JP2005271716A - Annular core wire of cable bead for tire and manufacturing method of core wire for that and annular core wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an annular core wire of a cable bead for a tire and a manufacturing method of the core wire for that and the annular core wire capable of securing the strength of a regular part and a welded part while facilitating a welding operation, and saving an annealing treatment after welding. <P>SOLUTION: The core wire 12 of the cable bead 11 for the tire contains iron (Fe) as a main component, carbon (C) of 0.1 to 0.3% by mass, both silicon (Si) and manganese (Mn) together of 2.2 to 2.9% by mass, and chromium (Cr) of 0.3 to 0.5% by mass. The content of manganese is set to be much more than that of silicon. The annular core wire 14 is obtained by saving annealing treatment and deburring after bending to form the core wire 12 and welding the starting end part and the dead end part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an annular core wire of a tire cable bead characterized by the composition of components constituting the core wire of a high-performance cable bead among tire beads, and a core wire for the same and a method for producing the annular core wire.

  Traditionally, cable beads are known to lead to improved performance for tires, but are very complex and costly to manufacture, and their use is limited to high performance tires. In a single-winding cable bead, which is a general method for manufacturing such a cable bead, a core wire is welded to form an annular core wire, and a single wire is wound around the core wire in a spiral manner, and the start and end of the wire are made of brass. It is manufactured by inserting into a thin tube made of metal and caulking.

  In other words, in order to spirally wind the winding around the circumferential surface of the annular core wire, the tip end of the winding is connected to the annular core wire from a winding bobbin wound with a length corresponding to one tire cable bead. Fix to a predetermined site by means such as tape. Thereafter, the annular core wire is rotated around its axis, and the winding bobbin is rotated in the direction of feeding the winding to revolve around the tangential axis of the annular core wire while rewinding the winding. That is, the winding bobbin passes through the inner diameter side of the annular core wire, and the winding stored in the winding bobbin is spirally wound around the circumferential surface of the annular core wire. In this manner, a cable bead having a circular cross section can be manufactured by inserting the front end and the end of the winding into a brass thin tube and caulking them.

  As this type of carbon steel wire, carbon (C) is 0.7 to 0.9 mass% and silicon (Si) is 0.2 to 0.7 as used for tire belt cords and bead wires. One having a composition of mass%, manganese (Mn) of 0.2 to 0.7 mass% and the balance of iron is known. For example, it is known that 0.2 to 0.4 mass% of chromium (Cr) is further added in order to improve the strength (see Patent Document 1).

Moreover, as an endless wire for a wire saw manufactured by welding both ends of a wire rod, carbon contains 0.02% by mass or less, silicon contains 0.10% by mass or less, manganese contains 0.10% by mass or less, What has a composition whose remainder is iron is known (for example, refer to patent documents 2).
JP-A-5-214443 (pages 2 and 4 to 6) JP 2003-55742 A (Pages 2 and 5 to 8)

  By the way, the core wire forming the annular core wire is required to have high strength and uniform strength on the circumference. However, in order to make a single core wire, it is necessary to connect the start and end portions of the wire. In this case, even if the end portion is processed and crimped, the thickness does not become uniform on the circumference. Moreover, although the thickness is uniform on the circumference by welding the start end portion and the end end portion, there are the following problems.

  1) As described in Patent Document 1, in a wire having a high carbon (carbon) composition (carbon is 0.7 to 0.9 mass%) that is usually used for bead wires, annealing is omitted and only welding is performed. For example, the strength of the welded portion is 50% or less with respect to the normal portion, which is not suitable because it is brittle and vulnerable to bending, and the difference from the normal portion is too large. Further, in order to maintain the strength of the welded portion, if two steps of welding and annealing are provided, the strength can be maintained at 80% or more of the strength of the normal portion, but the work time requires twice or more. Furthermore, paying close attention to the welding process and the annealing process, the strength of 80% or more of the normal part can be maintained only after success. However, the success rate of welding is low, and if it fails, it is necessary to cut and remove the part and perform welding again. In that case, even if it tries to weld, the length of a core wire becomes short and cannot be used, and must be discarded.

