Corrosion of Welded Metal Structures of Mining Equipment

2018 ◽  
Vol 69 (9) ◽  
pp. 2563-2566
Author(s):  
Dan Dobrota
Keyword(s):  
Carbon Concentration ◽  
Welded Joints ◽  
Construction Material ◽  
Working Environment ◽  
Mining Equipment ◽  
Metal Structures ◽  
Corrosion Phenomenon ◽  
Welding Regime ◽  
New Material ◽  
Initial Research

Mining equipment made of welded metal structures is strongly affected by the corrosion phenomenon due to the working conditions. Initial research has shown that the corrosion phenomenon is most pronounced in the area of cross-welded joints and welded T-shaped joints. In the researches, there was made a chemical analysis of the welded construction material used respectively of the new material and it was observed a reduction in carbon concentration in the material used, but also a substantial increase in the sulfur concentration compared to the new material. The pronounced corrosion of the metallic structure is influenced by the chemical composition change because the sulfur is a grafitizing and weakening element, and the decrease in carbon concentration causes a decrease in corrosion resistance. Also, the pronounced corrosion is due to the action of sulfurous acid (H2SO3) and hydrogen sulfide (H2S), elements that are present in the working environment of welded constructions. In order to achieve a reduction in the corrosion phenomenon, it is very important that the welded joints are made using the optimal parameters of the welding regime so as to obtain metallographic structure with finer granulations.

scholarly journals The optimization of welding regimes for obtaining corrosion resistant welded constructions

2019 ◽  
Vol 290 ◽  
pp. 01003
Author(s):  
Dan Dobrotă ◽  
Valentin Petrescu
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Welding Process ◽  
Optimal Parameters ◽  
Welding Wire ◽  
High Corrosion Resistance ◽  
Corrosion Resistant ◽  
Metal Structures ◽  
Corrosion Phenomenon ◽  
Welding Regime

Most of the technological equipment has welded metal structures in its composition, which are strongly affected by the corrosion phenomenon. In order to achieve a reduction of the corrosion phenomenon it is very important that the welded joints are made using optimal parameters of the welding regime. In the research were made 6 different welded specimens, respectively 3 for the welded T-shaped joint and 3 for the cross-welded joint. The welded joints were made of 10 mm thick using S 355JR steel by the MAG welding process and using welding wire G4 Si 1 as an additive. For the 6 specimens were made analyzes of the metallographic structure thus observing what are parameters of the welding regime that allows to obtain the welded joints with high corrosion resistance.

scholarly journals Evaluation of crack resistance of welded joints with soft interlayers

2022 ◽  
Vol 21 (4) ◽  
pp. 308-311
Author(s):  
K. A. Molokov ◽  
V. V. Novikov
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Crack Resistance ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Transverse Load ◽  
Structural Elements ◽  
Metal Structures ◽  
Characteristic Appearance ◽  
Reliability Indicator

Introduction. Welded joints in large-sized metal structures (e.g., in the structures of ship hulls) subject to low-cycle fatigue are considered. The characteristic appearance of soft interlayers, which are significantly plastically deformed under working loads, was noted. Deformation of the metal structure with damage, especially in the form of cracks, reduces the strength and reliability of structural elements and joints. Pre-deformation negatively affects plasticity; therefore, much depends on the residual plasticity of the cracking material. At the same time, with a decrease in residual plasticity, such an important reliability indicator as the resistance of the material to crack propagation — the fracture toughness – decreases. The paper is devoted to the development of a model that includes analytical dependences for assessing the crack resistance of metal structures and their welded joints with soft interlayers according to the crack resistance limit for all crack sizes.Materials and Methods. The theory and methods of linear mechanics of materials destruction, structural-mechanical approach are used. The calculation results were analyzed and compared to the experimental data and other analytical solutions. The numerical experiment was performed for the ferrite-perlite steel grades of 10, 50, 22K, St3sp, etc., widely used in industry, as well as for alloy steels hardened to medium and high strength of 30KhGSA, 37KhN3A, etc. Results. Analytical dependences are obtained for calculating the relative crack resistance limit according to three main known mechanical characteristics of the state of the material of the soft interlayer of the welded joint.Discussion and Conclusions. The results obtained can be used to assess the crack resistance of pre-deformed structural elements and welded joints (including those with soft interlayers) operating under a transverse load. The results of experimental data and analytical calculations are shown in dimensionless form, which enables to obtain invariant results with respect to the fracture toughness limit.

