M23C6 Carbides Research Articles

On the normal and inverse Portevin–Le Chatelier behavior in hot rolled Inconel 617 superalloy

In the present study the effect of hot rolling process on the normal and inverse Portevin-Le Chatelier behavior was investigated. The hot rolling process was carried out at 950 °C, 1050 °C, and 1150 °C to capture the effect of thermomechanical process on elimination or postponing of dynamic strain aging phenomenon in Inconel 617 during subsequent deformation process. The tensile test was performed within the temperature range between 350 °C and 750 °C at a constant strain rate. The microstructure evaluations were carried out by optical microscope and scanning electron microscope. The serrated flow was observed in the stress-strain curves at specific temperatures. The type of serrations changed from type B to type C at the strain rate of 5 × 10−4 s−1 as the tensile test temperature was enhanced. The change of normal PLC effect to the inverse PLC effect was intensified when the hot rolling temperature was increased; Hence, the inverse PLC effect was observed at 750 °C in the sample which had rolled at 1150 °C. Whilst the serrated flow was not seen at 750 °C in the samples which had rolled at 950 °C and 1050 °C. The critical strain, for the initiation of the serrated flow was found to reduce with the increasing temperature of hot rolling from 950 °C to 1150 °C. After tensile test, the microstructural evaluations revealed the proven substantial role of precipitation of γ′ and the Cr-rich M23C6 carbides in pinning of the mobile dislocations, which led to the inverse PLC effect.

Formation and evolution behavior of M6C carbide in a Ni-W-Cr superalloy

The carbide formation and evolution of a new Ni-26W-6Cr (wt.%) superalloy for the 800 °C molten salt reactor (MSR) was investigated by homogenization heat treatment tests and the effect of carbide characteristics on the plastic deformation behavior was further investigated by isothermal simulated tensile tests. The plastic deformation properties of Ni-26W-6Cr superalloys are associated with the morphological characteristics and distribution of carbides. During homogenization at 1220 °C, a unique phenomenon was discovered, that is, the precipitation of the acicular carbide. The XRD, TEM and EBSD results show that this acicular carbide is distributed along the particular crystal plane of the γ matrix. Based on crystallographic theory, there is no obvious orientation relationship between the carbide and the γ matrix, which is prone to cracking along the carbide/γ interface during deformation. After homogenization at 1220 °C for 48 h, the acicular M6C carbides dissolved and the discrete granular M6C carbides distributed diffusely at the grain boundaries can relieve stress concentration and strengthen the grain boundaries, reducing the deformation resistance of the alloy, effectively inhibiting grain boundary slip and thus inhibiting crack propagation, and improving the tensile strength and plasticity of the material.

Analysis of the As-Cast Microstructure and Properties of the Ni-Based Superalloy MAR-M247® Produced Via Directional Solidification

The presented research investigates MAR-M247® Ni-based superalloy castings produced via directional solidification at various mold preheating temperatures (1510, 1566 °C) and withdrawal rates (3.4, 5.0 mm/min). Casting analyses were carried out via thermodynamic simulations, differential scanning calorimetry (DSC), X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), scanning transmission electron microscopy (STEM), and tensile testing. On DSC curve, four effects have been registered during cooling: liquidus (1337 °C), formation of eutectic γ − γ′ (1315 °C), precipitation of Ni7(Hf, Zr)2 (1244 °C), and M5B3 borides (1201 °C). The castings’ primary and secondary dendrite arm spacing decreases with increasing withdrawal rates for both shell mold temperatures. The dendritic regions of the castings are characterized by a relatively homogenous microstructure, consisting of γ′ precipitates surrounded by the matrix, with a mean size in the range of 0.437 to 0.481 μm, depending on the casting parameters. In the interdendritic spaces, γ − γ′ eutectic, MC carbides, M5B3, Ni7(Hf, Zr)2, and M3C2 phases were identified. The ultimate tensile strength of the produced castings was in the range of 970 to 1088 MPa.

