)+Iγ′(004)]×100, and a component comprising this alloy, a material for an alloy which can form this alloy, and a process for producing this alloy. The present invention can provide a Cr—Al—Ni-base alloy possessing excellent corrosion resistance, hardness, wear resistance, releasability, fatigue strength, and planishing property in a molding face, a component comprising this alloy, a material for an alloy which can form this alloy, and a process for producing this alloy.

1 . A high hardness, high corrosion resistance and high wear resistance alloy, wherein
 said alloy is an aging heat treated Cr(chromium)-Al(aluminum)-Ni(nickel)-base alloy,   the proportion of a mixed phase of (α phase+γ′ phase+γ phase) precipitated at grain boundaries of γ phase grains in a metal structure in the cross section of the alloy is not less than 95% in terms of area ratio, and   the intensity ratio as measured by X-ray diffractometry of the alloy is not less than 50% and not more than 200% in terms of Iα(110)/[Iγ(200)+Iγ′(004)]×100.   
     
     
         2 . The high hardness, high corrosion resistance and high wear resistance alloy according to  claim 1 , which satisfies requirements that:
 (i) the average grain diameter (D) of unaged γ phase is not more than 500 μm; and   (ii) the total length of the average grain diameter (D) of unaged γ phase and the average precipitation width (W) of the mixed phase of (α phase+γ′ phase+γ phase) precipitated at the grain boundaries is not more than 2 mm.   
     
     
         3 . The high hardness, high corrosion resistance and high wear resistance alloy according to  claim 1 , which comprises not less than 25% by weight and not more than 60% by weight of Cr (chromium) and not less than 1% by weight and not more than 10% by weight of Al (aluminum) with the balance consisting of Ni (nickel), trace elements and incidental impurities. 
     
     
         4 . The high hardness, high corrosion resistance and high wear resistance alloy according to  claim 1 , which comprises not less than 30% by weight and not more than 45% by weight of Cr (chromium) and not less than 2% by weight and not more than 6% by weight of Al (aluminum) with the balance consisting of Ni (nickel), trace elements and incidental impurities. 
     
     
         5 . The high hardness, high corrosion resistance and high wear resistance alloy according to  claim 3  or  4 , wherein a part of Cr has been replaced with at least one element selected from Zr (zirconium), Hf (hafnium), V (vanadium), Ta (tantalum), Mo (molybdenum), W (tungsten), and Nb (niobium), provided that the total amount of replacement of Zr, Hf, V, and Nb is not more than 1% by weight, the amount of replacement of Ta is not more than 2% by weight, and the total amount of replacement of Mo and W is not more than 10% by weight. 
     
     
         6 . A high hardness, high corrosion resistance and high wear resistance component formed of an alloy according to  claim 1 . 
     
     
         7 . A material for a high hardness, high corrosion resistance and high wear resistance alloy which can form an alloy according to  claim 1  by subjecting the material to aging heat treatment. 
     
     
         8 . A material for a high hardness, high corrosion resistance and high wear resistance alloy according to  claim 7 , wherein said material is a solution treated material having such properties that the intensity ratio as measured by X-ray diffractometry is not more than 5% in terms of Iγ′(110)/[Iγ′(110)+Iα(110)+Iγ(200)+Iγ′(004)]×100 and is not more than 5% in terms of Iα(110)/[Iγ′(110)+Iα(110)+Iγ(200)+Iγ′(004)]×100, and
 the grain diameter is not more than 5 mm. 
 
     
     
         9 .- 11 . (canceled) 
     
     
         12 . A process for producing a high hardness, high corrosion resistance and high wear resistance alloy, said process comprising subjecting a material for an alloy according to  claim 8  to pretreatment heating prior to aging heat treatment, wherein the material is heated to 400 to 700° C. at a temperature rise rate of not less than 100° C./hr in the pretreatment heating. 
     
     
         13 . A process for producing a high hardness, high corrosion resistance and high wear resistance alloy, said process comprising subjecting a material for an alloy according to  claim 8  to pretreatment heating prior to aging heat treatment, wherein the material is held in a temperature range of 400 to 500° C. for at least 0.5 hr in the pretreatment heating. 
     
     
         14 . The process for producing a high hardness, high corrosion resistance and high wear resistance alloy according to  claim 12  or  13 , wherein the aging heat treatment is carried out at 500 to 850° C.