  2) On the other hand, if a wire with a low carbon composition (carbon is 0.30% by mass or less) is used, annealing is not required and the welding work time can be shortened. Although 90% of the strength of the part can be secured, the strength of the normal part itself is too low to be suitable as a core wire. Even the wire having the composition described in Patent Document 2 has an excessively low strength and is not suitable as a core wire of a cable bead.

  3) Therefore, the welding and annealing operations for connecting the start and end portions were performed with great care using a wire having a carbon composition in the intermediate range (carbon is 0.5 to 0.6 mass%). By using a wire having a carbon content of 0.5 to 0.6% by mass, the success rate of welding is higher than that of a wire having a content of 0.7 to 1.0% by mass, but the success rate of welding is still 100. Because it is not%, welding and annealing work was performed with great care, and even if the work time was more than doubled, there was something that had to be discarded.

  The present invention has been made paying attention to such problems existing in the prior art. The purpose of the ring is to make the welding operation easier, ensure the strength of the normal part and the welded part, and omit the annealing work after welding, and the annular core wire of the tire cable bead for that purpose, It is providing the manufacturing method of a core wire and a cyclic | annular core wire.

  In order to achieve the above object, the annular core wire of the cable bead according to claim 1 is composed mainly of iron (Fe), carbon (C) of 0.1 to 0.3% by mass, silicon ( The core wire of a tire cable bead containing 2.2 to 2.9% by mass of both Si) and manganese (Mn) and 0.3 to 0.5% by mass of chromium (Cr) is formed into an annular shape. The start end and the end end are welded together.

  The core wire of the cable bead according to claim 2 has iron (Fe) as a main component, carbon (C) at 0.1 to 0.3% by mass, silicon (Si) and manganese (Mn) as both components. And 2.2 to 2.9% by mass and 0.3 to 0.5% by mass of chromium (Cr).

  The core wire of the cable bead according to a third aspect of the present invention is the one according to the second aspect, wherein the manganese (Mn) content is set to be larger than the silicon (Si) content.

  According to a fourth aspect of the present invention, there is provided a method for producing an annular core wire of a cable bead, wherein the core wire of the tire cable bead according to the second or third aspect is formed into an annular shape, and the start end portion and the end portion thereof are welded. Then, the deburring operation is performed by omitting the annealing operation.

According to the present invention, the following effects can be exhibited.
According to the annular core wire of the cable bead of the invention described in claim 1, the carbon content is set to 0.1 to 0.3% by mass. For this reason, the welding which joins the start end part and termination | terminus part of a core wire becomes easy. Furthermore, the total content of both silicon and manganese components was set to 2.2 to 2.9% by mass, and the chromium content was set to 0.3 to 0.5% by mass. Therefore, the strength of the normal part and the welded part can be ensured, and the annealing work after welding can be omitted.

According to the core wire of the cable bead of the invention described in claim 2, a material capable of exhibiting the effect of the annular core wire of the invention according to claim 1 can be provided.
According to the core wire of the cable bead of the invention described in claim 3, in addition to the effect of the invention according to claim 2, the strength of the normal part and the welded part can be improved by the action of manganese in particular.

  According to the method for manufacturing an annular core wire of the cable bead of the invention according to claim 4, when welding the start end portion and the end end portion of the cable bead core wire, the welding operation is easy, and annealing is performed after the welding operation is performed. The operation can be omitted and the deburring operation can be performed, and the operation process can be simplified.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, in order to configure the cable bead 11 for a tire in the present embodiment, the core wire 12 is bent into an annular shape, and a welded portion 13 is formed by welding the start and end portions thereof, An annular core wire 14 is produced. In the annular core wire 14, a portion other than the welded portion 13 is a normal portion. As shown in FIGS. 1 and 2, in the cable bead 11, one winding 15 is wound around the circumferential surface of the annular core wire 14 in a spiral shape for a predetermined number of turns (eight times in this embodiment). A coupling member 16 is attached to one place on the outer periphery of the annular core wire 14, and the starting end of the winding 15 is held in the coupling member 16 in a sandwiched state. Further, the end portion of the winding 15 is inserted and held with respect to the coupling member 16 from the side opposite to the start end portion.

