Nonmetallic inclusions in rails made of electro-steel alloyed with chromium

2020 ◽  
Vol 62 (12) ◽  
pp. 936-942 ◽  
Author(s):  
A. A. Umanskii ◽  
A. V. Golovatenko ◽  
A. S. Simachev
Keyword(s):  
Hot Deformation ◽  
Ultrasonic Testing ◽  
Nonmetallic Inclusions ◽  
Relative Concentration ◽  
Metallographic Analysis ◽  
High Ductility ◽  
High Concentration ◽  
Metallic Inclusions ◽  
Significant Concentration

Type, relative concentration and size of most characteristic non-metallic inclusions for the elements of rails (head, web) from electro-steel of E79KhF and E90KhАF grades were determined on the basis of metallographic (with a microscope “OLYMPUS GX-51”) and spectral (using spectrometer “ARL iSpark” method “Spark-DAT”) analyses. It was found that the highest relative concentration of manganese sulfides (MnS) is 30.8 – 43.4 ppm. At the same time, 60 – 100 % of inclusions of this type are of small sizes (less than 4 μm), and it does not allow them to be detected using standard metallographic analysis with 100-fold magnification. The revealed high relative concentration of sulfide inclusions directly correlates with the established positive sulfur liquation in considered rail elements, which is up to 40 %. Despite the high concentration of manganese sulfides, their influence on the quality of rails can be considered not dangerous, taking into account their high ductility during hot deformation and the established prevalence of inclusions of this type with small size (less than 4 μm). Among inclusions of a silicate type, SiO2 inclusions (3.4 – 14.9 ppm) have a significant concentration. All detected inclusions of this type have a size not exceeding 4 μm. It was found that the concentration of complex inclusions containing alumina (Al2O3 – CaO – MgO, Al2O3 – CaO – MgO – CaS, Al2O3 – CaO, Al2O3 – MgO) is insignificant: in total it does not exceed 3.1 ppm and 1.6 ppm for individual types. The concentration of corundum (Al2O3) is also insignificant and does not exceed 0.3 ppm. In this case, alumina inclusions of small size (less than 6 μm) prevail. Due to the low contamination (taking into account the relative concentration and size of inclusions) with non-plastic silicate and alumina non-metallic inclusions, their influence on the quality of the rails was not significant. It is confirmed by the absence of defects detected during ultrasonic testing.

Research of quality of high-strength shipbuilding steel with high concentration of calcium

2019 ◽  
pp. 20-26
Author(s):  
V. G. Miliuts ◽  
V. V. Tsukanov ◽  
A. G. Pavlov ◽  
D. L. Smirnova
Keyword(s):  
Calcium Concentration ◽  
Nonmetallic Inclusions ◽  
High Strength ◽  
Calcium Content ◽  
Mechanical Tests ◽  
High Concentration ◽  
Shipbuilding Steel ◽  
Metallic Inclusions ◽  
Aluminum Deoxidation

The paper studies the microstructure, presence and qualitative composition of nonmetallic inclusions, mechanical tests of industrial smelting of high-strength shipbuilding steel with calcium concentration in the bucket sample of 0.009% have been performed. Steel with a high concentration of calcium is contaminated with a variety of stitch oxide inclusions, and therefore the mechanical properties of the rolled product are sharply reduced (impact strength, ductility in the Z-direction, fracture quality of technological samples). It is shown that the upper permissible limit of calcium content in steel is within the range 0.004–0.009%, but it is necessary to clarify it performing additional research. To ensure high purity of high-strength shipbuilding steel for non-metallic inclusions, it is vital to observe a strictly regulated technology of aluminum deoxidation and modification by ferrocalcium with obtaining the content of these elements in the metal in the previously recommended limits 0.01–0.02 and 0.002–0.004% respectively.

scholarly journals CONTENT MODIFICATION OF DIFFERENT TYPES OF NONMETALLIC INCLUSIONS DURING LOW-CARBON IF STEEL LADLE TREATMENT

