Investigation and testing, welding materials, consumables, auxiliary materials and welding joints
Mechanical properties of weld metal and welded joints under normal, high and low temperatures are tested and investigated. There are determined thermo-physical characteristics of the all weld metal (thermal conductivity coefficients, thermal expansion coefficients etc). Investigations and testing of weldability and technological properties of welding materials.
Investigation and measuring of temporary and residual stresses in welded (or other) constructions
Nondestructive testing methods are applied for measuring of stresses in welds and other structures using portable computerized equipment. Such equipment allows measurements to be conducted under production, assembling or other (on spot, in field) conditions.
Reduction and redistribution of residual welding stresses
In the scope of a NATO-Project a new method has been developed for reduction and redistribution of the residual welding stresses by local explosive treatment (LET). This method is especially very useful for large welded structures or other structures consisting of different metals in cases when a thermal treatment is not applicable.
New technologies for reduction and redistribution of the residual welding stresses in tanks and cisterns have been developed and applied.
Investigations for optimizing the relaxation process parameters are conducted in order to improve its efficiency. There are also investigated structure changes, welded joints properties and possibilities for their improving as well.
Development and approval of welding technologies and procedures
Welding procedures are developed, tested and approved in compliance with BDS EN ISO standards.
Developing of technologies and equipment for special welding methods:
- welding of pipes using magnetic controlled arc without additional weld metal (welding consumables)
- diffusion welding in vacuum of joints of different metals
- narrow gap welding of thick welded joints
Numerical modeling and simulation of welding processes
A data base for conducting of simulated investigations and verifications of numerical models has been created. New models of the thermal and deformation processes, the processes of structural and phase transformations during welding have been developed. The aim hereby is to give possibilities for prediction of the mechanical and technological properties of the welds and of optimization of welding procedures.