Ti and Nb alloying effect on the mechanical property of M7C3 carbide in 9Cr18Mo stainless steel: First-principles calculation

The effect of Ti and Nb alloying on the mechanical property of M7C3 carbide has not been thoroughly explored till date. Based on first-principle calculations, several parameters such as binding energy, mechanical properties and electronic structure were investigated and calculated systematically in this work. The results show that the Ti and Nb preferably substitute the Cr sites instead of Fe, due to the smaller formation enthalpy associates with Cr sites. Also, the substitution of Cr with Ti and Nb atoms lead to improve ductility of Fe3Cr4C3 and Cr3Fe4C3 phases. The ductility of the carbide phases could be improved as the G/B ratio decreases by alloying M7C3 carbide with Ti and Nb. The Cauchy pressures involved in substitution of Cr by Nb or Ti are larger than the pressures associated with the substitution of Fe in Cr3Fe4C3 or Fe3Cr4C3 phases. Furthermore, the initial anisotropy degree A increases to 0.9–1.1 after alloying with Ti or Nb. Mulliken population shows the presence of large amount of metallic bonds when the Cr is substituted with Ti or Nb elements in M7C3 carbide. The DOS shows a drop in intensity peaks after Ti or Nb alloying process. Thus the improved ductility associated with the Ti or Nb alloying process results from the interactions between Ti–Cr or Nb–Cr metallic bonds.

Corrosion Resistance Enhancement of Selective Laser Melted Cost‐Effective Interstitial Medium‐Entropy Alloy via Deep Cryogenic Treatment

An economically interstitial FeMnCrNiCu medium‐entropy alloy (MEA), which exhibits preferable corrosion resistance in 3.5 wt% NaCl solution, is fabricated by selective laser melting (SLM). Compared with annealing, which is one of the posttreatments for additive manufacturing, deep cryogenic treatment (DCT) also contributes significantly to the alloy properties and is expected to improve corrosion resistance. Herein, the corrosion behavior of SLM‐MEA after DCT in 3.5 wt% NaCl solution is investigated. DCT improves corrosion resistance by promoting the uniform distribution of precipitates in SLM‐MEA and changing the cation ratio in the passive film. After DCT, the corrosion current density of the SLM‐MEA in original and annealed state decreases by 27.07% and 62.69%, respectively. The annealed SLM‐MEA exhibits the worst corrosion resistance as a result of the precipitation of continuous Cr‐rich M23C6 carbides at grain boundaries. The face‐centered cubic structure of MEA does not change after annealing or DCT. Significantly, the number, size, and distribution of the precipitates are greatly affected. DCT after annealing promotes the uniform diffuse distribution of M23C6 carbides and nanoscale Cu‐rich particles while increasing the Cr+Ni/Fe+Mn ratio in the passive film, resulting in a significant improvement in corrosion resistance.

Effect of C content on microstructure and hot deformation behavior of a Ni-based superalloy

In this work, isothermal compression tests of a Ni-based superalloy were carried out at γ′ sub-solvus (1140 ℃) and γ′ super-solvus (1170 ℃) temperatures under a true strain 0.693. The effect of C contents (0.01 wt%, 0.04 wt% and 0.08 wt%) on the microstructural evolution and hot deformation behavior of the alloy was investigated. The formation of MC carbide is closely related to C content. Besides, the initial grain size decreased slightly with the increase of C content due to the effect MC carbides. During compression deformation at 1140 ℃, the peak stress increased with the increase of C content. When deformed at 1170 ℃, the 0.04 wt% C alloy has the lowest peak stress, because of the acceleration effect on dynamic recrystallization DRX by MC carbides. However, the 0.08 wt% C alloy has the highest peak stress, the dislocation density also increases with the number of MC carbides increase，which caused high working hardening rate and increased the peak stress in 0.08 wt% C alloy. The discontinuous dynamic recrystallization (DDRX) is the dominant mechanism during deformation at 1140 ℃, while the DDRX and continuous dynamic recrystallization (CDRX) occurred at the same time when deformed at 1170 ℃.

Comparative study on microstructure and mechanical properties of a novel nano-composite strengthening heat-resistant steel and two typical heat-resistant steels

In this study, a new nano-composite strengthening austenitic heat-resistant steel designed for ultra-super critical (USC) thermal power plants was analyzed in comparison with the traditional H3RC and S30432 heat-resistant steels to assess its reliability. The microstructure, precipitates, hardness, tensile property and low cycle fatigue behaviors of the three steels at room temperature and service temperature were characterized. The results show that the SP2215 has finer grains, higher twin density, more primary MX, NbCrN and M23C6 precipitates compared with the HR3C and S30432 steels. The main precipitates in the steels after solution treatment are secondary (Nb, V)(C, N) phase (MX). The subsequent aging treatment of the SP2215 steel results in precipitation of the M23C6 carbides at the grain boundaries and Cu-rich phase inside the grains. As a result, the SP2215 steel shows higher Vickers hardness, tensile and fatigue strength (400 MPa) at room temperature than the other two steels. Transgranular fracture is the dominant tensile fracture mechanism of the three steels at room temperature, while intergranular cracking becomes the main fracture mode at high temperature due to precipitation of the continuous M23C6 at the grain boundaries. At the temperature of 700 ºC, fatigue strength of the SP2215 under a peak stress lower than 450 MPa decreases only a little.