  The composition of the core wire 12 of the cable bead 11 thus configured has iron (Fe) as a main component, carbon (C) is 0.1 to 0.3% by mass, silicon (silicon, Si), and manganese (Mn ) And 2.2 to 2.9% by mass and 0.3 to 0.5% by mass of chromium (Cr). It is preferable that the content of manganese (Mn) is set to be larger than the content of silicon (Si) from the viewpoint of securing the strength of the core wire 12. Furthermore, the ratio of the manganese content to the silicon content is preferably 1.60 to 1.75. When this ratio is less than 1.60, the strength of the normal portion of the core wire 12 and the welded portion 13 tends to be insufficient. On the other hand, when it exceeds 1.75, the drawability of the core wire 12 tends to decrease.

  The core wire 12 usually contains inevitable impurities during the manufacturing process. Examples of such inevitable impurities include aluminum (Al), sulfur (S), phosphorus (P), and the like. Among these unavoidable impurities, aluminum causes a decrease in ductility, so that the content is preferably 0.03% by mass or less. Moreover, it is preferable that sulfur and phosphorus are 0.025 mass% or less content. The balance other than the carbon, silicon, manganese, chromium and unavoidable impurities is iron.

  Among the above compositions, carbon is an effective and economical element for securing the strength of the steel wire. The carbon content is set to a low content of 0.3% by mass or less, and the annealing work can be abolished. The carbon content is preferably 0.15 to 0.30 mass%. When the carbon content is less than 0.1% by mass, the target wire strength cannot be obtained, and when it exceeds 0.3% by mass, the core wire 12 is baked and annealed during welding. Disappear.

  Although silicon is a deoxidizer for carbon steel, the function of improving the strength of the core wire 12 can be exhibited by increasing the content. The silicon content is preferably 0.8 to 1.1 mass%. When the silicon content is less than 0.8% by mass, the strength required for the core wire 12 cannot be obtained. On the other hand, when the content exceeds 1.1% by mass, the ductility such as the twisting property after drawing as a wire is lowered, and it becomes unsuitable as a core wire. This silicon can synergistically improve the strength of the core wire 12 when combined with manganese and chromium.

  Manganese can contribute to improving the strength of the core wire 12 by making the content higher than the normal content (0.7 mass% or less). Furthermore, the strength of the core wire 12 can be further improved by combining manganese with silicon and chromium to exert a synergistic effect. The manganese content is preferably 1.4 to 1.8 mass%, more preferably 1.4 to 1.7 mass%. When the manganese content is less than 1.4% by mass, it is difficult to obtain the strength necessary for the core wire 12. On the other hand, when the content exceeds 1.8% by mass, the wire drawability as a wire is lowered, and wire drawing becomes difficult.

  Chromium refines the metal structure and improves the strength of the core wire 12 by combination with manganese and silicon. When the chromium content is less than 0.3% by mass, it is difficult to ensure the strength of the core wire 12. On the other hand, when the content exceeds 0.5% by mass, the working time of the heating operation becomes long in the manufacturing process of the wire, and the cost of the wire is excessively increased, which is inappropriate.

  The wire (core wire 12) having such a composition has a uniform bainite structure as a whole, that is, a structure formed in a temperature range intermediate between the pearlite formation temperature and the martensite formation temperature. Therefore, the wire is rich in toughness, excellent in wire drawing workability, and the core wire 12 does not require annealing during welding.

