| Medium manganese steel is a wear resistant material developed on the basis of traditional high manganese steel,which overcomes the disadvantage of poor work-hardening sensitivity for high manganese steel and exhibits the excellent impact wear-resistance.In this paper,the modified medium manganese steel plate of BTW was obtained by micro-alloying design,controlled heat treatment and composite modification treatment.The self-strengthening design of the deformation induced martensitic transformation is achieved under the medium or low-impact loads.Especially when a hardened surface material is worn away,the newly exposed surface of the substrate material has been rapidly enhanced,to achieve the natural combination of high surface hardness and high toughness substrate.The static corrosion,sliding frictional corrosion,corrosive abrasive wear and impact erosion abrasive wear behaviors in simulated mine water conditions were studied in this paper.The strengthening mechanism of medium manganese steel was further discussed.The main conclusions of the paper are as follows:The uniform corrosion weight loss and corrosion rate of manganese wear-resistant steel of BTW under different corrosion solutions and different corrosion cycles are lower than those of the martensitic wear-resistant steel,and the corrosion weight loss under the acidic conditions is the largest.The corrosion mechanism of BTW steel mainly includes the intragranular corrosion and local pitting corrosion.The number of pits pitted on surface of martensitic steel is more and deeper,and a large number of corrosion grooves with different depths are found at the same time.Under the same corrosive medium,the open circuit potential,corrosion potential and corrosion current of BTW steel are lower than that of martensitic steel.Impedance spectrum analysis shows that both steels are controlled by the electrode reaction.The radius of capacitive arc of BTW steel in all three corrosive medium is higher than that of HD450 steel.Among them,the acid medium has the smallest arc resistance,and the impedance value decreases most,and the corrosion degree is the highest.The friction coefficient of BTW steel and HD450 steel in sliding friction corrosion experiment decreases with the increase of normal load.Under the same conditions,the friction coefficient of BTW steel is slightly larger than that of HD450 steel,but the wear volume is much smaller than that of HD450 steel.The corrosion potential and corrosion current of both steels increase with the increase of normal load.The corrosion potential and corrosion current of BTW steel are all lower than that of HD450 steel.The impedance value decreases as the load increases.The impedance of BTW steel is significantly higher than that of HD450 steel.The sliding friction corrosion appearance of the two steels is mainly based on a large number of furrows and a small number of fatigue spalling pits,among which the pits of HD450 steel are more pitted,there are obvious corrosion grooves,and some of the corrosion products,the corrosion degree of BTW steel is lighter and shows better abrasion resistance.Under the condition of three kinds of mine water corrosive media,the sliding corrosion wear and corrosion wear rate of BTW steel are lower than that of martensitic wear-resistant steel.Deformation twin strengthening is one of the main causes of work hardening.The hardness of the subsurface layer under the three corrosive media reaches 528 HV,the depth of the hardened layer is about 500μm,and the hardness of the wear hardened layer exceeds that of the martensitic steel.The corrosion wear profile of BTW steel is mainly manifested in different shades of furrows and a small amount of fatigue spalling pits;HD450 steel has deeper furrows,more and more fatigue spalling areas,and both steels have unevenly distributed corrosion pits.The corrosion wear of BTW steel in agitated corrosive abrasive wear is smaller than that of martensitic wear-resistant steel.The obvious local corrosion characteristics can be found in the wear morphology.Corrosion products are accumulated in the corrosion wear surface.HD450 steel has deeper furrows and more corrosion products.Under the conditions of three kinds of mine water corrosion media,the impact erosion wear loss and wear rate of BTW steel are lower than those of martensitic wear-resistant steel.And the wear loss under acidic conditions is the highest.The impact wear of BTW steel sub surface layer 50μm hardness of 525 HV,far more than the substrate hardness,hardened layer depth of 3000μm,showing a good impact load work hardening performance.The impact corrosion wear mechanism of BTW is mainly manifested in the cutting wear and chisel wear of the furrows.At the same time with the local fatigue peeling,the furrow grooves and chisel pits of HD450 steel are more and deeper,and the impact corrosion wear and damage is relatively deepened.Under the condition of three mine water corrosive media,there are dislocation tangles,twins and martensite transformation structures in the wear layer of BTW.The average martensite transformation volume is about 32%.It can be considered that the wear resistance of BTW steel is enhanced.It is a composite strengthening mechanism including dislocation strengthening,twin strengthening,and deformation-induced martensitic transformation strengthening. |
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