Fe-ni based alloy for shadow mask raw material excellent in corrosion resistance and shadow mask material

Abstract

There is provided a Fe—Ni based alloy for shadow mask having high corrosion resistance, high rigidity and low thermal expansion and hardly generating rust even if being exposed in air in the course of circulation and transportation after the bright annealing as a middle step of the starting material production and a shadow mask material. A Fe—Ni based alloy for a shadow mask having an excellent corrosion resistance comprises C≦0.01 wt %, Si: 0.01-0.1 wt %, Mn: 0.01-0.1 wt %, Ni: 35-37 wt %, Cr≦0.1 wt %, Nb: 0.01-1.0 wt %, S≦0.0020 wt %, Al≦0.005 wt % and the balance being Fe and inevitable impurity, and a shadow mask material is comprised of the alloy having a proof strength at 0.2% of not less than 300 N/mm 2 and a thermal expansion coefficient of not more than 1.0×10 −6 /° C.

1 ) A Fe—Ni based alloy for a shadow mask having an excellent corrosion resistance comprising C≦0.01 wt %, Si: 0.01-0.1 wt %, Mn: 0.01-0.1 wt %, Ni: 35-37 wt %, Cr≦0.1 wt %, Nb: 0.01-1.0 wt %, S≦0.0020 wt %, Al≦0.005 wt %, and Mn/S=25-70 and the balance being Fe and inevitable impurity and having a thermal expansion coefficient at 30-100° C. of not more than 1.0×10 −6 /° C.  
     
     
         2 ) A Fe—Ni based alloy for a shadow mask according to  claim 1 , wherein a relation of Mn and S is rendered into Mn/S≧25.  
     
     
         3 ) A Fe—Ni based alloy for a shadow mask according to  claim 1 , wherein the alloy contains 0.005-1.0% in total of one or more selected from Ti, V, Zr, Ta, Hf and REM in addition to the above component composition.  
     
     
         4 ) A Fe—Ni based alloy for a shadow mask according to  claim 1 , wherein a maximum value of S concentration in a region ranging from a surface of the alloy to 150□ is not more than 20 times of a bulk.  
     
     
         5 ) A Fe—Ni based alloy for a shadow mask according to  claim 1 , wherein a crystal grain size is not less than No. 9 of ASTM grain size number.  
     
     
         6 ) A Fe—Ni based alloy for a shadow mask having an excellent corrosion resistance according to  claim 1 , wherein the alloy contains a non-metallic inclusion comprising one or more selected from silica (SiO 2 ), spinel (MgO□Al 2 O 3 ) and niobium oxide (Nb 2 O 5 ) in addition to MnO—FeO—SiO 2 —Nb 2 O 5 —MgO—Al 2 O 3 —CaO base composite oxide.  
     
     
         7 ) A shadow mask material having a high corrosion resistance, a high rigidity and a low thermal expansion comprised of a Ni—Fe based alloy as claimed in  claim 1 , and having a proof strength at 0.2% of not less than 300 N/mm 2  and a thermal expansion coefficient of not more than 1.0×10 −6 /° C.