Hydroreactor Tubesheet Design

Hydroreactor tubesheets require 2.25Cr-1Mo-V material and multi-layer narrow gap welding to ensure high-temperature strength (design temperature ≤475℃). Key indicators include an allowable stress ≥78MPa at 450℃ and compliance with ASME VIII-2 fatigue analysis requirements.

Tubesheet thickness is typically 1/5-1/4 of the shell diameter, with a 15% un-drilled ligament area required in the drilled region. A strength weld + expansion joint structure is used, with a tube hole bridge width ≥3 times the tube wall thickness to prevent hydrogen-induced disbonding.

During manufacturing, post-weld heat treatment at 620℃×8h is required, with hardness controlled between 180-220HB. In service, the hydrogen embrittlement tendency of the weld overlay (e.g., E309L+E347) needs to be monitored, and regular TOFD inspections should be performed.