Selection of Protective Coatings of Moulds for Castings of High-Manganese Cast Steel in Dependence of the Applied Moulding Sand Kind

2013 ◽  
Vol 58 (3) ◽  
pp. 853-857
Author(s):  
M. Holtzer ◽  
A. Bobrowski ◽  
D. Drożyński ◽  
J. Mocek
Keyword(s):  
Protective Coatings ◽  
Cast Steel ◽  
Silica Sand ◽  
High Manganese ◽  
Casting Surface ◽  
Hard Materials ◽  
Cast Steels ◽  
High Silica ◽  
Selection Of

Abstract High-manganese cast steels are characterised by a high abrasion resistance under friction conditions with a simultaneous influence of pressure and impacts. This cast steel is especially suitable for castings of excavator’s scoops, track links, streetcars crossovers, parts of crushers and mills for braking up of hard materials [1-4]. In order to obtain high quality castings of high-manganese cast steels in moulds on the high-silica sand matrices it is necessary to apply protective coatings, which prevent a direct contact between metal and matrix (SiO2). Manganese after being poured into a mould can undergo a partial oxidation forming MnO, which reacts with silica. As a result low-melting manganese silicates are formed, which in a form of a tight layer adhere to the casting surface, significantly increasing a labour input related to cleaning. Three kinds of protective coatings were tested: zirconium, corundum and magnesite. As a base moulding sands on high-silica sand matrices with three kinds of resol resins were applied. The quality of the obtained casting surface was assessed in dependence of the protective coating and resin kind and also in dependence of the metallostatic pressure value.

scholarly journals Investigations of Protective Coatings for Castings of High-Manganese Cast Steels

2013 ◽  
Vol 13 (1) ◽  
pp. 39-44 ◽  
Author(s):  
M. Holtzer ◽  
A. Bobrowski ◽  
D. Drożyński ◽  
J. Mocek
Keyword(s):  
Surface Quality ◽  
Protective Coatings ◽  
Cast Steel ◽  
Small Degree ◽  
Silica Matrix ◽  
Silica Sand ◽  
Hadfield Steel ◽  
High Manganese ◽  
Free Silica ◽  
High Silica

Abstract When cast steel castings are made in moulding sands on matrices of high-silica sand, which has a low fire resistance the problem of the so-called chemical penetration is distinctly visible. Whereas this effect appears to a small degree only when moulding sand matrices are of chromite, zircon or olivine sands. Therefore in case of making castings of high-manganese cast steel (e.g. Hadfield steel) sands not containing free silica should be applied (e.g. olivine sand) or in case of a high-silica matrix protective coatings for moulds and cores should be used. Two protective coatings, magnesite alcoholic (marked as coating 1 and coating 2) originated from different producers and intended for moulds for castings of the Hadfield steel, were selected for investigations. Examinations of the basic properties were performed for these coatings: viscosity, thermal analysis, sedimentation properties, wear resistance. In order to estimate the effectiveness of protective coatings the experimental castings were prepared. When applying coating 1, the surface quality of the casting was worse and traces of interaction between the casting material (cast steel) and the coating were seen. When protective coating 2 was used none interactions were seen and the surface quality was better.

scholarly journals SYSTEMATIC APPROACH TO ASSESSING THE QUALITY OF APPLYING A PROTECTIVE COATING FOR RESTORATION DETAILS OF TRANSPORT DESTINATION

2014 ◽  
Author(s):  
Andrey Dyomin
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Protective Coating ◽  
Systematic Approach ◽  
Structural Model ◽  
Protective Coatings ◽  
Comprehensive Approach ◽  
Technology Selection ◽  
Selection Of

The article presents a comprehensive approach to assessing the quality of the application andreinforcing anti-friction coatings in one technological cycle of technology recovery of crankshafts.Found that the use of methods of hardening and application wear-resistance coating must complysatisfactory level of performance tribosystems with acceptable processability, maintainability andeconomical efficiency processes of manufacturing and repair detail. Use of protective coatings in themanufacture and renovation of machinery parts makes demands for coatings and technologies for theirapplication, the need to ensure receipt of the surface layer with stable physical and mechanical properties.Proposed to assess the quality crankshafts, which were manufactured and repaired by applyingprotective coatings, using a structural model of implementation of decisions on technology selection of theapplication covering layer and cause-effect diagram to identify the factors that affect the quality of thecoating.

scholarly journals The Role of Chemical Composition of High-Manganese Cast Steels on Wear of Excavating Chain in Railway Shoulder Bed Ballast Cleaning Machine

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7794
Author(s):  
Janusz Krawczyk ◽  
Michał Bembenek ◽  
Jan Pawlik
Keyword(s):  
Chemical Composition ◽  
Cross Sections ◽  
Structural Integrity ◽  
Cast Steel ◽  
Maximum Speed ◽  
Chemical Compositions ◽  
Main Task ◽  
High Manganese ◽  
Cast Steels

