Free cutting alloy

Abstract

Provided is free cutting alloy excellent in machinability, preserving various characteristics as alloy. The free cutting alloy contains: one or more of Ti and Zr as a metal element component; and C being an indispensable element as a bonding component with the metal element component, wherein a (Ti, Zr) based compound including one or more of S, Se and Te is formed in a matrix metal phase. The free cutting alloy is more excellent in machinability, preserving various characteristics as alloy at similar levels to a conventional case. The effect is especially conspicuous, for example, when a compound expressed in a chemical form of (Ti, Zr) 4 C 2 (S, Se, Te) 2 as the (Ti, Zr) based compound is formed at least in a dispersed state in the alloy structure.

What is claimed is:  
     
         1 . Free cutting alloy constituted as ferrite containing stainless steel containing: 
 2 mass % or lower, including zero, Ni; 12 to 35 mass % Cr; and 0.021 to 0.4 mass % C;    one or more of Ti and Zr such that W Ti +0.52 W Zr =0.14 to 3.5 mass %, wherein W Ti  and W Zr  denote respective contents in mass % of Ti and Zr; and one or more of S and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01 to 0.8 mass % for Se so that the total amount of S content;    wherein S content is determined such that a value of W S /(W Ti +0.52W Zr ) is 0.45 or less, wherein W S  demotes a S content;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         2 . Free cutting alloy according to  claim 1 , the W so  value of which is less than 0.035 mass % when the following test is performed: an alloy test piece is prepared so as to have the shape of a rectangular prism in size of 15 mm in length, 25 mm in width and 3 mm in thickness with the entire surface being polished with No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm in width and 0.1 mm in thickness with a purity of 99.9% or higher as a S getter and 0.5 cc of pure water are sealed in a vessel of an inner volume of 250 cc together with said test piece; a temperature in said vessel is raised to 85° C. and said temperature is then kept there for 20 hr; and thereafter, a S content W SO  in mass % in said silver foil piece is analyzed.  
     
     
         3 . Free cutting alloy according to  claim 1 , containing 2 mass % or lower Si; 2 mass % or lower Mn; 2 mass % or lower Cu; and 2 mass % or lower Co.  
     
     
         4 . Free cutting alloy according to  claim 1 , containing one or more of Mo and W in the respective ranges of 0.1 to 4 mass % for Mo and 0.1 to 3 mass % for W.  
     
     
         5 . Free cutting alloy according to  claim 1 , containing: 0.05 mass % or lower P; and 0.03 mass % 0; and 0.05 mass % or lower N.  
     
     
         6 . Free cutting alloy according to  claim 1 , containing one or more of Te, Bi and Pb in the respective ranges of 0.005 to 0.1 mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass % for Pb.  
     
     
         7 . Free cutting alloy according to  claim 1 , containing one or more selected from the group consisting of Ca, Mg, B and metal elements classified as Group 3A in the periodic table of elements in the range of 0.0005 to 0.01 mass % for one element or as a total content of more than one elements combined.  
     
     
         8 . Free cutting alloy according to  claim 1 , containing one or more selected from the group consisting of Nb, V, Ta and Hf each of which is in a range of 0.01 to 0.5 mass %.  
     
     
         9 . Free cutting alloy constituted as martensite containing stainless steel containing: 
 2 mass % or lower, including zero, Ni; 9 to 17 mass % Cr;    one or more of Ti and Zr such that W Ti +0.52 W Zr =0.03 to 3.5 mass %, wherein W Ti  and W Zr  denote respective contents in mass % of Ti and Zr; and one or more of S and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01 to 0.8 mass % for Se;    and 0.19 mass % or more of C so as to satisfy the following formulae:    0.375 (W S +0.4 W Se  )<W C ≦1.5  (Formula A) 0.125 (W Ti +0.52 W Zr )<W C <1.5  (Formula B)    , wherein W Ti , W Zr  W C , W S  and W Se  denote respective contents of Ti, Zr, C, S and Se, all in mass %;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         10 . Free cutting alloy according to  claim 9  whose S content is determined such that a value of W S /(W Ti +0.52W Zr ) is 0.45 or less, wherein W S  demotes a S content.  
     
