One of the key processes that largely determines the quality of a permanent precision joint formed in the solid state under pressure and heat, which belongs to the class of solid-state topochemical reactions and proceeds in three main stages, is the formation of actual contact, which transitions to a state of physical contact (stage one) at a certain ratio of the level of thermal strain and the contact area. The latter is formed due to plastic strain and the shape change of microprotrusions on the surfaces being joined, which alters the mechanical properties of the resulting contact pads and the near-contact volume of the metal microprotrusions. To develop valid process parameters for producing a high-quality joint, it is important to establish the influence of temperature, pressure, and the height of microroughness of the contacting surfaces of the materials being joined on the kinetics of individual stages of the solid-state topochemical reaction under thermal strain. This paper presents the kinetic dependencies of contact formation during the period of active strain or active loading between dissimilar crystalline materials using the example of synthetic single-crystal corundum – MB copper (oxygen-free) and provides their physical and mathematical justification. Knowledge of the kinetic laws governing the formation of actual contact and the transition to physical contact at a certain ratio of the level of thermal strain action and stress state (the ratio of normal and tangential microstresses of the 2nd kind on the surface of contact pads and in the volume of microprotrusions) and the occurring mechano-physical-chemical processes on the surface of the forming contact pads and in the volume of microprotrusions, allows for a more rational consideration, construction and implementation of the technological process for obtaining a precision detachable (contact of the traction sheave with the cable) or permanent connection of materials in a wide variety of combinations, including those with different nature of chemical bonds and resistance to plastic strain, and will also allow for the consideration and assessment of the role of microstresses of the 2nd kind in the occurrence and propagation of microcracks in the grain of the metal and the provision of recommendations for the prevention of sudden brittle failure of welded building metal structures.