Machining Stresses and Initial Geometry on Bulk Residual Stresses Characterization by On-Machine Layer Removal

Aurrekoetxea, Maria; Lacalle, Luís Norberto López de; Llanos, Iñigo

doi:10.3390/ma13061445

Cited by 28 publications

(14 citation statements)

References 32 publications

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“…It may happen as a result of the presence of initial residual stresses in the base plates due to the application of other fabrication processes like machining, rolling, etc., before the welding operation. 41,42 These initial stresses influence the equilibrium state of residual stresses in the weld zone and can lead to intensified welding induced stresses. The regions away from the weld zone do not endure much higher temperature during welding, which could lead to stress relaxation.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of through-thickness residual stresses and microstructure in SA516 Gr. 70 steel welds

Taraphdar

Mahapatra

Pradhan

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part B:

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The critical working condition of nuclear power plant equipment necessitates meticulous determination of the welding process and parameters. In this work, some major influential factors of welding were investigated to observe their effects on the through-thickness residual stress distribution in multipass pressure vessel steel welds. In this regard, experiments were conducted to find the characteristics of residual stresses dispersed in SA516 Grade 70 steel welds of different groove geometries with distinct welding conditions. Three-dimensional finite element models of the weldments were developed considering a moving heat source with temperature-dependent material properties to simulate the welding thermal cycles and corresponding residual stress fields. Effects of weld groove geometry, number of weld passes, external constraints, and preheating on the through-thickness residual stress fields were studied. Additional attention was given to the evaluation of the heterogeneous microstructure and microhardness across the weld cross-section associated with their weld thermal history. Finally, the evolution of the through-thickness residual stresses attributed to subsequent weld passes was elaborated.

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Section: Resultsmentioning

confidence: 99%

Evaluation of through-thickness residual stresses and microstructure in SA516 Gr. 70 steel welds

Taraphdar

Mahapatra

Pradhan

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part B:

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show abstract

“…Improvements in the aircraft industry are critical to achieving the necessary improvements in almost every aspect of the air transportation system. To improve the performance of aircraft, efforts must mainly be focused on the assurance of sustainable aviation [ 34 ]. The most promising among these are drop-in alternative jet fuels that are renewable and lightweight structures.…”

Section: Resultsmentioning

confidence: 99%

Strength Analysis of a Rib-Stiffened GLARE-Based Thin-Walled Structure

et al. 2020

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This paper presents a new product, a glass laminate aluminium-reinforced epoxy (GLARE)-based thin-walled structure with a stiffener in the form of a longitudinal rib. The stiffening rib in an outer metallic layer of a GLARE-based panel was fabricated by the incremental sheet forming technique and Alclad 2024-T3 aluminium alloy sheets were used as adherends. The strength properties of the adhesive joint between the layers of the fibre metal laminates (FMLs) were determined in a uniaxial tensile test, peel drum test, tensile/shear test and short-beam three-point-bending test. Two variants of FMLs were considered, with an adhesive film and without an adhesive film between the adherends and the epoxy/glass prepreg. The FMLs were tested at three different temperatures that corresponded to those found under real aircraft operating conditions, i.e., −60 °C, room temperature and +80 °C. It was found that the temperatures do not affect the tensile strength and shear strength of the FMLs tested. However, there was a noticeable increase in the stiffness of samples stretched at reduced temperature. An additional adhesive film layer between the adherends and the glass/epoxy prepreg significantly improves the static peeling strength of the joint both at reduced and at elevated temperatures. A clear increase in the critical force at which buckling occurs has been clearly demonstrated in the uniaxial compression test of GLARE-based rib-stiffened panels. In the case of GLARE-based rib-stiffened panels, the critical force averaged 15,370 N, while for the non-embossed variant, it was 11,430 N, which translates into a 34.5% increase in critical force.

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“…Future research will focus on improving milling productivity (increasing feed and cutting speed), including machined surface integrity [14] study and residual stresses in big cast parts after heat treatment.…”

Section: Discussionmentioning

confidence: 99%

“…Metal composition and heat treatment conditions both affect the size of section that can be fully transformed [13]. There are not only metallurgical changes but additional concerns about residual stresses that can affect part shape after machining [14]. In the work here presented, several coupons were extracted per testpiece to check the casting variability, but the uniformity of both graphite (dispersion and nodule size) and ausferrite was excellent in all the cases.…”

Section: Introductionmentioning

confidence: 99%

Milling with ceramic inserts of austempered ductile iron (ADI): process conditions and performance

Lacalle

Valdivielso

Amigo

et al. 2020

Int J Adv Manuf Technol

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In the work here presented, the high performance of ceramic insert tools in milling of ADI 1000 iron casting is analyzed. Austempered ductile irons (ADI) are ductile iron castings with strength and mechanical properties enhanced after specific heat treatment, achieving 1000 MPa or even more. Sintered carbide tools are state of the art in many industrial applications, including iron casting machining, but ceramic inserts are a feasible and promising option since cutting speed can be improved by 5 or even 10 times. A complete testing campaign was performed, starting with coated sintered carbides and aiming at the use of whisker reinforced Al 2 O 3 ceramics and Si 3 N 4 tools. The two most important conclusions are as follows: firstly, that the milling type socalled up-milling (or conventional) is more recommended than down-milling, also known as climb milling, and secondly, that dry machining enhances ceramics performance in comparison with using emulsion coolants (oil in water). Finally, results regarding economic aspects were analyzed based on the tools cost-performance ratio.

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Machining Stresses and Initial Geometry on Bulk Residual Stresses Characterization by On-Machine Layer Removal

Cited by 28 publications

References 32 publications

Evaluation of through-thickness residual stresses and microstructure in SA516 Gr. 70 steel welds

Evaluation of through-thickness residual stresses and microstructure in SA516 Gr. 70 steel welds

Strength Analysis of a Rib-Stiffened GLARE-Based Thin-Walled Structure

Milling with ceramic inserts of austempered ductile iron (ADI): process conditions and performance

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