Form: This specification covers a corrosion and heat resistant steel in the form of three classes of welded and drawn tubing. Application: Primarily for parts and assemblies@ such as fluid lines subject to high pressures@ requiring corrosion resistance. Tubing has good oxidation resistance up to 1100?? (595??). Classification: The tubing covered by this specification is classified as follows: Class 1 - 0.125 in. (3.18 mm) length Ultrasonic Calibration Standard Class 2 - 0.060 in. (1. 52 mm) length Ultrasonic Calibration Standard Class 3 - Ultrasonic Testing not required If no class or Class 1 is specified@ Class 1 or Class 2 may be supplied. If Class 3 is specified@ any of the three classes may be supplied.