Transactions of Japan Society of Spring Engineers

Mechanical Properties of Cu-Ni-Sn Alloy for Flat Springs

Mikiko NISHIHATA, Kishio ARITA, Eiichi SAKITA, Masami TAKADA

1989 Volume 1989 Issue 34 Pages 1-7
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.1

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This paper describes the investigation carried out on the Cu-Ni-Sn alloy developed as the materials for lead frames, springs and connectors, and on the solder-laminated Cu-Ni-Sn alloy prepared for improving the corrosion resistance and soldering capacity (for eliminating the preliminary soldering step) of the Cu-Ni-Sn alloy.
The results showed that since the tensile strength and spring limit value of the Cu-Ni-Sn alloy were 500MPa and 450MPa, respectively, it can be used as a medium-conductivity (50% IACS) lead frame with better heat resistance and workability as well as a spring material.
The adherence and corrosion resistance of the solder of the solder-laminated Cu-Ni-Sn alloy were very good, and its mechanical strength was the same as that of the Cu-Ni-Sn alloy itself.

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Design Method for Coil Springs of Arbitrary Shape with Arbitrary Wire Cross Section under General Transient Excitations

Kosuke Nagaya

1989 Volume 1989 Issue 34 Pages 8-17
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.8

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This paper discusses dynamic stresses in coil springs of arbitrary shape with arbitrary coil cross section subjected to general transient displacement with consideration of end effects. An analytical method for finding normal and shear stresses in the coil by using the transfer matrix, the Laplace transform, the Fourier expansion and the Fourier expansion collocation methods based on the three dimensional theory of elasticity for curved rods has been presented.
For the circular wire cross section, the stress varies along the boundary of the cross section and has a maximum value at an interior point of the coil. This paper proposes the more effective coil springs having an oval wire cross section. Both the principal normal and shear stresses along the surface of the proposed coil subjected to a transient excitation have been calculated. It is clarified that the coils with the oval wire section of an appropriate aspect ratio have various advantages as compared with the circular cross section ones.

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Computerized Symbolic Manipulation in Analysis of Characterisics of Helical Spring

1st Report, Symbolic Generation of Finte Element Matrices

Takeshi SAWANOBORI, Jiancun WANG

1989 Volume 1989 Issue 34 Pages 18-25
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.18

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Upon analysing helical spring by using the finite element method, calculation of element matrices of spring elements enables to perform efficient analysis by using the established treating method. To obtain the element matrices, however, comparatively troublesome calculation such as derivation of a shape function is required. In order to analyse spring characteristics practically by applying the finite element method, laborious calculation in the course of deriving the element matrices must be reduced. This paper, therefore, describes in detail computerized symbolic manipulation for deriving the matrices from the shape functions of helical spring element to practically improve the finite element analysis for spring elements. In addition, the example of programing by REDUCE is shown, taking into account the present state in which a programming method for compzterized symbolic manipulation in not known well.

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Influence of Alloying elements on Warm relaxation

Yasuhiro OKI, Takahiko NAGAMATHU, Shinzo ASHIDA

1989 Volume 1989 Issue 34 Pages 26-31
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.26

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Oil-tempered wires and springs were prepared by adding the alloying elements such as C, Si, Mn, Cr, Mo, V and W to the base metal Si-Cr steel widely used for valve springs. The wires and springs were subjected to tension tests and warm clamping tests to examine the effects of chemical compositions on warm relaxation together with the relation between temper softening resistance and warm relation. As a result, it was found out that to improve warm relaxation the addition of Si making the matrix strong and of strong carbide-forming elements such as Mo, V and W was effective. Obvious correlation was obsrerved between temper softening resistance and residual strain, indicating that steels with greater temper softening resistances showed smaller residual shear strains.
Further, it was also revealed that the warm relaxation of the 2%Mo-2%Cr steel was far better than that of the Si-Cr steels.

