Fatigue failure of cold forging tooling: causes and possible solutions through fatigue analysis

Knoerr, Markus; Lange, Kurt; Altan, Taylan

doi:10.1016/0924-0136(94)90102-3

Cited by 50 publications

(26 citation statements)

References 4 publications

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“…The effect of multi-axial stress conditions can be correlated with uni-axial fatigue data under the assumption that all stress components oscillate synchronous with proportional mean values amplitudes. This results in a more flexible approach which was also chosen by e Knoerr et al [2]. A more generic approach is the local energy approach [12].…”

Section: Fatigue Life Modelingmentioning

confidence: 99%

“…For high volume cold forged parts with net shaped complex surfaces, fatigue cracking of the active tool elements is the leading cause of failure. The most efficient route to do this analysis is to use FEM to assess [2]:…”

Section: Fatigue Life Modelingmentioning

confidence: 99%

“…Currently overstressing in tooling can be estimated and reasonably well predicted using finite element modelling (FEM) including elastic defoemation with deviation of product shape [1], but life-span prediction for fatigue and wear with high tool hardness, as required in microforming, is a relatively new area needing further study [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…Knoerr et al [2] developed the analysis flow chart shown in Figure 4. They used a local strain approach for damage analysis (strain life data for active tool component required) and coupled this to data for strain amplitude and cycles to crack initiation (see Figure 5).…”

mentioning

confidence: 99%

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Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

et al. 2016

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Abstract:The current paper aims to review tooling life span, failure modes and models in cold microforming processes. As there is nearly no information available on tool-life for microforming the starting point was conventional cold forming. In cold forming common failures are (1) over stressing of the tool; (2) abrasive wear; (3) galling or adhesive wear, and (4) fatigue failure. The large variation in tool life observed in production and how to predict this was reviewed as this is important to the viability of microforming based on that the tooling cost takes a higher portion of the part cost. Anisotropic properties of the tool materials affect tool life span and depend on both the as-received and in-service conditions. It was concluded that preconditioning of the tool surface, and coating are important to control wear and fatigue. Properly managed, the detrimental effects from surface particles can be reduced. Under high stress low-cycle fatigue conditions, fatigue failure form internal microstructures and inclusions are common. To improve abrasive wear resistance larger carbides are commonly the solution which will have a negative impact on tooling life as these tend to be the root cause of fatigue failures. This has significant impact on cold microforming.

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Section: Fatigue Life Modelingmentioning

confidence: 99%

Section: Fatigue Life Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

et al. 2016

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“…Nagao et al [6] use the finite element software DEFORM to analyze the car forging parts and compare the optimal designed stress ring of die, to understand the pressure phenomenon forced on die, in order to increase the service life of die. Knoerr et al [7] use the integrated computer-aid simulation analysis system to calculate the force for the cold forging die, in order to investigate the problem points of over-force damage or fatigue damage. Wang et al [8] make improvements in the defective phenomenon, such as folding that caused by the flowing of blank.…”

Section: Introductionmentioning

confidence: 99%

Multi-stage forging on torx-pin screw with high torque

2017

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Abstract. The study assumes constant shear friction to simulate multi-stage forging on torx-pin screw with high torque using FEM commercial software. Because the screw head has a plum needle shape with the effect of high torque, the 3D simulation model is used to explore the effective stress, the effective strain, the velocity field, and the forging force in each stage. The forming pass schedule considers three stages to obtain the product, and uses the Deform-3D software to explore the feasibility of forming pass schedule. Finally, the realistic manufacturing of torx-pin screw can be carried out to compare with the simulation results to verify the acceptance of FEM simulation. The maximum dimension error between simulation and experiment is around 2.45%, thus the feasibility of FEM simulation to die design for manufacturing the torx-pin screw can be verified.

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Rolling Temperatures Modelling and Experimental Verification

Jeswiet

Nshama

1995

Proceedings of the Thirty-First International Matador Conference

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Fatigue failure of cold forging tooling: causes and possible solutions through fatigue analysis

Cited by 50 publications

References 4 publications

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

Multi-stage forging on torx-pin screw with high torque

Rolling Temperatures Modelling and Experimental Verification

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