Microstructural study of keyhole TIG welded nickel-based superalloy G27

The weld fusion zone (FZ) microstructure obtained after keyhole tungsten inert gas welding and post-weld solution heat treatments (PWSHTs) of a new nickel (Ni)-based superalloy called G27 is studied, and the grain growth behavior in the base material (BM) during PWSHTs is characterized. Microsegregation-induced interdendritic microconstituents in the FZ of as-welded G27 are identified by analytical (scanning) transmission electron microscopy ((S)TEM) as niobium (Nb)-rich MC carbides, Nb-rich Laves eutectic constituents, γ’ and η phases. The Laves eutectics are generally considered brittle and can adversely affect the mechanical properties of the weldment; thus, an hour PWSHTs were performed at 954 °C–1060 °C to eliminate the γ/Laves eutectics. PWSHT up to 1010 °C results in only partial removal of Laves eutectics with an excessive formation of η phase surrounding the Laves phase. Complete dissolution of Laves eutectics with no η phase formation is achieved after a PWSHT is performed at 1060 °C. Relative to INCONEL® alloy 718, the complete elimination of the γ/Laves eutectic constituents in the FZ of G27 through a PWSHT was proven to be achieved without causing excessive grain growth in the BM, which could be due to the pinning effect of the fine molybdenum (Mo)-rich precipitates, that are formed during solution heat treatment and identified as hexagonal close-packed phase particles through extensive (S)TEM analyses.

Effect of Heat Treatment Schedules on Creep Performance of Ni-Based Superalloy Mar-M247 at 871 °C and 250 Mpa

The effects of heat treatment (H1 and H2) on the creep behavior and microstructures of Mar-M247 at 871 °C/250 MPa are studied. The results show that the as-cast microstructure is composed of eutectics, γ phase, γ’ phase, MC and M23C6 carbides, while new M6C appears in heat-treated microstructures, indicating the transformation of carbides after heat treatments. The Mar-M247 is excellent, with over 1500 h of creep life, and H1 is 48% higher than H2. The addition of post-brazing and diffusion heat treatment in H2 is detrimental to creep resistance; the two steps promoted the transformation of MC into M23C6 in advance. The increase and coarsening of M23C6 would consume more γ-phase-forming elements, weakening the solution strengthening at grain boundaries. As a result, the resistance of the grain boundary and γ/γ’ interface to dislocation motion is significantly reduced, leading to the cracks’ initiation and propagation along the grain boundaries.

Microstructures, mechanical properties, and oxidation behavior of in-situ ultra-fine duplex carbides reinforced Ni-based superalloy composites

A Ni-based superalloy composite (FTSC) was successfully prepared by spark plasma sintering with Ti3SiC2 (15 vol%) and FGH97 alloy powders as precursors. During sintering, the weakly bonded Si layers de-intercalate from Ti3SiC2 and the remaining TiC is eroded by the elements of the matrix, which promoted in-situ precipitation of MC and M6C carbides. MC with core-shell structure builds up a semi-coherent interface with the alloy matrix: (1¯11¯)γ/γ'‖(11¯1)MC with [110]γ/γ'‖[110]MC. The Zener pinning effect of ultra-fine duplex carbides results in refinement of alloy grains and notably improvement in mechanical strength. Comparing to the alloy FGH97, the composite FTSC possesses 55% higher microhardness, 100% higher compressive yield strength and 92% higher flexural strength. On the other hand, the refined grains ensured fast formation of a protective alumina scale at surface, which provides high oxidation resistance for the composite.