The main task for a ballast bed is to transmit the sleeper pressure in a form of stress cone to the subsoil, provide proper drainage and resist the sleeper displacement. Poorly maintained ballast could severely limit the maximum speed capacity and create further problems with the structural integrity, possibly leading to a complete failure of a given rail line. To prevent the unwanted corollaries, the ballast bed has to be periodically cleaned with an appropriate machinery. In this paper the authors investigated the effect of the chemical composition on the physical properties of the ballast excavating chains made of high-manganese steels. The authors focused on the wear mechanism, work hardening ability and hardness in the cross-sections areas. A microstructure analysis was performed as well, and observations revealed divergent morphology of precipitations at the grain boundaries, which influenced the size of austenite grains. The deformation twins formed as a result of operation were noticed in the samples. Research has shown that less carbon and chromium reduces the hardness of cast steel, and it specifically affects the ability to strain hardening. The authors explained the role of adjustments in chemical composition in the operational properties of high-manganese cast steels. It has been shown in the paper that different chemical compositions affect the properties of the alloys, and this causes different types of wear. The high content of chromium increases the hardness of materials before and after plastic deformation hardening, which in the conditions of selector chains results in greater dimensional stability during wear of holes in pin joints and will be more susceptible to abrasive wear in the presence of dusts from the ballast than creep.

scholarly journals Justification of modernization of groundwater treatment station

2021 ◽  
Vol 263 ◽  
pp. 04049
Author(s):  
Zhanna Govorova ◽  
Olga Zubareva ◽  
Vasiliy Semenovykh ◽  
Ekaterina Muraveva ◽  
Olga Yankovskaya
Keyword(s):  
Drinking Water ◽  
Technical Condition ◽  
Silica Sand ◽  
Groundwater Treatment ◽  
Concrete Corrosion ◽  
High Silica ◽  
External Corrosion ◽  
Manganese Compounds ◽  
Iron And Manganese

The main contaminants of groundwater are iron and manganese compounds, increased hardness, which are removed at groundwater conditioning stations. The article reviews the existing station that was built according to a conventional design and uses the method of simplified aeration with the following filtration through high-silica sand. Assessment of the technical condition of the station showed that the elements of the building are limited to work The filters are in poor condition, some of the filters are out of service, there are concrete corrosion, destruction of finishing layers in filters’ building, internal and external corrosion of metallic pipelines and valves, which depend on he quality of transported water. Wear of the technological pipelines is over 80%. Analysis of the efficiency of the station showed that it operates at 50% capacity and at the same time does not provide standards for the hardness of drinking water. Water consumption for the station’s own needs is 1.5 times higher than it was designed. There are no processing and reusing facilities for flushing water. Results of the technical and technological inspection of the station showed that there is a need for immediate modernization of the station including the improvement of the groundwater purification technology and bringing he quality to the standards for drinking water.

scholarly journals Research on Reclamation and Activation of Moulding Sands Containing Water-Glass Hardened with Microwaves

2014 ◽  
Vol 14 (2) ◽  
pp. 105-110 ◽  
Author(s):  
M. Stachowicz ◽  
K. Granat
Keyword(s):  
Water Glass ◽  
Silica Sand ◽  
Subsequent Stage ◽  
Activation Process ◽  
Technological Properties ◽  
Scanning Microscope ◽  
Screen Analysis ◽  
Inorganic Binder ◽  
High Silica

Abstract Presented are results of a research on usability of an innovative reclamation process of microwave-hardened moulding sands containing water-glass, combined with activation of binder. After each subsequent stage of reclamation, quality of the reclaimed material was determined on the grounds of measurements of permeability and results of screen analysis. The reclaimed material was next used again to prepare new moulding sand. The sandmix based on high-silica sand prepared with water-glass grade 145, was subject to the following cyclical treatment operations: mixing components, consolidation, microwave hardening, cooling, heating the mould up to 800 °C, cooling to ambient temperature, mechanical reclamation dry and wet. It was found that the used-up and reclaimed sandmix containing water-glass is susceptible to the applied activation process of thermally reacted film of binder and, in addition, it maintains good quality and technological properties of high-silica base. Observations of surfaces of reclaimed high-silica grains with activated film of reacted inorganic binder were carried-out using a scanning microscope. Thanks to properly selected reclamation parameters, the high-silica base can be reused even five times, thus reducing demand for fresh aggregate and inorganic binder.

scholarly journals Evaluation of Microwave Heating of Protective Coatings Used in the Lost Foam Technology

