Experimental trials of compounds
Theoretical curves of the dependencies of the destructive stresses on the temperature of the sample during the test are indicated and stresses are indicated at which fragile destruction of the steel of various brands occurred. The destruction of samples without acute incisions occurred at stresses close to the limitation limit (curve /). The presence of acute incisions and a test at low temperature caused a decrease in the magnitude of the destructive stresses (curves //, ///). At temperatures below T0, destruction is of the nature of the separation, and the stresses do not exceed the limitation limit. The connection between the temperature and the stresses at which the crack that has arisen is possible is given by curves IV, V, VI. If the temperature is below the threshold of the caliper of TP, then the destruction occurs instantly and corresponds to low stresses. A curve is given from which it is clear that if the tendency of steel to fragile destruction, the temperature of the threshold of coldness and the concentration of stresses (residual voltage level) are known, then the conditions of fragile destruction can be predicted. During the experiments, it was noted that an uneven power of an intense state reduces the voltage level at which fragile destruction occurs. Analysis of the causes of fragile destruction of the metal shows that it is accompanied by a set of factors, the main of which are: 1) the quality of steel and its tendency to fragile destruction at low temperatures, close threshold of coldness; 2) the nature of the tense state associated with the load applies, residual stresses, a geometric change in the form that causes the concentration of stresses, and other.; 3) a decrease in the temperature of operation, causing an increase in the fragility of the metal. The main question in this problem is to identify the tendency of steel to fragile destruction. The presence of structural defects caused by various causes of a metallurgical nature, the tendency of steel and a phenomenon of a stick that reduces the length of the turnover, adversely affect the displacement of the threshold of coldness and contribute to the occurrence of fragile destruction.