A novel high nitrogen hot-work die steel 3Cr5Mo2SiVN achieving excellent hardness-strength-toughness balance

A novel high nitrogen hot-work die steel 3Cr5Mo2SiVN was manufactured by pressurized induction melting, possessing excellent hardness-strength-toughness balance under conventional heat treatment process. The results indicated that 3Cr5Mo2SiVN steel exhibited better hardness-toughness synergy compared with H13 steel. Meanwhile, its impact energy and elongation were improved by ca. 50% and 13% compared with H13 steel with similar hardness. The achievement of superior toughness of 3Cr5Mo2SiVN steel could be attributed to the following reasons: firstly, the higher fraction of operators 1 and 2, more uniform and refined close-packets and Bain groups as well as smaller effective grain size obtained a higher ratio of high angle grain boundaries, which resulted in the more changes of crack propagation direction and thus an increase of energy absorption. Secondly, the smaller size and number density of undissolved M(C, N) carbonitrides distributed along the prior austenite grain boundaries required greater tensile stress and then reduced grain boundary brittleness. For the strengthening mechanism, the precipitation strengthening increment was mainly provided by M(C, N) carbonitrides and M3C carbides for 3Cr5Mo2SiVN steel, and MC carbides for H13 steel, respectively. The smaller effective grain size and higher interstitial atom (C and N) content in the martensitic laths of 3Cr5Mo2SiVN steel were crucial factors in enhancing its strength.

Microstructural evolution and mechanical response of 304 stainless steel joint diffusion-bonded with micro-deformation

This study explicates the microstructural evolution and mechanical response of the joints of 304 stainless steel developed through micro-deformation diffusion bonding. The diffusion-bonded interface comprised the refined grains embedded with the intergranular M23C6 carbides and complex oxides, which was induced by dynamic recrystallization at 950 °C. The refined grains persisted at the bonding temperature of 950 °C due to the dynamic equilibrium of dislocations and pinning effect of intergranular particles. As the bonding temperature was raised to 1000 °C, the combination-grow up of grains was initiated caused by sufficient thermal activation and complete dissolution of M23C6 carbides. The interface was entirely migrated at 1050 and 1100 °C, and notably, the migration of interfacial grain boundaries played a greater role in diffusion bonding with an increase of bonding temperature. The interface with refined grains permitted a high joint strength (or impact load), while was incompetent to enhancing plasticity and particularly impact toughness. The migrated interface, in contrast, was provided with exceptional plasticity and impact toughness, attributed to its enhanced resistance to crack propagation. The joint prepared at 1050 °C for 60 min exhibited the optimum combination of ultimate tensile strength, fracture elongation, and impact toughness, and the ductile fracture was observed passing through the substrate instead of along the interface. In addition, the comprehensive performance of joints was degraded when the grains were excessively coarsened at 1100 °C for 60 min.

Tensile properties and deformation mechanisms of a solution treated Ni–Fe-based alloy at high temperatures

This study investigated the high-temperature tensile properties and deformation mechanisms of a solution treated Ni–Fe-based alloy ranging from 600 to 750 °C. The solution treated GH4070P (HT700P) alloy exhibits superior yield strength of 490 MPa and ultimate strength of 593 MPa at 700 °C. The major carbides in the alloy are the blocky MC and discrete-distributed M23C6. The MC and M23C6 carbides at the grain boundaries (GBs) can impede crack propagation, yet concurrently intensify the stress concentration. The transgranular and intergranular fractures are observed. Above 700 °C, micro-cracks emerge around M23C6 carbides at GBs and then are interlinked to form lengthy secondary micro-cracks, resulting in the intergranular fracture. The precipitation of γ′ precipitates during tension at 700 and 750 °C confers the alloy to a higher strength.

Effect of interstitial carbides on tribological properties of Co21Cr21Fe21Ni21V14.5C1.5 high entropy alloy at elevated temperature

High-entropy alloys (HEAs) with high wear resistance at elevated temperatures are desired for applications like turbine engine blades and internal combustion engines. By reducing the proportion of transition metal elements, the interstitial carbide in the form of doped non-metallic element C can reduce the preparation cost of HEA and improve its mechanical properties. The effect of 1.5 at% carbon doping at different sintering temperatures on microstructure, mechanical properties, and high-temperature tribological behavior was systematically investigated. The compressive strength and strain rate of C-doped HEAs sintered at 1200 °C were 969 ± 21 MPa, 8.43 ± 0.36%, which was improved by solution strengthening and carbide pegging dislocations. The wear mechanisms of C0 alloy at high-temperature are mainly oxidation wear, adhesion wear and delamination wear, while the wear mechanism of C10 alloy is mainly abrasive wear, adhesion wear, fatigue wear and oxidation wear. The combined effect of VC, M23C6 and M7C3 carbides and σ phase plays the role of anti-wear lubrication at RT∼800 °C, and the tribo-chemical reaction generates Cr2O3, NiCr2O4, NiO, and other compounds with high-temperature stability and oxidation resistance to form a thin dense oxide glaze layer, resulting in better anti-wear and friction reduction performance of C-doped alloy than undoped alloy.

