scholarly journals METHOD FOR HEAT TREATMENT OF THE RUNNING SURFACE OF THE HEAD OF THE PEARLITIC STEEL RAILS

2021 ◽  
Vol 73 (1) ◽  
pp. 9-15
Author(s):  
Roman KUZIAK ◽  
Valeriy PIDVYSOTS’KYY ◽  
Łukasz RAUCH ◽  
Maciej PIETRZYK ◽  
Tomasz ZYGMUNT
Keyword(s):  
Contact Fatigue ◽  
Industrial Process ◽  
High Hardness ◽  
Pearlitic Steel ◽  
Total Elongation ◽  
New Approach ◽  
Head Cooling ◽  
Hardening Process ◽  
Cooling Conditions ◽  
Strength And Ductility

The paper deals with the new approach to the optimization of the pearlitic rail’s head hardening process aimed at balancing the relation between strength and ductility of the head running surface. In the industrial process, efforts have been undertaken so far to maximize the hardness of the rail’s head while maintaining its pearlite structure, resulting in obtaining enhanced wear resistance and resistance to the contact fatigue defects initiation. The new approach, described in this paper, aims at designing the head hardening process enabling achievement of the high hardness of the running surface combined with high ductility expressed in terms of the total elongation. To achieve this aim of the investigation, a computer program was developed capable of predicting the occurrence of the phase transformations during rail head cooling and microstructure features after cooling. The program was linked with dedicated inverse module enabling the adjustment of the cooling conditions to achieve the required state of the pearlitic structure.

scholarly journals The Contact Mechanics of Novikov’s Surface-Hardened Gearing during Running-in Process

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Alexey Beskopylny ◽  
Nikolay Onishkov ◽  
Viktor Korotkin
Keyword(s):  
Cold Deformation ◽  
Contact Fatigue ◽  
High Hardness ◽  
Contact Spot ◽  
The State ◽  
Contact Strength ◽  
Friction Forces ◽  
Contact Surfaces ◽  
Defective Surface ◽  
The Impact

The article is devoted to the analysis of the state of the contact surfaces of the higher kinematic pair in the general case of relative motion, that is, in the presence of rolling, sliding, and twisting, which is characteristic of Novikov’s circular-screw gears. The purpose of the work is to assess the impact of friction forces, the state of contact surfaces after tool processing, and the localization of the instantaneous contact spot on the level of contact—fatigue durability of gears. Power contact in the presence of geometric slippage of the mating surfaces leads to a significant change in the initial geometry and the mechanical properties of surface layers. In the existing methods of calculations of contact strength, the effect of running-in is investigated insufficiently, which leads to an incorrect result, especially for gear with high hardness of the teeth. In this work, the conditions of contact interaction close to the real requirements are studied on the basis of experimental material, numerical solution of the contact problem, determination of the terms of the contact areas of slip, and adhesion within the instantaneous spot. The shape of the instant contact spot has asymmetry and can be approximated by an ellipse with the introduction of a correction factor. The running-in period is of a plastic nature with cold deformation and reduction of the roughness of surfaces. As a result of the run-in period, the area of actual contact (tooth height) is increased by 2 or more times. It is not desirable to spread the area of contact at the area of adhesion that initiates the formation of pitting. The presence of defective surface area on the level of contact strength does not have significant influence, because of the running-in period, but increases the risk of spalling and brittle fracture.

scholarly journals Hybrid Laser Deposition of Fe-Based Metallic Powder under Cryogenic Conditions

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 190 ◽  
Author(s):  
Aleksander Lisiecki ◽  
Dawid Ślizak
Keyword(s):  
Laser Cladding ◽  
Cross Sections ◽  
Energy Dispersive Spectrometer ◽  
High Hardness ◽  
Ambient Air ◽  
Laser Deposition ◽  
Influence Of Process Parameters ◽  
Cooling Conditions ◽  
Forced Cooling ◽  
Cryogenic Conditions

