Search Results

This recommended microscopic practice for evaluating the inclusion content in steel has been developed as a practical method of quantitatively determining the degree of cleanliness of steel. This method has been established as a reasonable control for steel mill operations and acceptance for production manufacturing. It has been widely accepted for carbon and alloy steel bars, billets, and slabs. Exceptions are resulfurized grades which are outside the limits of these photomicrographs and the high carbon bearing quality steels which are generally classified using ASTM E 45-60T, Method A, Jernkontoret Charts.

Case hardening may be defined as a process for hardening a ferrous material in such a manner that the surface layer, known as the case, is substantially harder than the remaining material, known as the core. The process embraces carburizing, nitriding, carbonitriding, cyaniding, induction, and flame hardening. In every instance, chemical composition, mechanical properties, or both are affected by such practice. This testing procedure describes various methods for measuring the depth to which change has been made in either chemical composition or mechanical properties. Each procedure has its own area of application established through proved practice, and no single method is advocated for all purposes. Methods employed for determining the depth of case are either chemical, mechanical, or visual, and the specimens or parts may be subjected to the described test either in the soft or hardened condition.