The lack of fusion between layers occurs due to low current and high welding speed.
The lack of fusion between layers is the acceptable defect. The repair is regulated by regulatory documents for welding.
Fig. 1. The lack of fusion between layers is seen in the form of two black Continue reading →
With the macro-analysis reveal defects that violate the metal continuity:
The etching methods depend on the metal type. The macro-analysis allows you to determine in steels the following:
Irrespective the Rockwell’s scale which is used, the main process operations of the tests in essence don’t change and are provided below:
The preliminary loading serves for the compensation of possible errors or gaps in Continue reading →
Upon the shift transition of one modification to another the atoms move to small distances, smaller interatomic. These movements are studied in cobalt in detail. At Т > 425°С in cobalt it is stable face-centered cubic lattice modification (β-Со), is below 425°C —modification (α-Со). Both packaging can be provided as the atomic layers alternating, packed by the identical method. The transformation of one packaging to another can be performed if to displace the closely packed atomic layer in parallel, the octahedral plane (111) β-Со from в position into а. Such shifts need to be made on every second layer.
It is necessary to clearly understand the difference between the terms «attestation» and «certification» relating to testing for welders. When we say that the welder was certified, it means that this welder demonstrated the sufficient skills to perform the weld. At the same time, the concept of «certification» belongs to the documents which confirm this certification. The welder who has successfully passed the test for the certification program can be called the «attested welder» Continue reading →
