The maximum value and the rate of rise of the internal plastic deformations (that the metal can withstand without destruction in the process of welding) have been accepted as the evaluation criterion of the weld metal resistance to the formation of hot cracks.
The tests are conducted as follows. A bead is deposited into the sample’s groove (Fig. 1) with the use of the tested welding materials. By means of the Ǿ22 mm holes, Continue reading →
For a crack in a metal to expand under the influence of the stretching forces, it is necessary to spend some work on the plastic deformation’ flowing along the forming crack’ borders and on the forming of new surfaces. D. Irwin and E. Orowan proposed to introduce the value of G that would express the plastic deformation’ work at the crack’s mouth with its advancement at the moment of the motion start expressed in a unit of length. The G value can be expressed as a unit of force per a Continue reading →
To a large extent, the process of generation is affected by the inclusion surface’ topography. If there are depressions on the surface, the critical dimension nucleus’ size and the work required for its formation are smaller than those for the flat surface. The influence that the nonisomorphic impurities exert on the process of crystal formation can be boosted if they have previously been in contact with the crystals of the given substance. At the temperatures that are not too low, under the influence of the crystal’s atoms, the structure of the impurity inclusion’ surface Continue reading →
Certification results of welding technology obtain practical value only after certification of individual welders for executing welding works in compliance with this technology. These two types of measures differ from each other in virtue of different goals of their existence. We will presume that suitable welding technologies were accepted and confirmed with the help of one or other method. To determine if the welders have enough qualification for executing qualitative Continue reading →
Tunnel pores represent one more type of extended pores. Usually tunnel pores with formation of contraction cavity represent the most dangerous defect in the case, if main designation of welded seam is in retaining gas or liquid; since at that exists the big possibility of leakage path formation.
