A. PHYSICAL CHARACTERISTICS
• Weight or density limitations
• Electrical conductivity
• Thermal conductivity
• Thermal expansion coefficient
• Magnetic properties
• Composition limitations
• Hardenability
• Fire resistance
• Toxicity
• Biofouling resistance
• Position within EMF table
• Weldability
B. MECHANICAL PROPERTIES
• Yield and Tensile strength
• Hardness
• Ductility (% elongation & % reduction of area)
• Fatigue resistance
• Toughness (notched impact resistance
• Fracture toughness
• Galling resistance
• Abrasion resistance
• Wear resistance
• Modulus of elasticity
• Bearing strength
• Temperature effects on mechanical properties
• Compressive strength
• Poisson’s ratio
• Shear modulus
• Effect of the direction of work on mechanical properties
C. DESIGN RESTRICTIONS
• Size & thickness
• Temperature
• Form
• Type of loading (static, dynamic, impact, alternating, cyclic)
• Cleanliness
• Surface finish
• Protection method
• Maintainability
• Velocity
• Contents or exposure to chemicals
• Depth
• Design life
• Applicable standards
D. CORROSION RESISTANCE
Consider the following for the particular zone in the marine environment of interest (i.e. marine atmosphere, splash zone, mud zone, immersion, etc.).
• General corrosion resistance
• Pitting and crevice corrosion resistance
• Corrosion resistance to contained fluids (e.g. H2S, CO2, formation water, drilling muds, completion fluids, acidizing chemicals, crude, etc.)
• Corrosion fatigue
• Corrosion erosion
• Seawater velocity effects
• Temperature effects on corrosion
• Susceptibility to stress corrosion cracking
• Fracture toughness in environment
• Susceptibility to hydrogen embrittlement (due to hydrogen from corrosion or cathodic protection)
• Fretting resistance
• Galvanic compatibility with mating parts
• Selective attack
• Bacterial corrosion
• Cavitation resistance
• Contamination of contents by corrosion products
• Ease of protecting or compatibility with planned protective measures
E. PROCESSING
• Melting practice
• Grain size
• Heat treatment
• Minimum hot work
• Casting process
• Forging process
• Joining method
• Effect of stress relieving on properties
• Repairability
• Formability
• Machinability
• Surface finish
• Compatibility with special processes (e.g. nitriding, plating, flame hardening, etc.)
F. QUALITY
• Mechanical property qualification
requirements
• Nondestructive examination
(PT,UT, RT, MT)
• Dimensional inspection
• Certification requirements
• Types of defects and acceptance criteria
• Traceability
• Weld procedure qualification
• Pipe bending procedure qualification
• Witness hold points
• Compliance to standards
G. COMMERCIAL
• Cost
• Availability in required size, form, condition, quantity
• Delivery and schedule requirements
• Restrictions on country of origin
• Approved vendors list
• Temperature
• Chemicals
• Fresh/Seawater
• Erosion
• Wave impacts
• Sunlight (UV) resistance
• Immersion, splash, fumes exposure
• Biological attack
• Marine fouling
Thanks for the tips!
ReplyDeleteYou could use Elcometer 500 to measure coating thickness