Method of manufacturing a blade with high hardness nitride layer

Abstract

A blade made of a carbon steel or alloy steel is subjected to a surface nitriding process to form a high hardness nitride layer having a thickness in the range of 10 μm to 100 μm and a Vickers hardness Hv of 1000 or more, and a silver oxide layer, a copper oxide layer, or a silver oxide and copper oxide layer is formed on the high hardness nitride layer of the blade by firing. Through this processing, the blade that has a high cutting maintaining ability and an excellent sanitization ability such as antibiosis, sterilization ability, and antimold ability is provided.

1 . A method of manufacturing a blade having a high hardness nitride layer, the method comprising:
 processing a metal steel plate so as to form a blade including a part therein to be formed as a cutting edge;   processing the blade prepared by the above process by quenching and curing treatment;   grinding the surface of the blade that was subjected to the quenching and curing treatment;   forming a cutting edge in the blade that was subjected to the surface grinding process, by grinding;   grinding the cutting edge formed by the above process finally; and   performing surface nitriding processing on the surface of the blade that was subjected to the finishing process for the cutting edge thereof to form a high hardness nitride layer having a thickness of 10 μm to 100 μm and the Vickers hardness Hv of 1000 or more, wherein the surface nitriding processing includes heating process at 600° C. or less.   
   
   
       2 . The method of manufacturing a knife having a high hardness nitride layer as set forth in  claim 1 , wherein the metal steel plate comprises 10% or more chromium as a stainless steel and has a HRC hardness of 35 or more by the quenching and curing treatment as a heat treatment. 
   
   
       3 . The method of manufacturing a blade having a high hardness nitride layer as set forth in  claims 1  or  2 , wherein the method further comprises a finishing process by grinding for forming a final cutting edge after the process for forming the high hardness nitride layer. 
   
   
       4 . The method of manufacturing a blade having a high hardness nitride layer as set forth in  claims 3 , wherein the method further comprises a process for forming an electroless nickel plating layer on the surface of the blade after the finishing process by grinding for forming a final cutting edge. 
   
   
       5 . The method of manufacturing a blade having a high hardness nitride layer as set forth in  claims 3  or  4 , wherein the method further comprises a process for forming a silver oxide layer, a copper oxide layer, or a silver oxide and copper oxide layer which is formed on the nitride layer or the electroless nickel plating layer of the blade, by dipping the blade in an aqueous solution of inorganic copper salt compounds, an aqueous solution of inorganic silver salt compounds, or the mixture solution of the aqueous solutions; or by applying the aqueous solution of the inorganic copper salt compounds, the aqueous solution of inorganic silver salt compounds, or the mixture solution of the aqueous solutions to the blade, and then performing heating and firing at a temperature of 450° C. or more.