JPH03213735A - Oil tempered wire excellent in spring formability - Google Patents

Abstract

PURPOSE:To prevent scale scattering at the time of coil forming as well as seizure to a forming die and obtain a coil spring with little dispersion in free length by providing the quenched and tempered wire material surface with a paint film made of ethylene tetrafluoride or trifluoride resin or the like. CONSTITUTION:The wire material surface of an oil tempered wire quenched and tempered (oil-temper processed) after cold-working is provided with a paint film made of synthetic resin obtained by the polymerization of olefin containing fluorine. This synthetic resin used for the paint film provided at the wire material surface is to be ethylene tetrafluoride or trifluoride resin. The wire material is formed into a coil spring using the forming die of a coiler, but even if brought into strong contact with the forming die, the wire material is not baked to the forming die, nor is there scale scattering at the time of coil forming. A coil spring with little dispersion of free length can be thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an oil tempered wire with improved spring formability.

[Prior Art] One of the well-known spring steels is oil-tempered wire, which is obtained by cold-working, quenching, and tempering a wire (oil-tempering treatment). When this oil-tempered wire is processed into a coil spring, for example, it comes into tight contact with the forming die of a coiling machine, so conventionally, as a technique to prevent seizure etc. and improve spring formability, compared to the surface of the wire, By generating FeJa-rich scale with a small coefficient of friction, applying mineral oil, or applying Fe, 0. A method is adopted in which Lynch's scale is formed and mineral oil is applied on top of it, and then the coiling process is performed.

[Problems to be Solved by the Invention] Among the three methods described above, in the method of generating FeJa-rich scale and the method of applying mineral oil on the scale, the scale is scraped off and scattered during spring forming. Therefore, it is not preferable in terms of environmental protection, and the spring formability is not necessarily satisfactory, and there is also the problem that the springs become entangled after the spring forming.

On the other hand, the method of applying mineral oil to the surface of the scale-free wire does not cause the problem of scale scattering, but the lubrication is insufficient and the spring formability is inferior to the first two methods, and there is also the problem of spring entanglement. There was also.

An object of the present invention is to solve the problems of conventional oil-tempered wires as described above and to provide a scale-free oil-tempered wire that has excellent spring formability including coiling properties.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides an oil-tempered wire in which a coating film made of a synthetic resin obtained by polymerizing a fluorine-containing olefin is provided on the surface of the wire after quenching and tempering.

The present invention also provides an oil tempered wire in which the synthetic resin constituting the coating film on the surface of the wire is a tetrafluoroethylene or trifluoroethylene resin.

(Function) Since the oil tempered wire of the present invention has a coating film of synthetic resin obtained by polymerizing olefin containing fluorine on its surface, for example, when it is processed into a coil spring using a forming die of a coiling machine. , this oil-tempered wire will not seize even if it comes into tight contact with the forming die.

Further, there is no scale scattering during coil forming, and a coil spring with less variation in free length can be obtained.

〔Example〕

The test wires were wires with a diameter of 4.0 and having the components shown in Table 1 below.
A wire rod made of silicon chromium @ (abbreviated as sc) and a wire rod made of chromium vanadium steel (abbreviated as C■) of Ommφ were prepared.

Table 1 (Chemical composition of test wires) Each of the above test wires was subjected to oil tempering treatment, but when heating the amount of scale generated on the surface in the air (abbreviated as A treatment), it was also possible to Samples were prepared under two conditions: heating (abbreviated as B treatment).

The sample wire produced by the above treatment B was further coated with mineral oil (0
The table below consists of the above-mentioned SC and C■ coated with appropriate coatings of tetrafluoroethylene resin (abbreviated as F), trifluoroethylene resin (abbreviated as T), and polychlorotrifluoroethylene resin (abbreviated as P). Ten types of oil tempered wires as shown in 2 were prepared.

Table 2 (Oil-tempered wire for test springs) Each oil-tempered wire shown in ■ to [phase] of Table 2 below was coiled using a butt pin to create a coil spring having spring specifications as shown in Table 3 below. was prepared as a sample material.

Table (Spring specifications) Next, the quality of the coiling lubrication was determined by measuring the variation in the free length of the spring of each sample material. In addition, when manufacturing the coil spring, the processing speed of the coil was increased and the wire drawing speed at which seizure occurred was measured as the critical speed, and the results are shown in Table 4 below.

On the other hand, during the processing of each 500 coils, a scale receiver was installed to catch the scale falling off from the wire rod, and the weight of the scale collected with this scale receiver was weighed. The results are shown in Table 5 below.

Table 4 (Spring free length variation and critical speed) Table (Scale falling off during coil processing) As is clear from the above, the temper wires of the embodiments of the present invention, that is, the temper wires ■~■ and ■~ shown in Table 2 [Phase] does not have scale falling off like conventional examples ■ and ■.
It is possible to maintain a good environment in the coil processing factory, and there is no scale falling off in the conventional examples ① and ②, but as is clear from Table 4, the coil processing speed can be improved in the case of the embodiment of the present invention. . Furthermore, the free length variation of the obtained springs is smaller than that of the conventional example, and a good yield can be obtained.

〔Effect of the invention〕

As explained above, since the oil-tempered wire of the present invention does not cause scale to fall off during coil processing, it is useful for improving the environment during the coil spring processing process.

Further, since the processing speed of the coil spring can be faster than that of conventional tempered wire, the manufacturing efficiency of the coil spring can be improved.

Furthermore, the coil springs manufactured using the oil-tempered wire of this invention have the advantage that good yields can be obtained because there is little variation in their free length; If ethylene resin is used, the effect will be even greater.

The oil-tempered wire of the present invention may have either a perfect circular cross section or an irregularly shaped cross section.

Claims (2)

[Claims] (1) An oil-tempered wire with excellent spring formability, which has a coating film made of a synthetic resin obtained by polymerizing olefin containing fluorine on the wire surface after quenching and tempering. (2) The oil tempered wire with excellent spring formability according to claim (1), wherein the synthetic resin constituting the coating film is a tetrafluoride or trifluoride ethylene resin.