Stainless steel material, method for producing same, and antibacterial and antiviral member

Abstract

A stainless steel material has ε-Cu phases exposed on a surface of the stainless steel material. The ε-Cu phases on the surface have an area ratio of 0.1 to 4.0%, an average particle size of 10 to 300 nm, and a maximum interparticle distance of 100 to 1000 nm.

1 . A stainless steel material having ε-Cu phases exposed on a surface of the stainless steel material, wherein the ε-Cu phases on the surface have an area ratio of 0.1 to 4.0%, an average particle size of 10 to 300 nm, and a maximum interparticle distance of 100 to 1000 nm. 
     
     
         2 . The stainless steel material according to  claim 1 , wherein the stainless steel material has a composition comprising: on a mass basis, 0.12% or less of C, 4.00% or less of Si, 6.00% or less of Mn, 0.050% or less of P, 0.030% or less of S, 20.00% or less of Ni, 10.00 to 32.00% of Cr, and 0.40 to 6.00% of Cu, the balance being Fe and impurities. 
     
     
         3 . The stainless steel material according to 2, wherein the stainless steel material is a ferritic stainless steel material having a C content of 0.10% or less, a Mn content of 2.00% or less, a Ni content of 4.00% or less, and a Cu content of 0.40 to 4.00%. 
     
     
         4 . The stainless steel material according to  claim 3 , further comprising one or more selected from: on a mass basis, 1.00% or less of Nb, 0.60% or less of Ti, 1.00% or less of V, 2.00% or less of W, 3.00% or less of Mo, 0.050% or less of N, 0.50% or less of Sn, 5.00% or less of Al, 0.50% or less of Zr, 0.50% or less of Co, 0.010% or less of B, 0.10% or less of Ca, and 0.20% or less of REM. 
     
     
         5 . The stainless steel material according to  claim 4 , wherein the stainless steel material has a Vickers hardness of 160 Hv or less. 
     
     
         6 . The stainless steel material according to  claim 2 , wherein the stainless steel material is an austenitic stainless steel having a Ni content of 4.00 to 20.00% and a Cu content of 2.00 to 6.00%. 
     
     
         7 . The stainless steel material according to  claim 6 , further comprising one or more selected from: on a mass basis, 1.00% or less of Nb, 1.00% or less of Ti, 1.00% or less of V, 2.00% or less of W, 6.00% or less of Mo, 0.350% or less of N, 0.50% or less of Sn, 5.00% or less of Al, 0.50% or less of Zr, 0.50% or less of Co, 0.020% or less of B, 0.10% or less of Ca, and 0.20% or less of REM. 
     
     
         8 . The stainless steel material according to  claim 7 , wherein the stainless steel material has a Vickers hardness of 190 Hv or less. 
     
     
         9 . The stainless steel material according to  claim 1 , wherein the stainless steel material has an antibacterial activity value of 2.0 or more in an antibacterial test according to JIS Z2801: 2010. 
     
     
         10 . The stainless steel material according to  claim 1 , wherein the stainless steel material has an antiviral activity value of 2.0 or more in an antiviral test according to ISO 21702: 2019. 
     
     
         11 . A method for producing a stainless steel material, comprising:
 a hot rolling step of hot-rolling a slab having a ferritic composition comprising: on a mass basis, 0.10% or less of C, 4.00% or less of Si, 2.00% or less of Mn, 0.050% or less of P, 0.030% or less of S, 4.00% or less of Ni, 10.00 to 32.00% of Cr, and 0.40 to 4.00% of Cu, the balance being Fe and impurities, or a slab having an austenitic composition comprising: on a mass basis, 0.12% or less of C, 4.00% or less of Si, 6.00% or less of Mn, 0.050% or less of P, 0.030% or less of S, 4.00 to 20.00% of Ni, 10.00 to 32.00% of Cr, and 2.00 to 6.00% of Cu, the balance being Fe and impurities, to obtain a hot-rolled material, wherein a finish hot rolling ending temperature is 700 to 900° C. when the slab has the ferritic composition, or a finish hot rolling ending temperature is 850 to 1050° C. when the slab has the austenitic composition;   a cooling step of cooling the hot-rolled material obtained in the hot rolling step from 900 to 500° C. at an average cooling rate of 0.2 to 5° C./sec; and   a heat treatment step of heating the hot-rolled material cooled in the cooling step at 750 to 850° C. for 4 hours or more.   
     
     
         12 . The method for producing the stainless steel material according to  claim 11 ,
 wherein the slab having the ferritic composition further comprises, on a mass basis, 1.00% or less of Nb, 0.60% or less of Ti, 1.00% or less of V, 2.00% or less of W, 3.00% or less of Mo, 0.050% or less of N, 0.50% or less of Sn, 5.00% or less of Al, 0.50% or less of Zr, 0.50% or less of Co, 0.010% or less of B, 0.10% or less of Ca, and 0.20% or less of REM,   wherein the slab having the austenitic composition further comprises, on a mass basis, 1.00% or less of Nb, 1.00% or less of Ti, 1.00% or less of V, 2.00% or less of W, 6.00% or less of Mo, 0.350% or less of N, 0.50% or less of Sn, 5.00% or less of Al, 0.50% or less of Zr, 0.50% or less of Co, 0.020% or less of B, 0.10% or less of Ca, and 0.20% or less of REM.   
     
     
         13 . The method for producing the stainless steel material according to  claim 11 , further comprising a surface layer removal step of performing washing with an acid and/or polishing after the heat treatment step. 
     
     
         14 . The method for producing the stainless steel material according to  claim 11 , further comprising a cold rolling and annealing step of performing a cold rolling, followed by an annealing treatment within 300 seconds. 
     
     
         15 . An antibacterial and antiviral member comprising the stainless steel material according to  claim 1 .