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Fatigue Property of Electroless Ni Plated Springs

Toshio OSONE, Naoki HIJIKATA

1989 Volume 1989 Issue 34 Pages 32-37
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.32

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As a means of surface strengthening, electroless Ni plating was applied to valve springs to raise the fatigue strength. Electroless Ni plating is known to have a superior adhesion and easy to harden by heating at a low temperature around 300°C.
To the hardened Ni plated layer, shot peening or glass bead honing was performed to give residual stress. Though in as-plated condition or in as-heated condition the fatigue strength of valve springs decreases, electroless Ni plated layer of 20μm in thickness, heated at 300°C and then honed, was found to increase the fatigue strength remarkably about ten times as long as that of the conventional non-plated valve springs.

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The Effects of Modified Ausforming on Structure of Spring Steel

Atsushi SUGIMOTO, Tatsuo TANAKA, Takao OHKI, Yoshihiro WAKIKADO

1989 Volume 1989 Issue 34 Pages 38-43
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.38

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Modified ausforming is one of effective methods of toughening the steel. In this paper, we made simulated experiments to get basic knowledge of modified ausforming of spring steel, with the simulator hot working, and investigated effect by modified ausforming to hardness and structure. And we investigated how it influenced effect by modified ausforming, by changing conditions of modified ausforming such as working temperature.
This main conclusions are summarized as follows:
(1) Quenched hardness rises and martensite is refined by modified ausforming.
(2) In the case of modified ausforming at 650°C in SUP9A, the diffusion transformation is accelerated and hardning is imperfect, so the hardness remarkably drops. And in the case of the process at more than 800°C, the effects of the process decreace by recrystallization.
(3) With the prolongment of the air cooling time before quenching, the effect of modified ausforming decrease by recovery and recrystallization.
(4) Tempered hardness rises by modified ausforming.

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Thermo-mechanical Treatment Simulator

Michihiko AYADA, Toyoyuki HIGASHINO

1989 Volume 1989 Issue 34 Pages 44-52
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.44

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From the viewpoint of weiht saving, it has recently been required to develop high-strength and high-toughness spring steel. Thermo-mechanical treatment (T. M. T.) process would be one of the effective methods to achtieve high mechanical properties of spring steel. Although several studies have been making in this field, it was difficult to obtain the advantage of T. M. T. process, because of the difficulty to control the combination of heating, cooling and forming process effectively. A new compact type T. M. T. simulator based on cotinuous multi-step compression, was developed to study the mechanism of the T. M. T. process. It will be possible for this simulator to apply some different T. M. T. processes such as work-quenching and warm temper forging etc. This paper is mainly concerned with the outline of this simulator and some experimental results of T. T. A., T. T. T. diagrams and ausforming. By using this simulator, the appropriate process to improve mechanical properties of spring steel would be obtained.

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Application of Personal Computers in Spring manufacturing Line

Katsunori MIYAZAKI

1989 Volume 1989 Issue 34 Pages 53-58
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.53

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To produce many spring products in small scale with high productivity and high quality, the method of giving flexibility and stability to a spring manufacturing line is important. As a measure to solve the above problem, this paper shows an example where a software technique, the most outstanding feature of which is essentially flexibility, is tried to be combined with a production technique.

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Long-Term Elevated Temperature Setting Properties of Oil Tempered Cr-Si Steel Wire (SWOSC-V) and Stainless Steel Wire (SUS304-WPB) Springs

Committee for High Temperature Springs

1989 Volume 1989 Issue 34 Pages 59-84
Published: March 31, 1989
Released on J-STAGE: February 26, 2010

DOIhttps://doi.org/10.5346/trbane.1989.59

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When the Committee was organized, there were some opinions concerning the comprehensive method for the estimation of long-term setting properties from experimental short-time data. For this kind of problem it seemed indispensable for springs used at elevated temperatures, the Committee took up this as one of collaborative studies.
Fourteen affiliates participated in the comprehensive test in intermittent procedure to get 3, 000 hours setting properties up to 400°C on the two kinds of steel wire springs. The setting values or residual shear strain have an inclination not to saturate, but increase ever after the 3, 000 hours setting. Both the steel wire springs have a transition in setting behavior at a certain temperature level. On the test data up to 3, 000 hours, it was possible to express the residual shear strain as a constitutive equation. The equation can be used for extrapolation to predict long-time setting values.

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