May/June_AMP_Digital

FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 1 8 3 9 temperature gradients show that faster cooling with basket quenching results in a higher temperature gradient than conveyer quenching, Fig. 3(a) and (c); the exception is 3(b). Fig. 2 — CFDmodel and plots of simulation results; thermocouple measurements for air quenching a cylinder block with riser attached. Fig. 3 — Air flow and air pockets surrounding a cylinder head for four different air quenching configurations, 60 seconds into quenching. The location of the high temperature gradient indicates that the regions between thewater jacket and intake port are sus- ceptible to high residual stress (Fig. 5). WATER QUENCH PROCESS FOR CYLINDER HEADS The physics of water quenching are more involved than those in air quenching. The Vir- tual Manufacturing Group at Ford Motor Co. adapted the quench model framework by AVL FIRE, which is based on a Eulerian-Eulerian multiphase model, and developed its own pro- prietary database to simulate the boiling wa- ter process in quenching. Extensive work was carried out on computation and experiments to validate the numerical methods. CFD sim- ulations compared with lab experiments on cooling curves confirm that the CFD model is accurate and can predict a temperature profile for every quenching orientation without cali- bration (Fig. 6). Vapor patterns and vapor pockets for six different quench orientationswere also studied (Fig. 7). Cooling curves and temperature-gradi- ent plots illustrate that orientation has little im- pact on overall cooling characteristics (Fig. 8). In addition, maximum temperature gradients are similar except they occur at different times, even though the vapor pattern and locations of vapor pockets are drastically different in each quenching orientation. For both rear face up (RE) and cam cover face up (CC) quenching, the high temperature gradient appears in the intake port area, similar to the air quenching cases (Fig. 9). 7