Restoration of parts from heat-resistant steels by arc surfacing in conditions of high humidity

2020 ◽  
pp. 168-175
Author(s):  
Viktor S. Drizhov
Keyword(s):  
Hydrogen Content ◽  
Experimental Studies ◽  
Resistance Index ◽  
Research Purpose ◽  
Local Cooling ◽  
Heat Resistant ◽  
Deposited Metal ◽  
Thermal Influence ◽  
Heat Resistant Steels

The main technological processes for restoring parts are welding surfacing processes. The reliability of restored parts is usually determined by the quality of the welded joint. The quality of the deposited metal is influenced by hydrogen, but the effect of hydrogen on destruction during reheating has not been sufficiently studied. (Research purpose) The research purpose is studying the effect of increased hydrogen content on the resistance of the deposited metal to destruction during heat treatment. (Materials and methods) The studies were performed on small-sized samples made of heat-resistant 15Kh24MFA and 15Kh1N1F steel. The prepared samples were applied with deposited rollers under local cooling. Tests of welded samples were carried out under conditions of isothermal relaxation of applied stresses. The change in the saturation of the deposited metal with hydrogen occurred as a result of wetting the argon during surfacing. (Results and discussions) The article describes that when the hydrogen content of the deposited metal increases, the resistance index decreases by 20 percent. Preheating samples before welding to a temperature of 300 degrees Celsius increases the resistance of the deposited metal. (Conclusions) Experimental studies have shown that the hydrogen content in the deposited metal negatively affects the resistance to destruction. The article shows that the zone of thermal influence is the most dangerous area of crack generation during surfacing.

EXPANSION OF TECHNOLOGICAL CHARACTERISTICS OF THE HARROWING UNIT

2021 ◽  
Vol 1 (142) ◽  
pp. 83-88
Author(s):  
Aleksandr Slepenkov ◽  
◽  
Sergey Kulinchenko ◽  
Sergey Shchitov ◽  
Evgeniy Kuznetsov
Keyword(s):  
Experimental Studies ◽  
Research Purpose ◽  
Design Parameters ◽  
Necessary Condition ◽  
Technological Parameters ◽  
Depth Of Processing ◽  
Technological Characteristics ◽  
Low Load ◽  
Priority Direction

Improving the quality of pre-sowing tillage is a priority direction. Harrowing with the use of heavy disc harrows is one of the operations of pre-sowing tillage. An important task when using heavy disc harrows is to ensure sufficient load on the working body. (Research purpose) The research purpose is in increasing the efficiency of the harrowing process by adjusting the coupling weight in the tractor-harrow link using special devices. (Materials and methods) It is important to match the necessary condition of balance between the load on the working body and the traction qualities of the tractor with a low load-bearing capacity of the soil. The article describes a regulator of the coupling weight of the harrowing unit, for which was applied a patent. The article presents the general types of connection of the device with the disk harrow frame. (Results and discussion) The proposed device allows you to redistribute the weight of the unit, thereby automatically changing the load on the working body. Authors performed experimental studies on the influence of the main design parameters of the devices on the operation of the machine and tractor unit. (Conclusions) The proposed device allows, by expanding the design and technological parameters, to regulate the depth of processing, traction characteristics and speed of the harrowing unit.

scholarly journals Effect of Electrode Waterproof Coating on Quality of Underwater Wet Welded Joints

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2947 ◽  
Author(s):  
Jacek Tomków ◽  
Dariusz Fydrych ◽  
Kamil Wilk
Keyword(s):  
Hydrogen Content ◽  
Welded Joints ◽  
High Strength ◽  
Industrial Applications ◽  
Cold Cracking ◽  
Diffusible Hydrogen ◽  
Deposited Metal ◽  
Covered Electrodes ◽  
Steel Joints

In this paper, the effects of different hydrophobic coatings on the surface of covered electrodes on the quality of wet welded carbon steel joints were discussed. Commonly available hydrophobic substances used in industrial applications were selected for the research. The aim of using waterproof coatings was to check the possibility to decreasing the susceptibility of high-strength low-alloy S460N steel to cold cracking. During experiments diffusible hydrogen content in deposited metal determination by mercury method, metallographic macro- and microscopic testing and hardness measurements were performed. Investigations showed that waterproof coatings laid on covered electrodes can improve the quality of wet welded joints, by decreasing the Vickers HV10 hardness in heat-affected zone and decreasing the diffusible hydrogen content in deposited metal, which minimalize possibility of cold cracking.