2019 ◽  
Vol 62 (5) ◽  
pp. 345-352 ◽  
Author(s):  
D. V. Gorkusha ◽  
K. V. Grigorovich ◽  
A. V. Karasev ◽  
O. A. Komolova
Keyword(s):  
Nonmetallic Inclusions ◽  
Ladle Treatment ◽  
Gas Analysis ◽  
Metallographic Analysis ◽  
Steel Ladle ◽  
Interstitial Free ◽  
If Steel ◽  
Low Carbon ◽  
Metallic Inclusions ◽  
Fractional Gas Analysis

Development of advanced materials for the automotive industry allows us to produce a lighter body without losing strength characteristics of the structure. It became possible by the creation and subsequent introduction into the production of such steel grades as IF (Interstitial Free) – steel with no interstitial solute atoms to strain the solid iron lattice and IF-BH (Bake Hardening) – steel with hardening during hot drying. The article provides a brief overview of the history of the emergence of IF steel and the current situation in the production of it in Russia. One of the quality criteria for steels of IF grades is purity of the metal by non-metallic inclusions (NMI), which negatively affect the plastic properties of the material, lead to the formation of surface defects of flat rolled products and reduce the manufacturability due to a decrease in the casting speed of steel, as they cause overgrowing of steel casting nozzles. The article presents investigation results of the content, composition, size and morphology of non-metallic inclusions (NMI) in the metal samples taken at all stages of ladle treatment and casting of IF steel grade production using quantitative metallographic analysis, electrochemical dissolution (ED) followed by X-ray microanalysis of isolated inclusions, Auger electron spectroscopy and fractional gas analysis (FGA). As a result of the analysis of inclusions in the studied samples using a scanning electron microscope, according to morphological features, five characteristic types of inclusions were identified, which reduce the performance properties and strength cha racteristics of the materials produced from them. Results of the analysis of nonmetallic inclusions in metal samples obtained by the ED method are in good agreement with the results of the determination of oxide nonmetallic inclusions by the FGA method. The method of fractional gas analysis shows the dynamics of changes in the content of various types of oxide nonmetallic inclusions during the secondary (ladle) treatment of steel. It is shown that application of the FGA method allows to make analysis of causes of the harmful NMI formation in the metal and to correct operations at ladle treatment.

The Study of Nonmetallic Inclusions Formation for Kaplan Blades during the Solidification Process

2017 ◽  
Vol 891 ◽  
pp. 113-118
Author(s):  
Cinca Ionel Lupinca ◽  
Constantin Marta ◽  
Cristian Fanica ◽  
Ana Maria Budai
Keyword(s):  
Nonmetallic Inclusions ◽  
Solidification Process ◽  
Chemical Parameters ◽  
River Waters ◽  
Casting Technology ◽  
Physical Chemical ◽  
Metallic Inclusions ◽  
Hydraulic Turbines ◽  
Elaboration Process

The exploitation durability of Kaplan hydraulic turbines blades is first of all determined by their structure, by the steel elaboration technology, respectively by the content of non-metallic inclusions and later by the physical-chemical parameters of the exploitation environment.This paper presents a study regarding the situations in which the elaboration-casting technology of Kaplan blades using alloyed austenitic stainless steel, X5CrNiMo17-13-3 which has an important role in the quality of castings. Thus, the authors verify the formation of sulfides and of oxi-sufides during the steel elaboration process, treatment during a liquid state and their influence in the castings behavior to wearing. It is a well known fact that the presence of sulfides and oxi-sufides in the cast blades structure accelerates the corrosion process in contact with river waters.

Modifying and Micro-Alloying Effect on Carbon Steels Microstructure

2021 ◽  
Vol 316 ◽  
pp. 359-363
Author(s):  
Ainagul Toleuova ◽  
Gulnaz Musina ◽  
Saule Kaldybayeva
Keyword(s):  
Nonmetallic Inclusions ◽  
Cast Steel ◽  
High Surface ◽  
Carbon Steels ◽  
Metallographic Analysis ◽  
Alloying Effect ◽  
Metallic Inclusions ◽  
The Matrix ◽  
Resistance To Brittle Fracture ◽  
High Surface Activity

Small additives of elements exhibiting high chemical activity with respect to iron and impurities, included in its composition, have a complex effect on the structure and properties of steel. Moreover, as a result of the modifying and refining effect of micro-additives, the amount, dispersion and morphology of nonmetallic inclusions change, and when alloying the matrix, hardenability, uniformity of structure and resistance to brittle fracture of steels change, too. The article presents a metallographic analysis of carbon steel deoxidized by a complex Са – Ва alloy. Deoxidation of steel using the complex Са – Ва alloy allows significant reducing the content of nonmetallic inclusions, modifying residual nonmetallic inclusions into favorable complexes with their uniform distribution in the volume of steel, and significant increasing the mechanical properties of steel. The high surface activity of barium makes it possible to consider barium as a rather effective modifier. The use of barium in alloys leads to grinding of non-metallic inclusions, homogenization of liquid metal, lowering the liquidus temperature, grinding of primary grains of cast steel, and increasing technological ductility.