The purpose of this study was to demonstrate the novel technique of laser deposition of Fe-based powder under cryogenic conditions provided by a liquid nitrogen bath. Comparative clad layers were produced by conventional laser cladding at free cooling conditions in ambient air and by the developed process combining laser cladding and laser gas nitriding (hybrid) under cryogenic conditions. The influence of process parameters and cooling conditions on the geometry, microstructure, and hardness profiles of the clad layers was determined. The optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and XRD test methods were used to determine the microstructure and phase composition. The results indicate that the proposed technique of forced cooling the substrate in a nitrogen bath during the laser deposition of Fe-based powder is advantageous because it provides favorable geometry of the clad, low dilution, a narrow heat-affected zone, a high hardness and uniform profile on the cross-sections, homogeneity, and refinement of the microstructure. The influence of the forced cooling on microstructure refinement was quantitatively determined by measuring the secondary dendrite arm spacing (SDAS). Additionally, highly dispersed nanometric-sized (200–360 nm) precipitations of complex carbides were identified in interdendritic regions.

Study on the Surface Plasma Hardening Treatment and Anti-Penetration Mechanism of Armor Steel

2013 ◽  
Vol 690-693 ◽  
pp. 2141-2144
Author(s):  
Kai Ping Yu ◽  
Feng Wang ◽  
Rong Gang Chen ◽  
Jun Jun Zong
Keyword(s):  
Surface Hardening ◽  
Protective Layer ◽  
High Hardness ◽  
Surface Plasma ◽  
Hardening Process ◽  
Plasma Transferred Arc ◽  
Hardening Treatment ◽  
Penetration Ability ◽  
Penetration Mechanism ◽  
Armor Steel

Plasma surface hardening process was performed to improve the surface on the 22SiMn2TiB steel by plasma transferred arc. Experiments were carried out to characterize the hardening qualities. The anti-penetration ability and mechanism were analyzed, and hardness protective layer can improve greatly the ability of armor protection. The dual hardness armor steel composed of high hardness panel and basic backplane was developed based on the experimental results.

scholarly journals Pengaruh Media Pendingin Terhadap Kekerasan Baja Tahan Karat Martensitik Type 431 Pada Proses Hardening dan Tempering

2018 ◽  
Vol 1 (02) ◽  
pp. 27-32
Author(s):  
Suyanta Suyanta ◽  
Subagiyo Subagiyo ◽  
Syamsul Hadi ◽  
Zahratul Jannah
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Air Conditioning ◽  
Cutting Tool ◽  
High Hardness ◽  
Air Cooling ◽  
Water Cooling ◽  
Cooling Medium ◽  
Hardening Process ◽  
Cooling Media

Stainless steels consist of several types such as Austenitic, Ferritic and Martensitic, Martensitic is one of the stainless steels that has a hardenability property, so it is suitable to be used as cutting tool components which require high hardness and corrosion resistance . The purpose of this study was to obtain information about the hardness of stainless steel martensitic type of hardening results with variations of cooling media. Methods of research used were experiments, ie hardening process by heating the material up to 1100oC temperature, held for 30 minutes, then cooled quickly on water, oil and the air, then heated back to 400oC temperature, cooled slowly, the results tested the hardness of Rockwell C method The results showed the type of stainless steel type martensitic 431 increased significantly after the Hardening process of 21.20 HRC before hardening, and after the hardening process to 47 , 6 HRC with water cooling, 47.9 HRC with oil cooling medium and 46.5 HRC for air cooling media, hardness after tempering down ranges from 6-7 HRC to 41.7 HRC for hardening with water cooling medium 41, 2HRC hardening results with oil cooling medium, and 40,4HRC un tuk hardening results with air conditioning medium.

