Transactions of Japan Society of Spring Engineers

On the Properties of High Strength Oil Tempered Carbon Steel Wire

Hideyoshi TSUBONO, Tsuyoshi NISHIMURA, Tadayoshi FUJIWARA, Hiroichi IO ...

1985 Volume 1985 Issue 30 Pages 1-10
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.1

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In this paper, we described the properties of high strength oil tempered wires that were manufactured by the new type furnace equipped with high frequency induction heater. High strength grade wires were obtained for commercial carbon steel and Si-Cr steel by the method of tempering at the low temperature.
The test results are as follows:
(1) In this new manufacturing process, wire is heated rapidly to austenitizing temperature and austenite grain size is controlled fine. Therefore, 195kgf/mm² grade high strength oil tempered carbon steel wire shows good mechanical properties.
(2) High strrength oil tempered carbon steel wire shows high fatigue strength and low residual shear strain in the clamping test at the room temperature. But, heat resitivity of this wire is less than that of Si-Cr steel oil tempered wire.
(3) The heat sensitivity of high strength oil tempered carbon steel wire is more than that of usual grade wire. Therefere, tempering temperature after coiling must be controlled more severely in the use of this wire.

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Some Properties of Ultra Clean Spring Steel

Makoto SAITO, Yukio ITO

1985 Volume 1985 Issue 30 Pages 11-19
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.11

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There is a recent tendency to develope a motorcar's suspension coil spring that can be used under higher-stressed condition and to develope a valve spring having a higher-level of strength therefore creating better engine performance. Although there is a difference between the level of requirement for suspension coil spring and valve spring steel, improvement of fatigue property is a common destination. In order to achieve this purpose, making the raw material ultra clean may be one of the effective methods.
To get ultra clean steel, the degassing method which satisfies low cost and mass production is applied. And ultra clean steel is examined and tested for the properties needed in suspension coil spring and valve spring steel. The following results are obtained.
(1) Producing Ultra-Low Oxygen steel (ULO steel) which oxygen content is less than 15ppm is one of the effective way to realize a suspension coil spring satisfying 200kgf/mm² high stress level.
(2) ULO+UL·TiN steel produced by ultra low oxygen and ultra low TiN process posseses almost the same endurance limit as the Vacuum Arc-furnace Remelted steel. Therefere, this steel is used for the raw material as a valve spring satisfactorily.

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Development of High Strength, Conductive Stainless Steel Wire for Springs

Susumu YAMAMOTO, Kazuyoshi SATO

1985 Volume 1985 Issue 30 Pages 20-24
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.20

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This paper discussed the development of high strength, conductive stainless steel wire for springs. Although copper-alloyed metals such as phosphor bronze and beryllium copper have been conventionally used when high strength, electrically conductive materials are required, they have, in fact, presented such problems as insufficient strength (including fatigue and torsion), poor heat resistance and corrosion resistance, as well as virtually no abrasion resistance. The material discussed in this paper is a stainless steel wire containing a copper core, and thus greatly improves upon the above problems. The conductivity of this material was 200 to 400% greater than that of high strength copper alloys: its strength was of course superior to copper alloys, being only 10-30% less than stainless steel itself. Accordingly, this material is expected to be used in springs, shafts, electrical poles, and other applications requiring electrical conductivity.

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Characteristic of Coil Spring of TiNi Shape Memory Alloy

Shigemi SATO, Toshio HAMANO, Shigeru KAWAGUCHI, Seiichi SAITO

1985 Volume 1985 Issue 30 Pages 25-32
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.25

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This paper is concerned with a coil spring of TiNi shape memory alloy. Three basic models (condition of constant temprature, condition of constant load, condition of constant deflection) can be taken for the study of both SMA spring itself and the combined application with a bias coil spring. The spring characteristics in each model were tested, and the relationship of the characteristic between each models was obtained.
The main conclusion can be shown as follows:
(1) As for three basic models for SMA spring, the characteristic value obtained from one model, is not always the same with that obtained from the other model.
(2) When in the combined use with a bias coil spring, if the spring-rate of bias coil spring is relatively small, the characteristic of the SMA spring can be estimated by the loading characteristic at constant temprature.
(3) The hysteresis of the P-δ, δ-T, and T-P planes in the combined condition, coresponds to that of the SMA coil spring.

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Positioning of Coiling Tool in 2-Fingers System

Kazunori TSUSHIMA, Takahiko KUNOH, Michifumi KAWAI, Motohiro KITAGAWA, ...

1985 Volume 1985 Issue 30 Pages 33-43
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.33

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In this paper, we describe an experimental study of positioning of coiling tool in cold working methad of helical springs in 2-figers system. The summary of the experimental results are shouwn as follows.
(1) Experimental reults agree well with the theoretical results on the assumption that the wire forming curve of the shape of helical compression springs during coiling consists of two circular arcs.
(2) Ratio of displacement in two fingers should be kept constantly in order to keep central position of formed springs on the acting line of cutting blade.
(3) It is found that contact points between wire and fingers move to a constant direction. Therefore position of two fingers should be hold on the line with a constant angle to a vertical line.