Ground water quality of selected areas of Punjab and Sind Provinces, Pakistan: Chemical and microbiological aspects

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Ionic Concentration ◽  
Chloride Ions ◽  
Potassium Ions ◽  
Ammonium Ions ◽  
High Concentration ◽  
Phosphate Ions ◽  
Sodium Magnesium ◽  
Very High ◽  
Microbiological Aspects

The assessment of groundwater is essential for the estimation of suitability of water for safe use. An attempt has been made to study the groundwater of selected areas of Punjab (Sheikhupura & Sahiwal) and Sindh (Sindh, Jawar Dharki and Dharki), Pakistan. The results indicate that pH, color and odor were all within limits of WHO that is pH ranges 6.5–8.5, colorless and odorless, respectively. The high values of suspended solids were observed in the Sindh-1 and Dharki samples. Microbiologically only Sahiwal and Jawar Dharki were found fit for drinking purpose. Trace metals analysis of Sheikhupura-1 and Sindh-1 showed that values do not fall within limits of WHO for Iron. The ionic concentration analysis showed that high bicarbonate (HCO3-), ions are present in the samples of Sahiwal and Dharki; Sindh-1 and Jawar Dharki samples showed very high concentration for chloride ions, all samples were satisfactory level for sulphate (SO42-), sodium, magnesium and phosphate ions except samples of Sindh-1 and Jawar Dharki. High concentration of calcium and potassium ions was observed in samples of Sindh-1, while all other samples were found fit for drinking purposes in respect of nitrate, nitrite and ammonium ions. The high concentration of Fluoride was found only in Sheikhupura-2 samples.

Benefits of Using Diamond Dies for Cold Alternate Drawing of Magnesium Alloys

2016 ◽  
Vol 716 ◽  
pp. 13-21 ◽  
Author(s):  
Vladimir Stefanov Hristov ◽  
Kazunari Yoshida
Keyword(s):  
Magnesium Alloy ◽  
Weight Ratio ◽  
High Strength ◽  
Wire Drawing ◽  
High Ductility ◽  
Element Analysis ◽  
The Wire ◽  
Shearing Strain ◽  
Drawing Method

In recent years, due to its low density and high strength/weight ratio, magnesium alloy wires has been considered for application in many fields, such as welding, electronics, medical field (for production of stents). But for those purposes, we need to acquire wires with high strength and ductility. For that we purpose we proposed alternate drawing method, which is supposed to highly decrease the shearing strain near the surface of the wire after drawing, by changing the direction of the wire drawing with each pass and thus acquiring high ductility wires.We have done research on the cold alternate drawing of magnesium alloy wires, by conducting wire drawing of several magnesium wires and testing their strength, hardness, structure, surface and also finite element analysis, we have proven the increase of ductility at the expense of some strength.In this research we are looking to further improve the quality of the drawn wires by examining the benefits of using diamond dies over tungsten carbine dies. Using the alternate drawing method reduces the strength of the drawn wires and thus lowering their drawing limit. By using diamond dies we are aiming to decrease the drawing stress and further increase the drawing limit of the alternate drawn wires and also improve the quality of the finishing surface of the wires. With this in mind we are aiming to produce a good quality wire with low diameter, high ductility, high strength and fine wire surface.

scholarly journals STUDIES ON THE BACTERIOPHAGE OF D'HERELLE

1925 ◽  
Vol 42 (4) ◽  
pp. 483-497 ◽  
Author(s):  
Jacques J. Bronfenbrenner ◽  
Charles Korb
Keyword(s):  
Quantitative Evaluation ◽  
Bacterial Species ◽  
Relative Concentration ◽  
Serial Dilution ◽  
The Other ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
High Concentration ◽  
Average Size ◽  
Broth Dilution

