Ferrite grain size and pearlite lamellar spacing are hardly changed 3. However, the number of ferrite is reduced. Thereby increasing the strength of the steel. With the prior austenite grain size, when the grain size is greater than 5, ie, the heating temperature is greater than 00, the precipitation hardening effect of vanadium no longer changes with temperature, and the austenite grain size abruptly grows. As a result, the amount of change in strength and plasticity is reduced. Therefore, the slope of the curve decreases, and the performance of the 45 steel under this test condition mainly depends on the volume fraction of proeutectoid ferrite. The mechanical properties of 4 out 45 non-quenched and tempered steel and iron 4 conclusions increase with the prior austenite grain size. The volume fraction of pro-eutectoid ferrite decreases, the hardness and strength of 45 steel increase, and the plasticity decreases, when the heating temperature exceeds 1000. , The amount has decreased, Liu Wen 4 and so on. Journal of Iron and Steel Research, China University of Science and Technology. Shanghai Shanghai Science and Technology Press. 1983.
Liu Wenchang. Mechanical Engineering Materials, 19926333.
The relationship between the volume fraction of the body.
Effect of Load on High Temperature Wear Characteristics of Nickel Base Alloy Coatings Li Zhiqu, Jing Xin, Zhou Ping'an, Zhao Zhenye, Shao Hesheng, 21.Beijing Aeronautical Materials Research Institute. Beijing 100095;2. China University of Mining and Technology Beijing Campus, Beijing 100083;3. China Academy of Agricultural Mechanization Sciences, Beijing 100083 High temperature and wear under low load and high load are maintained due to the high hardness of the coating. Small wear volume per unit area. At high temperature and high load 6, the wear of the coating is caused by the formation of a white and bright layer of the coating wear layer, and the wear volume is significantly increased. The oxide wear shoulder covered with the wear surface of the coating, especially a dense oxide layer, plays a protective role in the coating.
The formation of oxide wear shoulders and their protective effect on the wear surface during extensive wear of the mortar contribute to the initial wear of severe wear to slight wear. However, most of the previous studies were carried out under a small load of 10N, and rarely involved in the case of higher loads. Nickel-based alloy coatings are mostly used to improve the wear resistance of the workpiece surface at room temperature and high temperatures. This paper studies the dry friction sliding wear characteristics of nickel-based alloy coatings at high temperatures of 200 and under high-load wear.
The high-temperature dry-friction sliding wear characteristics of Ni-based alloys and stainless steels have been compared with those of ultra-high-strength stainless steels, and more than 20 papers have been published. Contact Tel. 010 Fund Project Beijing Institute of Aeronautical Materials Academy Foundation 991573 Influence of initial heat excitement on the volume of nickel-based alloys NA40N å¼‹ coating wear volume influence Surface morphology and wear layer microstructure Room temperature 20 wear surface morphology . From low-magnification image loss to micro-plough. The progressive enlargement in the white area is a large amount of granular debris covering the wear surface; 5 is the room temperature morphology, which is known from the low magnification phase 51 . A black band in the wear direction of the wear surface. On which 151 can be black. It is higher than the coating wear surface and is smooth and flat.
Coating wear surface. Instead, it is formed and covered by wear debris during wear. The observation of the light gray area above the black area is the wear surface of the coating and there is a lot of micro-ploughing and some types of adhesion of the nickel-based alloy coating wear patterns. Plowing and sticking. The comparison of the wear profile of the 6th load shows that the wear surface is covered by the wear cover layer and the cover layer 61 1 on the wear surface is much smoother and denser at 130 o'clock; high magnification can be observed; there is micro-ploughing and adhesion on the damage surface. Morphology, therefore, wear under high temperatures, pruning and sticking. And sticking is more severe than at room temperature. Comparing different morphologies and high temperature wear patterns, it can be seen that at high temperature and high load, the abrasive layer is much denser than that at high temperature and low load and at room temperature.
Was in 9 training; 1 mild 650, wear tissue morphology. When wear occurs at high loads, a white and bright layer 8 appears on the wear layer and is worn out. There is no white bright layer, combined with the above-mentioned wear surface coating. When the wear occurs on both the room temperature and the high temperature, a coating layer appears on the wear surface, and the white coating material is formed by the coating tissue itself during wear. Falling off during the covering process. Only in high temperature 200, and high wear damage when the wear layer appears white bright layer 1 surface coating spectral analysis of the wear of the nickel-base alloy coating wear surface overlay analysis 1 test method 1.1 coating preparation of nickel-based Chemical composition of the alloy coating raw material powder 1. The coating preparation uses a vacuum sintering process. 40 steel pin samples for the substrate. Its size is èš1 30. Under vacuum conditions, the 970 is kept at 35, such as with furnace cooling. Coating thickness 2. Rockwell hardness is 581 busy.
