Stainless steel for use under circumstance where organic acid and saline are present

Abstract

The present invention provides a stainless steel which is suitable for use in the food manufacturing plant, particularly a soy sauce manufacturing plant. A stainless steel to be used in the environment which contains organic acid and common salt comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, Ni; 40.0 wt % or less, 16.0 wt %≦Cr≦26.0 wt %, 2.0 wt %≦Mo≦8.0 wt %, 0.05 wt %≦Al≦0.100 wt %, 0.10 wt %≦N≦0.30 wt %, Mg: 0.005 wt % or less, Ca; 0.0010 wt % or less and balance consisting of Fe and inevitable impurities, and satisfying equation (1), Cr+3.3Mo+20N≧38   (1) wherein, Cr, Mo and N show the content of each ingredients by weight %.

1 - 9 . (Cancelled)  
     
     
         10 . A stainless steel to be used in the environment which contains organic acid and common salt comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, Ni; 40.0 wt % or less, 16.0 wt %≦Cr≦26.0 wt %, 2.0 wt %≦Mo≦8.0 wt %, 0.05 wt %≦Al≦0.100 wt %, 0.10 wt %≦N≦0.30 wt %, Mg: 0.005 wt % or less, Ca; 0.0010 wt % or less and balance consisting of Fe and inevitable impurities, and satisfying equation (1),  
         Cr+3.3Mo+20N≧38   (1)  
       wherein, Cr, Mo and N show the content of each ingredients by weight %.  
     
     
         11 . The stainless steel of  claim 10 , wherein the organic acid is at least one selected from the group consisting of amino acid, citric acid and lactic acid.  
     
     
         12 . An austenitic stainless steel to be used in the environment which contains organic acid and common salt comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, 15.0 wt %≦Ni≦40.0. wt %, 16.0 wt %≦Cr≦26.0 wt %, 2.0 wt %≦Mo≦8.0 wt %, 0.05 wt %≦Al≦0.100 wt %, 0.10 wt %≦N≦0.30 wt % and balance consisting of Fe and inevitable impurities, and satisfying equation (1),  
         Cr+3.3Mo+20N≧38   (1)  
       wherein, Cr, Mo and N show the content of each ingredients by weight %.  
     
     
         13 . The stainless steel of  claim 12 , wherein the organic acid is at least one selected from the group consisting of amino acid, citric acid and lactic acid.  
     
     
         14 . A stainless steel to be used in a food manufacturing plant comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, Ni; 40.0 wt % or less, 16.0 wt %≦Cr≦26.0 wt %, 2.0 wt %≦Mo≦8.0 wt %, 0.05 wt %≦Al≦0.0010 wt %, 0.10 wt %≦N≦0.30 wt %, Mg: 0.005 wt % or less, Ca; 0.0010 wt % or less and balance consisting of Fe and inevitable impurities, and satisfying equation (1),  
         Cr+3.3Mo+20N≧38   (1)  
       wherein, Cr, Mo and N show the content of each ingredients by weight %.  
     
     
         15 . An austenitic stainless steel to be used in a food manufacturing plant comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, 15.0 wt %≦Ni≦40.0. wt %, 16.0 wt % <Cr <26.0 wt %, 2.0 wt %≦Mo≦8.0 wt %, 0.05 wt %≦Al≦0.100 wt %, 0.10 wt %≦N≦0.30 wt % and balance consisting of Fe and inevitable impurities, and satisfying equation (1),  
         Cr+3.3Mo+20N≧38   (1)  
       wherein, Cr, Mo and N show the content of each ingredients by weight %.  
     
     
         16 . (New) The austenitic stainless steel according to  claim 10 , wherein the stainless steel satisfies the equation (2),  
         Si+Al−100(Ca+Mg)≧0   (2)  
       wherein Si, Al, Ca and Mg show the content of each ingredients by weight %.  
     
     
         17 . The stainless steel according to  claim 10 , wherein the stainless steel is used in the soy sauce or vinegar manufacturing plant.  
     
     
         18 . The stainless steel according to  claim 10 , wherein the stainless steel further contains at least one selected from the group consisting of 0.01 wt %≦Cu≦1.0 wt %, 0.01 wt %≦W≦1.0 wt % and 0.01 wt %≦Co≦1.0 wt %.  
     
     
         19 . The stainless steel according to  claim 10 , wherein the stainless steel further contains 0.001 wt %≦B≦0.010 wt %.  
     
     
         20 . The austenitic stainless steel according to  claim 12 , wherein the stainless steel satisfies the equation (2),  
         Si+Al−100(Ca+Mg)≧0   (2)  
       wherein Si, Al, Ca and Mg show the content of each ingredients by weight %.  
     
     
         21 . The stainless steel according to  claim 12 , wherein the stainless steel is used in the soy sauce or vinegar manufacturing plant.  
     
     
         22 . The stainless steel according to  claim 12 , wherein the stainless steel further contains at least one selected from the group consisting of 0.01 wt %≦Cu≦1.0 wt %, 0.01 wt %≦W≦1.0 wt % and 0.01 wt %≦Co≦1.0 wt %.  
     
     
         23 . The stainless steel according to  claim 12 , wherein the stainless steel further contains 0.001 wt %≦B≦0.010 wt %.  
     
     
         24 . The austenitic stainless steel according to  claim 14 , wherein the stainless steel satisfies the equation (2),  
         Si+Al−100(Ca+Mg)≧0   (2)  
       wherein Si, Al, Ca and Mg show the content of each ingredients by weight %.  
     
     
         25 . The stainless steel according to  claim 14 , wherein the stainless steel is used in the soy sauce or vinegar manufacturing plant.  
     
     
         26 . The stainless steel according to  claim 14 , wherein the stainless steel further contains at least one selected from the group consisting of 0.01 wt %≦Cu≦1.0 wt %, 0.01 wt %≦W≦1.0 wt % and 0.01 wt %≦Co≦1.0 wt %.  
     
     
         27 . The stainless steel according to  claim 10 , wherein the stainless steel further contains 0.001 wt %≦B≦0.010 wt %.  
     
     
         28 . The austenitic stainless steel according to  claim 15 , wherein the stainless steel satisfies the equation (2),  
         Si+Al−100(Ca+Mg)≧0   (2)  
       wherein Si, Al, Ca and Mg show the content of each ingredients by weight %.  
     
     
         29 . The stainless steel according to  claim 15 , wherein the stainless steel is used in the soy sauce or vinegar manufacturing plant.  
     
     
         30 . The stainless steel according to  claim 15 , wherein the stainless steel further contains at least one selected from the group consisting of 0.01 wt %≦Cu≦1.0 wt %, 0.01 wt %≦W≦1.0 wt % and 0.01 wt %≦Co≦1.0 wt %.  
     
     
         31 . The stainless steel according to  claim 15 , wherein the stainless steel further contains 0.001 wt %≦B≦0.010 wt %.