scholarly journals The Influence of Former Process Steps on Changes in Hardness, Lattice and Micro Structure of AISI 4140 Due to Manufacturing Processes

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1102
Author(s):  
Florian Borchers ◽  
Brigitte Clausen ◽  
Lisa C. Ehle ◽  
Marco Eich ◽  
Jérémy Epp ◽  
...  
Keyword(s):  
Electrical Discharge Machining ◽  
Surface Condition ◽  
Electrochemical Machining ◽  
Manufacturing Processes ◽  
Initial Material ◽  
Thermal Impact ◽  
Initial State ◽  
Surface Conditions ◽  
Aisi 4140 ◽  
Machining Operations

The surface and subsurface conditions of components are critical for their functional properties. Every manufacturing process modifies the surface condition as a consequence of its mechanical, chemical, and thermal impact or combinations of the three. The depth of the affected zone varies for different machining operations and is related to the process parameters and characteristics. Furthermore, the initial material state has a decisive influence on the modifications that lead to the final surface conditions. With this knowledge, the collaborative research center CRC/Transregio 136 “Process Signatures” started a first joint investigation to analyze the influence of several machining operations on the surface modifications of uniformly premanufactured samples in a broad study. The present paper focusses on four defined process chains which were analyzed in detail regarding the resulting surface conditions as a function of the initial state. Two different workpiece geometries of the same initial material (AISI 4140, 42CrMo4 (1.7225) classified according to DIN EN ISO 683-2) were treated in two different heat treating lines. Samples annealed to a ferritic-perlitic microstructure were additionally deep rolled as starting condition. Quenched and tempered samples were induction hardened before further process application. These two states were then submitted to six different manufacturing processes, i.e., grinding (with mainly mechanical or thermal impact), precision turning (mainly mechanical), laser processing (mainly thermal), electrical discharge machining (EDM, mainly thermal) and electrochemical machining (ECM, (mainly chemical impact). The resulting surface conditions were investigated after each step of the manufacturing chain by specialized analysis techniques regarding residual stresses, microstructure, and hardness distribution. Based on the process knowledge and on the systematic characterizations, the characteristics and depths of the material modifications, as well as their underlying mechanisms and causes, were investigated. Mechanisms occurring within AISI 4140 steel (42CrMo4) due to thermal, mechanical or mixed impacts were identified as work hardening, stress relief, recrystallization, re-hardening and melting, grain growth, and rearrangement of dislocations.

scholarly journals Comparison of Different Manufacturing Processes of AISI 4140 Steel with Regard to Surface Modification and Its Influencing Depth

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 895 ◽  
Author(s):  
Florian Borchers ◽  
Brigitte Clausen ◽  
Sandro Eckert ◽  
Lisa Ehle ◽  
Jeremy Epp ◽  
...  
Keyword(s):  
Electrical Discharge Machining ◽  
Surface Condition ◽  
Electrochemical Machining ◽  
Manufacturing Processes ◽  
Initial State ◽  
Electron Microscopic ◽  
Dislocation Generation ◽  
Process Step ◽  
Aisi 4140 ◽  
Machining Operations

The surface and subsurface conditions of components are significant for their functional properties. Every manufacturing process step changes the surface condition due to its mechanical, chemical and/or thermal impact. The depth of the affected zone varies for different machining operations, and is predetermined by the process parameters and characteristics. Furthermore, the initial state has a decisive influence on the interactions that lead to the final surface conditions. The aim of the investigation presented here is to compare the influence of the load characteristics over the depth applied to manufactured components by several different machining operations and to determine the causing mechanisms. In order to ensure better comparability between the surface modifications caused by different machining operations, the same material was used (AISI 4140; German steel grade 42CrMo4 acc. to DIN EN 10083-3) and annealed to a ferritic-pearlitic microstructure. Based on interdisciplinary cooperation within the collaborative research center CRC/Transregio 136 “Process Signatures”, seven different manufacturing processes, i.e., grinding, turning, deep rolling, laser processing, inductive heat treatment, electrical discharge machining (EDM) and electrochemical machining (ECM), were used, and the resulting surface zones were investigated by highly specialized analysis techniques. This work presents the results of X-ray measurements, hardness measurements and electron microscopic investigations. As a result, the characteristics and depths of the material modifications, as well as their underlying mechanisms and causes, were studied. Mechanisms occurring within 42CrMo4 steel due to thermal, mechanical, chemical or mixed impacts were identified as phase transformation, solidification and strengthening due to dislocation generation and accumulation, continuum dynamic recrystallization and dynamic recovery, as well as chemical reactions.