  Now, when preparing the core wire 12 of a cable bead, iron (Fe) is the main component, the content of carbon (C) is reduced to the above range, and the content of silicon (Si) and manganese (Mn). Is increased to the above range, and the chromium (Cr) content is set to be added within the above range to prepare a wire for the core wire 12. The wire is drawn from the bus bar to a predetermined thickness, for example, 3 mm in diameter, using a wire drawing machine.

  Subsequently, as shown in FIG. 1, the core wire 12 is bent into an annular shape, and the welded portion 13 is formed by welding the start end portion and the end end portion thereof, thereby producing the ring core wire 14. At this time, since the carbon content of the core wire 12 (that is, the carbon content of the wire) is decreased, the welding operation can be performed easily and quickly. The decrease in the strength of the core wire 12 due to the decrease in the carbon content can be sufficiently compensated by increasing the amounts of silicon and manganese and adding chromium.

According to the embodiment described in detail above, the following effects are exhibited.
-In the core wire 12 of the cable bead 11 for tires in this embodiment, carbon content was set to the small quantity of 0.1-0.3 mass%. For this reason, the welding operation which joins the start end part and termination | terminus part of the core wire 12 becomes easy, while failure of welding can be lost, welding time can be shortened and the quality of the welding part 13 can be stabilized.

  Furthermore, the total content of both silicon and manganese components was set to 2.2 to 2.9% by mass, and the chromium content was set to 0.3 to 0.5% by mass. Therefore, the strength of the normal part and the welded part can be ensured, and the annealing work after welding can be omitted.

  Specifically, the strength in the normal part of the core wire 12 is 9,500 N or more (1344 MPa or more) with a diameter of 3.0 mm, and the strength in the welded part 13 can be 75% or more of the strength in the normal part. And the intensity | strength in the welding part 13 can ensure 7500N or more (1060 Mpa or more) with a diameter of 3.0 mm, and can prevent the extreme strength fall in the welding part 13. FIG.

In addition, since the manganese content is set to be greater than the silicon content, the strength of the normal part and the welded part 13 can be improved by the action of manganese in particular.
The annular core wire 14 of the cable bead 11 is manufactured by bending the core wire 12 having the above-mentioned composition into an annular shape, welding the start end portion and the end portion, and then performing the deburring operation without the annealing operation. Is done. For this reason, when welding the start end part and the terminal end part of the core wire 12 of the cable bead 11, the welding work is easy, and after performing the welding work, the annealing work can be omitted and the deburring work can be started. It is possible to simplify the process and stabilize the quality.

Examples and comparative examples will be given below to describe the embodiment more specifically.
(Examples 1-3 and Comparative Examples 1-5)
The compositions of carbon (C), silicon (Si), manganese (Mn) and chromium (Cr) are set as shown in Tables 1 and 2, and Examples 1 to 3 and conventional examples embodying the embodiments are shown. Wires for the core wire 12 as Comparative Examples 1 to 5 were obtained. As unavoidable impurities, aluminum was contained at 0.03% by mass or less, and sulfur and phosphorus were contained at 0.025% by mass or less. The balance is iron (Fe). These wires were drawn from a bus bar to a diameter of 3.0 mm using a normal dry wire drawing machine.

  Subsequently, using a welding machine BS-3A type manufactured by Hakusan Co., Ltd. as a welding machine, each wire was bent into an annular shape, and the starting end and the terminating end were welded under the same conditions. About this welding operation, in Examples 1-3, since content of carbon (C) was reduced to 0.1-0.3 mass%, it could carry out easily. And the intensity | strength in the normal part and the welding part 13 of each wire was measured. That is, using a tensile tester with a maximum load of 5 tons made by Shimadzu Corporation, each wire was gripped according to JIS G 3510, and the tensile strength was 50 mm / min. Was measured. The strength was expressed in Newton (N) and the tensile strength was expressed in (MPa). The results are shown in Tables 1 and 2. In Tables 1 and 2, the reference value 100 of the welding time indicates the value in the case of welding only (Examples 1 to 3, Comparative Example 1 and Comparative Examples 3 to 5), and the percentage with respect to the reference value is welding and The percentage is obtained by dividing the total annealing time by the welding time (Comparative Example 2).

