Cryogenic steels

Topic overview

For cryogenic service, yield strength is not the governing property. Resistance to brittle fracture at design temperature, HAZ stability, correct weld metal, low hydrogen and complete traceability are decisive. The process window must be qualified at the required test temperature.

Has toughness of parent material, HAZ and weld metal been demonstrated for the design temperature, thickness and stress state?

Low plastic deformation and rapid crack propagation mean prevention must combine design, material and fabrication controls.

Coarse grain, local hard structures or inappropriate tempering can give lower toughness than the parent material.

What the module covers

• Cryogenic steels and welded joints
• 1. Material concepts for low-temperature service
• 2. Thermal-cycle control
• 3. Controls that routine VT cannot replace
• Pre-production checklist
• Practical rule