Rectangular tire bead wire and manufacturing method therefor

Abstract

Disclosed in the present invention are a rectangular tire bead wire and a manufacturing method therefor. The manufacturing method comprises the following steps: carrying out die drawing on a wire rod to obtain a circular-section wire; galvanizing the circular-section wire; and rolling the galvanized circular-section wire at least twice to obtain a rectangular-section wire, wherein first rolling is two-roll rolling: rolling the circular-section wire into a flat-section wire, and the remaining rolling is four-roll rolling: rolling the flat-section wire into a rectangular-section wire. The present invention improves the uniformity and compactness of a wire coating, thereby improving the general performance of the wire; also improves the toughness of the rectangular wire and the filling rate of the R angle of the wire; and simplifies the production process, and facilitates reduction of the production costs.

Description

Rectangular bead steel wire and preparation method thereof Technical Field

[0001] The invention belongs to the technical field of tire bead wires and relates to a rectangular tire bead wire and a preparation method thereof. Background Art

[0002] The bead ring is the primary load-bearing component of the tire bead, carrying approximately 70% of the inflation pressure. Its performance is inextricably linked to tire safety. Conventional bead rings are made of circular-cross-section bead wire, resulting in linear contact between the wires and high contact stress. In contrast, rectangular bead rings feature surface contact between the wires, providing greater structural stability and improving tire load-bearing capacity and durability.

[0003] The surface coating of rectangular bead wire is mainly Zn coating, which can significantly improve the corrosion resistance of the steel wire. In order to improve the filling rate in the steel wire ring, the edge of the rectangular bead wire has a smaller R angle. In order to ensure high strength and dimensional stability, the thickness / width ratio of the rectangular bead wire needs to be controlled within a certain range, and the finished steel wire has high tensile strength. These product characteristics make the production of rectangular bead wire difficult. When using traditional fixed die drawing, although the shape accuracy and smoothness of the steel wire are good, the mold wears severely, especially at the rounded corners. The mold life is very short, and it is difficult to achieve mass production. When using roller die drawing production, although the mold life is long, the dimensional accuracy and smoothness of the formed rectangular steel wire product are poor, the rounded corners are difficult to fill, and it is difficult to meet product quality requirements.

[0004] Chinese patent CN201510861043.3 provides a rectangular cross-section steel wire for radial tires and a method for making a wire bead. This patent requires tempering treatment. The lead bath tempering at 380-450°C affects the density and uniformity of the zinc coating. In addition, the roller drawing process affects the dimensional accuracy and smoothness of the rectangular steel wire product, making it difficult to fill in rounded corners.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a rectangular bead steel wire and a preparation method thereof, thereby improving the uniformity and density of the steel wire coating and improving the cleaning performance of the steel wire; at the same time, the toughness of the rectangular steel wire and the filling rate of the steel wire R angle are improved; the production process is simplified, which is conducive to reducing production costs.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] A method for preparing a rectangular bead wire comprises the following steps:

[0009] The wire rod is die-drawn to obtain a round cross-section steel wire;

[0010] Galvanizing of round cross-section steel wire;

[0011] The galvanized round-section steel wire is rolled at least twice to obtain a rectangular-section steel wire; the first pass is two-roll rolling to roll the round-section steel wire into a flat-section steel wire, and the other passes are four-roll rolling to roll the flat-section steel wire into a rectangular-section steel wire.

[0012] Optionally, the surface of the wire rod is pretreated before the wire rod is drawn into a die.

[0013] Optionally, the pretreatment includes mechanically descaling, cleaning, boron coating and drying the surface of the wire rod in sequence.

[0014] Optionally, the galvanized round-section steel wire is rolled three times to obtain a rectangular-section steel wire; the first pass is two-roll rolling, which rolls the round-section steel wire into a flat-section steel wire, and the height of the flat-section steel wire is 1.15 to 1.45 times the height of the rectangular-section steel wire; the second and third passes are four-roll rolling, and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 2% to 10%.

[0015] Optionally, the height of the flat cross-section steel wire is 1.25 to 1.35 times the height of the rectangular cross-section steel wire; and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 4% to 6%.

[0016] Optionally, the carbon content of the wire rod is 0.65-0.95%; the diameter of the wire rod is 5.50-7.00 mm.

