Effects of damage evolution on tensile strength measurement of nuclear graphite material by ring compression test

This paper deals with friction properties and deformation resistance during hot forming of Mg-Al-Ca-Mn series magnesium alloys. Friction coefficients between dies and magnesium alloys were obtained by ring compression tests that used graphite, PTFE, and an oil lubricant in a hot-forging process. Hot forging was performed under various conditions to clarify the effects of types of lubricants and slide motion of the press machines on friction properties. Two types of slide motion, a constant velocity motion and a pulse motion were selected in the ring-compression test. It was found that graphite with an oil lubricant effectively eliminated die sticking in hot forming of magnesium alloys. The isothermal deformation resistances were derived using friction coefficients obtained by ring-compression tests as well as finite-element simulations. The predicted stress strain curves with temperature were examined with the stress-strain relationship obtained in experiments using a servo press and demonstrated the effectiveness of the proposed method.

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Studies on friction behaviour of aluminium AA4032 alloy during forging using ring compression test

International Journal of Engineering Science and Technology ◽

10.4314/ijest.v13i3.3 ◽

2021 ◽

Vol 13 (3) ◽

pp. 23-36

Author(s):

Desalegn Wogaso ◽

Mohammed Hamda

Keyword(s):

Friction Factor ◽

Metal Surface ◽

Palm Oil ◽

Compression Test ◽

Metal Flow ◽

Work Piece ◽

Ring Compression Test ◽

Ring Compression ◽

Friction Behaviour ◽

Selection Of

In metal forming, friction has a negative effect on the deformation load & energy requirements, homogeneity of metal flow, quality of formed surfaces, etc.; however, its effect can be reduced through the use of proper lubricants. Mostly, in industrial applications, selection of proper lubricant for specific material is challenging and quantification of magnitude of friction at diework piece interface is essential. Hence, for metallic alloys, a realistic friction factor is needed to be known and used at the diework piece interface for better control of deformation process. Thus, this research, generally, aims at experimental investigation of the friction behavior of aluminum AA4032 alloy and selection of suitable lubricant for its effective processing using ring compression test and finite element (FE) simulations. Meanwhile, the effect of metal surface conditions and different lubricants namely palm oil, grease, emulsion oil and dry conditions on the friction behaviour has been evaluated. A commercial FEM software, DEFORM 3D, is used to analyze the flow of metal, determine the geometry changes of the specimen and generate friction calibration curves. The results revealed that the nature of metal surface and lubricating conditions have significantly affected the metal flow pattern, deformation load requirement, induced effective stress and strain, and geometry of the metal. The friction factor at die-work piece is determined for different lubricating conditions. Among lubricants employed, palm oil is found to be suitable and effective for industrial processing of aluminium AA4032 alloy, specifically for forging. The FE simulation results are in a good agreement with the experimental one.

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Evaluation of Cold Forging Lubricants for Steel by Ring Compression Test with Rotating Die

Journal of the Japan Society for Technology of Plasticity ◽

10.9773/sosei.59.53 ◽

2018 ◽

Vol 59 (687) ◽

pp. 53-58

Author(s):

Masatoshi SAWAMURA ◽

Yasuhiro YOGO ◽

Michiaki KAMIYAMA ◽

Noritoshi IWATA

Keyword(s):

Compression Test ◽

Cold Forging ◽

Ring Compression Test ◽

Ring Compression

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Effect of lubrication on hardness in the ring compression test

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406215586590 ◽

2015 ◽

Vol 230 (12) ◽

pp. 1939-1950 ◽

Cited By ~ 4

Author(s):

CH HariKrishna ◽

MJ Davidson ◽

CH Nagaraju ◽

B Anil Kumar

Keyword(s):

Boric Acid ◽

Strain Hardening ◽

Compression Test ◽

Hardness Distribution ◽

Simulation Studies ◽

Ring Compression Test ◽

Ring Specimen ◽

Ring Compression ◽

Different Types ◽

Metallic Ring

This paper focuses on the hardness distribution in the AA2014-T6 ring specimens upset under rigid dies. Three different types of lubricants namely soap, boric acid and vaseline were employed as lubricants and the friction factor corresponding to the lubricant employed was evaluated using standard ‘Ring compression test’. The strain distributions obtained from the simulation studies were used to predict the hardness inside the ring specimen. The hardness measured experimentally was validated with the predicted hardness and it was found that the errors in the predicted results were less than 10%. The hardness variations inside the upset metallic ring specimens were compared with the deformed solid cylinders to understand the behavior of differential strain hardening. It can be reported from the experimental and predicted results that the hardness is not uniform inside the deformed ring specimen and it varies at the bulge head; on the surface and along the neutral plane.

