A computational model is presented in this article for the prediction of microstructural development during heat treating of steels and resultant room-temperature hardness. This model was applied in this study to predict the hardness distribution in end-quench bars (Jominy hardness) of heat treatable steels. It consists of a thermodynamics model for the computation of equilibria in multicomponent Fe-C-M systems, a finite element model to simulate the heat transfer induced by end quenching of Jominy bars, and a reaction kinetics model for austenite decomposition. The overall methodology used in this study was similar to the one in the original work of Kirkaldy. Significant efforts were made to reconstitute the reaction kinetics model for austenite decomposition in order to better correlate the phase transformation theory with empiricism and to allow correct phase transformation predictions under continuous cooling conditions. The present model also expanded the applicable chemical composition range. The predictions given by the present model were found to be in good agreement with experimental measurements and showed considerable improvement over the original model developed by Kirkaldy et al.

SUMMARYBy combining discrete Kirchhoff theory with least-squares smoothed shape functions, an improved quadrilateral thin-plate bending element is derived. This element exhibits improved performance over an earlier DKQ element in predicting both displacements and stresses. Numerical examples are presented comparing the element with many other quadrilateral elements for standard test problems.

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There is an ongoing interest in the development and use of renewable base stocks to formulate quenchants. The most common criterion of vegetable oils as renewable base stocks is their biodegradability and that they be non-toxic. A comprehensive overview of all aspects of vegetable oils that impacts their potential for commercial use is provided. Topics discussed include: vegetable oil structure, processing, physical properties, classification, biodegradation and toxicity; oxidation and inhibition; wetting and wetting kinematics; and applications. As a class, vegetable oil-based quenchant formulations reported in the literature to date exhibit a number of disadvantages, the most notable being their relatively poor thermal-oxidative stability in comparison with petroleum oil-based quenchants in use. Potential pathways to vegetable oil-based fluid compositions that may rival the thermal-oxidative stability of many petroleum oil-based quenchants were introduced.