1. Q: What is the typical impact test requirement for ASTM A333 Gr.6 at its minimum design temperature?
A: Minimum average Charpy V-Notch impact energy of 13 ft-lbs (18 J) at -45°C for longitudinal specimens.
2. Q: Why is ASTM A135 pipe generally not used for critical structural or pressure applications?
A: It is an ERW pipe specification for general use, with less stringent mechanical property and testing requirements compared to A53 or A106.
3. Q: What is "Galling" in carbon steel threaded connections?
A: A form of wear caused by adhesion and friction between mating threads, which can seize the connection. It's mitigated by using thread compounds (dope).
4. Q: What is the main purpose of applying a black or hot-dip galvanized (HDG) coating on pipes like ASTM A53?
A: Black coating (often a lacquer) provides basic atmospheric corrosion protection. HDG (zinc coating) provides superior sacrificial corrosion protection for outdoor exposure.
5. Q: What is the key factor limiting the maximum allowable stress for carbon steel at elevated temperatures?
A: Creep Strength. At temperatures above approximately 425°C, time-dependent plastic deformation (creep) becomes the design-limiting factor.
