Improving the contact strength of V-belt pulleys using plastic deformation

2022

The paper presents experimental studies and obtained statistical models of the influence of processing modes on the quality of the surface layer and cyclic durability of reinforced machine parts. It was established that the main influence on the strengthening effect, the depletion of the plasticity reserve of the metal and the formation of residual stresses are exerted by the effective gap of the cutter, the effective tension and the profile radius of the roller. The results showed that dimensional combined running-in ensures high cyclic durability of strengthened parts under conditions of multi-cycle fatigue load, which reaches 8 million cycles, which is 3.5 times greater than the durability of a non-reinforced part and 1.5 times - the durability of a part strengthened by surface plastic deformation Studies have shown that the greatest cyclic durability of the part is ensured at the minimum values of the effective cutter gap, the maximum values of the profile radius and the value of the effective roller tension of 0.6 mm, which corresponds to the degree of exhaustion of the plasticity reserve by processing with dimensional compatible rolling Ψ ≈ 0.65. On the basis of the results of theoretical and experimental studies, a methodology and algorithm for the design of processing technology by dimensional combined running-in were developed. A computer program has been developed that allows you to calculate the quality of the surface layer and cyclic durability of the part based on the specified modes, as well as to assign rational processing modes that ensure the specified quality of the surface layer and cyclic durability. Based on the results of research, a technological process of strengthening processing of machine parts by combined dimensional running-in has been developed, which allows forming compressive residual stresses in the surface layer of the processed part, as well as increasing productivity up to 2 times while maintaining or improving the specified quality parameters of the surface layer of the processed part.

Section: Research Resultsmentioning

confidence: 99%

Study of the Stress-Strain State of the Surface Layer During the Strengthening Treatment of Parts

2022

“…The amount of wear of the sock in plowshares, restored by welding tires made of steel 45 with sormite surfacing and vibration hardening, respectively, 1.2 and 1.1 times less than in plowshares made of steel L-53 and steel 65G, subjected to vibration hardening. Wear on the wall thickness of plowshares, restored by welding tires made of steel 45 with surmaite surfacing and vibration hardening, respectively, 1.54 and 1.2 times less compared to the wear of plowshares made of steel L-53 and steel 65G subjected to vibration hardening [9].…”

Section: Fig 2 Curves Of Changes Of Efforts On a Blade Depending On A...mentioning

confidence: 98%

Investigation of the process of surfacing and vibration deformation during the restoration of plowshares and discs of tillage machines

2021

The analysis of ploughshare wear is given in the article and the characteristic requirements to the technological process of restoration of their worn surfaces are established. The choice of restoration technology was justified taking into account the nature of defects and the degree of wear of the working surfaces of cutting elements, their material, hardness, design parameters, accuracy of processing and cost of repairs. Quantitative and qualitative assessment of the reliability of the cutting elements of the plowshares of tillage machines, restored by different methods, was carried out by comparison with the same indicators of the new ones. Analysis of the condition of restored and new plowshares was carried out on their wear in the process of laboratory and operational tests. Laboratory researches on strengthening of plowshares by a method of vibration deformation were carried out on the specially made installation consisting of the following main knots: vibroexciter IV-105 with adjustable unbalance; hydraulic lifting systems; auxiliary equipment. The deformation rate was regulated by a V-belt double-circuit variator of the pump drive. To study the effect of normal and vibration load on the strength characteristics of the processed material, the study was performed on samples-models, and then - on the details. The samples were new plowshares, experimental studies on which provided the identity of the nature of the course of wear of their cutting elements. It is experimentally established that the hardness of the material on the surface of the blade, depending on the technological process of restoration was: restored by welding tires of steel 45 with surmaite surfacing and vibration hardening - 71-74 HRC; new plowshares made of L-53 steel, subjected to vibration hardening 66-68 HRC; new from 65G steel and strengthened by vibration deformation 57-59 HRC

“…When approaching one electrode of a given shape (tool) to another (workpiece), the surface of the latter will take the shape of the surface of the first. The productivity of the process and the quality of the resulting surface are mostly determined by the parameters of the electric pulses (their duration, tracking frequency, pulse energy) [7].…”

Section: Fig 4 Profilometer "Surtronic 25"mentioning

confidence: 99%

Increasing the Wear Resistance of Restored Car Parts by Using Electrospark Coatings

2023

The work scientifically substantiates the application of effective technology for the restoration of worn car parts by applying new electrospark coatings based on electroerosion nanomaterials. The developed technology is characterized by technological flexibility, cheapness, simplicity, does not require the use of expensive and scarce materials and equipment, and also meets the requirements of environmental safety. The proposed technology can be used to restore a wide range of parts for cars, tractors and other machines. Experimentally established dependences of the effect of the properties of electroerosive materials on the properties of electrospark coatings of restored car parts. It is shown that the content of nano-sized particles in the electrode material contributes to the improvement of the physical and mechanical properties of electrospark coatings. The dependences of the influence of the properties of electrospark coatings on the resource of restored car parts were experimentally established. It is shown that the resource of the shafts of turbocompressors restored according to the recommended technology is higher than the resource of new shafts by an average of 1.5 times. Experimentally established rational modes of applying wear-resistant coatings to worn shafts of turbocompressors, which provide the necessary complex of physical and mechanical properties of the coating and the given resource of the shafts as a whole (rotation frequency of the part, min - 1 - 50; electrode feed, mm/min - 0.4 ... 0.5). The characteristics of wear resistance of electrospark coatings of turbocompressor shafts, obtained using electroerosion nanomaterials, were studied. It is shown that the average value of the coefficient of friction of the electrospark coating was 0.146 instead of 0.486 without coating, which is 3.3 times lower. According to the results of production tests, it was found that the duration of operation of the turbocharger, with the restored method of electrospark treatment with a nanostructured electrode shaft, increased by 2.1 times compared to a new industrially manufactured shaft. Thus, when abrasive material containing a fraction of 0.1...0.4 mm was introduced, the operating time of the turbocompressor with a restored shaft was 12.8 hours, and the operating time of the turbocompressor with a new shaft without wear of the nominal size was 8.1 hours.