Preheating before welding
WBT-Electron has ample opportunities to preheat at your location.
Preheating to prevent hydrogen cracking. Preheating prior to welding can be done in order to slow down the cooling rate.
Preheating is considered in the following circumstances:
Preheating prior to welding has nothing to do with metallurgical phenomena
Naturally preventing lack of fusion is paramount. Whenever welding heat is transported too rapidly to the surrounding material, the liquid material contains too little heat in order to melt the edges of the welding joint.
Preheating involves the lowering of the temperature between the weld and the material to be welded. Because of that thermal tension remains less. The purpose of preheating is to prevent hardening as a result of which hydrogen cracking can occur.
The lowering of the cooling rate causes less hardening of the heat-affected zone (HAZ). There is more time for the hydrogen present to escape from the crystal lattice.
Hydrogen cracks can be caused by 4 factors:
Preheating is the norm defined in NEN-EN-1011 part 2: “The welding of metallurgical materials. Welding of ferritic steels”.
WBT-Electron rents professional preheating equipment. We have at our disposal units that can be monitored remotely using alerts. Our systems register temperatures at time intervals. This registration can be monitored online. If required deviations can be sent using SMS / email messages.