     
         11 . Free cutting alloy according to  claim 10 , the W so  value of which is less than 0.035 mass % when the following test is performed: an alloy test piece is prepared so as to have the shape of a rectangular prism in size of 15 mm in length, 25 mm in width and 3 mm in thickness with the entire surface being polished with No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm in width and 0.1 mm in thickness with a purity of 99.9% or higher as a S getter and 0.5 cc of pure water are sealed in a vessel of an inner volume of 250 cc together with said test piece; a temperature in said vessel is raised to 85° C. and said temperature is then kept there for 20 hr; and thereafter, a S content W SO  in mass % in said silver foil piece is analyzed.  
     
     
         12 . Free cutting alloy according to  claim 9  further containing: 2 mass % or lower Si; 2 mass % or lower Mn; 2 mass % or lower Cu; and 2 mass % or lower Co.  
     
     
         13 . Free cutting alloy according to  claim 9  further containing one or more of Mo and W in the respective ranges of 0.1 to 4 mass % for Mo and 0.1 to 3 mass % for W.  
     
     
         14 . Free cutting alloy according to  claim 9  further containing: 0.05 mass % or lower P; and 0.03 mass % or lower O; and 0.05 mass % or lower N.  
     
     
         15 . Free cutting alloy according to  claim 9  further containing one or more of Te, Bi and Pb in the respective ranges of 0.005 to 0.1 mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass % for Pb.  
     
     
         16 . Free cutting alloy according to  claim 9  further containing one or more selected from the group consisting of Ca, Mg, Band metal elements classified as Group 3A in the periodic table of elements in the range of 0.0005 to 0.01 mass % for one element or as a total content of more than one elements combined.  
     
     
         17 . Free cutting alloy according to  claim 9  further containing one or more selected from the group consisting of Nb, V, Ta and Hf each of which is in a range of 0.01 to 0.5 mass %.  
     
     
         18 . Free cutting alloy constituted as austenite iron containing alloy containing: 
 2 to 50 mass % Ni; 12 to 50 mass % Cr; 5 to 85.926 mass % Fe; 0.021 to 0.4 mass % C.    one or more of Ti and Zr such that W Ti +0.52 W Zr =0.03 to 3.5 mass %, wherein W Ti  and W Zr  denote respective contents in mass % of Ti and Zr; and one or more of S and Se in the respective ranges of 0.01 to 1 mass % for S and 0.01 to 0.8 mass % for Se so that the total amount of S and Se is more than the C content;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         19 . Free cutting alloy according to  claim 18  whose S content is determined such that a value of W S /(W Ti +0.52W Zr ) is 0.45 or less, wherein W S  and W C  demote a S content and a C content, respectively.  
     
     
         20 . Free cutting alloy according to  claim 19 , the W so  value of which is less than 0.035 mass % when the following test is performed: an alloy test piece is prepared so as to have the shape of a rectangular prism in size of 15 mm in length, 25 mm in width and 3 mm in thickness with the entire surface being polished with No. 400 emery paper; a silver foil in size of 10 mm in length, 5 mm in width and 0.1 mm in thickness with a purity of 99.9% or higher as a S getter and 0.5 cc of pure water are sealed in a vessel of an inner volume of 250 cc together with said test piece; a temperature in said vessel is raised to 85° C. and said temperature is then kept there for 20 hr; and thereafter, a S content W SO  in mass % in said silver foil piece is analyzed.  
     
     
         21 . Free cutting alloy according to  claim 18  further containing: 4 mass % or lower Si; 4 mass % or lower Mn; 4 mass % or lower Cu; and 4 mass % or lower Co.  
     
