a In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method.
b No hardness limits are specified, but the maximum variation is restricted as a manufacturing control in accordance with 7.8 and 7.9.
c For through-wall hardness tests of Grades L80 (all types), C90, T95 and C110, the requirements stated in HRC scale are for maximum mean hardness number.
a In the case of coupling material, unless otherwise specified in the purchase agreement, the manufacturer’s internal requirements shall govern.
b Special clearance couplings shall also have a black band.
c Seal-ring couplings shall also have a blue band.
Person 2: “Casing is typically installed in sections, while tubing is usually installed in one continuous length. Casing is also typically installed in the wellbore before the drillingprocess begins, while tubing is usually installed after the drilling process is complete. Additionally, casing is typically used to isolate different zones in the wellbore, while tubing is used to transport oil and gas from the reservoir to the surface.”
Understanding the Benefits of Using Casing and Tubing in Oil and Gas drilling operations