| Wear and tear is the most common form of material failure in life.With the rapid development of modern agriculture,agricultural mechanization has been popularized throughout the country.Plowshare is the main wear part of scarifier.Due to the large area of cultivated land in China,the economic loss caused by the wear of Plowshare is huge.The plowshare is operated on sand,loam and rock at the bottom,and its working conditions are relatively severe.At present,China's plowshare still relies on a large number of imports.Therefore,it is of great social and economic significance to develop a new type of wear-resistant material which is easy to control and cheap,to improve the service life of the plowshare and to realize the localization of the wear-resistant plowshare.According to the working conditions and performance requirements of plowshare,this project uses multi-element medium carbon low alloy steel as the basic material,and designs 4groups of chemical composition and 16 groups of isothermal quenching heat treatment process schemes.Through the structural analysis and performance test of samples obtained from different composition and process,a group of optimal composition ratio and a group of most appropriate heat treatment process are determined Based on the analysis of the fluid temperature field,solidification temperature field and porosity of the plowshare,the best casting process plan of the plowshare was determined,and the pilot production was carried out.The results show that with the increase of carbon content,the hardness of experimental steel increases gradually,while the impact toughness decreases.When the carbon content is0.480%,the comprehensive mechanical properties are the best;with the increase of isothermal quenching temperature and time,the number of lower bainite in experimental steel increases,the structure of lower bainite becomes coarser,the hardness decreases,while the impact toughness increases,and the wear resistance decreases.After 920?×1.5h+290?×3h heat treatment,the Rockwell hardness of experimental steel can reach 49.2hrc,the impact toughness can reach 167 J/cm~2,and the loss weight of experimental steel is 0.32037g after 2 hours wear time under the load of 1kg,which can meet the working condition requirements of Plowshare in sandy soil.Under the condition that the preheating temperature of the 15 mm thick chilling material is200?,the medium carbon bainitic steel plowshare prepared by chilling was installed in Jiangbei Farm of Jiamusi,and the effect is remarkable.After cultivation of 100 mu,the wear loss of plow tip is about 1mm,and its service life is 2-3 times longer than that of ordinary high manganese steel plowshare,which is low in cost and simple in technology.It is suitable for mass production and can better replace 65Mn Steel plowshare. |
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