EXPANSION OF TECHNOLOGICAL CHARACTERISTICS OF THE HARROWING UNIT

2021 ◽  
Vol 1 (142) ◽  
pp. 83-88
Author(s):  
Aleksandr E. Slepenkov ◽  
◽  
Sergey N. Kulinchenko ◽  
Sergey V. Shchitov ◽  
Evgeniy E. Kuznetsov
Keyword(s):  
Experimental Studies ◽  
Research Purpose ◽  
Design Parameters ◽  
Necessary Condition ◽  
Technological Parameters ◽  
Depth Of Processing ◽  
Technological Characteristics ◽  
Low Load ◽  
Priority Direction

Improving the quality of pre-sowing tillage is a priority direction. Harrowing with the use of heavy disc harrows is one of the operations of pre- sowing tillage. An important task when using heavy disc harrows is to ensure sufficient load on the working body. (Research purpose) The research purpose is in increasing the efficiency of the harrowing process by adjusting the coupling weight in the tractor–harrow link using special devices. (Materials and methods) It is important to match the necessary condition of balance between the load on the working body and the traction qualities of the tractor with a low load- bearing capacity of the soil. The article describes a regulator of the coupling weight of the harrowing unit, for which was applied a patent. The article presents the general types of connection of the device with the disk harrow frame. (Results and discussion) The proposed device allows you to redistribute the weight of the unit, thereby automatically changing the load on the working body. Authors performed experimental studies on the influence of the main design parameters of the devices on the operation of the machine and tractor unit. (Conclusions) The proposed device allows, by expanding the design and technological parameters, to regulate the depth of processing, traction characteristics and speed of the harrowing unit.

Research of quality of production of the key connections basic units

2020 ◽  
pp. 106-112
Author(s):  
Anatoliy T. Lebedev ◽  
Roman V. Pavlyuk ◽  
Anton V. Zakharin ◽  
Pavel A. Lebedev ◽  
Nikolay A. Mar’in
Keyword(s):  
Quality Control ◽  
Normal Distribution ◽  
Stress Concentrator ◽  
Experimental Studies ◽  
Research Purpose ◽  
Contact Method ◽  
Technical Requirements ◽  
The Law

When considering the work of key connections with broken geometry of the working surfaces of the units, we can observe that often the key is not properly fixed in the groove of the shaft and sleeve and when rotating the coupling, it skews and perceives the transmitted torque unevenly at some point, which is a stress concentrator. (Research purpose) The research purpose is to increase the durability of keyways by preventing failures through quality control of the manufacture of their basic units. (Materials and methods) Authors have noted that the standard keyway has three fitments: "shaft-hub", "shaft-keyway" and "hub-keyway". It was shown that in these couplings the manufacturer provided gaps of various sizes for the convenience of disassembly and assembly of the connection, directly affecting the performance and durability of the connection as a whole. The geometric dimensions of keyway coupling were monitored by contact method using electronic micrometers MCC-25, MCC-50 and MCC-75 to measure the width of the keys and the diameter of the shafts and indicator nutromers NI-18 and NI-50 with an indicator head 1IG for keyways and internal diameters of pulleys. (Results and discussion) It has been revealed that the dispersion of the tolerance fields of the key width coincides with the law of normal distribution. It was found the presence of defects in width in the supplied keys, the value of which reached 15 percent. It was determined that the technical requirements for hardness and roughness corresponded to GOST 23360-78. It was noticed when checking the diametrical dimensions of the coupling "shaft-sleeve" the presence of deviations from the technical conditions, which during assembly can lead to the formation of a large gap in the keyway coupling. (Conclusions) Performed theoretical and experimental studies have allowed to establish the probability of obtaining gaps and tightness in common key coupling.

Optimizing Gas-Assisted FIB Processes: The Importance of Oft-Ignored Secondary Parameters

2004 ◽  
Author(s):  
C. Rue ◽  
S. Herschbein ◽  
C. Scrudato ◽  
L. Fischer ◽  
A. Shore
Keyword(s):  
Focused Ion Beam ◽  
Vacuum Chamber ◽  
Ion Beam ◽  
Memory Capacity ◽  
Metal Films ◽  
Deposited Metal ◽  
Influence Process ◽  
Focused Beams ◽  
Gas Pressures

Abstract The efficiency of Gas-Assisted Etching (GAE) and depositions performed using the Focused Ion Beam (FIB) technique is subject to numerous factors. Besides the wellknown primary parameters recommended by the FIB manufacturer (pixel spacing, dwell time, and gas pressures), certain secondary factors can also have a pronounced effect on the quality of these gas-assisted FIB operations. The position of the gas delivery nozzle during XeF2 mills on silicon is examined and was found to affect both the milling speed and the texture on the floor of the FIB trench. Limitations arising from the memory capacity of the FIB computer can also influence process times and trench quality. Exposing the FIB vacuum chamber to TMCTS during SiO2 depositions is found to temporarily impede the performance of subsequent tungsten depositions, especially following heavy or prolonged TMCTS exposure. A delay period may be required to achieve optimal tungsten depositions following TMCTS use. Finally, the focusing conditions of the ion beam are found to have a significant impact on the resistance of FIB-deposited metal films. This effect is attributed to partial milling of the deposition film due to the intense current density of the collimated ion beam. The resistances of metal depositions performed with intentionally defocused ion beams were found to be lower than those performed with focused beams.