Experimental studies of the influence of technological heredity on the damage to wheels of high hardness

2020 ◽  
pp. 12-14
Author(s):  
M.I. Biserikan ◽  
S.V. Petrochenko ◽  
K.V. Averkov ◽  
A.A. Rauba
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Contact Fatigue ◽  
High Hardness ◽  
The State ◽  
Maximum Height ◽  
Technological Heredity ◽  
Fatigue Defect

The influence of technological heredity on the interaction of the wheel and rail is considered. The state of the surface of the samples for the presence of contactfatigue defects is estimated. A relationship is established between the maximum height of waviness on the surface of the roller and the rate of damage to its surface. The dependence of the number of loading cycles of the rollers on the height of the waviness and the distribution of the run of the wheels of increased hardness between the turnings are constructed, which is consistent with experimental data. Keywords wheel, rails, contact-fatigue processes, technological heredity, wear, fatigue defect, wheel of increased hardness. [email protected]

THE PROBLEM OF DISPOSAL AND DESTRUCTION OF SEWAGE SLUDGE AND ITS SOLUTIONS (REVIEW)

2017 ◽  
pp. 35-48
Author(s):  
I.M. Karp ◽  
K.Ye. Pyanykh ◽  
Ye.Ye. Nikitin
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Industrial Wastewater ◽  
Industrial Process ◽  
High Hardness ◽  
Thermal Methods ◽  
Sludge Disposal ◽  
Oxidative Pyrolysis ◽  
Agricultural Use ◽  
Harmful Substances

Sewage sludge of cities usually are formed of municipal and industrial wastewater. They contain many harmful substances such as heavy metals, mineral substances, harmful substances of organic origin wastes (solid domestic wastes, feces, etc.), bacterial pollutants. The problem of utilizing and secure disposal of precipitation of urban wastewater (WWS) is a global. It is not solved fully by this time. European trends of sewage sludge disposal are the reduction or total ban on their agricultural use and disinfecting organic pollutants by thermal methods. Acquires distribution WWS combustion in a fluidized bed. Low-temperature technology of sewage sludge disposal in which the heavy metals remain in the solid residue of the process are interesting. This are pyrolysis, oxidative pyrolysis and gasification. The Gas Institute of NAS of Ukraine conducted preliminary tests of utilizing of dry granular WWS in the reversed process of gasification. Producer gas and pellets with high hardness were obtained; pellets can be used as fillers in construction. Technological scheme of the industrial process is proposed. Bibl. 24, Fig. 7, Tab. 1.

A New Approach Towards Life Prediction of Case Hardened Bearing Steels Subjected to Rolling Contact Fatigue

2017 ◽  
Vol 6 (4) ◽  
pp. 20160099
Author(s):  
Abir Bhattacharyya ◽  
Nikhil Londhe ◽  
Nagaraj Arakere ◽  
Ghatu Subhash
Keyword(s):  
Life Prediction ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
New Approach ◽  
Bearing Steels

An Investigation to the Behavior of Fatigue Crack and Rail Selection for High-Speed

2010 ◽  
Vol 154-155 ◽  
pp. 1131-1136
Author(s):  
Wen Zhong ◽  
Jia Jie Hu ◽  
Cai Yun Wang ◽  
Peng Shen ◽  
Qi Yue Liu
Keyword(s):  
Fatigue Crack ◽  
Plastic Flow ◽  
Fatigue Damage ◽  
High Speed ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Hardness ◽  
Rolling Contact ◽  
Wear Volume ◽  
Surface Fatigue Crack

The rolling tests of railway rail were performed using a JD-1 wheel/rail simulation facility without any lubricant. The failure behaviour of rail rollers with different materials, was investigated in detail by examining wear volume and wear scar using optical microscopy (OM) and scanning electronic microscopy (SEM). The results indicate that rail material with a high hardness appears less plastic flow after rolling test. When the plastic flow is small, the wear resistance of material appears better. However, the crack propagation is more significant and fatigue damage is more severe. There is a mutual competitive relationship between wear and surface fatigue crack. A high wear rate can reduce rolling contact fatigue damage by removing constantly surface cracks. The analysis shows that U71Mn rail is more suitable for the high-speed railway.

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