Influence of pre-drilling on hardness and tensile failure of formed internal threads in thin-walled AZ91 cast alloys

Sarafraz, Yashar; Koch, Alexander; Felinks, Nils; Biermann, Dirk; Walther, Frank

doi:10.1016/j.engfailanal.2021.105783

Cited by 5 publications

(1 citation statement)

References 26 publications

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“…The criterion that needs to be considered to select the proper lightweight design (LWD) strategy is not only limited to the low-weight material but also depends on the criterion such as low cost, short manufacturing time, high safety, long lifetime, or low environmental impact [1]. Manufacturing the internal thread using thread forming instead of conventional thread cutting can enhance the martial properties by inducing the work-hardening in thread profiles (VDI 3334), which can affect the static and dynamic properties of the formed threads [2,3]. Thread forming as a chipless process eliminates the cost-intensive chip removal, which reduces the environmental impact.…”

Section: Introductionmentioning

confidence: 99%

Effect of Core Hole Diameter on Tensile and Fatigue Properties of the Helically Formed Internal Thread in AlSi10MnMg Cast Alloys

Sarafraz,

Felinks,

Biermann

et al. 2023

SSP

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The manufacturing of internal thread using the helical thread forming process (Punch Tap) as a novel high-performance manufacturing technology provides high productivity by reducing the tool path, which can save manufacturing time up to 75% compared to the conventional thread forming process. For instance, cast gearboxes in the transport sector consisting of numerous internal threads can benefit from this manufacturing method to realize detachable joints. While the required core hole diameter for conventional (cut) tapping depends on the thread dimension, this diameter depends either on the material properties for the thread forming process. The proper core hole diameter according to material flow possibility enables forming of complete thread profiles, which can consequently enhance the mechanical properties of the thread. This study aims to analyze the effect of the core hole diameter on the quality of the formed threads in AlSi10MnMg cast profiles. M6 threads were formed into the pre-drilled core holes with two different diameters. CT-scan analysis indicated that reducing the core hole diameter decreases the inner volume of the formed internal thread, which is justified by better material flow and complete forming of the thread profiles. Adaptation of the manufacturing parameters according to the material properties enhanced the geometry of the formed thread profiles. This enhancement increased the tensile and fatigue strengths of the detachable joints by subjecting the four initially formed threads at the top of manufactured nuts to the static and cyclic loads.

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Section: Introductionmentioning

confidence: 99%

Effect of Core Hole Diameter on Tensile and Fatigue Properties of the Helically Formed Internal Thread in AlSi10MnMg Cast Alloys

Sarafraz,

Felinks,

Biermann

et al. 2023

SSP

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Parameters affecting the quality of friction drilled holes and formed thread in austenitic stainless steel AISI 304

Bassiouny

Al-Makky

Youssef

2023

Int J Adv Manuf Technol

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The main purpose of this research paper is to improve the quality of the friction-drilled holes and formed thread by investigating the influence of the input working parameters that have not been investigated yet on the quality of the produced bores. Due to lack of research related to the hardness macro- and microstructure of formed threads, experiments were conducted to investigate these important issues. Finally, a tension test was performed to compare the performance of the form tapped thread with the conventionally cut thread. The experiments were conducted on difficult-to-cut material AISI 304 stainless steel workpieces with (2 and 3 mm) wall thicknesses. Tungsten carbide friction drills with diameters (Ø9.2, Ø7.3, and Ø4.5 mm) were used to perform the experiments. The effects of the ratio of workpiece thickness (t) to tool diameter (dT), rotational speed (N), and feed speed (f) on the hole diametral oversize (U), cylindricity error, and collar height were studied. The analysis of variance (ANOVA) showed that the t/d ratio was the most significant factor affecting the mean cylindricity error and the collar height. By comparing the performance of the three tools, it was noticeable that the friction drill Ø7.3 realized better results in terms of mean hole diametral oversize and mean cylindricity error. The elevated temperature associated with high plastic deformation during the processes resulting in fine grains with high hardness values were observed at the heat-affected zone. The longer effective thread length of the formed thread realized higher strength values than the cut thread. Graphical abstract

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Failure analysis of formed internal threads in flow drilled bores of AlSi10Mg cast profiles

Sarafraz

Felinks

Biermann

et al. 2023

Engineering Failure Analysis

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Influence of pre-drilling on hardness and tensile failure of formed internal threads in thin-walled AZ91 cast alloys

Cited by 5 publications

References 26 publications

Effect of Core Hole Diameter on Tensile and Fatigue Properties of the Helically Formed Internal Thread in AlSi10MnMg Cast Alloys

Effect of Core Hole Diameter on Tensile and Fatigue Properties of the Helically Formed Internal Thread in AlSi10MnMg Cast Alloys

Parameters affecting the quality of friction drilled holes and formed thread in austenitic stainless steel AISI 304

Failure analysis of formed internal threads in flow drilled bores of AlSi10Mg cast profiles

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