Composite wire comprising a carbon-steel core and a...

Details Composite wire comprising a carbon-steel core and a... Composite wire comprising a carbon-steel core and a...

1999-07-29

2001-11-27

Jones, Deborah (Department: 1775)

Stock material or miscellaneous articles

All metal or with adjacent metals

Composite; i.e., plural, adjacent, spatially distinct metal...

C428S685000, C428S625000, C428S375000, C428S379000, C428S389000

Reexamination Certificate

active

06322907

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a composite wire, preferably of small diameter and high mechanical resistance, comprising a carbon-steel core and a stainless-steel outer layer.
2. Discussion of the Background
Fine wires, with diameter less than I mm, having a tensile strength in excess of 2000 MPa, used to manufacture, for example, guy wires, cables for the reinforcement of conveyor belts or pipes under pressure, elastomer reinforcement wires or cables, in general are obtained by fine wiredrawing of a machine wire made of high-carbon steel containing approximately 0.8% carbon, 0.5% manganese, 0.3% silicon, the remainder being essentially iron. These wires have the disadvantage of being sensitive to corrosion, which leads to risks of premature breaking in service. This problem of corrosion resistance also exists for wires of greater diameter, and it has been proposed to remedy it by using composite wires comprising a core made of high-carbon steel identical to that which has just been described, and a thin outer layer made of austenitic stainless steel of the SUS 304 type containing 17% to 19% chromium, 9% to 11% nickel, approximately 0.1% carbon, the remainder being iron and impurities resulting from processing. This is the case, in particular, in Japanese patent applications JP 56 148410 and JP 56 152922. But the solutions proposed by these patent applications do not make it possible to obtain diameters less than 1 mm and tensile strengths in excess of 2000 MPa. These limits result, in particular, from the formation of chromium carbides at the interface between the high-carbon steel and the stainless steel at the time of the thermal treatments required for wiredrawing.
In order to limit the detrimental effect of the chromium carbides at the interface between the high-carbon steel and the stainless steel, it has been proposed, in Japanese patent application JP 41 87336, to intercalate a fine layer of copper between the high-carbon steel and the stainless steel. There thus may be obtained a wire with a diameter of 0.7 mm, the tensile strength of which is 2000 MPa. But, with this technique, it is not possible to obtain a lesser diameter and a higher resistance; in addition, this technique requires the depositing of a layer of copper on the high-carbon steel core, which complicates manufacturing.
SUMMARY OF THE INVENTION
One object of this invention is to remedy these drawbacks and to provide a wire with a diameter less than 1 mm and a tensile strength higher than 2000 Mpa, having a good resistance to corrosion.
To this end, the invention provides a composite wire comprising a carbon-steel core and a stainless-steel outer layer. This wire is preferably such that:
the chemical composition of the carbon steel comprises, consists essentially of, or consists of, by weight:
0.15%≦C≦0.6%
0.1%≦Si≦0.3%
0.3%≦Mn≦1%
0%≦V≦0.3%
the remainder comprising, consisting of, or consisting essentially of iron and impurities resulting from processing,
the chemical composition of the stainless steel comprises, consists essentially of, or consists of, by weight:
0.005%≦C≦0.05%
0.005%≦N≦0.05%
0.1%≦Si≦2%
0.1%≦Mn≦5%
5%≦Ni≦12%
10%≦Cr≦20%
0%≦Mo≦3%
0%≦Cu≦4%
the remainder comprising, consisting essentially of, or consisting of iron and impurities resulting from processing,
the diameter of the wire is less than 1 mm and the tensile strength of the wire is higher than 2000 MPa.
The chemical composition of the carbon steel preferably is such that:
S≦0.02%
P≦0.02%
Al≦0.005%
N≦0.008%
The ratio of the stainless-steel wire section to the total wire section preferably ranges between 5% and 20%.
The chemical composition of the carbon steel may be chosen such that:
0.15%≦C≦0.35%
0.5%≦Mn≦1%
and that of the stainless steel such that:
9%≦Ni≦12%
15%≦Cr≦20%
1.5%≦Cu<4%
this composition furthermore satisfying the relationship:
−150≦551−462×(C+N)−9.2×Si−20×Mn−13.7×Cr−29×(Ni+Cu)−18.5×Mo<−55
In this case, there may be obtained a wire the diameter of which ranges between 0.1 mm and 0.8 mm. and the tensile strength of which ranges between 2100 MPa and 2700 MPa. Wiredrawing then may be performed without intermediate thermal treatment.
The chemical composition of the carbon steel also may be such that:
0.35%≦C≦0.6%
0.3%≦Mn<0.6%
and the chemical composition of the stainless steel such that:
−55≦551−462x(C+N)−9.2×Si−20×Mn—13.7×Cr−29×(Ni+Cu)−18.5×Mo≦−30
The chemical composition of the stainless steel preferably should be such that:
C+N≦0.06%
Also preferably, the copper content of the stainless steel should range between 3% and 4%.
There then may be obtained a wire the diameter of which ranges between 0.1 mm and 0.8 mm and the tensile strength of which ranges between 2700 MPa and 3400 MPa. Wiredrawing for this wire requires an intermediate thermal treatment which:
when the carbon content ranges between 0.35% and 0.45%, may be a hardening by cooling at a rate in excess of 100° C./s after austenitizing between 950° C and 1050° C. for about 5 s, followed by a tempering between 550° C. and 650° C. for about 5 s,
when the carbon content ranges between 0.45% and 0.6%, may be either a patenting between 550° C. and 6000° C., or an ongoing cooling to ambient temperature at a rate in excess of 200° C./s after an austenitizing between 950° C. and 1050° C. for about 5 s.
The wire according to the invention may be used in particular for the reinforcement of elastomers.


REFERENCES:
patent: 4917969 (1990-04-01), Pircher et al.
patent: 5366569 (1994-11-01), Mueller et al.
patent: 5772105 (1998-06-01), Zadno-Azizi et al.
patent: 5837326 (1998-11-01), Dallaire et al.
patent: 0 059 070 (1982-09-01), None
patent: 0 225 983 (1987-06-01), None
patent: 0 851 039 (1988-07-01), None
patent: 0 546 549 (1993-06-01), None
patent: 0 761 426 (1997-03-01), None
patent: 1 305 419 (1973-01-01), None
patent: 61-255781 (1986-11-01), None
Patent Abstracts of Japan; Murai Teruyuki; vol. 006, No. 039; Mar. 10, 1982; (w/ Copy of Japanese Language Abstract 56 154239; Nov. 28, 1981).
Patent Abstracts of Japan; Noma Tetsuo; vol. 016, No. 507; Oct. 20, 1992; (w/copy of Japanese Language Abstract 04 187336; Jul. 6, 1992).
Patent Abstracts of Japan; Murai Teruyuki; vol. 006, No. 035; Mar. 3, 1982; (w/copy of Japanese Language Abstract 56 152922; Nov. 26, 1981).
Patent Abstracts of Japan; Murai Teruyuki; vol. 006; No. 033; Feb. 27, 1982; (w/ copy of Japanese Language Abstract 56 148410; Nov. 17, 1981).
Patent Abstracts of Japan; Shimizu Sumio; vol. 011, No. 111; Apr. 8, 1987 & JP 61 255781; Nov. 13, 1986.

Affiliated with

Also associated with

Rating

Composite wire comprising a carbon-steel core and a... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Composite wire comprising a carbon-steel core and a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite wire comprising a carbon-steel core and a... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2608484