The microanalysis is often used for the reason establishment of the various details destruction during operation.
The microscopic analysis consists in a research of the metal structure at large increases with the help of the microscope. The observed structure is called a microstructure.
The microanalysis allows you to explain in many cases the reasons of the slots properties change depending on change of the chemical composition and Continue reading →
From the moment of emergence of interest in viscosity of metals numerous and various test methods have been developed for measurement of this major property. Speaking about ability of metals to absorb energy, it is necessary to understand that metals absorb energy gradually. First of all, a certain amount of energy is spent for origin of a crack. Then additional energy for increase or distribution of such crack is required.
Some impact tests with a notch allow the crack propagation energy to be measured Continue reading →
Like a normal polymorphic transformation, the shear transition begins heterogeneously. The germs appear, apparently, in places where there are corresponding dislocation nodes. The crystals grow rapidly at a speed of> 103m/sec. Since the thermal motions of atoms do not play an important role in the shear transformation, it occurs at a great speed and at temperatures close to absolute zero. The rate of polymorphic transformation is particularly large in a defect-free crystal. If a growing crystal meets a boundary, a sub-boundary, or a cluster of dislocations, growth by a shear is usually stopped: partial dislocations stop at the defect. The violation of the fit (joints) of lattices and the appearance of a normal interphase boundary with the distorted packing of atoms can also occur as Continue reading →
The sequence of actions for the welder’s certification is included below:
The similar phenomenon shall be watched also in case of drop metal transfer, but in a little smaller level. At the same time, it is necessary to consider that the greatest vapors concentration of the metal evaporating generally from the active spot on an electrode in connection with rounding of a drop the gas flow going from an electrode, most likely, will be not on an arc pole axis under a drop, and in its peripheral parts of a drop on each side, at the same time, the vapors concentration of the electrode over a drop shall be noticeable more, than under a drop. What also promotes lowering of conductance of plasma under a drop in connection with the smaller potential of vapors ionization of metal in comparison with the potential of Continue reading →
