Mathematical model of dynamic processes during frictional hardening of the cylindrical surfaces of parts

The mathematical model of the elastic machine system has been developed, and describes the dynamic processes that occur during the frictional hardening of cylindrical surfaces of parts using a tool with transverse grooves on its working part, which forms a surface hardened metal layer with nanocrystalline structure. Transverse grooves on the working part of the tool increase the intensity of deformation of the surface layer in the contact area of the tool-part and the oscillating processes of the system. Differential equations that describe this process are based on Lagrange equations of the second kind. Based on the solution of the model’s the systems of equations, it is possible to determine the velocity and magnitude of displacement of a special device with autonomous drive of the tool, tool and treatment part during machining, reaction of device supports and spindle unit.

THE USE OF CARBON, HIGH-CHROMIUM STEELS FOR LINERS OF MUD PUMPS AND DRILLING RIGS

The paper shows that high temperature heating (from 1 100 to 1 170 0C) for the subsequent quenching of high-chromium steels of a martensitic-carbide class 95X18 and X12MFL provides structure to the metal base, which consist of high-carbon containing martensite and residual metastable austenite with some carbides. The resulting structure has a high capacity for frictional hardening. Experiments with cold processing treatment of the analyzed steels also showed that after high-temperature quenching with subsequent cooling to -70 0C, sufficient cooling martensite is formed, which in combination with residual metastable austenite, provides an increase of abrasive wear resistance by 25 % compared to high temperature annealing.

HEAT TREATMENT OF WEAR RESISTANT STEELS FOR DRILLING RIG PUMPS

The influence of heat treatment different options on wear resistance of steels of trademarks Kh12MFL and 150KhNML applied in manufacturing of mud pumps is reviewed. It is shown that the steel Kh12MFL is superior in wear resistance than the steel 150KhNML at abrasion. The martensite-carbide structure of both steels obtained at quenching at normal temperatures, from 900 to 1000 0С, ensures a good hardness (61-64 HRC). The analysis of the residual austenite contents influence on wear resistance was also made. It was determined that residual austenite formed after high temperature quenching (110-1170 0С) was metastable and had a tendency to transform into carbon containing martensite of deformation in the process abrasive wearing. This allowed steels to have a maximum wear resistance because of ensuring a high ability to frictional hardening of the working surface.