[0017] Optionally, the cross-sectional area of ​​the circular cross-sectional steel wire is 1.05 to 1.15 times the cross-sectional area of ​​the rectangular cross-sectional steel wire.

[0018] Optionally, the cross-sectional area of ​​the circular cross-sectional steel wire is 1.10 times the cross-sectional area of ​​the rectangular cross-sectional steel wire.

[0019] Optionally, the wire rod is plated with 0.20-0.70 g of zinc per kg of wire rod.

[0020] A rectangular tire bead wire is prepared by the preparation method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a rectangular bead steel wire and a preparation method thereof, which eliminates the need for lead bath tempering treatment of the steel wire, reduces softening and dissolution of the zinc coating of the steel wire during tempering, improves the uniformity and density of the coating, and enhances the adhesion to rubber. Furthermore, the production process can be simplified, thereby reducing production costs.

[0023] The roll forming process and reasonable forming process parameters make the residual stress generated when the steel wire is deformed relatively small, and the geometric dimensions are easy to control; the steel wire is not easy to deviate, which improves the performance of the steel wire rod; at the same time, the toughness of the rectangular steel wire product is improved, so that the rectangular steel wire has a higher number of bending and torsion times, and the steel wire R angle filling rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a cross-sectional view of a rectangular bead steel wire and a preparation method thereof according to an embodiment of the present invention;

[0025] FIG2 is a schematic diagram of rolling a rectangular bead wire and a preparation method thereof according to an embodiment of the present invention;

[0026] FIG3 is a cross-sectional view of a rectangular bead steel wire and a preparation method thereof before rolling according to an embodiment of the present invention;

[0027] FIG4 is a cross-sectional view of a rectangular bead wire and a preparation method thereof, wherein the flat cross-section steel wire is rolled by two rollers according to an embodiment of the present invention;

[0028] FIG5 is a schematic diagram of a four-roll rolling process of a rectangular bead wire and a preparation method thereof according to an embodiment of the present invention;

[0029] FIG6 is a front view of FIG5 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0031] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0032] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, percentages or ratios and other numerical values ​​used in this specification and the appended claims are to be understood as being modified in all instances by the term "about." In addition, all ranges disclosed herein are inclusive and independently combinable.

[0033] Example 1

[0034] As shown in Figures 1 to 6, a method for preparing a rectangular bead wire includes the following steps:

[0035] S1, mechanically descaling, cleaning, boron coating, and drying the surface of a wire rod with a carbon content of 0.65% and a diameter of 5.50 mm.

[0036] S2, drawing the wire rod treated in S1 on a straight-through dry drawing machine to obtain a circular cross-section steel wire; the cross-sectional area of ​​the circular cross-section steel wire is 1.05 times the cross-sectional area of ​​the finished rectangular cross-section steel wire;

[0037] S3, galvanizing the round cross-section steel wire; 0.20% zinc is plated per kilogram of wire rod;

[0038] S4, the galvanized round-section steel wire is rolled three times to obtain a rectangular-section steel wire; the first pass is two-roll rolling, which rolls the round-section steel wire into a flat-section steel wire, and the height of the flat-section steel wire is 1.15 times the height of the rectangular-section steel wire; the second and third passes are four-roll rolling, and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 2%.

[0039] A rectangular tire bead wire is prepared by the preparation method.

[0040] Example 2

[0041] As shown in Figures 1 to 6, a method for preparing a rectangular bead wire includes the following steps:

[0042] S1, mechanically descaling, cleaning, boron coating, and drying the surface of a wire rod having a carbon content of 0.80% and a diameter of 6.50 mm.

[0043] S2, drawing the wire rod treated in S1 on a straight-through dry drawing machine to obtain a circular cross-section steel wire; the cross-sectional area of ​​the circular cross-section steel wire is 1.10 times the cross-sectional area of ​​the finished rectangular cross-section steel wire;

[0044] S3, galvanizing the round cross-section steel wire; 0.45g of zinc is plated per kilogram of wire rod;

[0045] S4, the galvanized round-section steel wire is rolled three times to obtain a rectangular-section steel wire; the first pass is two-roll rolling, which rolls the round-section steel wire into a flat-section steel wire, and the height of the flat-section steel wire is 1.30 times the height of the rectangular-section steel wire; the second and third passes are four-roll rolling, and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 5%.