Method of Microelectrode with Electrochemical Machining and its Applications

2007 ◽  
Vol 339 ◽  
pp. 360-364 ◽  
Author(s):  
Zhen Long Wang ◽  
Bao Guo Zhu
Keyword(s):  
Surface Property ◽  
Scanning Probe Microscopy ◽  
High Frequency ◽  
Electrical Discharge Machining ◽  
Electrochemical Machining ◽  
Present Situation ◽  
Scanning Probe ◽  
Fabrication Technology ◽  
Tungsten Filament ◽  
Short Pulses

According to the present situation of microelectrode machining, the fabrication technology of microelectrode is put forward by the method of high frequency short pulses in electrochemical machining (ECM). The mechanism of pulses ECM is depicted firstly. Then the system of ECM is designed. After the experiment of technology analyzed, a microelectrode with nice surface is machined successfully. The diameter of the microelectrode is 7μm and the radius of its top is 50nm, which is made of tungsten filament. It could provide the simple electrode for further electrical machining or micro probe for scanning probe microscopy. The surface property, structure, and microhardness of the microelectrode are analyzed. The surface property and the machining capability of the microelectrode are compared with the microelectrode machined by electrical discharge machining (EDM). The superiority of the microelectrode machined by ECM is shown fully. The practicability and reliability are proved by the research of experimentations.

A geostatistical approach to winter road surface condition estimation using mobile RWIS data

2019 ◽  
Vol 46 (6) ◽  
pp. 511-521
Author(s):  
Lian Gu ◽  
Tae J. Kwon ◽  
Tony Z. Qiu
Keyword(s):  
Robust Regression ◽  
Surface Condition ◽  
Road Surface ◽  
Road Maintenance ◽  
Surface Conditions ◽  
Modelling Framework ◽  
Geostatistical Approach ◽  
Winter Road ◽  
Systematic Framework

In winter, it is critical for cold regions to have a full understanding of the spatial variation of road surface conditions such that hot spots (e.g., black ice) can be identified for an effective mobilization of winter road maintenance operations. Acknowledging the limitations in present study, this paper proposes a systematic framework to estimate road surface temperature (RST) via the geographic information system (GIS). The proposed method uses a robust regression kriging method to take account for various geographical factors that may affect the variation of RST. A case study of highway segments in Alberta, Canada is used to demonstrate the feasibility and applicability of the method proposed herein. The findings of this study suggest that the geostatistical modelling framework proposed in this paper can accurately estimate RST with help of various covariates included in the model and further promote the possibility of continuous monitoring and visualization of road surface conditions.

scholarly journals Study the effect of process parameters on Electric Discharge Machining: Literature Review

2019 ◽  
Vol 4 (1) ◽  
pp. 68-80
Author(s):  
Sandeep Yadav ◽  
Deepak k ◽  
Sarthak Sharma ◽  
Lalit Vashishth
Keyword(s):  
Automotive Industry ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Work Piece ◽  
Manufacturing Processes ◽  
Machining Parameters ◽  
Tool Wear Rate ◽  
Electric Discharge Machining ◽  
Thermoelectric Energy ◽  
Dies And Moulds

Electrical discharge machining (EDM) is one of the earliest non-conventional method of manufacturing processes. This process based on thermoelectric energy between work piece and electrodeand they must have electrical conductivity to generate the spark. A spark generated between work piece and electrode, and removes the material from work piece through melting and vaporizing. EDM produced various types of products such as dies and moulds. EDM is used to manufacture the parts of aerospace, automotive industry and surgical components. The effect of the machining parameters on surface roughness, metal removal rateand tool wear rate are studied.

scholarly journals Experimental Research on Discharge Forming Cutting-Electrochemical Machining of Single-Crystal Silicon

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bin Xin ◽  
Wei Liu
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Electrochemical Machining ◽  
Single Crystal Silicon ◽  
Recast Layer ◽  
Movement Speed ◽  
Crystal Silicon ◽  
Wedm Process

During the wire electrical discharge machining (WEDM) process, a large number of discharge pits and a recast layer are easily generated on the workpiece surface, resulting in high surface roughness. A discharge forming cutting-electrochemical machining method for fabricating single-crystal silicon is proposed in this study to solve this problem. On the same processing equipment, single-crystal silicon is first cut using the discharge forming cutting method. Second, electrochemical anodic reaction technology is used to dissolve the discharge pits and recast layer on the single-crystal silicon surface. The machining mechanism of this process, the surface elements of the processed single-crystal silicon and a comparison of the kerf width are analyzed through experiments. On this basis, the influence of the movement speed of the copper foil electrode during electrochemical anodic dissolution on the final surface roughness is qualitatively analyzed. The experimental results show that discharge forming cutting-electrochemical machining can effectively eliminate the electrical discharge pits and recast layer, which are caused by electric discharge cutting, on the surface of single-crystal silicon, thereby reducing the surface roughness of the workpiece.

scholarly journals Nitrous Oxide Fluxes from a Commercial Beef Cattle Feedlot in Kansas

2014 ◽  
Vol 7 ◽  
pp. ASWR.S12841 ◽  
Author(s):  
Orlando A. Aguilar ◽  
Ronaldo Maghirang ◽  
Charles W. Rice ◽  
Steven L. Trabue ◽  
Larry E. Erickson
Keyword(s):  
Nitrous Oxide ◽  
Beef Cattle ◽  
Agricultural Soils ◽  
Environmental Concern ◽  
Surface Condition ◽  
Emission Rates ◽  
Surface Conditions ◽  
Air Temperatures ◽  
Cattle Feedlots ◽  
Cattle Feedlot