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Discussion: “The Validity of Mathematical Solutions for Determining Friction From the Ring Compression Test” (Male, Alan T., and DePierre, Vincent, 1970, ASME J. Lubr. Technol., 92, pp. 389–395)

Journal of Lubrication Technology ◽

10.1115/1.3451421 ◽

1970 ◽

Vol 92 (3) ◽

pp. 396-396

Author(s):

B. Avitzur

Keyword(s):

Compression Test ◽

Ring Compression Test ◽

Ring Compression

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Study of Influence of Superimposed Hydrostatic Pressure on Ductility in Ring Compression Test

Journal of Materials Engineering and Performance ◽

10.1007/s11665-020-05114-z ◽

2020 ◽

Vol 29 (10) ◽

pp. 6581-6590 ◽

Cited By ~ 1

Author(s):

Amir Partovi ◽

M. M. Shahzamanian ◽

P. D. Wu

Keyword(s):

Hydrostatic Pressure ◽

Compression Test ◽

Ring Compression Test ◽

Ring Compression

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Development of a Testing Method for the Identification of Friction Coefficients for Numerical Modeling of the Shear-Clinching Process

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.639.469 ◽

2015 ◽

Vol 639 ◽

pp. 469-476 ◽

Cited By ~ 5

Author(s):

Martin Müller ◽

Ulrich Vierzigmann ◽

Réjane Hörhold ◽

Gerson Meschut ◽

Marion Merklein

Keyword(s):

Compression Test ◽

Manufacturing Industry ◽

Dissimilar Materials ◽

High Strength Steels ◽

High Strength ◽

Ring Compression Test ◽

Friction Coefficients ◽

Testing Method ◽

Ring Compression ◽

Joining Process

Global competition as well as social and scientific megatrends strongly influence the modern car manufacturing industry. One of the most important approaches is the implementation of lightweight constructions. Therefore, the usage of high performance materials with tailored properties gains importance. For safety-relevant components such as automotive passenger cells it is necessary to minimize deformation to reduce the risk of injury for the vehicle occupants during a car accident. Thus, hot stamped high-strength steels have been established. High-strength and low formability of this kind of materials represent new challenges for joining technologies. One possibility to join high-strength steels is the newly developed shear-clinching technology. Due to the use of a combined cutting and joining process, the connection of dissimilar materials with high difference in strength and formability can be achieved. Further research to ensure process reliability and to improve the strength of the joint is required. One possible approach for this is the numerical investigation of the material flow during the joining process. Therefore, the definition of process parameters for the finite element model is necessary. A big impact on the quality of the results has the accuracy of the used friction values. As established testing methods are not suitable for modeling the rather complex tribological system between the joining partners of the shear-clinching process, an innovative testing method is needed. Studies in the field of sheet-bulk metal forming already demonstrated the applicability of the ring compression test for sheet metals. This paper presents a concept for the adaption of the ring compression test to the specific needs of the investigated shear-clinching process. The numerical identification of the friction coefficients is validated by experimental data and first results are qualified by experimental and simulative shear-clinching joints.

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Friction in Hot Forging of Chrome Steel Covered with Oxide Scale Film Generated at Steam Atmosphere

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.622-623.194 ◽

2014 ◽

Vol 622-623 ◽

pp. 194-200

Author(s):

Ryo Matsumoto ◽

Shohei Harada ◽

Hiroshi Utsunomiya

Keyword(s):

Oxide Scale ◽

Compression Test ◽

Hot Forging ◽

Chemical Compositions ◽

Ring Compression Test ◽

Chrome Steel ◽

Air Atmosphere ◽

Ring Compression ◽

Plastic Deformation Behavior ◽

Shear Friction

The hot ring compression test of chrome steel covered with an oxide scale film is carried out to examine the effects of the oxide scale film on the hot forging characteristics. For changing the chemical compositions of the oxide scale, the oxide scale film is generated at air or steam atmosphere. The nominal coefficient of shear friction of the chrome steel covered with the oxide scale film is estimated from the plastic deformation behavior during the ring compression test. The estimated coefficient of shear friction of the chrome steel covered with the oxide scale film is found to be lower than that of the chrome steel without the oxide scale film. Furthermore, the oxide scale generated at steam atmosphere provides lower friction characteristics in comparison with the oxide scale generated at air atmosphere. The mechanism of the reduction of friction with the oxide scale is discussed.

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