     
         22 . Free cutting alloy according to  claim 18  further containing one or more of Mo and W in the respective ranges of 0.1 to 10 mass % for Mo and 0.1 to 10 mass % for W.  
     
     
         23 . Free cutting alloy according to  claim 18  further containing: 0.05 mass % or lower P; and 0.03 mass % or lower O; and 0.05 mass % or lower N.  
     
     
         24 . Free cutting alloy according to  claim 18  further containing one or more of Te, Bi and Pb in the respective ranges of 0.005 to 0.1 mass % for Te; 0.01 to 0.2 mass % for Bi; and 0.01 to 0.3 mass % for Pb.  
     
     
         25 . Free cutting alloy according to  claim 18  further containing one or more selected from the group consisting of Ca, Mg, B and metal elements classified as Group 3A in the periodic table of elements in the range of 0.0005 to 0.01 mass % for one element or as a total content of more than one elements combined.  
     
     
         26 . Free cutting alloy according to  claim 18  further containing one or more selected from the group consisting of Nb, V, Ta and Hf each of which is in a range of 0.01 to 0.5 mass %.  
     
     
         27 . Free cutting alloy constituted as electromagnetic stainless steel containing: 
 0.01 to 3, the upper limit not included, mass % Si;    2 mass % or lower Mn;    to 25 mass % Cr;    0.01 to 5, the lower limit not included, mass % Al;    one or more of Ti and Zr so that X defined by the following formula 1 is in the range of 0.05 to 0.5 mass %;    C in the range of 0.02 X to 0.06 X mass %, wherein X is expressed by the following formula 1;    one or more of S, Se and Te in the range of (Z−0.07)X to (Z+0.07)X mass %, wherein X, Z and Y are values of the respective following formulae 1, 3 and 2;    Ti %+0.52 Zr %=X  (Formula 1) S %+0.41 Se %+0.25 Te %=Y  (Formula 2) 32(C %/X−0.125) 2 =Z  (Formula 3)    Fe being the main component of the alloy;    inevitable impurities;    wherein Pb content is less than 0.01 mass %;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         28 . Free cutting alloy according to  claim 27  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         29 . Free cutting alloy according to  claim 27  further containing one or more selected from the group consisting of B and metal elements classified as Group 3A in the periodic table of elements in the respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or lower for one or more of metal elements classified as Group 3A in the periodic table of elements in total.  
     
     
         30 . Free cutting alloy according to  claim 29  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         31 . Free cutting alloy constituted as electromagnetic stainless steel containing: 
 0.01 to 3, the upper limit not included, mass % Si;    2 mass % or lower Mn;    to 25 mass % Cr;    0.01 to 5, the lower limit not included, mass % Al;    one or more of Ti and Zr so that X defined by the following formula 1 is in the range of 0.05 to 0.5 mass %;    C in the range of 0.19 X to 0.26 X mass %, wherein X is expressed by the following formula 1;    one or more of S, Se and Te in the range of (Z−0.07)X to (Z+0.07)X mass %, wherein X, Z and Y are values of the respective following formulae 1, 3 and 2;    Ti %+0.52 Zr %=X  (Formula 1) %+0.41 Se %+0.25 Te %=Y  (Formula 2) 32(C %/X−0.125) 2 =Z  (Formula 3)    Fe being the main component of the alloy;    inevitable impurities;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         32 . Free cutting alloy according to  claim 31  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         33 . Free cutting alloy according to  claim 31  further containing one or more selected from the group consisting of Pb, B and metal elements classified as Group 3A in the periodic table of elements in the respective ranges of 0.15 mass % or lower for Pb, 0.01 mass % or lower for B; and 0.1 mass % or lower for one or more of metal elements classified as Group 3A in the periodic table of elements in total.  
     
