Standard for comparing various shaped sections to round bars, used for determining the response to hardening characteristics when heat treating low-alloy and martensitic corrosion-resistant steels.
Source: API SPEC 8C, Drilling and Production Hoisting Equipment (PSL 1 and PSL 2), Fifth Edition, April 2012. Global Standards
Source:API SPECIFICATION 7K, Drilling and Well Servicing Equipment, Sixth Edition, December 2015. Global Standards