Q: What is "Graphitization" in carbon steel pipes?
A: A long-term, high-temperature degradation where carbide in the steel decomposes into graphite, weakening the structure. It's a concern in power plant piping after decades of service.
Q: What is "Erosion-Corrosion"?
A: Accelerated material loss due to the combined action of corrosive media and mechanical wear from fluid flow, often at elbows or restrictions.
Q: Why is proper "Welding Procedure Specification" (WPS) critical for carbon steel pipes?
A: To ensure the weld has mechanical properties matching the base metal and to avoid defects like cracking, especially in higher carbon or thicker pipes which are prone to hardening in the heat-affected zone (HAZ).
Q: What is "PWHT" and when is it required?
A: Post Weld Heat Treatment. It involves heating the welded component to a specific temperature to relieve residual stresses and improve the toughness of the HAZ, often required for thick-walled pipes or specific service conditions.
Q: What key factors influence the choice between seamless and welded pipe for a project?
A: Pressure rating, corrosive/erosive service, material specifications, size availability, project budget, and code requirements. Seamless is preferred for critical high-pressure/temperature services, while welded is cost-effective for many low-to-medium duty applications.
