Basic Considerations for Material Selection for Process Service

DOE-HDBK-1132-99

An acceptable materials selection process evaluates at least the performance,

maintenance, service life, quality control requirements, life-cycle cost, inspection,

and reliability requirements necessary to minimize/prevent component failure or

degradation from all known mechanisms. This involves a literature review, tests,

weldability, code approval, availability of product forms and an industrial base,

identification of the critical parameters and limits, and properly prepared material

specifications that address the applicable failure and degradation mechanisms.

Basic Considerations for Material Selection for Process Service . When determining

5.2

an appropriate material for a specific process service, the following considerations

should be evaluated:

Establish the design life and performance requirements for process system

components such as vessels, tanks, heat exchangers, piping, valves, and

pumps.

Define the expected or actual stream analysis of the process flow. The stream

analysis should include constituent partial pressures, percent chemical species

by weight/volume, flow velocities, and contaminant levels. Possible upset

conditions, including startup and shutdown environmental conditions, should be

considered.

Define the expected operating pressures and temperatures of the process

streams. Startup and shutdown conditions, as well as possible special operating

conditions like steam-out cleaning of equipment, should be considered. Possible

brittle fracture and fatigue failure of materials should be considered.

Identify the desired material mechanical properties. The mechanical properties

to consider include tensile and yield strength at design temperature, hardness,

fatigue strength, creep strength, toughness, desired wear, and corrosion

Establish the calculated or expected design radiation dose over the design life of

the system. This is important for polymeric materials, which include thermosets,

thermoplastics, and elastomers due to possible degradation effects. Additionally,

consideration of detrimental off-gassing from nonmetallic materials in tritium

service should be included.

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