scholarly journals Properties of welded joints of metal structures after hardening deformation-heat treatment

2014 ◽  
Vol 2 (1(16)) ◽  
pp. 57
Author(s):  
Алла Петрівна Штихно ◽  
Валерій Іванович Алімов ◽  
Олександр Олександрович Полянський ◽  
Дмитро В’ячеславович Васютченко
Keyword(s):  
Heat Treatment ◽  
Welded Joints ◽  
Metal Structures

Active methods of teaching mathematics in primary school

2020 ◽  
Vol 60 (11) ◽  
pp. 173-176
Author(s):  
Ainura Oktay Binnatova ◽  
◽  
Valida Igor Agaeva ◽  
Ilaha Iltifat Rzaeva ◽  
◽  
...  
Keyword(s):  
Teaching Methods ◽  
Cluster Structure ◽  
Positive Mood ◽  
Educational Process ◽  
Working Environment ◽  
Teaching Mathematics ◽  
Mathematics Problem Solving ◽  
New Knowledge ◽  
New Material ◽  
Mathematics Problem

Active methods at the beginning of the educational process help the teacher to provide a certain working environment and positive EU weather. Such methods include “greeting with your elbows”, “greeting with your eyes”, aimed at ensuring the positive mood of students. Active methods of detection of goals, expectations and resources can include such methods as “Orchard”, “Lemon Tree”, “snowflake Meadow”, “Brain storming”, “cluster structure” and other methods aimed at introducing the new material with interest and introducing students into the process of searching for new knowledge can be included in the active methods related to the presentation of the lesson material. Key words: teaching methods, active methods, goals, tasks, mathematics, problem solving, activation of thinking, independence

Analysis on the Steady-state Performance and Losses of a Bent-axis Type Hydraulic Motor Used in Heavy Earth Moving Machinery

2021 ◽  
Author(s):  
Ajit Kumar Pandey ◽  
Amit Kumar ◽  
Nitish Kumar
Keyword(s):  
Steady State ◽  
Electric Motor ◽  
Underground Mining ◽  
Operating Conditions ◽  
Constant Speed ◽  
Working Environment ◽  
Variable Load ◽  
Mining Equipment ◽  
Mining Operations ◽  
Design Guideline

Hydraulic components play a significant role in the mining and construction equipment. It is responsible for smooth change in the output speed, torque, and power of the machine. The hydrostatic drive powered by a constant speed electric motor is widely used in the propel system of the mining equipment. Regulation of the displacements of the pump and the hydro-motor of the drive facilitates the control of the straight running and steering of the machines. In the present scenario, better efficiency and ease of control are the critical aspects to be considered in the design and selection of the hydraulic pump and motor used in underground mining operations. The bent axis hydro-motor is one such equipment that is an electro-hydraulic component that can work in an adverse working environment. The present study deals with the performance analysis of fixed displacement bent axis hydro-motor at different operating parameters such as different temperatures, sizes, viscosity at different loads, and drive speed. For analysis, the hydraulic drive consists of a variable displacement pump rotated by a constant speed electric motor and a fixed displacement hydro-motor. The regulation of the pump displacement controls the speed of the drive. Manually controlled hydrostatic drive propels the said machine against variable load demands. The present work investigates the performances of the hydro-motor used in the mining and construction machine through detailed modeling and experimentations. The steady-state performances are analyzed in terms of slip, torque losses and efficiency of the hydro-motor. The study finds the design guideline to operate the hydrostatic drive using such motors in a reasonable efficiency zone. The model is validated for various operating conditions of the equipment by comparing the predicted results with the test results. The outcome of the present work will be expedient for the preliminary design and assortment of similar hydraulic component used in the mobile, mining equipment.

Application of Wood-Plastic Composites in Exhibition Design

2014 ◽  
Vol 496-500 ◽  
pp. 2416-2420 ◽  
Author(s):  
Yue Lei ◽  
Lun Li
Keyword(s):  
Early Stage ◽  
Construction Material ◽  
Chemical Properties ◽  
Exhibition Design ◽  
Wood Plastic Composites ◽  
Plastic Composites ◽  
Rapid Fabrication ◽  
Project Construction ◽  
New Material ◽  
Physical And Chemical