2015 ◽  
Vol 15 (2) ◽  
pp. 65-70
Author(s):  
B. Opyd ◽  
K. Granat
Keyword(s):  
Protective Coating ◽  
Protective Coatings ◽  
Microwave Drying ◽  
Drying Time ◽  
Polymeric Foam ◽  
Lost Foam ◽  
Aluminium Silicates ◽  
Proper Operation ◽  
Selection Of

Abstract Presented are results of a preliminary research on determining a possibility to use microwave radiation for drying casting protective coatings applied on patterns used in the lost foam technology. Taken were measurements of permittivity ετ and loss factor tgδ at 2.45 GHz, as well as attempts were made of microwave drying of a protective coating based on aluminium silicates, applied on shapes of foamed polystyrene and rigid polymeric foam. Time and results of microwave drying were compared with the results obtained by drying at 50 °C by the traditional method commonly used for removing water from protective coatings. Analysis of the obtained drying kinetics curves demonstrated that selection of proper operation parameters of microwave equipment permits the drying time to be significantly shortened. Depending on kind of the pattern material, drying process of a protective coating runs in a different way, resulting in obtaining different quality of the dried coating.

scholarly journals Influence of additives in core-forming mixture

2017 ◽  
Vol 62 (1) ◽  
pp. 335-338
Author(s):  
I. Vasková ◽  
M. Hrubovčáková ◽  
M. Conev
Keyword(s):  
Great Emphasis ◽  
Silica Sand ◽  
Casting Defects ◽  
Labor Intensity ◽  
Casting Surface ◽  
The Core ◽  
Quality Surface

Abstract In recent years, ingredients, also known as additives, which appreciably affect the quality of the casting surface, come to the fore. Additives - lower the temperature at which SiO2 (major component of silica sand) begins to soften and create a melt on the surface of the grains, increase the reactivity and decrease the temperature of a transition to tridimite and cristobalit. These passages support the increase of volume of subsurface sand stress and the tension for the formation of burrs and other casting defects on the surface of the core or the mold. Nowadays, as a great emphasis is put on the quality of the casts, it is therefore necessary to pay attention to these additives, which can effectively reduce the labor intensity in the production of castings and ensure a quality surface of castings.

ON THE EXPERT’S RIGHT TO BE PRESENT AT LEGAL PROCEEDINGS

2016 ◽  
Vol 15 ◽  
pp. 163-171
Author(s):  
M. G. Shcherbakovskiy
Keyword(s):  
Initial Data ◽  
Legal Proceedings ◽  
Reliable Assessment ◽  
Data Acquiring ◽  
Selection Of

The article discusses the reasonsfor an expert to participate in legal proceedings. The gnoseological reason for that consists of the bad quality of materials subject to examination that renders the examination either completely impossible or compromises objective, reasoned and reliable assessment of the findings. The procedural reason consists ofa proscription for an expert to collect evidence himself or herself. The author investigates into the ways of how an expert can participate in legal proceedings. If the defense invites an expert to participate in the proceedings, then it is recommended that his or her involvement should be in the presence of attesting witnesses and recorded in the protocol. In the course of the legal proceedings an expert has the following tasks: adding initial data, acquiring new initial data, understanding the situation of the incident, acquiring new objects to be studied, including samples for examination. An expert’s participation in legal proceedings differs from the participation of a specialist or an examination on the scene of the incident. The author describes the tasks that an expert solves in the course of legal proceedings, the peculiarities ofan investigation experiment practices, the selection of samples for an examination, inspection, interrogation.

Implementasi Voip Server Berbasis IPV6 Dengan Raspberry PI

2019 ◽  
Vol 9 (01) ◽  
pp. 47-54
Author(s):  
Rabbai San Arif ◽  
Yuli Fitrisia ◽  
Agus Urip Ari Wibowo
Keyword(s):  
Internet Protocol ◽  
Wireless Transmission ◽  
Raspberry Pi ◽  
Test Results ◽  
Average Delay ◽  
Ipv6 Network ◽  
Ip Network ◽  
Selection Of ◽  
Better Than

Voice over Internet Protocol (VoIP) is a telecommunications technology that is able to pass the communication service in Internet Protocol networks so as to allow communicating between users in an IP network. However VoIP technology still has weakness in the Quality of Service (QoS). VOPI weaknesses is affected by the selection of the physical servers used. In this research, VoIP is configured on Linux operating system with Asterisk as VoIP application server and integrated on a Raspberry Pi by using wired and wireless network as the transmission medium. Because of depletion of IPv4 capacity that can be used on the network, it needs to be applied to VoIP system using the IPv6 network protocol with supports devices. The test results by using a wired transmission medium that has obtained are the average delay is 117.851 ms, jitter is 5.796 ms, packet loss is 0.38%, throughput is 962.861 kbps, 8.33% of CPU usage and 59.33% of memory usage. The analysis shows that the wired transmission media is better than the wireless transmission media and wireless-wired.

Sign in / Sign up

Export Citation Format

Share Document