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Development of Rapid X-Ray Stress Analyzer by means of Double PSPC and its Performances

Katsuhiko OGISO, Toshio HAMANO, Masanobu ITOH, Shigemi SATOH, Akira OH ...

1985 Volume 1985 Issue 30 Pages 44-51
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.44

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For the purpose of reducing measuring time, the Rapid Analyzer of X-ray Stress (RAXS), installed with double Position Sensitive Proportional Counter (PSPC), was deveroped.
The divergent slit employded was parallel beam slit. Some experimental approches, in which the influence of insident beam width ranges from 1 to 5mm, with both X-Ray line profile broadness and X-Ray strain sensitivity was studied, showed that there are no differences of those values between 5mm and 1mm beam width.
It was also found that the apparent stress caused by the misalignment to sample, was about 2.5Kgf/mm² per 1mm.
The measurement by means of Schaal method can be made in about 5sec., and this means that the measurement time can be reduced to one-two hundredth to one-fourhundredth, comparing with the conventional equipment.
This equipment has already been installed in NHK Spring Co. Ltd., for measuring the residual stress of automotive springs.

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Problems in Evaluting Non-Metallic Inclusions in Materials for Spring Use

Inquiry Committee for Evaluation of Non-Metallic

1985 Volume 1985 Issue 30 Pages 52-67
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.52

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Adequate control of non-metallic inclusions (nmi) is one of the key techniques for modern spring materials to ensure their advanced quality and thus elevated fatigue performances. The paper describes the results of an inquiry study on the methods to evaluate nmi in steels actually employed in different field of industries, such as steel manufacturers, wire manufacturers, spring manufacturers, and spring users, in Japan.
Analysis of data reveals that the majority of the evaluating methods are the microscopic ones: the most popular is the microscopic testing method in the Japanese Industrial Standards (JIS), followed by the methods by the American Society for Testing and Materials, and other non-authorized methods practiced especially by the wire and spring manufacturers. It is pointed out that the focus of different ploblems related to nmi is on the fatigue properties of valve and/or suspension springs. The microscopic method in JIS currently used can be effective at the steel manufacturing stage from quality control point of view, though it may not be enough valid to quantify the effect of nmi acting as eventual fatigue origin.

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Evaluation on Corrosion Resistances of Various Surface-treated Materials

Surface-treated Materials' Corrosion Resistance

1985 Volume 1985 Issue 30 Pages 68-116
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.68

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Eight kinds of surface treatments, including widely known zinc electroplating and chemical conversion film treatment, were applied to smoll-size coiled springs, sheet springs and straigth-line wires, and their corrosion resistances were evaluated.
The testing methods were the salt spray test, air-exposing test, fatigue test and their conbinations, and the following results were obtained.
1. The properties of a variety of surface teratment methods were roughly understood.
2. The corrosion resistances and behavior of the various surface treated materials were made clear.
3. Differences in resulting corrosion-resistance evaluation due to the testing methods and correlations between them-for example, obvious correlation between the air-exposing day and the salt spray time-were clarified.

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Tool marks affecting the fatigue strength of wire springs

[in Japanese]

1985 Volume 1985 Issue 30 Pages 117-149
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.117

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There may be anxious about various kinds of tool marks caused on wire springs while they are being formed. From among those various tool marks affecting the fatingue strength, we picked up three kinds of tool marks caused on compression coil springs and two kinds of tool marks caused on tension coil springs and we investigated detrimental influence of those tool marks affecting the fatigue strength. We will hereunder summarize the investigation results.
Scratch defects on the first coil of compression coil spring caused by cut end of the wire do not affect the fatigue strength so much. But in case that the depth of tool mark caused on the inner and outer sides of coil spring is about 3% or more of the wire diameter and such a spring is not shot-peened, then the fatigue strength will be weakened by about 50% compared to that of the spring without tool mark. In this case, however, if the spring is shot-peened, the above percentage will be reduced to 10 to 30 in spite of the same depth of tool mark. Furthermore, the tool mark caused on the inner side of the spring will have greater influence to the fatigue strength than that of the outer side of the spring will do.
The tool mark caused on the inner side of hook of tension coil spring will weaken the fatigue strength remarkably, in case that the ratio of width of tool mark to its depth is small. In this investigation, however, no remarkable difference was noticed concerning the tool marks caused on the foot of hook.

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Study on Sag Test of Hot Coiled Compressive Spring for Suspension

[in Japanese]

1985 Volume 1985 Issue 30 Pages 150-168
Published: March 31, 1985
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1985.150

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The sag of coil spring has usually been estimated by creep test or relaxation test. However, the condition of those tests are not standardized.
The aim of this paper is to present the experimental results which could give some assistance for standardizing the method of sag test. It was realized that the measurement of sag should be made at normal load of coil spring and the appropriate time of test was 96 hours. Experiments were also carried out about the influence of temperature and the correlation between the sag of coil spring and that of those tests.
For estimating the sag-resistance of material, three testing methods, which are torsional-creep method, torsional-relaxation method, and hysteresis loop method, were compared. The conclusion in that the torsional creep method have been reasonable accuracy, and good correlation with the sag of coil spring.

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