Evolution of microstructure and 800 °C/294 MPa stress rupture property of cast Ni-based superalloys during long-term thermal exposure: Role and behavior of primary MC carbide

The role and behavior of primary MC carbide and their effects on the microstructure and stress rupture property of the cast Ni-based superalloys during long-term thermal exposure at elevated temperature are systemically investigated in this work. It is found that the chemical compositions of primary MC are proportional to the Nb/Ti and (Ti + Nb)/(Mo + W) ratios of alloys. During long-term thermal exposure, the thermal stability of primary MC can be quantitatively evaluated by its decomposition degree defined as Dt=(V0-Vt)/V0 × 100%, which is closely associated with the Nb/Ti and (Mo + W)/Cr ratios of alloys. The decomposition process, degree, form and mechanism of primary MC are revealed in detail. The STEM observations with the EDS analyses show that primary MC decomposition is an inter-diffusion process of elements between the primary MC carbide and γ matrix, which can increase the volume fraction of γ' phase, restrain the precipitation of topologically close-packed (TCP) phases and promote the coarsening of grain boundaries (GBs). The combination of these microstructural evolutions, together with the appropriate Al + Ti + Nb and W + Mo contents in the matrix, eventually results in a remarkable improvement in the stress rupture property of long-term thermally exposed cast Ni-based superalloys.

Influence of Tempering Temperature on Abrasive-Wear Performance of High-Chromium-Based Multicomponent White Cast Iron

Recently, high-Cr multicomponent white cast iron after quenching is known to have superior abrasive-wear resistance. However, this material is prone to cracking due to the precipitation of very hard carbides resulting in very limited application. However, the cracking tendency might be reduced by appropriate tempering temperature. Therefore, the three-body abrasive-wear resistance of 18 wt.% and 27 wt.% Cr based on 3 wt.% Mo, W, V, and Co with different temperatures of tempering was studied. These are abbreviated as 18Cr MCCI and 27Cr MCCI. The tempering temperature range was 653–813 K with an interval of 20 K after the quenching process. The quenched specimens were used as comparison materials, and three tempered specimens were selected. Thus, there are quenched (Q), quenched-tempered at low temperature (TLT), quenched-tempered at medium temperature (TMT), and quenched-tempered at high temperature (THT) specimens. From the results, it can be known that the wear resistance of the material decreases as Cr percentage and tempering temperature increase. Therefore, the 18Cr MCCI Q has better wear performance than specimens of other conditions. Yet, different results occur in the group of 27Cr MCCI. The material is more wear-resistant after tempering despite the lower hardness of the material. This might be owing to the higher fracture toughness of the M7C3 carbide, which is higher after the tempering process compared with quenching only. Therefore, it can be said that it is important to maintain the hardness of the material to achieve better wear resistance. However, in materials containing large M7C3 carbides, the fracture toughness of carbides should also be considered.

Microstructural evolution and mechanical properties of 60Si2CrVNb spring steel under quenching-tempering heat treatment process

This study investigated the evolution of microstructure and mechanical properties of 60Si2CrVNb spring steel under different quenching and tempering processes. The morphology of martensite, precipitate phases, and carbides, as well as the analysis of mechanical properties, were examined. The results revealed that the highest ultimate tensile strength (2260 MPa) and yield strength (2091 MPa) of 60Si2CrVNb spring steel were achieved through austenitization at 900 °C and subsequent tempering at 350 °C, which is related to the maximum dislocation strengthening effect. The optimal combination of mechanical properties for 60Si2CrVNb spring steel was obtained by quenching at 900 °C for 30 min and tempering at 400 °C for 90 min. Under these conditions, the steel exhibited an ultimate tensile strength of 2084 MPa, yield strength of 1846 MPa, elongation of 10.8%, and area reduction of 41.5%. Increasing the quenching temperature resulted in the gradual dissolution of undissolved carbides, an increase in the average grain size of austenite, coarsening of martensite, and an initial increase and subsequent decrease in tensile strength and plasticity. Furthermore, the fracture type transformed from ductile fracture to mixed fracture of ductile and brittle. On the other hand, the increasing tempering temperature led to a decrease in dislocation density and gradual decomposition of martensite lath boundaries. Additionally, the type of carbides changed from small-sized M2C and MC carbides to large-sized M3C, M7C3, and M23C6 carbides. As a result, the tensile strength of the steel decreased significantly, while its plasticity steadily increased. Moreover, the fracture behavior transformed from brittle fracture to ductile fracture.

