Analysis for a crack of the manhole in a reactor of Ethidene Diamine unit

Inhalt:
A crack of the manhole were found in the D-2310 main reactor of an Ethidene Diamine unit in a chemical company during quality acceptance of installation. The methods of macroscopic examination, chemical composition analysis, hardness test, metallographic examination and fracture analysis were used to analyze the cause of the crack. The results showed that too high welding temperature, non-uniform welding line energy and unstable electrode quality were the main reasons for the welding heat crack. The repair measures of this crack were suggested at last, which can be used as a reference to prevent the welding heat crack in manufacturing processes.