Development of Upsetting-Extrusion Type Tribometer for Evaluating Lubrication Coating Performance in Cold Forging

2014 ◽  
Vol 966-967 ◽  
pp. 281-289 ◽  
Author(s):  
Zhi Gang Wang ◽  
Shinobu Komiyama ◽  
Yasuharu Yoshikawa
Keyword(s):  
Zinc Phosphate ◽  
Side Surface ◽  
Extrusion Process ◽  
Peak Height ◽  
Expansion Ratio ◽  
Cold Forging ◽  
Maximum Height ◽  
Phosphate Coating ◽  
Multi Stage ◽  
Surface Expansion

A new upsetting-extrusion type tribometer is developed to investigate the performance of a lubrication coating on the side surface of a billet in multi-stage cold forging. In this tribometer, the lubrication coating on the billet surface is first destroyed by the upsetting process and then evaluated by the extrusion process. The frictional shear factor of the lubrication coating is obtained by plotting the measured extrusion load and the position after the extrusion of a centerline drawn on the billet in advance on the calibration curve obtained by FEM. Experimental results using a zinc phosphate coating and a dry in-place type coating showed that the reduced peak height Rpk is more appropriate than the maximum height Rz to express the effect of the surface roughness of tool on galling generation. When no galling occurs, the frictional shear factor hardly varies with the type of the lubrication coating and the surface expansion ratio. The anti-galling ability of the dry in-place type coating is greatly improved by a two-stage shot blast before the lubrication coating and reaches a level better than the zinc phosphate coating.

Development of Upsetting-Extrusion Type Tribometer for Evaluating Lubrication Coating Performance in Cold Forging

2013 ◽  
Vol 554-557 ◽  
pp. 833-843 ◽  
Author(s):  
Zhi Gang Wang ◽  
Shinobu Komiyama ◽  
Yasuharu Yoshikawa
Keyword(s):  
Zinc Phosphate ◽  
Side Surface ◽  
Extrusion Process ◽  
Peak Height ◽  
Expansion Ratio ◽  
Cold Forging ◽  
Maximum Height ◽  
Phosphate Coating ◽  
Free Expansion ◽  
Multi Stage

A new upsetting-extrusion type tribometer has been developed to investigate the performance of the lubrication coating on the side surface of a billet in the multi-stage cold forging. In this tribometer, the lubrication coating is first destroyed by the upsetting process due to the free expansion of the billet surface and then evaluated by the extrusion process. The frictional shear factor of the lubrication coating is obtained by plotting the measured extrusion load and the position after the extrusion of a centerline drawn on the billet in advance on the calibration curve obtained by FEM. Experimental results using a zinc phosphate coating and a dry in-place type coating showed that the reduced peak height Rpk is more appropriate than the maximum height Rz to express the effect of the surface roughness of tool on galling generation. When no galling occurs, the frictional shear factor hardly varies with the type of the lubrication coating and the surface expansion ratio. The anti-galling ability of the dry in-place type coating is greatly improved by a two-stage shot blast before the lubrication coating and reaches a level better than the zinc phosphate coating.

Lubricating Performance of Residual Zinc Phosphate Coating on Forged Specimen in Bowden-Leben Sliding Test

2018 ◽  
Vol 767 ◽  
pp. 124-130 ◽  
Author(s):  
Osamu Kada ◽  
Zhi Gang Wang
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Zinc Phosphate ◽  
Cold Forging ◽  
Phosphate Coating ◽  
Specimen Temperature ◽  
Tool Surface ◽  
Residual Thickness ◽  
Surface Expansion ◽  
Sliding Test

The lubricating performance of the zinc phosphate coating employed generally in cold forging is evaluated with Bowden-Leben sliding test by changing friction conditions such as the coating thickness, specimen temperature, the tool surface roughness, contact pressure and sliding speed. A specimen for the friction test is prepared from the inner surface of an extruded square cup and the residual thickness of the lubrication coating on the specimen is controlled by using the surface expansion in forward extrusion of the cup. Experimental results showed that the specimen temperature has the strongest influence on the friction coefficient. With an increase of the specimen temperature, the friction coefficient gradually decreases until 473K, and then increases sharply. With an increase of the tool surface roughness, the friction coefficient increases slightly. Friction coefficient is formulated as a function of the specimen temperature and the tool surface roughness. The anti-galling ability of the coating is affected by the residual thickness of lubrication coating, the specimen temperature and the tool surface roughness.

