Cracking problems in site construction occurring in the weld and HAZ (heat affected zone) can usually
be traced back to the presence of hydrogen resulting from lack of attention given to consumables during
storage. Figure 4 illustrates a situation in which hydrogen-assisted cracking in the heavy weld between the
nozzle and end plate of a heat exchange initiated a brittle fracture in the end plate. In this instance the
electrodes had been stored in an unheated corrugated sheet hut, with condensation streaming down the
walls. Such abuse of electrodes is thankfully less common now than in the past, but vigilance must be
exercised to avoid the problem. On small contracts it is frequently proposed that an accommodation office,
often the foreman’s office, is used as an electrode store. This can be equally unacceptable in critical cases
since temperature and humidity may reach intolerable levels. Equally important are electrode baking and
drying ovens and cabinets. They should have efficient temperature control, and allow free circulation of air.
Damp electrodes held in an air-tight container may not reach the required maximum hydrogen potential
levels, regardless of the holding time.