Numerical Simulation on Quenching Temperature Field of 40Cr Steel

2010 ◽  
Vol 154-155 ◽  
pp. 417-420
Author(s):  
Di Cui ◽  
He Liang
Keyword(s):  
Field Work ◽  
Cooling Curve ◽  
Work Piece ◽  
Security Assessment ◽  
Quenching Temperature ◽  
Temperature Changes ◽  
Complex Process ◽  
Medium Flow ◽  
Quenching Process ◽  
40Cr Steel

The quenching process is a complex process, which involves quenching medium flow field, work piece temperature and stress field. In this paper, the 40Cr steel belt wheel is chosen for the sample of finite element method to simulate the quenching process. The temperature changes with time at any position in the work piece are directly reflected in the actual quenching process. The cooling curves of center and general surface are obtained after simulation. Combined with cooling curve of transformation of under cooled austenite, it is easy to predict whether the technological results meet the performance of organization, and conduct a security assessment of the work piece.

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

Regulation of Heat Production by Large Moths

1967 ◽  
Vol 47 (1) ◽  
pp. 21-33
Author(s):  
JAMES EDWARD HEATH ◽  
PHILLIP A. ADAMS
Keyword(s):  
Oxygen Consumption ◽  
Heat Loss ◽  
Low Temperatures ◽  
Cooling Curve ◽  
O2 Consumption ◽  
Internal Temperature ◽  
Warm Up ◽  
Temperature Changes ◽  
Thoracic Temperature ◽  
Silk Moth

1. Moths ‘warm-up’ prior to flight at mean rates of 4.06° C./min. in Celerio lineata and 2.5° C./min. in Rothschildia jacobae. The abdominal temperature rises only 2-3° C. during activity. 2. Oxygen consumption of torpid sphinx moths increases by a factor of 2.27 as temperature changes from 26° to 36° C. 3. Oxygen consumption during ‘warm-up’ increases with duration of ‘warm-up’ from about 1000 µl./g. min during the initial 30 sec. to nearly 1600µl./g. min. during the 3rd min. This increase compensates for increasing heat loss from the thorax during ‘warm-up‘. 4. When the moths are regulating thoracic temperature, oxygen consumption increases with decreasing air temperature from a mean of about 400µl./g. min at 31° C. to about 650µl./g. min. at 26° C 5. Values of O2 consumption calculated from the cooling curve of C. lineata are about 85% of the measured values of O2 consumption. 6. The giant silk moth, Rothschildia jacobae, regulates thoracic temperature during activity between about 32° and 36° C. at ambient temperature from 17° to 29° C. Moths kept at high temperatures are active longer, have more periods of activity and expend more energy for thermoregulation than moths kept at low temperatures. 7. Large moths increase metabolism during active periods to offset heat loss and thereby maintain a relatively constant internal temperature. In this regard they may be considered endothermic, like birds and mammals. 8. We estimate that male moths use 10% of their stored fat for thermoregulation, while females may use 50%.

Effects of Zero Time Holding Quenching Temperature on Tempering Microstructure and Mechanical Properties of 40Cr Steel

2020 ◽  
Vol 993 ◽  
pp. 492-496
Author(s):  
Peng Xiao Zhu ◽  
Yi Li ◽  
Bo Chen ◽  
Kun Feng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Impact Test ◽  
Wear Loss ◽  
Quenching Temperature ◽  
Impact Performance ◽  
Zero Time ◽  
40Cr Steel ◽  
Holding Temperature

The effects of different zero-holding quenching temperatures on the tempering microstructure, mechanical properties and wear resistance of 40Cr were studied. The results showed that the microstructure of 40Cr was tempered sorbite and a small amount of unmelted ferrite after quenching at 850 °C and tempering at 550 °C for 2 h. Tempered sorbite was obtained after quenching at 880 °C～910 °C and tempering at 550 °C for 2 h. With the increasing of quenching temperature at zero holding temperature, the tensile strength and yield strength of 40Cr increased, while the elongation and impact toughness decreased. With the decreasing of impact test temperature, the ballistic work of 40Cr decreased gradually, and decreased fastest between 0 °C～-20 °C. 40Cr had the best impact performance after quenching at 850 °C and tempering at 550 °C for 2 h. 40Cr had the smallest wear loss after quenching at 880 °C and tempering at 550 °C for 2 h. Its wear marks were smooth, and had the shallowest furrows and ridges.

scholarly journals THEORETICAL ASPECTS OF DIGITAL CREATION TOPOGRAPHIC PLAN

2021 ◽  
Vol 3 (163) ◽  
pp. 30-34
Author(s):  
O. Afanasyev ◽  
I. Zavada
Keyword(s):  
Coordinate System ◽  
Computer Software ◽  
Field Work ◽  
Process Data ◽  
Digital Maps ◽  
Complex Process ◽  
Software Product ◽  
Materials Used ◽  
Digital Plan ◽  
The City

