Wire rod, steel wire, and manufacturing method thereof
View Patent ↗The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.
1. A wire rod with a composition comprising: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; Cr: 0-0.5 mass %; Ni: 0-0.5 mass %; Co: 0-0.5 mass %; V: 0-0.5 mass %; Cu: 0-0.5 mass %; Nb: 0-0.1 mass %; Mo: 0-0.2 mass %; W: 0-0.2 mass %; B: 0-30 ppm; REM: 0-50 ppm; Ca: 0-50 ppm; Mg: 0-50 ppm; Zr: 0-100 ppm; and the balance including Fe and inevitable impurities, wherein
97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite,
0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite, and
the wire rod has a diameter of 3-16 mm.
2. The wire rod according to claim 1 , wherein the cross-section of the wire rod is occupied by the pearlite, and at least one selected from the pro-eutectoid cementite, a bainite, a pseudo pearlite, a ferrite, a grain boundary ferrite, and a martensite.
3. A manufacturing method of the wire rod according to claim 1 or 2 , comprising:
hot-rolling a billet with a composition including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; Cr: 0-0.5 mass %; Ni: 0-0.5 mass %; Co: 0-0.5 mass %; V: 0-0.5 mass %; Cu: 0-0.5 mass %; Nb: 0-0.1 mass %; Mo: 0-0.2 mass %; W: 0-0.2 mass %; B: 0-30 ppm; REM: 0-50 ppm; Ca: 0-50 ppm; Mg: 0-50 ppm; Zr: 0-100 ppm; and the balance including Fe and inevitable impurities, so as to obtain a rolled wire rod having a diameter of 3-16 mm;
coiling the rolled wire rod at a temperature of 955° C. or more; and
performing a patenting treatment by immersing the rolled wire rod of 900° C. or higher into a molten salt bath at a temperature of 500° C.-600° C.
4. A manufacturing method of the wire rod according to claim 1 or 2 , comprising:
hot-rolling a billet with a composition including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; Cr: 0-0.5 mass %; Ni: 0-0.5 mass %; Co: 0-0.5 mass %; V: 0-0.5 mass %; Cu: 0-0.5 mass %; Nb: 0-0.1 mass %; Mo: 0-0.2 mass %; W: 0-0.2 mass %; B: 0-30 ppm; REM: 0-50 ppm; Ca: 0-50 ppm; Mg: 0-50 ppm; Zr: 0-100 ppm; and the balance including Fe and inevitable impurities, so as to obtain a rolled wire rod having a diameter of 3-16 mm;
coiling the rolled wire rod at a temperature of 950° C. or more; and
performing a patenting treatment by starting cooling of the rolled wire rod of 900° C. or higher, cooling the rolled wire rod in a manner that a cooling rate Y for cooling the rolled wire rod from 900° C. to 650° C. is controlled to satisfy Formula 1, and finishing a pearlite transformation at a temperature of 650° C.-500° C.:
Y ≧exp(( C %−0.66)/0.12) (Formula 1)
5. A manufacturing method of the wire rod according to claim 1 or 2 , comprising:
preparing a rolled wire rod with a composition including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; Cr: 0-0.5 mass %; Ni: 0-0.5 mass %; Co: 0-0.5 mass %; V: 0-0.5 mass %; Cu: 0-0.5 mass %; Nb: 0-0.1 mass %; Mo: 0-0.2 mass %; W: 0-0.2 mass %; B: 0-30 ppm; REM: 0-50 ppm; Ca: 0-50 ppm; Mg: 0-50 ppm; Zr: 0-100 ppm; and the balance including Fe and inevitable impurities, and a diameter of 3-16 mm, and reheating the rolled wire rod to a temperature of 1010° C.-1050° C.; and
performing a patenting treatment by starting cooling of the rolled wire rod of 900° C. or higher using a lead bath or a fluidized bed at a temperature of 500° C.-600° C.
6. The wire rod according to claim 1 , wherein the amount of C in the composition is 1.05-1.30 mass %.
7. The wire rod according to claim 1 , wherein the amount of C in the composition is 1.10-1.30 mass %.
8. The wire rod according to claim 1 , wherein an inclusion including Si and O is formed.
9. The manufacturing method of the wire rod according to claim 3 , wherein, in the hot-rolling step, a temperature of a final rolling is 1010° C.-1050° C.
10. The manufacturing method of the wire rod according to claim 4 , wherein, in the hot-rolling step, a temperature of a final rolling is 1010° C.-1050° C.
11. The manufacturing method of the wire rod according to claim 3 , wherein the rolled wire rod is coiled at a temperature of 960° C. or more.
12. The manufacturing method of the wire rod according to claim 3 , wherein the rolled wire rod is coiled at a temperature of 975° C. or more.
13. The manufacturing method of the wire rod according to claim 4 , wherein the rolled wire rod is coiled at a temperature of 955° C. or more.
14. The manufacturing method of the wire rod according to claim 4 , wherein the rolled wire rod is coiled at a temperature of 965° C. or more.
15. The manufacturing method of the wire rod according to claim 5 , wherein the rolled wire rod is coiled at a temperature of 1020° C.-1050° C. or more.