[0046] A rectangular tire bead wire is prepared by the preparation method.

[0047] Example 3

[0048] As shown in Figures 1 to 6, a method for preparing a rectangular bead wire includes the following steps:

[0049] S1, mechanically descaling, cleaning, boron coating, and drying the surface of a wire rod with a carbon content of 0.95% and a diameter of 7.00 mm.

[0050] S2, drawing the wire rod treated in S1 on a straight-through dry drawing machine to obtain a circular cross-section steel wire; the cross-sectional area of ​​the circular cross-section steel wire is 1.15 times the cross-sectional area of ​​the finished rectangular cross-section steel wire;

[0051] S3, galvanizing the round cross-section steel wire; 0.70g of zinc is plated per kilogram of wire rod;

[0052] S4, the galvanized round-section steel wire is rolled three times to obtain a rectangular-section steel wire; the first pass is two-roll rolling, which rolls the round-section steel wire into a flat-section steel wire, and the height of the flat-section steel wire is 1.45 times the height of the rectangular-section steel wire; the second and third passes are four-roll rolling, and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 10%.

[0053] A rectangular tire bead wire is prepared by the preparation method.

[0054] The main performance indicators of rectangular bead wire (long axis 2.57mm short axis 1.37mm) produced by roller rolling without tempering and roller drawing with tempering are shown in Table 1

[0055] Table 1 Comparison of rectangular bead wire indicators

[0056] As can be seen from the table, the rectangular bead wire produced by the roll-rolled non-tempered process has higher product dimensional accuracy than the steel wire produced by the roll-pulled tempered process; in addition, the rectangular steel wire produced by the roll-rolled non-tempered process has a 20% higher adhesion to rubber than the roll-pulled tempered process; the R angle is smaller, and the number of bending and torsion times are higher than those of the roll-pulled tempered process.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a rectangular tire bead wire, characterized in that: The following steps are involved: The wire rod is die-drawn to obtain a round cross-section steel wire; Galvanizing of round section steel wire; The galvanized round-section steel wire is rolled at least twice to obtain a rectangular-section steel wire; the first pass is two-roll rolling to roll the round-section steel wire into a flat-section steel wire, and the other passes are four-roll rolling to roll the flat-section steel wire into a rectangular-section steel wire.

2. The method for preparing a rectangular bead wire according to claim 1, characterized in that: Before the wire rod is drawn into the die, the surface of the wire rod is pretreated.

3. The method for preparing a rectangular bead wire according to claim 2, characterized in that: The pretreatment includes mechanically descaling, cleaning, boron coating and drying the surface of the wire rod in sequence.

4. The method for preparing a rectangular bead wire according to claim 1, characterized in that: The galvanized round-section steel wire is rolled three times to obtain a rectangular-section steel wire; the first pass is two-roll rolling to roll the round-section steel wire into a flat-section steel wire, and the height of the flat-section steel wire is 1.15 to 1.45 times the height of the rectangular-section steel wire; the second and third passes are four-roll rolling, and the cross-sectional shrinkage rate of the steel wire in each rolling pass is 2% to 10%.

5. The method for preparing a rectangular bead wire according to claim 4, characterized in that: The height of the flat cross-section steel wire is 1.25 to 1.35 times the height of the rectangular cross-section steel wire; the cross-section shrinkage rate of the steel wire in each rolling process is 4% to 6%.

6. The method for preparing a rectangular bead wire according to claim 1, characterized in that: The carbon content of the wire rod is 0.65-0.95%; the diameter of the wire rod is 5.50-7.00 mm.

7. The method for preparing a rectangular bead wire according to claim 1, characterized in that: The cross-sectional area of ​​a circular cross-sectional steel wire is 1.05 to 1.15 times that of a rectangular cross-sectional steel wire.

8. The method for preparing a rectangular bead wire according to claim 7, characterized in that: The cross-sectional area of ​​a circular cross-sectional steel wire is 1.10 times that of a rectangular cross-sectional steel wire.

9. The method for preparing a rectangular bead wire according to claim 1, characterized in that: Each kilogram of wire rod is plated with 0.20-0.70g of zinc.

10. A rectangular bead wire, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9.

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