More and more attention is being paid to non-destructive testing of connecting elements. Currently, ultrasound control is widely used. A prerequisite for an effective and reliable process of ultrasonic testing is the grain size of the analysed metal. One option for influencing non-grain size of a steel part is to vary the heat treatment and tempering conditions. As part of the study, an assessment was made of the heat treatment modes of steel parts for grain size. It has been established that by changing the heat treatment and tempering regime it is possible to obtain grain with a size of 3-5 points. The optimal mode of the heat treatment process was selected, which allows to obtain the minimum grain size of 4-5 balls that is acceptable for ultrasonic testing.

Alloys used for the manufacture of various structures must be strong and easy to process. Under certain conditions, hydrogen can adversely affect the fracture characteristics of most structural alloys. A classic example is hydrogen embrittlement of high-strength martensitic steel, which is the result of a high concentration of hydrogen in the metal. An extremely high internal concentration of hydrogen in such alloys can be created during chemical or electrochemical processing, such as etching, electroplating, and removing coatings used in the production of a particular product. Over time, this hydrogen forms bubbles and cracks on the internal surfaces of grain boundaries or inclusions and causes slow destruction. This type of embrittlement, caused by hydrogen located in the internal volumes of the alloy and developing during the stay of the alloy under external load, is called internal hydrogen embrittlement. This embrittlement is typical for a large number of alloys used in mechanical engineering. The article discusses the features of the origin of hydrogen and the form of its existence in structural alloys. The process of hydrogen embrittlement in alloyed structural steels is studied. The method of performing analysis on the "G8 GALILEO" hydrogen analyzer for structural alloys is adapted and described. The corresponding results of the work and recommendations are given.