РОЗРОБКА МЕТОДУ НЕРУЙНІВНОГО КОНТРОЛЮ ЯКОСТІ ЗАГАРТОВАНИХ ГІЛЬЗ ЦИЛІНДРІВ АВТОТРАКТОРНОЇ ТЕХНІКИ

Abstract

The main part of tractor engines is the cylinder liner, which depends on the life of the machine as a whole. It is made of gray cast iron (SCh20 DSTU 1412-85) with the addition of alloying elements and subjected to the working surface of HDTV hardening. Now quality control is carried out by destructive methods (assessment of hardness, durability, structure) on specially cut templates on 1 piece. from a party to 80-100 pieces of each melting. Such control does not ensure the reliability of products, both in the quality of the base metal and heat treatment. The solution to this problem is possible by developing non-destructive quality control of each product in different periods of the process process with assessment of the properties and stress level of both the base metal (corresponding to the outer surface) and the hardened layer (inner working surface). The intensity of cylinder wear depends on the conditions of friction of the cylinder-piston ring, which are affected by the design features of the engine (power, speed, compression ratio, cooling system, as well as fuel supply and combustion, air and oil purification system), quality of fuel and oil, operating conditions and wear resistance of the cylinder material. Wear of cylinders during friction paired with a piston ring during engine operation occurs as a result of a combination of many processes occurring simultaneously: destruction of microprojections of surfaces that are destroyed by repeated plastic deformation during engagement, as well as the destruction of tired origin; setting of the material of the microprojections with subsequent deep tearing of the metal particles during the destruction of the setting unit; accumulation of abrasive particles that contribute to the intensification of wear; abrasive action of dust particles, contribution products, solid inclusions on the surface of collapsing bodies; chemical corrosion under the influence of high temperatures of gaseous products of fuel combustion; electro-chemical corrosion from the action of acids formed during the dissolution of gaseous products in condensed water vapor on the walls of the cylinders.