The experiments reported above confirm the fact that lytic principle is distributed in active solution in a state of indivisible units. This permits its quantitative evaluation by serial dilution, as well as by plating on agar. The latter method, however, often gives readings considerably lower than those obtained by the broth dilution method of titration. By varying the concentration of agar it has been possible to show that the discrepancy is due to adsorption of the lytic agent on agar. When the concentration of the latter is increased from 0.3 per cent to 2.5 per cent the number of plaques of lysis is reduced more than 100 times. At the same time the average size of the plaques also decreases approximately to one-tenth of the original. The size, as well as the number of plaques, has been found to depend also on the condition of the culture employed in titration. Thus, when the culture exposed to the action of lytic agent is composed of young susceptible bacteria, the greater the concentration of bacteria, the smaller the plaques. When the culture is composed partly of young and partly of old susceptible bacteria, both the size and the number of the plaques are diminished with the increase in the relative concentration of old bacteria. On the other hand, presence in the culture of resistant bacteria does not affect either the size or the number of the plaques so long as the relative concentration of susceptible bacteria in the culture is sufficient to allow formation of them. The plaques appearing in the presence of a high concentration of resistant variants in the culture are relatively indistinct owing to overgrowth. Under carefully controlled conditions the size of plaques is found to be determined by the character of the lytic filtrate. Thus in the case of lytic agents which act upon more than one bacterial species the size of the plaques remains constant, irrespective of the bacterial substratum used for the production of the active filtrate.

Features of ultrasonic control of butt welded joints of polyethylene pipes

2020 ◽  
pp. 46-52
Author(s):  
N.P. Aleshin ◽  
D.M. Kozlov ◽  
L.YU. Mogilner
Keyword(s):  
Quality Control ◽  
Welded Joints ◽  
Ultrasonic Testing ◽  
Ultrasonic Inspection ◽  
Mechanical Tests ◽  
Ultrasonic Control ◽  
Lack Of Fusion ◽  
Polyethylene Pipes ◽  
End To End

The reliability of ultrasonic testing (UT) of the quality of welded joints of polyethylene pipelines, made end-to-end with a heated tool, is considered in comparison with mechanical tests and radiography. The greatest detection of solid defects is provided by ultrasonic inspection with the use of chord tipe probes (not less than 90 %). When detecting defects translucent for ultrasound (lack of penetration, lack of fusion, etc.), the reliability decreases to 70÷80 %. Keywords: welding, polyethylene pipeline, quality control, ultrasonic testing, chord tipe probe. [email protected]

Species Composition of the Lichen Biota in Industrially Polluted Territories of Leninsky District of Irkutsk

2021 ◽  
Vol 31 (4) ◽  
pp. 541-545
Author(s):  
Evgeny Kharin ◽  
Olga Belykh
Keyword(s):  
Species Composition ◽  
Morphological Changes ◽  
Environmental Damage ◽  
High Concentration ◽  
Passive Monitoring ◽  
Industrial Pollutants ◽  
Lichen Biota ◽  
Complex Influence ◽  
Lichen Indication

In the context of the development of infrastructure in Siberian cities, the issues of the state of the areas with accumulated environmental damage is especially relevant. It is mentioned in the article that lichen indication is an efficient method of passive monitoring of environment for industrial pollutants caused by morphological changes occurring in sensitive objects. The results of the lichen floristic research of Leninsky district of Irkutsk are presented, a list of revealed lichens including 9 genera and 12 species is given, a taxonomic list of this area is discussed. Lichenological objects were mapped. Distribution of lichens in the area of research is investigated with regard to the presence of recreational and residential zones. The authors draw a conclusion about the presence of «lichens deserts» which are caused both by the absence of the respective substratum and high concentration of pollutants. High concentration of pollutants is caused by complex influence of different enterprises on the quality of air.

Assessment of the quality of spot-welded joints by ultrasonic testing

2006 ◽  
Vol 20 (5) ◽  
pp. 350-354
Author(s):  
A Ambroziak ◽  
Z Koralewicz ◽  
M Korzeniowski ◽  
P Kustron
Keyword(s):  
Welded Joints ◽  
Ultrasonic Testing ◽  
Spot Welded
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