It is a well known practical observation that hot tearing can be reduced or eliminated in controlled casting conditions that prevent formation of large temperature and stress gradients.
If feeding serves only to close the space between separated dendrites, inadequate feeding cannot be the reason for hot tearing; there are open and filled hot tears.
Experiments in which several magnesium alloys were poured into preheated molds determined the critical preheat temperature above which hot tearing does not occur.
The researchers tried to simulate similar conditions and determine what hot tearing criterion matches prior experimental observations.
This type of specimen, sometimes referred to as "harp" casting, frequently is used for determining hot tearing susceptibility.
Instead of finding the pressure drop under applied strain rate, the critical strain rate that causes hot tearing was estimated.
On another front, recent research suggests that inflammation may contribute to chronic, ineffective tearing
Tearing energy values were determined for new hose covers and tubes, specimens aged in a forced air oven at various temperatures for various times, specimens aged in two different power steering fluids (designated fluid A and fluid B), and specimens made from hoses removed from impulse testing.
Aging causes the critical tearing energy of both CPE and CSM compounds to decrease, regardless of the specifics of the aging conditions.
Table 2 shows values of the tearing energy of both tubes and covers removed from impulse testing after various numbers of cycles.
The critical tearing energy of the elastomers from which power steering hose is made decreases with aging.
We have previously shown that the rate of aging of an elastomer can be predicted by combining results of critical tearing energy experiments on oven aged specimens with the measured oxidative induction time determined using DSC (ref.
(2) ln(r) = - 10545(1/T) + 11.93 where r is the decrease in tearing energy per second of aging, and T is the absolute temperature.
Which of the following proteins remains relatively stable during reflex tearing
Sahoo, MTL, concluded that filtering, degassing and the addition of Mischmetal (alone or in combination) improve the metal's hot tearing