What is the primary purpose of minimum bolt stress in gasketed joints?

• A. Prevent bolt loosening
• B. Maintain gasket seating stress
• C. Minimize bolt torque
• D. Maximize clamping force

Answer: (B)

Gasketed joints seal by keeping the gasket pressed against the flange surfaces. The minimum bolt stress is the lower bound preload on the bolts, chosen to keep the gasket in contact and maintain the seating stress as conditions change—such as gasket relaxation and internal pressure variations. By ensuring this minimum preload, the gasket remains seated and the seal is preserved during operation. It’s not primarily about preventing bolt loosening, nor about maximizing clamping force or minimizing torque; those are secondary concerns, while maintaining gasket seating stress is what directly sustains the seal.