Flow Conditioning in Heat Treatment by Gas and Spray Quenching

Gas quenching has been known for centuries as a convenient, affordable method to heat treat ferrous alloys. Heated parts are taken out of the furnace and quenched at ambient pressure, casually using a blower to increase the heat exchange. Technical developments in the metal industry, over the last decades, have seen a constant improvement of the ratio of heat exchange, e.g. by using pressured chambers, specific blowers, and a variety of gases and gas mixtures. The current gas quenching technologies are adapted to heat treatable metals found in the automotive industry, requesting a minimum heat exchange ratio, also depending on the part geometry. Little has been however investigated concerning the quenched batch, defined as the arrangement of the heated parts onto a single- or multiple-layer charge carrier. The present work, through a combination of experimental and numerical techniques, provides guidelines to adapt the batch to a specific gas flow pattern (spatial fitting), and to adapt the gas flow pattern to the batch structure (temporal fitting). Measurement techniques have been developed to assess the flow patterns inside industrial quenching chambers. Evaluated flow structures have been converted to numerical boundary conditions for extended simulations tools. Simulations have helped implementing technical solutions for flow correction in industrial gas quenching chambers. Furthermore, simulations have served the design of batches of various geometries, to improve both quenching homogeneity and intensity. Both experimental and numerical results confirmed the advantages of gas quenching for the homogeneous heat treatment of automotive steel grades, and demonstrated the potential of various flow correcting devices, such as perforated plates and cylindrical flow ducts. Heat treatment gas and spray quenching has also been integrated into the forging and the turning process chains of single components, successfully optimizing the lean process flow (automation, quality, and time), for various high-performance materials and part geometries

Characterization of the clamping and internal residual stresses effects on the distortion of Inconel 718 parts resulting from turning

The understanding of phenomena related to machining processesintheaerospace industry isstill the subject of study intheresearch community. This is due to the constrained geometric tolerances to ensure optimal performance and safety. Few studies have yet focused on the effect of the clamping sequence on part distortions during the machining process. Thus, the development of machining sequences, in particular the positioning of clamping points, still requires optimisation regarding the geometry to be machined. This contribution focuses on a first step of a study that aims to characterize workpiece distortions resulting from a multi-stageprocess in relation tothe clamping, cutting forcesand the initial ormachining induced stresses. To validate the approach, an insitu methodology for characterising the defects has been developed alongside a particular workpiece holder based on an industrial procedure is set up in order to observe and limit the part distortion along the whole process.The machining sequence is divided into two machining stepsseparated by unclampingand clampingoperations. Frontal axisymmetric grooves are machined in turning on both sides of a thin Inconel718 elementary disks. These operations are subject to in situ measurement on bothside of the workpiece. A laser profilometer and laser point sensorsare usedbetween each pass and at each stage of the machining sequenceoperation. The collected data will beused in a next step to validate a numerical model that predicts the evolution of the distortions of the part during the entire machining proces

Design of power-transmitting shifts

Power transmission shafting which is a vital element of all rotating machinery is discussed. Design methods, based on strength considerations for sizing shafts and axles to withstand both steady and fluctuating loads are summarized. The effects of combined bending, torsional, and axial loads are considered along with many application factors that are known to influence the fatigue strength of shafting materials. Methods are presented to account for variable amplitude loading histories and their influence on limited life designs. The influences of shaft rigidity, materials, and vibration on the design are discussed

Aeronautical engineering: A special bibliography with indexes, supplement 82, April 1977

This bibliography lists 311 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1977

Turbopump systems for liquid rocket engines

The turbopump system, from preliminary design through rocket engine testing is examined. Selection of proper system type for each application and integration of the components into a working system are dealt with. Details are also given on the design of various components including inducers, pumps, turbines, gears, and bearings

Aeronautical Engineering. A continuing bibliography, supplement 112

This bibliography lists 424 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1979

Aeronautical engineering: A continuing bibliography with indexes (supplement 204)

This bibliography lists 419 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1986

Advances in CAD/CAM/CAE Technologies

CAD/CAM/CAE technologies find more and more applications in today’s industries, e.g., in the automotive, aerospace, and naval sectors. These technologies increase the productivity of engineers and researchers to a great extent, while at the same time allowing their research activities to achieve higher levels of performance. A number of difficult-to-perform design and manufacturing processes can be simulated using more methodologies available, i.e., experimental work combined with statistical tools (regression analysis, analysis of variance, Taguchi methodology, deep learning), finite element analysis applied early enough at the design cycle, CAD-based tools for design optimizations, CAM-based tools for machining optimizations

Special Issue of the Manufacturing Engineering Society (MES)

This book derives from the Special Issue of the Manufacturing Engineering Society (MES) that was launched as a Special Issue of the journal Materials. The 48 contributions, published in this book, explore the evolution of traditional manufacturing models toward the new requirements of the Manufacturing Industry 4.0 and present cutting-edge advances in the field of Manufacturing Engineering focusing on additive manufacturing and 3D printing, advances and innovations in manufacturing processes, sustainable and green manufacturing, manufacturing systems (machines, equipment and tooling), metrology and quality in manufacturing, Industry 4.0, product lifecycle management (PLM) technologies, and production planning and risks

Aeronautical engineering: A continuing bibliography with indexes, supplement 100

This bibliography lists 295 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in August 1978