Seizure Strength Improvement for Phosphate-Stearate Coatings Involved in Cold Forging of Steel

1992 ◽  
Vol 114 (2) ◽  
pp. 248-252 ◽  
Author(s):  
Ph. Hivart ◽  
J. P. Bricout ◽  
J. Oudin ◽  
J. Y. Dauphin
Keyword(s):  
Mechanical Strength ◽  
Zinc Phosphate ◽  
Zinc Stearate ◽  
Cold Forging ◽  
Attractive Alternative ◽  
Phosphate Coating ◽  
Test Results ◽  
Phosphate Bonding ◽  
Strength Improvement ◽  
Tangential Friction

A seizure test particularly well suited to evaluate the mechanical strength of phosphate-stearate coatings has been developed. Test results, including tangential friction force and time at the onset of seizure, are related to the effective phosphate bonding and to lubricant reactive effects. It is shown that seizure is delayed if the phosphate coating is annealed at 500°C just before soaping. The γ-Zn3 (PO4)2 formation which occurs with a decrease in volume induces cracking along hopeite needles and causes an increase in reactive surface for soaping and, therefore, an increase in the quantity of zinc phosphate converted into zinc stearate. Improvement of the phosphate coating by annealing at 500°C before soaping may be an attractive alternative to the use of molybdenum disulfide lubricants.

Evaluation of lubricants without zinc phosphate precoat in multi-stage cold forging

CIRP Annals ◽  
2015 ◽  
Vol 64 (1) ◽  
pp. 285-288 ◽  
Author(s):  
Z.G. Wang ◽  
S. Komiyama ◽  
Y. Yoshikawa ◽  
T. Suzuki ◽  
K. Osakada
Keyword(s):  
Zinc Phosphate ◽  
Cold Forging ◽  
Multi Stage

Influence of Processing Parameters on Bonding Conditions in Backward Extrusion Forged Bonding

2012 ◽  
Vol 504-506 ◽  
pp. 387-392 ◽  
Author(s):  
Yoshinori Yoshida ◽  
Takamasa Matsubara ◽  
Keisuke Yasui ◽  
Takashi Ishikawa ◽  
Tomoaki Suganuma
Keyword(s):  
Tensile Test ◽  
Processing Parameters ◽  
Expansion Ratio ◽  
Cold Forging ◽  
Process Conditions ◽  
Backward Extrusion ◽  
Metallurgical Bonding ◽  
Wire Cutting ◽  
Surface Expansion ◽  
Cylindrical Cup

In this study, conditions of metallurgical bonding between steel and aluminum in cold forging process is investigated. Two-layered cylindrical cup of the materials is produced in cold backward extrusion in five processing velocity conditions. Small tensile test specimens are cut off at the bonding boundary in the product using a wire-cutting machine and the bonding strength on the boundary is measured in tensile test using the specimens. Fractured contact surfaces are observed with an electron microscope for investigation of bonding. Finite element analyses for the backward extrusion are conducted and surface expansion ratio and interface pressure on the boundary are calculated. The influence of process conditions, extrusion velocity and surface expansion ratio and boundary pressure, on the bonding are investigated.

New Evaluation Method for Lubricant in Forging Process

2006 ◽  
Author(s):  
Shigekazu Ito ◽  
Hiroaki Yoshida ◽  
Sachihiro Isogawa ◽  
Yoshihisa Doi ◽  
Kuniaki Dohda
Keyword(s):  
Surface Area ◽  
Compression Test ◽  
Evaluation Method ◽  
Zinc Phosphate ◽  
Expansion Ratio ◽  
Ring Compression Test ◽  
Ring Compression ◽  
Surface Expansion ◽  
Area Expansion ◽  
Forging Load