Structural Evolution of 10% Cr–3% Co Steel Microalloyed with Re and Cu during Creep Au 923 К

Structural evolution of the tempered lath martensite of the 10% Cr--3% Co steel microalloyed with rhenium and copper with a low nitrogen content and a high boron content during creep at 923 K was investigated for the purpose of establishment of the rison of decrease in creep resistance of this steel under the low applied stress. The tempered martensite lath structure of 10%Cr-3%Co steel with an average lath size of 370 nm and a high dislocation number density of 2 ×1014 m–2 was observed after normalizing at 1323 K with the following tempering at 1043 K for 3 h. The structure was stabilized by M23C6 carbides, M6C carbides, and NbX carbonitrides. During long-term creep, the lath structure strongly experienced an evolution: the width of the martensitic laths increased significantly, dislocation density decreased, the Laves phase and Cu-enriched particles remarkably coarsen. Such structural evolution correlates with an appearance of creep strength breakdown on curves “Applied stress vs. Time to failure” and “Minimum creep rate vs. Applied stress”. Significant coarsening of the Laves phase particles and Cuenriched particles via formation of the large particles with sizes more than 250 nm along high-angle boundaries and full dissolution of the fine particles with sizes less than 50 nm along low-angle boundaries of martensite laths is considered to be the main cause of degradation of the creep resistance of the steel studied.

Evolution of centerline carbides in a martensitic stainless steel slab during reheating treatment

The formation and evolution of centerline carbides in a martensitic stainless steel slab are investigated using various characterization techniques. The intensive formation of carbides was observed close to the shrinkage cavity at the centerline of the slab. Carbide structures include a complex eutectic-like mixture of δ-ferrite and M7C3 phases with M6C carbides at the δ/M7C3 interface. Nano-sized M7C3 particles also precipitate in the δ holding the orientation relationship of1¯10δ∥100M7C3;111δ∥100M7C3.This complex structure was surrounded by the retained γ. The decomposition of the coarse M7C3 was investigated after the reheating treatment to 1200, 1250, and 1300 °C. It was found that by increasing the reheating temperature, coarse M7C3 carbide completely decomposed, whereas δ-ferrite islands enlarged due to the thermodynamic stability of δ-ferrite at high temperatures. At the same time, the retained austenite reduces because of homogenizing of the segregated solutes. The new formation of M23C6 and the growth of M6C were identified after reheating to 1200 °C, while all carbides were fully decomposed at 1250 and 1300 °C. The effect of reheating temperature on the decomposition process of coarse carbide was further discussed.

EFFECT OF QUENCHING HOLDING TIME ON MICROSTRUCTURE AND PROPERTIES OF HIGH SILICON HYPEREUTECTIC HIGH CHROMIUM CAST IRON

In this paper, the effects of different quenching holding times on the microstructure and properties of high-silicon hypereutectic high-chromium cast iron (Fe–4.0C–35.0Cr–1.9Si) were investigated. The effect of quenching holding time on the microstructure of high silicon hypereutectic high chromium cast iron was analyzed by optical microscope, scanning electron microscope and X-ray diffractometer. The hardness and wear resistance of high-silicon hypereutectic high-chromium cast iron quenched at 1150∘C for different time were tested by Rockwell hardness tester, microhardness tester and wear tester. The results show that the microstructure of as-cast high-silicon hypereutectic high-chromium cast iron is mainly composed of pearlite matrix and M7C3 carbide. Quenching heat treatment makes part of the matrix transform from pearlite to martensite, and precipitate a small amount of M[Formula: see text]C6 type secondary carbide. With the increase of quenching holding time from 1[Formula: see text]h to 6[Formula: see text]h, the amount of martensite transformation gradually increases, the primary carbide has no obvious change, the eutectic carbide tip dissolves, and the morphology gradually becomes smooth. The hardness and wear resistance both increase first and then decrease. After 4 hours of insulation, the hardness reaches the highest 60.5HRC, which is increased by 3 HRC compared to 1 hour of insulation. The wear resistance increases by 22.1% compared to 1 hour of insulation. At this time, the wear resistance is the best.