The system of indicators of the quality of the carbon-carbon composite materials and technologies of their production

2018 ◽  
pp. 127-132
Author(s):  
T. N. Antipova ◽  
D. S. Shiroyan
Keyword(s):  
Composite Material ◽  
Low Cost ◽  
Experimental Studies ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Optimal Number ◽  
Laboratory Equipment ◽  
Carbon Composite Material ◽  
Carbon Composite Materials

The system of indicators of quality of carbon-carbon composite material and technological operations of its production is proved in the work. As a result of the experimental studies, with respect to the existing laboratory equipment, the optimal number of cycles of saturation of the reinforcing frame with a carbon matrix is determined. It was found that to obtain a carbon-carbon composite material with a low cost and the required quality indicators, it is necessary to introduce additional parameters of the pitch melt at the impregnation stage.

EVALUATION OF TRIBOTECHNICAL PROPERTIES OF THE COATING OBTAINED BY ELECTRIC SPARK HARDENING

2020 ◽  
Vol 4 (141) ◽  
pp. 157-163
Author(s):  
IL’YA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Wear Resistance ◽  
Reference Sample ◽  
Optical Microscope ◽  
Research Purpose ◽  
Tribotechnical Properties ◽  
Uncoated Surface ◽  
Before And After ◽  
Materials Used ◽  
Friction Track

When applying coatings using various methods on the surfaces of moving parts that work in joints, it is important to make sure that the coatings are strong and wear-resistant in order to return them to their original resource. All existing hardening technologies and materials used to perform coatings have their own characteristics, therefore, the quality of the resulting coatings can be judged only after specific tests. (Research purpose) The research purpose is in evaluating the properties of the coating obtained by the method of electric spark hardening, and its ability to resist friction and mechanical wear. (Materials and methods) Authors conducted tests on the basis of the "Nano-Center" center for collective use. A coating was applied on the BIG-4M unit with a VK-8 hard alloy electrode, tribological properties were evaluated on a CSM Instruments TRB-S-DE-0000 tribometer, the width of the friction track was measured after the test using an inverted OLYMPUS gx51 optical microscope, and samples were weighed before and after the test on a VLR-200 analytical balance. Conducted research in accordance with GOST 23.224-86 and RD 50-662-88 guidelines. (Results and discussion) The article presents performed tests on the run-in and wear resistance of the coating. The samples were worked on with a step-by-step increase in the load. During the tests, the friction force was drawed on the diagram. Authors compared the results with the reference sample, an uncoated surface. (Conclusions) The resulting coating has better run-in and wear resistance compared to the standard, and the increase in wear resistance in dry friction conditions is very significant.

Cultivation of Rapeseed in the Southern Urals and Its Rational Use

2020 ◽  
Vol 67 (1) ◽  
pp. 78-86
Author(s):  
Nikolay S. Sergeev ◽  
Mikhail V. Zapevalov ◽  
Alexander V. Gritsenko
Keyword(s):  
Southern Urals ◽  
Research Purpose ◽  
Partial Replacement ◽  
Biodiesel Fuel ◽  
Forest Steppe ◽  
The Southern Urals ◽  
Rational Use ◽  
Chelyabinsk Region ◽  
Spring Rape

In the continental climate of the southern Urals, rapeseed compares favorably with many forage and traditional silage crops with a high protein content and adaptive properties. The cultivation of rapeseed guarantees the production of its own seeds, up to 40 percent of oil, 60 percent of cake and 98 percent of rapeseed flour. (The research purpose) The research purpose is in improving the efficiency of rapeseed cultivation and rational use of rapeseed seeds, rapeseed flour and oil in the agricultural production in the Chelyabinsk region. (Materials and methods) The influence of various forecrops on the productivity and quality of spring rape seeds in the links of grain-pair crop rotations in the Northern forest-steppe of the Chelyabinsk region were studied. Authors have analyzed the chemical composition of the soil and seeds of spring rape after various forecrops. (Results and discussion) The article proposes to reduce energy costs during pressing and reduce residual oil in the cake after pre-grinding of rapeseed by cutting method using a centrifugal-rotary shredder. The article shows that rapeseed flour has a good flowability and is easily mixed with other feeds. It was found that partial replacement of concentrates with rapeseed flour in the amount of 8-12 percent of the total weight in the diet of lactating cows contributes to an increase in milk productivity by 1.1-1.8 kilograms in terms of milk of 4 percent fat content. (Conclusions) It has been revealed that in order to increase the yield and quality of spring rape seeds, it is necessary to place them on the best forecrops. It was found that when 75 percent of rapeseed oil is mixed with 25 percent of diesel fuel, the obtained biodiesel is not inferior to diesel in terms of energy indicators. The article proves that when cultivating rapeseed for seeds on an area of 100 hectares, it is possible to produce 94.5 tons of biodiesel fuel, 106.0 tons of cake with an oil content of 5 percent and 8.4 tons of oil sludge, the estimated economic effect after sale is of 3,813,325 rubles.

scholarly journals Z-phase Formation during Creep and Aging in 9–12% Cr Heat Resistant Steels

2006 ◽  
Vol 46 (5) ◽  
pp. 769-775 ◽  
Author(s):  
Kota Sawada ◽  
Hideaki Kushima ◽  
Kazuhiro Kimura
Keyword(s):  
Phase Formation ◽  
Heat Resistant ◽  
Heat Resistant Steels

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

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