On the Construction of Analytical Cooling Curves from ASTM D6200 Data Using Multi-Variable Gradient Descent Method

2021 ◽  
Author(s):  
James Jan ◽  
D. Scott MacKenzie
Keyword(s):  
Cooling Rate ◽  
Oil Quality ◽  
Standard Test ◽  
Descent Method ◽  
Test Method ◽  
Cooling Curve ◽  
Gradient Descent Method ◽  
Mathematical Function ◽  
Current Standard ◽  
Characteristic Points

Abstract ASTM D6200 is a standard test method to evaluate cooling characteristics of quench oils. The test produces six discrete numbers representing the cooling characteristics: three temporal scales (time to cool to 600°C, 400°C, and 200°C), two cooling rates (max cooling rate and cooling rate at 300°C), and one temperature scale (at max cooling rate). One of the main purposes of ASTM D6200 is to monitor the oil quality to ensure gears are properly quenched. The current standard only includes specifications for gear quenching oil and its applications are limited to physical testing. The intent of this research is to explore the possibility of broadening the support for more quenchants and extending applications to virtual engineering. This research includes two parts. The first part is the development of a systematic method to identify the characteristic points of a cooling curve. The second part is the construction of an analytical cooling curve based on the characteristic points. The analytical cooling curve is a mathematical function of temperature versus time that can provide temperature at any given time in the quenching process. In addition, the curve is differentiable to provide the cooling rate information at any given time as well.

scholarly journals ASTM Single Fiber Room Temperature Test Standard Development

1998 ◽  
Author(s):  
Janet B. Hurst ◽  
William S. Hong ◽  
Mary L. Gambone ◽  
John R. Porter
Keyword(s):  
Standard Test ◽  
Industrial Test ◽  
Discussion Groups ◽  
Test Method ◽  
Task Group ◽  
Ceramic Fibers ◽  
Current Standard ◽  
Single Filament ◽  
Wide Range ◽  
American Society

Development of an updated single filament test standard for tensile strength determination has been undertaken by a joint government-industry task group under the auspices of the Subcommittee C28.07 of the American Society for Testing and Materials (ASTM). This update was initiated in response to a need expressed by people involved with fiber testing. A fiber testing workshop in 1991 attracted a wide range of attendees with concerns regarding the uniformity of testing methods and comparability of resulting data in the fiber literature. With the inception of a C28.07.07 Task Group for Ceramic Fibers, an effort to conduct round robin testing was begun among interested government and industrial test facilities. User surveys and discussion groups were also employed to determine areas of concern with the current standard test method, ASTM D 3379-75. Shortcomings in the current standard were identified and methods of addressing these areas were discussed with experts including fiber manufacturers, testing facilities and composite manufacturers. Among the main concerns was the method and application of fiber diameter measurements.

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.

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