METHOD FOR PRODUCING JOURNAL PART OF 9 TO 12% Cr STEEL TURBINE ROTOR, AND JOURNAL PART PRODUCED BY THE METHOD

Abstract

In a journal part of a 9 to 12 wt % Cr steel turbine rotor, a groove face is formed, and on the groove face, a lower build-up layer is formed by using a first welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, V: 0.03 to 0.10 wt %, and a remainder composed of Fe and inevitable impurities, and further on this lower build-up layer, an upper build-up layer is formed using a second welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, and a remainder consisting of Fe and inevitable impurities.

what is claimed is: 
     
         1 . A journal part of a 9 to 12 wt % Cr steel turbine rotor, comprising:
 a groove face in a region corresponding to a journal part of the 9 to 12 wt % Cr steel turbine rotor;   a lower build-up layer formed, on the groove face, by monolayer build-up welding using a first welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, V: 0.03 to 0.10 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less; and   an upper build-up layer formed, on the lower build-up layer, by multilayer build-up welding using a second welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less,   wherein a stress is removed on the journal part formed with the upper build-up layer,   wherein V is contained in the % by weight in the first welding material for welding the lower build-up layer, to suppress generation of a ferrite structure in deposited metal in the vicinity of the bond part after removal of stress, and to promote generation of uniform tempered martensite structure and bainite structure, and   wherein generation of ferrite structure in deposited metal in the vicinity of a weld bond part having the lower build-up layer and the upper build-up layer is suppressed, and generation of uniform tempered martensite structure and bainite structure is promoted.   
     
     
         2 . A journal part of a 9 to 12 wt % Cr steel turbine rotor, comprising:
 a groove face in a region corresponding to a journal part of the 9 to 12 wt % Cr steel turbine rotor;   a lower build-up layer formed, on the groove face, by monolayer build-up welding using a first welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.25 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, V: 0.03 to 0.10 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less; and   an upper build-up layer formed, on the lower build-up layer, by multilayer build-up welding using a second welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less,   wherein a stress is removed on the journal part formed with the upper build-up layer,   wherein V is contained in the % by weight in the first welding material for welding the lower build-up layer, to suppress generation of a ferrite structure in deposited metal in the vicinity of the bond part after removal of stress, and to promote generation of uniform tempered martensite structure and bainite structure, and   wherein generation of ferrite structure in deposited metal in the vicinity of a weld bond part having the lower build-up layer and the upper build-up layer is suppressed, and generation of uniform tempered martensite structure and bainite structure is promoted.   
     
     
         3 . A journal part of a 9 to 12 wt % Cr steel turbine rotor, comprising:
 a groove face in a region corresponding to a journal part of the 9 to 12 wt % Cr steel turbine rotor;   a lower build-up layer formed, on the groove face, by monolayer build-up welding using a first welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, V: 0.03 to 0.10 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less; and   an upper build-up layer formed, on the lower build-up layer, by multilayer build-up welding using a second welding material containing C: 0.10 to 0.25 wt %, Si: 0.20 to 0.80 wt %, Mn: 1.0 to 2.5 wt %, Ni: 0.4 to 1.0 wt %, Cr: 1.0 to 3.0 wt %, Mo: 0.2 to 1.5 wt %, and a remainder composed of Fe and inevitable impurities containing P: 0.015 wt % or less and S: 0.010 wt % or less,   wherein a stress is removed on the journal part formed with the upper build-up layer,   wherein V is contained in the % by weight in the first welding material for welding the lower build-up layer, to suppress generation of a ferrite structure in deposited metal in the vicinity of the bond part after removal of stress, and to promote generation of uniform tempered martensite structure and bainite structure,   wherein a machining process and a rolling process are conducted on the part where the stress is removed, and   wherein generation of ferrite structure in deposited metal in the vicinity of a weld bond part having the lower build-up layer and the upper build-up layer is suppressed, and generation of uniform tempered martensite structure and bainite structure is promoted.