The Influence of Residual Stresses Induced by Near-Net-Shape Blanking Processes on the Fatigue Behavior under Bending Loads

Stahl, Jens; Muller, D. R.; Pätzold, Isabella; Golle, Roland; Tobie, Thomas; Volk, Wolfram; Stahl, Karsten

doi:10.1088/1757-899x/651/1/012086

Cited by 8 publications

(17 citation statements)

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“…For example, Lara et al and Maronne et al found that a small die clearance is beneficial [20,21]. In earlier works of the presenting authors, it was shown that the chosen shear cutting process influences the part's residual stress state [30] which significantly alters the resulting fatigue strength [29]. Here, we were able to show that higher shear cutting-induced compressive residual stresses are able to increase the part fatigue strength.…”

Section: Introductionsupporting

confidence: 60%

Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

et al. 2021

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The manufacturing of case-hardened gears usually consists of several complex and expensive steps to ensure high load carrying capacity. The load carrying capacity for the main fatigue failure modes pitting and tooth root breakage can be increased significantly by increasing the near surface compressive residual stresses. In earlier publications, different shear cutting techniques, the near-net-shape-blanking processes (NNSBP’s), were investigated regarding a favorable residual stress state. The influence of the process parameters on the amount of clean cut, surface roughness, hardness and residual stresses was investigated. Furthermore, fatigue bending tests were carried out using C-shaped specimens. This paper reports about involute gears that are manufactured by fineblanking. This NNSBP was identified as suitable based on the previous research, because it led to a high amount of clean cut and favorable residual stresses. For the fineblanked gears of S355MC (1.0976), the die edge radii were varied and the effects on the cut surface geometry, hardness distribution, surface roughness and residual stresses are investigated. The accuracy of blanking the gear geometry is measured, and the tooth root bending strength is determined in a pulsating test rig according to standardized testing methods. It is shown that it is possible to manufacture gears by fineblanking with a high precision comparable to gear hobbing. Additionally, the cut surface properties lead to an increased tooth root bending strength.

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Section: Introductionsupporting

confidence: 60%

Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

et al. 2021

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“…Nevertheless, a smaller die clearance does not always improve the fatigue strength, as shown by [14]. The results published in [15,16] were able to show that the variation of shear cutting parameters leads to very different cut surface qualities and has a high influence on the fatigue strength of shear cut edges. In particular, a two-stage shear cutting process was able to increase the fatigue strength as it greatly reduced the damage of the shear affected zone.…”

Section: Introductionmentioning

confidence: 97%

Effect of One- and Two-Stage Shear Cutting on the Fatigue Strength of Truck Frame Parts

Stahl

Pätzold

Golle

et al. 2020

JMMP

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The longitudinal and transverse beams of trucks are manufactured with a large number of holes to fasten brackets for springs, fuel tanks, batteries etc. The quality of the holes, which is particularly influenced by the manufacturing process, has a major influence on the fatigue strength of the beams and thus the service lifetime of the vehicle. In most cases, the holes are produced using the highly economical shear cutting process. Previous investigations have shown that the fatigue strength of thin sheets can be increased by adjusting the shearing parameters and using a two-stage shear cutting process. This paper discusses the difference between one- and two-stage shear cutting on the hole quality of components made of S500MC (1.0984, thickness 8 mm) and its resulting fatigue strength. The hole quality is characterized by the geometry of the shear cut surface, its roughness, microstructure, and microhardness. It was shown that the two-stage shear cutting process allows producing holes of better quality than the ones manufactured by a one-stage shear cutting process. Furthermore, this resulted in an improved fatigue behavior.

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“…The fatigue behavior of the parts is illustrated in figure 5. The fatigue tests are described in [5]. In for all parts manufactured with r S < 20 µm compared to those manufactured with r S = 200 µm.…”

Section: Fatigue Behaviormentioning

confidence: 99%

“…Residual stresses in tangential and axial direction measured on three positions of specimen manufactured by Blanking (B) with a die clearance of 3 % with two different active element edge radii (a), and the surface deviation of the produced sheet metal strips together with the result published in[5] (b).…”

mentioning

confidence: 99%

“…BV and PBwBH show different values for different edge preparations. For PBwBH this is most likely Fatigue strength of parts manufactured by the five NNSBPs for the two different active element edge radii (r S = 200 µm and r M < 20 µm with thick line, r S < 20 µm and r M = 200 µm with thin line) on the left, for two different die clearances (ur = 0.5 % with solid line, ur = 1.0 % with dashed line) in the middle, and a comparison between parts with and without a stress relief heat treatment after the blanking operation (stress relief heat treated part in orange) on the right together with the data published in[5].…”

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confidence: 99%

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Inﬂuence of Shear Cutting Process Parameters on the Residual Stress State and the Fatigue Strength of Gears

Muller¹,

Stahl²,

Pätzold³

et al. 2020

Preprint

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Shear cutting is used for manufacturing various parts ranging from e.g. simple washers to complex gears. The latter are typically subjected to cyclic loading and fail foremost due to fatigue damages. Hereby, the parts lifetime is mainly determined by: the geometry, the applied load, the material, the hardness, the roughness and the residual stress state. While numerous research works deal with the inﬂuence of the process parameters on the hardness and the parts geometry, the inﬂuence of the process parameters on the residual stress state and on the resulting fatigue strength has not been investigated in detail, yet. In an earlier publication, suitable shear cutting techniques, which allow to achieve a high amount of clean-cut and a favorable residual stress state were compared. In this paper, the inﬂuence of the process parameters on the residual stress state and the resulting bending fatigue strength are addressed. To simulate the bending stress occurring in the tooth root, C-shaped specimens were manufactured by diﬀerent blanking techniques. The die-clearance and punch and die edge radii were varied with these blanking techniques. After measuring the cut-surface geometry, the hardness distribution and the surface roughness, the fatigue strength was determined in a pulsating test rig. By carrying out residual stress measurements using x-ray diﬀraction and simulating the material ﬂow behavior using the Finite-Element-Method, basic mechanisms, which are inﬂuencing the residual stress state and the resulting bending fatigue strength, were identiﬁed and will be presented and discussed in the paper.

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The Influence of Residual Stresses Induced by Near-Net-Shape Blanking Processes on the Fatigue Behavior under Bending Loads

Cited by 8 publications

References 1 publication

Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

Effect of One- and Two-Stage Shear Cutting on the Fatigue Strength of Truck Frame Parts

Inﬂuence of Shear Cutting Process Parameters on the Residual Stress State and the Fatigue Strength of Gears

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