The elemental content 12 high temperature dry friction sliding wear tester is based on elbow pin type 10 abrasive disc type abrasive wear tester and is transformed into a test device capable of dry friction sliding wear test at both room temperature and high temperature. 5. Before the wear test The sample surface was electroless nickel plated to reduce the effect of high temperature oxidation on the test results. The specimens were pre-ground on thin abrasive discs and 600 grit sandpaper to ensure that the entire face had the same surface finish. The size of the disc to be ground with the pin sample was Â± 1505. The material in the village was 651 steel. Heat 1 hardness after 4345 book adjustment before rent test rent. The end faces of the pin are in contact with the disc surface. The initial heating temperature is selected at room temperature of 200, 350, 500650 respectively; the sliding speed is selected within the range of 1013, and the sliding distance is 24, 1. The sample is at index 0 The balance was weighed on an electro-optical analysis. Before and after the wear, it was put into alcohol and cleaned by ultrasonic. The warm air is dried, and the weights are weighed separately. The difference between the two weights is the wear loss weight and is converted into the wear volume per unit area. The wear volume is referred to below as the wear volume. Each pin sample and disc corresponded to the secondary wear process. Before each wear, the disc wear track was first sanded with whetstone and 600 grit sandpaper to make it smooth and smooth, and then the disc was cleaned with alcohol. Each set of tests was repeated 3 times and the test results were arithmetically averaged. Relative error of data 15.
Microstructure wear surface morphology and wear layer microstructure of Ni-base alloy coating.
2 Test results 21 The microstructure of the town-base alloy coating, such as ftl, precipitated out. 5. It can be seen. Precipitates are mainly boride carbides and silicides.
Among them, boride carbides mainly play a reinforcing role. The silicide mainly improves the process performance of the coating grout process.
22 Ni-based alloy coating at high temperature dry friction sliding wear characteristics out. 1 set 40. Temperature Zhuang 35 or less. With the increase of temperature.
The wear volume gradually increases; between 350650,. The wear volume remains basically the same when the load, such as the seven-grind, material (1), reaches its maximum, and then the wear volume gradually decreases with increasing temperature but still maintains a high level; from a slowly increasing almost linear relationship; after more than 200. When the load is less than 6, the wear volume increases slowly and rapidly increases between 60901 and remains greater than 9 coffee.
2.3 grinding technology zoom observation P caution in the wear surface is the form of debris is still micro-milling it at room temperature to see, high enthalpy at room temperature, high-load grinding observation can be bright layer is not likely to be in the system 2.4 grinding technology! The micro-ploughing removes worn-out granular debris, and the covering layer contains a large number of oxygen atoms, and part or all of the elements in the bright composition are converted into oxidized particles. Tan cover can be approximated by pod oxides; no, the composition of the overburden formed by temperature wear is very different. The relative or absolute nickel content at room temperature wear is significantly lower than that at high temperature wear. 3 Analysis and discussion When worn at room temperature, the hardness of the Ni-based alloy coating is higher than that of the grinding disc.
Has high wear resistance; at high temperatures and low load conditions. Nickel-base alloy coating wear layer does not form a bright white layer, the coating still maintains a high high temperature hardness, has a good anti-wear performance 3; but at high temperatures and high loads of 60, when the next wear. A white layer appears on the wear layer. At this time, due to the combined effect of frictional heat and external heat source, the wear layer recrystallized and formed a new product. At this time, the structure of the new product has undergone a fundamental change, so the high temperature hardness of the nickel-base alloy coating cannot be used to measure wear at this time. For the base alloy coating, under this condition, the matrix will not form a high-strength and high-hardness phase such as martensite due to phase transformation. Therefore, when the high temperature and high load 601 wears, the bright white layer of the wear layer causes the high temperature hardness to decrease and wear. The volume increases significantly by 3 in this wear system. After the shoulders are formed, they are not completely out of the wear track, and some of them remain in the track to participate in the wear process, and the wear shoulder itself is also hard. The white bright layer itself undergoes a large deformation when it is formed. The hardness is low; and for the nickel 3 black ribbon zone 1 black ribbon zone enlargement like 0 micro-ploughing and adhesion occurs in series. A large number of researches have been carried out. 3 In the similar dry-friction sliding wear system, the osmium oxides are soon waved to form silicides.
And in the wear Ling-Large 1 poly-Dong Jian 3. Under the squeezing effect formed, the presence of 8 reduces the direct contact with the grinding material and thus reduces the wear of the material, which is the situation at room temperature and low load wear 4. In this In the wear system, the load is less than 60 ã€‚. Due to the strong shear extrusion effect, a large oxide coating layer 5 is formed on the surface; in the past, this phenomenon was rarely observed because the effect of oxide wear debris was studied only at a low load of 10. In the case of wear under high temperature and high load of 20060, due to the nickel content, 91 oxide plasticity is added, and 6 is added. This is favorable for the formation of a dense oxide layer such as a heavy metal on the worn surface. Therefore, when the high temperature and high load is 200å½¡601, the wear surface coverage is better than the commercial temperature and the covering coverage at room temperature. Reflected in the wear and tear on the high temperature wear and tear in the body wear increases with wear and 1.4 down 2.
