Introduction to Pressure Vessel Fabrication

Pressure vessels are critical components in industries such as oil & gas, power generation, chemicals, and pharmaceuticals. They store gases or liquids at pressures substantially different from ambient pressure, making their design and fabrication a matter of utmost precision and safety.

Design & Engineering Phase

The journey begins with detailed engineering using advanced CAD and FEA (Finite Element Analysis) software. Engineers calculate wall thickness, stress points, and material requirements based on operating pressure, temperature, and fluid characteristics. Designs must comply with ASME Section VIII Div 1 & 2, IS 2825, or IBR codes depending on the application and region.

Material Selection

Choosing the right material is crucial. Common materials include carbon steel (SA-516 Gr.70), stainless steel (SA-240 304/316L), and alloy steel (SA-387). Each material is verified with mill test certificates and undergoes incoming inspection including dimensional checks and chemical analysis.

Fabrication Process

Key fabrication steps include plate cutting (CNC plasma or laser), rolling and forming of shells, welding of longitudinal and circumferential seams using SAW, GTAW, or GMAW processes. All welders are certified to ASME Section IX. After welding, Post-Weld Heat Treatment (PWHT) is performed when required to relieve residual stresses.

Non-Destructive Testing (NDT)

Every weld is inspected through a combination of radiographic testing (RT), ultrasonic testing (UT), magnetic particle inspection (MPI), and dye penetrant testing (DPT). Hydrostatic testing at 1.3 to 1.5 times the design pressure validates the vessel integrity before dispatch.

Quality Assurance & Certification

Throughout the process, a comprehensive quality plan is followed. Third-party inspection agencies like BVIS, TÜV, or Lloyds are often involved. Final documentation includes material traceability records, weld maps, NDT reports, and a data report as per applicable code.

At Subhawati Projects Private Limited, we have delivered 500+ pressure vessels for clients across India, adhering to the highest standards of quality and safety.