DensiForm® Technology for Wrought-Steel-Like Performance of Powder Metal Components

Trasorras, Juan R. L.; Nigarura, Salvator; Sigl, Lorenz S.

doi:10.4271/2006-01-0398

Cited by 6 publications

(3 citation statements)

References 6 publications

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“…Based on the results of roller tests, flank and root carrying capacity of different gear geometries were tested, [13][14][15]. These investigations show that PM gears are competitive to conventional gears.…”

Section: Influence Of the Density On Mechanical Propertiesmentioning

confidence: 99%

Fundamental study of surface densification of PM gears by rolling using FE analysis

Klocke

Schröder

Kauffmann

2007

Prod. Eng. Res. Devel.

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The complex shape of gears is very attractive to the near-net-shape PM technology. The strength of conventional PM parts is reduced by the residual porosity due to the power law relationship between the density and the mechanical properties. The maximum stresses in gears are found in the tooth root and the flank near or directly at the surface, so that by a local densification of the near surface layer the maximum load carrying capacity of the complete gear can be increased. This surface densification can be achieved by a rolling process. Due to the own elastic-plastic behavior of PM materials and due to the continuous change of the contact conditions during rolling, the process is too complex to be described analytically. To gain a better understanding of the process, the numerical simulation is a capable method. In this paper an FEA model is prepared and verified based on an experimental investigation. Additionally, case studies were carried out in order to analyze the relationship between the process parameters and the densification result.

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Section: Influence Of the Density On Mechanical Propertiesmentioning

confidence: 99%

Fundamental study of surface densification of PM gears by rolling using FE analysis

Klocke

Schröder

Kauffmann

2007

Prod. Eng. Res. Devel.

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“…As the highest service stresses occur at or near the part's surface, it is sufficient to densify just these high stressed regions [7,8], as porosity can positively remain in lower stressed areas to reduce the parts weight and for noise damping. Figure 1: Mechanical properties as a function of porosity [8] Due to the enhanced strength and the cost savings realized with net-shape production, powder metallurgy expanded fast in automotive power train applications in the last years [9] and is now the biggest market for P/M parts. The most frequently produced parts are gears, which are successfully used in engines and gearboxes [1].…”

Section: Introductionmentioning

confidence: 99%

FEM-Supported Development of a Radial Forging Process for Surface Densification of P/M Gears

2009

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Because of its capability for net-or near-net shape production, P/M technology is well suited for the production of complex shapes such as gears. Nevertheless, the usage of P/M parts has been limited for a long time on low to moderate stress applications due to their porosity. To improve the mechanical properties of P/M gears, the high stressed regions have to be densified. As the highest service stresses for gears occur in a thin layer below the surface, it's sufficient to densify just the cogs surface and keep porosity with its positive influence on weight and noise damping over the rest of the gear. Due to new surface treatment processes, which provide a local densification of high stressed areas up to full density, P/M components are now successfully used in high performance applications. One new idea for surface densification of P/M gears is the use of a specific radial forging process. To prove the applicability and to generate specific knowledge about the new process, FEM studies have been done before running pilot trials. The main purpose of the FEM studies is the investigation of the influence of preform and die design on surface densification and the expectable dimensional accuracy. Therefore different ways of forging the cogs have been investigated. The deduced basic coherences and process characteristics enable a demonstration of advantages and disadvantages of the planned process. Hence, basic conditions for an application of the radial forging process for gear productions are deduced.

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“…The radius of the circular arc R at the tooth-root fillet was designed to be 0.9 mm, the same as for H2. This gear is denoted as S. A surface densification process (DensiForm® (5) ) was achieved after sintering to improve the strength. It is a precise cold forming process.…”

Section: Dimensions and Heat Treatment Of Test Gearsmentioning

confidence: 99%

Comparison of Bending Fatigue Strength among Spur Gears Manufactured by Various Methods (Influence of Manufacturing Method on Bending Strength)

Yamanaka

Matsushima

Miwa

et al. 2010

JAMDSM

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This paper deals with an experimental evaluation of bending fatigue strengths for hobbed, forged, sintered and austempered ductile iron (ADI) spur gears. The module is 2.5 and the number of teeth is 26 in the test gears. The materials of the test gears are SCr420H for hobbed and forged gears, prealloyed powder metal with 1.5 wt.% Mo for sintered gears, and FCAD 1100-15 for ADI gears. All gears except ADI gears were carburized. The pulsator bending fatigue tests were carried out for the test gears. Then the relationship between the strength and the manufacturing cost is obtained. The forged gear has the high strength of 3% and low cost compared with the hobbed gear. It is the best among the four gears. The sintered and ADI gears have approximately half the strength and cost of the hobbed gear. These gears are effective when cost is a high priority. In the progress of the fatigue tests, comparisons of strength among gears having different tooth-root forms were needed. The nominal stress obtained from actual measured profile data using a noncontact-type measuring machine is suitable for comparing the fatigue strength in gears having different root forms.

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DensiForm® Technology for Wrought-Steel-Like Performance of Powder Metal Components

Cited by 6 publications

References 6 publications

Fundamental study of surface densification of PM gears by rolling using FE analysis

Fundamental study of surface densification of PM gears by rolling using FE analysis

FEM-Supported Development of a Radial Forging Process for Surface Densification of P/M Gears

Comparison of Bending Fatigue Strength among Spur Gears Manufactured by Various Methods (Influence of Manufacturing Method on Bending Strength)

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