At room temperature, looking for the product temperature below 71 Moses, the edge of the oxide, the formation of micro-convex 5 Ji played a protective role on the wear surface. At this time, due to the abrasion resistance of the coating layer, the change of the material properties of the coating material and the formation of the dan spoon are not significant, and the wear characteristics of the wear are not high.
60, when worn down. The combined effect of load and temperature has caused a dramatic change in the organizational properties of the wear layer material itself. The wear characteristics of the material at this time should be burned down and burned on page 16. Why does the composite material containing 8,0 show an overheating phenomenon at 54,55? 4 and 5 are the SEM images and the energy spectrum analysis of the position of the 3,6066 interface is known from 5. The contents of elbow 8 and heart 1 near the interface were 4.39 and 2 47, respectively. The contents in the matrix were 1.25 and 1.23, respectively. This enrichment reduced the vicinity of the interface near the interface of the 6,66 matrix 3,6066 aluminum matrix composites. 1 Curves Some scholars have used the energy dispersive spectrograph on transmission electron microscopy (TEM) to determine the distribution of the zero-centered near-human 0 interface and found them. The mass value of 1 value of the previous value in the left and right interfaces of the interface was 2,71. 4. The chemical state of 8 busy people 1 was studied by using ray photoelectron spectroscopy and Auger energy spectrum technology. Some segregation was found on the interface. Analyzed from the aspect of thermodynamics. The material cools from high to low temperatures. Since the expansion coefficient of the matrix is â€‹â€‹larger than that of the mask, the particles are several times larger, resulting in a greater tensile stress at the interface near the matrix. 1. If the core 1 is originally from the continuum, 1; Hume 1 is segregated. You will be able to live in by changing the solution. 4 in. Because their atomic radii are larger than 1, the lattice constant of the matrix near the interface will inevitably increase, and the volume of the matrix will expand. This expansion just reduces the volumetric shrinkage of the substrate caused by the cooling, which reduces the interface tensile stress. Therefore, the segregation of elbows 8 and 1 at the 3 redundant 1 interface favors the reduction of interfacial energy and volume free energy. The mountain is fast, solid, and the interface is less segregated. The subsequent hot extrusion and solution treatment at higher temperatures provide enough energy for the diffusion of the elbow, and, enabling it to spontaneously deflect toward the interface. Poly.
3.2 The solution temperature is not under the premise of burning. The higher the solution temperature. The more rapid and sufficient the enhanced solution dissolves into the solid solution. The more uniform the distribution of alloying elements in the solid solution, the better the solid solution strengthening and aging strengthening of the alloy. but. Excessively high solution temperature will cause significant grain growth, thereby reducing the performance of the alloy. The reason why the hardness value of 530 is low in solid solution may be that 530 is close to the over-sintering temperature and the grain has grown up, and it is solid to the household 5,1; the peak-to-peak peak reproducibility is high 7.1. Intensification of solid solution is not sufficient. It is known from 3. 515, the hardness value in solution is generally higher. And the peak hardness is significantly higher than 500, and 53,1. In summary, 515 is the best solution temperature.
Conclusion 1 The spray deposition of 8 016066 aluminum matrix composites and elemental segregation 2 spray deposition 8; 016066 aluminum matrix composites solution temperature and over-burning temperature are lower than the matrix alloy; 3 spray deposition 3; 016066 aluminum The optimum solution temperature of the base composite material is 515, and at 540, overheating, 1 sheet, etc. Rare Metal Materials and Engineering, 199 2 American Gold, Society. Edit the 12th Handbook of the Ninth Edition. 1.1 Beijing Jikai Industrial Press, 1988.
I, Qiu 1 Magic +.1 industry association standards. Number 1; 1 Detachment of Science and Technology Literature Publishing House Chongqing Branch. 198 Continued from page 14 Previous studies have not been noticed due to the use of small loads.
4 Conclusion 1 In this wear system. Nickel-based alloy coatings wear at room and elevated temperatures. 1 Under the conditions of low temperature and low cost, the damage is light both at high temperature and high load 200.;6, then there is more serious wear, 2 high temperature and high load 20,160, the formation of the lower wear layer of white bright layer makes it lose its original Hardness is the direct cause of the significant increase in wear volume; on the other hand, the denseness of the oxide layer formed under high temperature and high load increases. After the wear volume reaches its maximum value, it decreases slightly with increasing temperature, Liu Zuomin. Study on High Temperature Friction and Wear Characteristics of Elbow 50 High Speed â€‹â€‹Steel 1. Journal of Tribology, 1997, 1715562.
Xi Xi. Study on microstructure and high temperature wear characteristics of vacuum fusion bonded gold coatings. China University of Mining and Technology Beijing University PhD, Science and Technology, 1998 6 Chemical Machinery Research Institute of the Ministry of Chemical Industry. Corrosion and protection manual. Corrosion theory. Test and monitoring 1 Beijing Chemical Industry Press. 1989.5.