A lubricant plays a very important role in forging. It can reduce the forging load and make for smooth knockout. The tribo-simulator tests that have often been used as standard evaluation methods for metal forming lubricants includes the ring compression test and spike forging test. However, the forging of components such as flange bolt and constant velocity joint is more severe than a spike forging test or ring compression test. Thus, the development of an evaluation method for lubricants for use in more severe conditions is much awaited. We have developed a new evaluation tribometer using backward extrusion with a taper punch. The new device is called a “Taper Cup Tribometer.” The taper cup test can evaluate lubricity under large deformation conditions. In this test, the surface expansion ratio can be controlled by changing the punch stroke. The surface expansion ratio of the new taper cup tribometer is around 15 to 50, as calculated by fine element analysis. The results of lubricant evaluation in cold forging of carbon steel are as follows. Zinc phosphate has a lower forging load than other lubricants, making it clear that it is a superior lubricant. Oil, on the other hand, has a high forging load and poor lubrication characteristics. The taper cup Tribometer can evaluate the friction characteristics of lubricants. Furthermore, MoS2 shows a higher forging load than zinc phosphate in the region of higher surface area expansion ratio around 12. The forging load of oil is higher than zinc phosphate in the region of higher surface area expansion ratio around 4. In this way, the new taper cup tribometer can recognize the forging limit for the lubricant under the forging load.

Galling Generation Mechanism in Upsetting-Ball Ironing Test

2018 ◽  
Vol 767 ◽  
pp. 111-116
Author(s):  
Zhi Gang Wang ◽  
Shinobu Komiyama
Keyword(s):  
Fem Simulation ◽  
Generation Mechanism ◽  
Cold Forging ◽  
Starting Position ◽  
Point Tracking ◽  
Billet Surface ◽  
Multi Stage ◽  
Starting Point ◽  
Initial Billet ◽  
Surface Expansion

An upsetting-ball ironing test has been developed to investigate the lubricating performance of coatings in multi-stage cold forging. By using this test, the lubricating performance of a zinc phosphate free coating called “dry in-place coating” was evaluated and improved, and now the dry in-place coating is used worldwide due to its high anti-galling ability and low environmental impact. In this study, galling generation mechanism in the upsetting-ball ironing test is investigated by using the point tracking function in FEM simulation. Scratches on ironed surface are generated at the starting point of ironing and the width and depth of scratches increase gradually with the increasing ironing stroke. It is revealed that all points on a scratch have been in contact with the same point of the ball. The lubrication coating on the billet surface peels off locally with the onset of ironing and some contamination particles enter the interface between the billet and the ball and thus cause scratches. Galling takes place at the ironing stroke of around 10 mm when the billet of 14 mm in diameter and 32 mm in height is upset to 45 percent reduction in height and then ironed by the ball of 10 mm in diameter. It is found that all points on the ironed surface at the starting position of galling are not on the initial billet surface but come from the inside of the billet. These points come out at the ironing stroke of 4 mm due to the dividing flow in the surface layer. It is concluded that galling in the upsetting-ball ironing test is generated by the extremely large surface expansion.

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

scholarly journals Generalized optimizations of two-stage forging of micro/meso copper fastener

2018 ◽  
Vol 185 ◽  
pp. 00002
Author(s):  
Shih-Hsien Lin ◽  
Un-Chin Chai ◽  
Gow-Yi Tzou ◽  
Dyi-Cheng Chen
Keyword(s):  
Simulation Analysis ◽  
Effective Strain ◽  
Cold Forging ◽  
Two Stage ◽  
Forming Simulation ◽  
Multi Stage ◽  
Element Simulation ◽  
Die Stress ◽  
Stress Optimization ◽  
Forging Force

Three are generalized simulation optimizations considering the forging force, the die stress, and the dual-goals in two-stage forging of micro/meso copper fastener. Constant shear friction between the dies and workpiece is assumed to perform multi-stage cold forging forming simulation analysis, and the Taguchi method with the finite element simulation has been used for mold-and-dies parameters design simulation optimizations considering the forging force, die stress, and dual-goals. The die stress optimization is used to explore the effects on effective stress, effective strain, velocity field, die stress, forging force, and shape of product. The influence rank to forging process of micro/meso copper fastener for three optimizations can be determined, and the optimal parameters assembly consider die stress can be obtained in this study. It is noted that the punch design innovation can reduce the forging force and die stress.

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