What is the result of welding or operating austenitic stainless between 800-1500 F?

What is the result of welding or operating austenitic stainless between 800-1500 F?

• A. Carbide precipitation (weld decay or sensitization)
• B. Hydrogen embrittlement
• C. Phase transformation
• D. Grain growth

Answer: (A)

When austenitic stainless steels are heated into the tempering/sensitization range (roughly in the mid-temperature band of 800–1500 °F), chromium carbides precipitate at grain boundaries. This precipitation uses up chromium in the surrounding grains, creating chromium-depleted zones at the boundaries. Those depleted boundaries become highly susceptible to intergranular corrosion, especially in adverse environments, a condition known as sensitization. In welded or heat-affected zones, this manifests as weld decay, where corrosion attacks follow the grain boundaries along the weld line. So the main outcome in this temperature window is carbide precipitation leading to sensitization and weld decay. Hydrogen embrittlement is driven by hydrogen content and stress rather than this specific thermal exposure, and while phase transformations or grain growth can occur under other conditions, they are not the primary effect of operating in this range for austenitic stainless steel.

When austenitic stainless steels are heated into the tempering/sensitization range (roughly in the mid-temperature band of 800–1500 °F), chromium carbides precipitate at grain boundaries. This precipitation uses up chromium in the surrounding grains, creating chromium-depleted zones at the boundaries. Those depleted boundaries become highly susceptible to intergranular corrosion, especially in adverse environments, a condition known as sensitization. In welded or heat-affected zones, this manifests as weld decay, where corrosion attacks follow the grain boundaries along the weld line.

So the main outcome in this temperature window is carbide precipitation leading to sensitization and weld decay. Hydrogen embrittlement is driven by hydrogen content and stress rather than this specific thermal exposure, and while phase transformations or grain growth can occur under other conditions, they are not the primary effect of operating in this range for austenitic stainless steel.