     
         34 . Free cutting alloy according to  claim 31  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         35 . Free cutting alloy constituted as electromagnetic stainless steel containing: 
 0.01 to 3, the upper limit not included, mass % Si;    2 mass % or lower Mn;    to 25 mass % Cr;    0.01 to 5, the lower limit not included, mass % Al;    one or more of Ti and Zr so that X defined by the following formula 1 is in the range of 0.05 to 0.5 mass %;    C in the range of 0.02 X to 0.26 X mass %, wherein X is expressed by the following formula 1;    one or more of S, Se and Te in the range of (Z+0.07)X to (Z+0.45)X mass %, wherein X, Z and Y are values of the respective following formulae 1, 3 and 2;    Ti %+0.52 Zr %=X  (Formula 1) S %+0.41 Se %+0.25 Te %=Y  (Formula 2) 32(C %/X−0.125) 2 =Z  (Formula 3)    Fe being the main component of the alloy;    inevitable impurities;    wherein Pb content is less than 0.01 mass %;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         36 . Free cutting alloy according to  claim 35  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         37 . Free cutting alloy according to  claim 35  further containing one or more selected from the group consisting of B and metal elements classified as Group 3A in the periodic table of elements in the respective ranges of 0.01 mass % or lower for B; and 0.1 mass % or lower for one or more of metal elements classified as Group 3A in the periodic table of elements in total.  
     
     
         38 . Free cutting alloy according to  claim 35  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         39 . Free cutting alloy constituted as electromagnetic stainless steel containing: 
 0.01 to 3, the upper limit not included, mass % Si;    2 mass % or lower Mn;    to 25 mass % Cr;    0.01 to 5, the lower limit not included, mass % Al;    one or more of Ti and Zr so that X defined by the following formula 1 is in the range of 0.05 to 0.5 mass %;    C in the range of 0.02 X to 0.26 X mass %, wherein X is expressed by the following formula 1;    one or more of S, Se and Te in the range of (Z+0.45)X to (Z+0.70)X mass %, wherein X, Z and Y are values of the respective following formulae 1, 3 and 2;    Ti %+0.52 Zr %=X  (Formula 1) S %+0.41 Se %+0.25 Te %=Y  (Formula 2) 32(C %/X−0.125) 2 =Z  (Formula 3)    Fe being the main component of the alloy;    inevitable impurities;    and wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         40 . Free cutting alloy according to  claim 39  further containing one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V.  
     
     
         41 . Free cutting alloy containing 20 to 82 mass % Ni and the part except for Ni of which is mainly constituted by one or more of Fe and Cr further containing: 
 one or more of Ti and Zr so that X defined by the following formula 1 in the range satisfying a relation of 0.05≦X≦3;    one or more of S, Se and Te so that Y defined by the following formula 2 in the range satisfying a relation of 0.014≦Y≦0.5 X;    C in the range satisfying a relation of 0.2 Y≦W C ≦0.3, wherein when a Ti content is indicated by W Ti  in mass %, a Zr content by W Zr  in mass %, a C content by W C  in mass %, a S content by W S  in mass %, a Se content by W Se  in mass % and a Te content by W Te  in mass %, the following formulae 1 and 2 are given in order to define X and Y:    X (mass %)=W Ti +0.52 W Zr   (formula 1) Y (mass %)=W S +0.41 W Se +0.25 W Te   (formula 2);    one or more of Si, Mn and Al in the respective ranges of 1 mass % for Si, 1 mass % for Mn and 1 mass % for Al;    wherein a (Ti, Zr) based compound containing one or more of Ti and Zr as a metal element component, C being an indispensable element as a bonding component with the metal element component, and one or more of S, Se and Te is dispersed in a matrix metal phase.    
     
     
         42 . Free cutting alloy according to  claim 41  further containing one or more of Mo and Cu in the respective ranges of 7 mass % or lower for Mo and 7 mass % or lower for Cu.  
     
     
         43 . Free cutting alloy according to  claim 41  further containing 12 mass % or lower Cr.  
     
     
         44 . Free cutting alloy according to  claim 41  further containing 18 mass % or lower Co.