| Scraper conveyer,as the core transportation equipment for the implementation of high yield and high efficiency comprehensive mechanized coal mining technology,can not only adapt to all kinds of complex terrain environment,but also play an important role in the transport of coal,coal miner operation guidance and hydraulic support.As a key component of the scraper conveyor,the central trough's wear and failure often leads to multiple faults,shortened service life and other supporting equipment can't run normally,which seriously affects the production efficiency and safety of coal mining.Therefore,it is very necessary to study the tribological characteristics of the central trough.The obtained research results can provide relevant theoretical data support for the design optimization of the central trough and even the complete machine of the scraper conveyor,reduce faults,extend service life,safe operation and other aspects,and have important practical significance and social application value.Based on the characteristics of the material of the middle groove,the sliding wear behavior of the middle groove of different materials is studied,and the influence of the strength level and microstructure of the middle groove material on its sliding wear behavior and wear type is analyzed.The study found that for materials of different strength levels,as the strength level increases,the corresponding sliding wear resistance gradually increases,and the type of wear gradually changes from adhesive wear and abrasive wear to fatigue wear and abrasive wear;for the same For materials with strength levels,the martensite + lower bainite composite structure has better strength and toughness than a single lath martensite structure,and its sliding wear resistance is also better.The wear types are all compound wear under the synergistic effect of abrasive wear,fatigue wear and adhesive wear.However,the degree of abrasive wear and fatigue wear of a single lath martensite structure material is relatively more serious.Combined with the actual service environment of the middle groove of scraper conveyor,the influence of corrosion time,corrosion medium on the corrosion behavior of the middle groove and the influence of corrosion medium on the sliding wear behavior of the middle groove pre-corrosion were studied.It is found that the corrosion rate of NM400 wear-resisting steel is gradually accelerated and the degree of corrosion peeling is gradually intensified with the prolonging of corrosion cycle in acidic medium.Under the same corrosion period and different corrosive media,the NM400 wear-resisting steel has the largest weight loss and the fastest corrosion rate in acidic media,which makes it more susceptible to corrosion.Under different corrosive media,the corrosion morphology of NM400 wear resistant steel shows local pitting corrosion and crack.In acidic medium,the corrosion pitting pit of NM400 wear resistant steel is deeper,and the crack is more,and the corrosion degree is the most serious.Under different corrosion media,the corrosion products of NM400 wear resistant steel are mainly Fe3O4,?-Fe OOH and ?-Fe OOH.In the sliding corrosion wear test,the wear failure types of NM400 wear resistant steel under different corrosive media are mainly corrosive wear,abrasive wear and fatigue wear.The wear and damage degree of NM400 wear resistant steel is more serious in acid medium.In addition,there are some non-uniform pitting pits on the corrosion wear surface of NM400 wear resistant steel in acidic medium,which will aggravate the spalling of the wear surface.In alkaline medium,the lamellar corrosion products on the corrosion wear surface of NM400 wear resistant steel can play a certain protective role and slow down the wear of the matrix.Considering the temperature of the service environment of the scraper conveyor and the frictional heat during operation,the influence of temperature on the sliding wear behavior of the middle groove is studied and analyzed.The study found that at room temperature to 300?,the change of the average friction coefficient of the test steel first increased,then decreased,and then gradually stabilized.At 50?,the average friction coefficient of the test steel is the largest,and the average friction coefficient of the test steel changes slightly from 200 to300?.50??300?,the generation of oxides is the main reason for the decrease of the average friction coefficient of the test steel.At room temperature to 300?,the sliding wear loss of the test steel first increased,then decreased,and then slowly increased again.At 50?,the test steel has the largest sliding wear loss and poor sliding wear resistance;at 150?,the test steel has the smallest sliding wear loss and better sliding wear resistance.At room temperature to 300?,the wear types of the test steel are mainly the synergistic effect of abrasive wear,extrusion deformation wear and trace oxide wear.As the temperature increases,a certain amount of stable attached oxides will be produced during the re-wearing process of the worn surface of the test steel,which can reduce wear to a certain extent.Based on the previous test results,with the aid of EDEM discrete element simulation analysis software,the material transportation process in the middle groove of the scraper conveyor is simulated,and the wear condition of the middle groove under different material characteristics is analyzed.Simulation analysis found that as the wear constant of the middle groove material increases(the strength/hardness decreases),the wear depth of the middle groove gradually increases,and the degree of wear gradually increases.The middle groove shows a characteristic of uneven wear as a whole.The wear degree near the chain channel is the most serious,and this wear characteristic has nothing to do with the material properties of the middle groove.While rationally selecting the material of the middle groove,local optimization of the position near the middle groove chain can effectively improve the uneven wear characteristics of the middle groove,thereby prolonging the overall service life of the middle groove,increasing the utilization rate of materials,and reducing the manufacturing and manufacturing of the middle groove.The cost of repairs. |
PDF Full Text Request