Welding, Fabrication, Examination, and Testing

DOE-HDBK-1132-99

Define the expected environmental conditions. Likely conditions to be

considered are embedment in soil or concrete, exposure to corrosive

atmospheres, use of thermal insulation, or attachment of electrical or steam-heat

tracing.

Determine the need for material decontamination if the process service is

radioactive. Consideration should be included for enhanced surface finishes or

materials suitable for decontamination solutions.

Identify any historical materials documenting performance experience with similar

process streams and operating conditions. Successful past usage may indicate

suitable service, but careful comparison of the process conditions should be

considered.

Welding, Fabrication, Examination, and Testing . Fabrication processes, including

5.3

welding, forming (hot and cold), bending, threading, etc., should be controlled or

restricted based on the type of material used and the intended process service. The

following factors should be addressed:

Certain metallic materials may be susceptible to cracking during or following

welding. For example, aluminum bronzes and some aluminum alloys may suffer

hot cracking (cracking during solidification); chromium molybdenum alloys are

air-hardenable and may need elevated preheat temperatures to avoid weld-metal

and heat-affected-zone cracking. It is important to distinguish between weld-

deposit cracking and heat-affected zone or base-metal cracking.

Some process services may require special heat treatments to reduce the risks

of stress-corrosion cracking. For example, a heat treatment may be required for

carbon-steel welds and cold bends in carbon steel exposed to caustics,

hydrogen sulfide, or amines.

Welding, hot forming, and heat treatment operations on certain materials may

degrade their corrosion resistance. Austenitic stainless steels and some nickel

alloys are examples of materials that can become susceptible to stress-corrosion

cracking in certain environments as a result of these operations. Limitations and

controls on welding and hot forming operations may be needed. Additionally,

special heat treatment may be required to prevent stress-corrosion cracking.

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