Earlier it was considered, that both in basic material and in welded joint cracks existence is not acceptable, and their origination during product service signifies its almost instantaneous destruction.
However, in practical situation it was found, that it is almost impossible to manufacture the product without cracks and quite often the constructions have to Continue reading →
Metallurgical processes, occurred during point fusing, in spite of short-term of their behavior, are reproduced, apparently, with the same completeness level, as during real production facing.
The symmetry of fused point allows to apply to it strains of two types: tearing-off, which causes normal stresses σ in fusion zone and torsion, which causes tangential Continue reading →
Surface tension (γ) on the surface of crystal and liquid influence on the critical size of the nucleus. The bigger is energy of interphase boundary, the more energy fluctuations are necessary and nucleuses origination is found more difficult. Melt capability for overcooling depends on similarity of packing of atoms short-range order in liquid and crystal state. If the similarity is small, the surface tension between crystals and liquid is big and bigger fluctuations energies will be necessary Continue reading →
General program of enterprise about technology attestation by tests conducting is:
– Welding parameters determination;
– Examination of equipment’s and materials’ aptitude;
– Assemblage for welding and execution of welding process observation with registration all significant parameters and results;
The cold crack (chipping off) is the most frequent defect of fusion zone during fusion, which is located in certain distance from the fusion surface. The temperature conditions of these cracks formation and character of their development gives basis to connect the process of their formation with delayed fracture phenomenon.
When developing method of evaluation of susceptibility to chipping off formation Continue reading →