表１に示したように、実施例１〜３においては、ワイヤの組成として炭素（Ｃ）を０．１〜０．３質量％に減少させたが、珪素（Ｓｉ）及びマンガン（Ｍｎ）の両成分を合せて２．２〜２．９質量％に増加させ、クロム（Ｃｒ）を０．３〜０．５質量％含有させた。このため、ワイヤの通常部及び溶接部１３における強度を高めることができ、強度保持率も８１％以上の高い値を確保することができ、かつ溶接後に焼鈍作業を省略することができた。

As shown in Table 1, in Examples 1 to 3, carbon (C) was reduced to 0.1 to 0.3% by mass as the wire composition, but silicon (Si) and manganese (Mn) Both components were combined and increased to 2.2 to 2.9% by mass, and chromium (Cr) was contained in an amount of 0.3 to 0.5% by mass. For this reason, the strength in the normal part of the wire and the welded part 13 can be increased, the strength retention rate can be secured at a high value of 81% or more, and the annealing work can be omitted after welding.

  On the other hand, as shown in Table 2, when the wire composition is 0.56% by mass of carbon (Comparative Example 1), the wire strength in the normal part is high, but the strength in the welded part is not annealed after welding. Was low. Although the comparative example 2 which annealed after welding with the same material as the comparative example 1 improved the intensity | strength of the welding part, it required the welding time more than twice. In Comparative Examples 3, 4 and 5, in which annealing after welding can be omitted and the carbon content is decreased, manganese and silicon are increased, and chromium is added in order to increase the strength retention in the welded portion, the strength in the normal portion It lacked itself.

It should be noted that the embodiment can be modified and embodied as follows.
-When the chromium content is set high within the above range, the manganese and silicon content is set low within the above range, or when the chromium content is set low within the above range, In addition, the silicon content can be set high within the above range.

  -Regarding the silicon and manganese contents, the silicon content can be lowered when the manganese content is increased, and the silicon content can be increased when the manganese content is lowered.

-Nickel can be added to improve the toughness of the steel.
Next, the technical idea that can be grasped from the embodiment will be described below.
(1) The core wire of the cable bead for tire according to claim 1 or 2, wherein a ratio of the content of manganese (Mn) to the content of silicon (Si) is 1.60 to 1.75. When comprised in this way, the intensity | strength of the normal part of a core wire and a welding part can be improved.

  (2) The silicon (Si) content is 0.8 to 1.1 mass%, and the manganese (Mn) content is 1.4 to 1.8 mass%. The core wire of the cable bead for tire as described in the technical concept (1). When comprised in this way, the intensity | strength of the normal part of a core wire and a welding part can be improved.

The partially broken front view which shows the cable bead in embodiment. Sectional drawing which shows a cable bead.

Explanation of symbols

  11 ... cable bead, 12 ... core wire, 14 ... annular core wire.

Claims (4)

Iron (Fe) as the main component, carbon (C) is 0.1 to 0.3% by mass, silicon (Si) and manganese (Mn) are combined, 2.2 to 2.9% by mass, and chromium A cable bead for tire, comprising: a core bead of a tire cable bead containing 0.3 to 0.5% by mass of (Cr) formed into an annular shape, and a start end and a terminal end thereof being welded and joined. Ring core wire. Iron (Fe) as the main component, carbon (C) is 0.1 to 0.3% by mass, silicon (Si) and manganese (Mn) are combined, 2.2 to 2.9% by mass, and chromium A core wire of a cable bead for a tire containing 0.3 to 0.5 mass% of (Cr). The core wire of the tire cable bead according to claim 2, wherein the manganese (Mn) content is set to be larger than the silicon (Si) content. The core wire of the tire cable bead according to claim 2 or 3 is formed in an annular shape, and after welding the start and end portions thereof, the deburring operation is performed by omitting the annealing operation. Manufacturing method of annular core wire of tire cable bead.

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