Mostly used in packing and outdoor facilities in the early stage, wood-plastic composites are gradually applied to other design sectors thanks to their advantageous features including cost efficiency, environmental protection, recyclability as well as being easy to be processed and fabricated. The application of this kind of green and new material in the exhibition design sector will be beneficial to developing the standardized structure and rapid fabrication in the exhibition design to save the project construction material costs and shorten erection time. In this article, the feasibility and ecological significance of using wood-plastic composites in the exhibition sector are explored from the aspects of the physical and chemical properties of the wood-plastic composites as well as their processing methods.

scholarly journals Use of Steel Industry Wastes for the Preparation of Self-Cleaning Mortars

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 621 ◽  
Author(s):  
José Balbuena ◽  
Luis Sánchez ◽  
Manuel Cruz-Yusta
Keyword(s):  
Steel Industry ◽  
Diffuse Reflectance ◽  
Construction Material ◽  
Added Value ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
New Material ◽  
Lamination Process ◽  
Self Cleaning

An important problem, which must be solved, is the accumulation of industrial waste in landfills. Science has an obligation to transform this waste into new products and, if possible, with high added value. In this sense, we propose the valorization of the waste which is generated in the steel lamination process (HSL) through its conversion into a new material with photocatalytic activity which is suitable for use as an additive to obtain a self-cleaning construction material. The valorization of steel husk lamination waste is achieved through a grinding process, which allows the sample to be homogenized, in size, without altering its phase composition, and a thermal treatment that turns it into iron oxide, which acts as a photocatalyst. These residues, before and after treatment, were characterized by different techniques such as PXRD (Powder X-Ray Diffraction), TGA (Thermogravimetric Analysis), SBET (Specific surface area, Brunauer-Emmett-Teller), SEM (Scanning Electron Microscopy) and Diffuse reflectance (DR). MB and RhB tests show that this material is capable of self-cleaning, both of the material itself and when it is incorporated into a construction material (mortar). In addition, the NOx gas elimination test shows that it is also capable of acting on greenhouse gases such as NOx.

scholarly journals Rheodynamic Concrete as a Progressive Viability in the field of Concrete Technology

2020 ◽  
Vol 9 (3) ◽  
pp. 319-327
Keyword(s):  
Fly Ash ◽  
Rice Husk Ash ◽  
Construction Material ◽  
Working Environment ◽  
Construction Work ◽  
Self Compacting Concrete ◽  
Concrete Technology ◽  
The World ◽  
By Products ◽  
Safe Working

The most important material which is used for the construction of any concrete structure is concrete itself. It is considered to be as a versatile construction material as its properties can be changed by various means, with the help of different elements and as and when required. Rheodynamic Concrete or Self-Compacting Concrete is a special form of concrete which can easily flow into any kind of formwork uniformly, without facing the problem of bleeding and segregation, gives a better finish, has a great characteristic of placement, requires no vibration, and thus gives a safe working environment. Due to a number of merits, this type of concrete had becoming popular in the construction work. Simultaneously, the big industries across the world are producing the by products such as fly ash, rice husk ash, etc. Thus, this paper represents a review, which is done to incorporate these wastes by – products in Self-Compacting Concrete and observe, how the different properties of the same has been modified effectively and efficiently.

THE STUDY ON THE PROPERTIES OF Ca CONCRETE UNDER NATURAL ENVIRONMENT

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Atsushi Shimabukuro
Keyword(s):  
Compressive Strength ◽  
Natural Environment ◽  
Construction Material ◽  
Past Research ◽  
Cement Concrete ◽  
Natural Exposure ◽  
New Material ◽  
Urban Heat ◽  
Water Absorbability ◽  
Entrained Air

The Ca-based solidification material has neutrality so that it would be expected to be new material to reduce environmental load instead of cement in the construction field. The concrete using this material, which is Ca concrete, is useful for construction material from past research. In previous researches, we showed that the compressive strength of Ca concrete and the compressive strength of AE concrete, which contains the entrained air, had nearly equal strength under same mixture condition, and the behavior under compression loading of Ca concrete showed a tendency similar to cement concrete. Also, the compressive strength of Ca concrete obtained the stable strength when it had the curing for four weeks. Therefore, Ca concrete would be used in the same way as cement concrete for construction field. This study investigates to consider further properties of Ca concrete. Particularly, it is paid attention to the water absorbability, water retentivity, and the compressive strength under natural environment. As a result, it is clear that the Ca concrete has the higher water absorbability and the water retentivity as compared with cement concrete and the compressive strength of Ca concrete under natural exposure does not decrease even if the length of natural exposure passes for 104 weeks. Hence, the Ca concrete would apply to construction material under natural environment as one of the measures against urban heat island phenomenon.

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