Theoretical bases of creation of the digital topographic plan of district are considered, the analysis of the materials used for creation of the digital topographic plan of district is carried out. Types and features of application of topographic plans are analyzed. The most suitable geo-basis for creating a digital plan has been identified. Studies have shown that a 1: 500 scale geo-base is quite informative and most optimal for creating digital and conventional topographic plans in the city. Without additional removal, 1: 500 scale plans allow for the transition to smaller scale plans. According to current national regulations, a single coordinate and altitude system should be used to create topographic plans. Today, the only state coordinate system USK-2000 is used, which replaced the coordinate system SK-42, which is based on the Krasovsky ellipsoid and the Gauss-Krueger projection. Possibilities of development of electronic topographic plans with use of modern software complexes are investigated. Computer software allows you to process data as accurately as possible and perform tasks quickly. Among the main software packages used to create an electronic topographic plan of the area are AutoCAD, Digitals, Geonics, COMPASS, MapInfo Pro, Topocad. The choice of software product depends on the breadth of the task, the modernity of surveying instruments and their own software. An analysis of the software used in the creation of digital maps and topographic plans, which showed that the choice of a particular product depends on the breadth of the task, the modernity of surveying instruments and their own software. AutoCAD software is universal and fully adapted to modern geodetic problems. The use of AutoCAD software will ensure the final processing of data obtained during field work and the completion of the digital topographic plan of the area. The procedure for creating a digital topographic plan of the area using Digitals and AutoCAD software is considered. Creating a digital topographic plan of the area is a complex process consisting of several stages, which are described in the article.

scholarly journals Experimental investigations of Jominy End Quench test using CuO nanofluids

2017 ◽  
Vol 12 (10) ◽  
pp. 4455-4464
Author(s):  
Baskaran M ◽  
Vijayakumar KCK ◽  
Bharathiraja Moorthy
Keyword(s):  
Heat Transfer ◽  
Mild Steel ◽  
Colloidal Suspensions ◽  
High Hardness ◽  
Average Diameter ◽  
Cooling Curve ◽  
Experimental Investigations ◽  
Work Piece ◽  
Quenching Effect ◽  
Quenching Medium

Nanofluids are the new class of quenching medium with colloidal suspensions of nanoparticles in base fluids, which improves the heat transfer characteristics. The present work has been focused on the quenching effect of mild steel and EN-8 steel with nanoparticles dispersed quenching medium. The different volume concentrations of nanofluids have been prepared by adding CuO nanoparticles with the average diameter of less than 50 nm in distilled water. Three volume concentrations (0.01%, 0.05% and 0.1%) of nanofluids have been prepared. EN8 and mild steel rod have machined as per Jominy end quench standard. The materials are heated up to 900⁰C and the heated specimens are Jominy end quenched by using nanofluid. Heat transfer during the cooling has been recorded by interfacing the LabVIEW software, NI-DAQ kit and thermocouple. Then the hardness values are measured at different points on the work piece to examine the change in hardness of the quenched specimens. The result shows that, 0.05% volume concentration nanofluid exhibits a higher heat transfer rate; consequently the high hardness value has been achieved as compared with other specimens. The same effect has been observed with cooling curve, which was recorded by LabVIEW during the quenching process.

Optimization of Quenching Process Parameters of 15CrNiMo Steel Used for Roller Bit Bits

2019 ◽  
Vol 944 ◽  
pp. 351-356
Author(s):  
Sheng Rui Su ◽  
Ren Bo Song ◽  
Chi Chen ◽  
Wen Sheng Ji ◽  
Shi De Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lath Martensite ◽  
Holding Time ◽  
Quenching Temperature ◽  
Obvious Effect ◽  
Tempering Temperature ◽  
The Core ◽  
Quenching Process ◽  
Test Steel ◽  
The Relationship

The microstructure and mechanics of 15CrNiMo steel with different quenching temperatures (800°C, 825°C, 850°C, 875°C, 900°C) and different quenching holding time (15min, 25min, 35min) were studied for steel 15CrNiMo for roller bit. The relationship between the properties of different quenching parameters and the mechanical properties such as microstructure, impact toughness and hardness was analyzed. The results show that the microstructure of the annealed precursor is mainly ferrite and pearlite. With the increase of quenching temperature, the ferrite is gradually reduced, the lath martensite is gradually increased, and the martensite grains tend to grow. The strength increases first and then decreases, and the plasticity increases slightly. The quenching and holding time has no obvious effect on the test steel, and the austenitization of the core is the best time. The best quenching temperature is 850°C, the best holding time is 25 min, (tempering temperature is 220°C, tempering holding time is 50 min) and the mechanical properties are optimal.

