DIRECT ANSWERA proposed material substitution needs a written comparison of specification and edition, chemistry, mechanical and toughness properties, temperature limits, corrosion behavior, thickness, welding, heat treatment and inspection. The design authority and owner approve before purchase or fabrication.
Substitution comparison
- Original and proposed product forms and standards
- Design temperature, pressure and corrosion service
- Weld/PWHT/NDE and availability effects
- Drawing, calculation and certificate revisions
Relevant manufacturing capability
- Drawing, datasheet and equipment-list manufacturability review
- Self-manufactured and coordinated-supply scope identification
- Technical, quality, document and delivery clarification
Key notes
- A similar grade name or higher nominal strength is not sufficient equivalence.