| Induction harden A form of heat treatment using high frequency electrical current. This process changes the steel's atomic structure, rendering it more tough and shock resistant. Cold finished A process that occurs at the cold finished mill, whereby the steel with a slightly larger diameter than nominal is passed through an exacting dimensional die. This operation occurs on a draw bench, and imparts the mechanical properties to the steel. Yield Strength During a pull test, the point at which permanent deformation of a steel sample occurs. Yield strength is measured in pounds per square inch (psi). Heat Lot Number A number that records and documents the characteristics of a given steel lot starting in the hot roll state, and facilitates traceability. Similar to a serial number, but for a batch of steel. Certificate of Analysis A document that indicates the characteristics of a given steel batch, including the chemical makeup and mechanical properties. The characteristics added at Savik include chrome thickness and heat treatment, if applicable. Skip hardening A heat treatment that alternates hardened and non hardened areas on the same bar. The facilitates machining and threading, especially rolled threads. Nominal Diameter Starting diameter for cases where the required diameter is under a nominal diameter. For example, 1.000" diameter ground to 0.995" diameter is said to be five thousands under nominal. Case The area on an induction hardened bar where the heat treatment is visible and/or quantifiable. Hardness in Rockwell C The unit of measure used to quantify the hardness of the induction heat treatment. For example, the typical hardness before heat treatment is approximately 22 Rockwell C (HRc) whereas the same bar after induction hardening will have a surface hardness of 58 HRc. |
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