Influence of Quenching Temperature on Microstructure and Properties of 40Cr Steel by Zero Time Holding Quenching

2011 ◽  
Vol 215 ◽  
pp. 25-28 ◽  
Author(s):  
An Ming Li ◽  
Meng Juan Hu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Lath Martensite ◽  
Metallographic Analysis ◽  
Treatment Technology ◽  
Quenching Temperature ◽  
Heat Treatment Technology ◽  
Austenite Grains ◽  
Zero Time ◽  
40Cr Steel

The effect of quenching temperature on the microstructure and mechanical properties of 40Cr steel by zero time holding quenching were studied. The results showed that the strength and hardness of 40Cr steel increased with the increase of quenching temperature in the range of 860~940°C, the strength and hardness reach the maximum at 920°C and then decrease. The metallographic analysis shows austenite grains of the samples by “Zero Time Holding” Quenching have been refined compared with the traditional heat treatment technology. Fine lath martensite was obtained by the “zero time holding” quenching due to the smaller austenitic crystal grain and the uneven distribution of the carbon concentration in austenitic crystal grain.

scholarly journals Effect of Agitation, Temperature, and Quenching Medium on Cooling Curve and cooling rate for Steels

2018 ◽  
Vol 21 (4) ◽  
pp. 473-478
Author(s):  
Hala S. Hasan ◽  
Reham H. Khaleefah ◽  
Nasser A. Al haboubi ◽  
Raad D. Salman
Keyword(s):  
Heat Transfer ◽  
Steel Sample ◽  
Cooling Curve ◽  
Temperature History ◽  
Stainless Steel Sample ◽  
Cooling Curves ◽  
Ability To Work ◽  
Cooling Stage ◽  
Quenching Process ◽  
Transfer Properties

The control of quenching process has been investigated in this study by developing a quench system design to simulate the quenching process and measure the time – temperature history inside the sample during the cooling stage. The main purpose of this quench system is to evaluate the quench power of different quenchant at different conditions (type, temperature and agitation).A stainless steel sample was used with a suitable measurement as a probe in designing this quench system.The performance of two of quenchants (water and brine) with different conditions was investigated, and the designed probe was used to illustrate the effect of quenching parameters (quenchant type, temperature and its agitation) on cooling curves and cooling rate.The quenching system has proven its ability to work effectively and the results showed that heat transfer properties were significantly affected by quenchant parameters.

scholarly journals MULTITEMPORAL 3D MAPPING OF POST-EARTHQUAKE RECOVERY PHASE WITH UAS: CASE STUDY VRISA, LESVOS, GREECE

2020 ◽  
Vol VI-3/W1-2020 ◽  
pp. 123-130
Author(s):  
G. Tataris ◽  
N. Soulakellis ◽  
K. Chaidas
Keyword(s):  
Point Clouds ◽  
Field Work ◽  
Recovery Phase ◽  
Correct Selection ◽  
3D Mapping ◽  
3D Point Clouds ◽  
Complex Process ◽  
High Resolution Images ◽  
New Buildings

Abstract. The recovery phase of an earthquake-affected settlement is a time-consuming and complex process that requires monitoring, which is now possible using UAS. The purpose of this paper is to present the methodology followed and the results obtained by the exploitation of UAS for rapid multitemporal 3D mapping during the recovery phase of Vrisa traditional settlement, Lesvos island, Greece, which was highly damaged by the earthquake (Mw=6.3) on 12th June 2017. More analytically, three (3) flight campaigns covering the period July 2017 – May 2020 took place by means of an UAS for collecting high-resolution images on: i) 19th May 2019, ii) 29th September 2019, iii) 17th May 2020. Structure from Motion (SfM) and Multi Stereo View (MSV) methods have been applied and produced: i) Digital Surface Models – DSMs, ii) 3D Point Clouds – 3DPC and iii) Orthophoto-maps, of Vrisa. In parallel, GIS capabilities has been exploit to calculate building volumes based on: a) DSM produced by UAS image processing, b) DEM produced by 233 RTK measurements and c) building footprints derived by the digitization of the orthophoto-map of 25th July 2017. The methodology developed and implemented achieves extremely reliable results in a relatively easy, fast and economically feasible way, which is confirmed with great precision by field work. By applying the above-described methodology, it was possible to monitoring the recovery phase during July 2017 and May 2020 which 302/340 buildings that had been severely damaged by the earthquake have been demolished. A small number of new buildings have also been rebuilded and small number of buildings that have just begun excavations for their construction. An important parameter for obtaining reliable data and comparable results is the correct selection of flight parameters and their maintenance at all times when it is decided to take data, without affecting the accuracy of the results from taking photos or videos. Automation in the future of the proposed methodology can significantly accelerate the achievement of reliable results without the intermediate interpretation of orthophoto-maps.

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