Emission of greenhouse gases, including nitrous oxide (N2O), from open beef cattle feedlots is becoming an environmental concern; however, research measuring emission rates of N2O from open beef cattle feedlots has been limited. This study was conducted to quantify N2O emission fluxes as affected by pen surface conditions, in a commercial beef cattle feedlot in the state of Kansas, USA, from July 2010 through September 2011. The measurement period represented typical feedlot conditions, with air temperatures ranging from -24 to 39°C. Static flux chambers were used to collect gas samples from pen surfaces at 0, 15, and 30 minutes. Gas samples were analyzed with a gas chromatograph and from the measured concentrations, fluxes were calculated. Median emission flux from the moist/muddy surface condition was 2.03 mg m−2 hour−1, which was about 20 times larger than the N2O fluxes from the other pen surface conditions. In addition, N2O peaks from the moist/muddy pen surface condition were six times larger than emission peaks previously reported for agricultural soils.

scholarly journals Road Surface Condition Forecasting in France

2009 ◽  
Vol 48 (12) ◽  
pp. 2513-2527 ◽  
Author(s):  
L. Bouilloud ◽  
E. Martin ◽  
F. Habets ◽  
A. Boone ◽  
P. Le Moigne ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Initial Conditions ◽  
Meteorological Data ◽  
Surface Condition ◽  
Road Surface ◽  
Snow Layer ◽  
Surface Conditions ◽  
The Road ◽  
Road Surface Temperature ◽  
On The Road

Abstract A numerical model designed to simulate the evolution of a snow layer on a road surface was forced by meteorological forecasts so as to assess its potential for use within an operational suite for road management in winter. The suite is intended for use throughout France, even in areas where no observations of surface conditions are available. It relies on short-term meteorological forecasts and long-term simulations of surface conditions using spatialized meteorological data to provide the initial conditions. The prediction of road surface conditions (road surface temperature and presence of snow on the road) was tested at an experimental site using data from a comprehensive experimental field campaign. The results were satisfactory, with detection of the majority of snow and negative road surface temperature events. The model was then extended to all of France with an 8-km grid resolution, using forcing data from a real-time meteorological analysis system. Many events with snow on the roads were simulated for the 2004/05 winter. Results for road surface temperature were checked against road station data from several highways, and results for the presence of snow on the road were checked against measurements from the Météo-France weather station network.

scholarly journals Induction of Highly Dynamic Shock Waves in Machining Processes with Multiple Loads and Short Tool Impacts

2019 ◽  
Vol 9 (11) ◽  
pp. 2293 ◽  
Author(s):  
Andreas Tausendfreund ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
Shock Waves ◽  
High Speed ◽  
Short Pulse ◽  
Milling Process ◽  
Manufacturing Processes ◽  
Speckle Photography ◽  
Machining Processes ◽  
Initial State ◽  
Multiple Loads ◽  
Measurement Results

In order to study the mechanical loads of a workpiece in manufacturing processes such as single-tooth milling, in-process measurements of workpiece deformations are required. To enable the resolution of shock waves due to the mechanical impact of the tool, a novel measurement system based on speckle photography is introduced to measure the dynamic deformations and strains with a high temporal and spatial resolution. The measurement results indicate deformations and strains propagating through the workpiece with the speed of sound triggered by the tool impact (i.e., the tool impact is shown to induce shock waves during milling). Finite element simulations of the workpiece behavior are performed in addition, which support the experimental findings. In the considered case, the dynamic excitation subsides after 300 ms. Hence, in processes with even shorter cyclic multiple loads, the tool encounters an already excited initial state during machining, which needs to be taken into account when precisely modeling the milling process and the resulting workpiece quality. Finally, the measurement results demonstrate that speckle photography in combination with modern high-speed cameras and compact short-pulse lasers provides a deeper understanding of individual manufacturing processes.

Energy efficiency of machining operations: A review

2016 ◽  
Vol 231 (11) ◽  
pp. 1871-1889 ◽  
Author(s):  
Mariyeh Moradnazhad ◽  
Hakki Ozgur Unver
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Metal Cutting ◽  
Cutting Parameters ◽  
Future Research ◽  
Manufacturing Processes ◽  
Comprehensive Overview ◽  
Cutting Processes ◽  
Machining Operations ◽  
Optimization Of Cutting Parameters

Manufacturing processes are among the most energy intensive on earth. As negative ecological and economic impacts increase, reducing energy consumption is becoming critically important. In this article, a comprehensive overview of energy-saving strategies and opportunities for increasing energy efficiency in manufacturing operations is presented, with a focus on metal cutting processes. The issues and approaches involved in energy efficiency of machine tools and machining operations are reported in the literature and a structured research methodology is proposed for this purpose including prediction and modelling of machine energy consumption, determining the relationship between process energy consumption and process variables for material removal processes and optimization of cutting parameters in order to reduce energy consumption. Numerous techniques for increasing energy efficiency in manufacturing processes are identified and summarized, strengths and weaknesses of previous studies are discussed and potential avenues for future research are suggested.

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