scholarly journals TUNGSTEN RECOVERY FROM OXIDE DURING FLUX CORD WIRE SURFACING

2019 ◽  
Vol 62 (3) ◽  
pp. 215-221
Author(s):  
N. A. Kozyrev ◽  
R. E. Kryukov ◽  
V. M. Shurupov ◽  
N. V. Kibko ◽  
L. P. Bashchenko
Keyword(s):  
Chemical Composition ◽  
Nonmetallic Inclusions ◽  
Tungsten Powder ◽  
Aluminum Production ◽  
Metallographic Analysis ◽  
Austenite Grain Size ◽  
Cored Wire ◽  
Gas Cleaning ◽  
Primary Austenite ◽  
Austenite Grain

 Influence of introduction of tungsten powder and tungsten concentrate into surfacing flux-cored wire on structure, structural components microhardness, hardness and wear of the surfacing layer has been studied. Flux cored tungsten-containing wires of H- and E-types according to the IIW classification were manufactured for surfacing in laboratory. Powders of silicon KR-1 (GOST 2169 – 69), manganese MR-0 (GOST 6008 – 82), chromium PKhA-1M (industrial standard TU 14-1-1474 – 75), vanadium VEL-1 (industrial standard TU 48-0533 – 71), nickel PNK-1l5 (GOST 9722 – 97), aluminum PAP-1 (GOST 5494 – 95), tungsten PVT (industrial standard TU 48-19-72 – 92) and iron powder PZhV-1 (GOST 9849 – 86) were used as fillers. In some wires tungsten concentrate KSh-4 (GOST 213 – 83) produced by “AIR” mining company” JSC was used instead of tungsten powder. Gas cleaning dust of aluminum production of the following chemical composition: 21.00 – 43.27 % Al2O3; 18 – 27 % F; 8 – 13 % Na2O; 0.4 – 6.0 % K2O; 0.7 – 2.1 % CaO; 0.50 – 2.48 % SiO2; 2.1 – 2.3 % Fe2O3; 12.5 – 28.2 % Cgen; 0.03 – – 0.90 % MnO %; 0.04 – 0.90 % MgO; 0.09 – 0.46 % S; 0.10 – – 0.18 % P (by weight) was used as a carbon-containing reducing agent. Wire with diameter of 5mm manufactured at laboratory installation ASAW 1250 tractor was used for surfacing. Surfacing modes were: Is = 400 – 450 A; Ud = 32 ÷ 36 V; Vs = 24 ÷ 30 m/h. Surfacing was performed under a layer of AN-26S flux and flux made of silicomanganese slag; number of deposited layers – 5. Chemical composition of deposited metal was determined, metallographic analysis of deposited layer was carried out: size of the former austenite grain, size of martensite needles, degree of contamination by nonmetallic inclusions were stated and wear tests were carried out, hardness and microhardness were measured. The possibility in principal of using tungsten concentrate instead of tungsten powder in studied flux cored wires is shown, degree of tungsten extraction was calculated. For H-type fluxcored wire, introduction of tungsten concentrate instead of tungsten powder into the charge of wire does not increase contamination of deposited layers with nonmetallic inclusions and reduces size of the primary austenite grain. Use of tungsten concentrate in E-type flux-cored wire manufacturing helps to reduce size of the primary austenite grain and size of martensite needles, increasing microhardness of martensite in structure of deposited layer. Introduction of tungsten concentrate instead of tungsten powder into the composition of the charge of H-type wire provides a significant increase in hardness and wear resistance of deposited layer.

scholarly journals Study of properties of cored wire based on ferrochrome gas-cleaning dust

2019 ◽  
Vol 75 (3) ◽  
pp. 365-372 ◽  
Author(s):  
N. A. Kozyrev ◽  
A. A. Usol’tsev ◽  
A. N. Prudnikov ◽  
R. E. Kryukov ◽  
A.. R. Mikhno
Keyword(s):  
Wear Resistance ◽  
Chemical Composition ◽  
Statistical Processing ◽  
Aluminum Production ◽  
Recovery Coefficient ◽  
Cored Wire ◽  
Gas Cleaning ◽  
Filling Materials ◽  
Study Results ◽  
Cored Wires

Applying of wear-resistant alloyed coatings by build-up welding is one of methods to provide high operation properties of technological, metallurgical in particular equipment. Technologies of strengthening by direct alloying or reducing of alloying materials from oxide phases by reducing agent directly in the arc during building-up are most efficient ones. For build-up, cored wires are used frequently nowadays. A possibility to manufacture cored wires based on ferrochrome production gas-cleaning dust and powders of silicon, aluminum, and aluminum production gas-cleaning dust as reducing agents considered. Chemical composition and relation between cored wires components quoted. Manufacturing of 5 mm diameter wire accomplished at laboratory facility by running through draw plate. Duringestimation of efficiency of the manufactured cored wires application a regime of build-up was selected, study of chemical composition of built-up metal carried-out, wearing tests made, measuring of built-up samples hardness carried-out. Coefficients of chrome recovery coefficient at different relation between filling materials were calculated. Statistical processing of the study results accomplished statistical dependences of components content influence onthe built-up layer properties plotted. Study of the built-up showed, that chrome recovery in the built-up layer depends completely on the cored wire filling coefficient. At that under other conditions being equal, the hardness always correlates with the wear, and increase of chrome concentration results in reduction of the surface wear. Dependents of mass share elements comprising the cored wire content on built-up layer hardness and its wear resistance determined. The dependences obtained can be used for forecasting of builtup layer hardness and its wear resistance while built-up metal chemical composition varying.

scholarly journals V. Development of new powder wires for building-up. A powder wire based on dust of gas cleaning systems of silicomanganese

2018 ◽  
pp. 101-106
Author(s):  
N. A. Коzyrev ◽  
R. E. Kryukov ◽  
A. S. Nepomnyaschikh ◽  
A. A. Usol’tsev ◽  
М. V. Popova
Keyword(s):  
Chemical Composition ◽  
Nonmetallic Inclusions ◽  
Statistical Processing ◽  
Optical Microscope ◽  
Aluminum Production ◽  
Production Plant ◽  
Powder Wire ◽  
Gas Cleaning ◽  
Study Results ◽  
Wear Tests

A new powder wire developed by using dust of gas cleaning systems of silicomanganese production plant and powder of gas cleaning systems of aluminum production at different proportion of components. As components the following was used: dust of gas cleaning systems of aluminum production plant, % (mas.): 21–46.23 Al2O3; 18–27 F; 8–15 Na2O; 0.4–6 K2O; 0.7–2.3 CaO; 0.5–2.48 Si2O; 2.1–3.27 Fe2O3; 12.5–30.2 Ctotal; 0.07–0.9 MnO; 0.06–0.9 MgO; 0.09–0.19 S; 0.1–0.18 P, and dust of gas cleaning systems of silicomanganese production plant, % (mas.): 2.43 Al2O3; 1.32 Na2O; 5.56 K2O; 6.4 CaO; 29.19 SiO2; 0.137 BaO; 7.54 MgO; 0.23 S; 0.04 P; 1.067 Fe; 27.69 Mn; 2.687 Zn; 3.833 Pb.The building-up was done under a flux, made of slag of silicomanganese plant of Zapadno-Sibirsky steel-works, havin the chemical composition (%, mas.): 6.91–9.62 Al2O3; 22.85–31.70 CaO; 46.46–48.16 SiO2; 0.27–0.81 FeO; 6.48–7.92 MgO; 8.01–8.43 MnO; 0.28–0.76 F; 0.26–0.36 Na2O; 0.62 K2O; 0.15–0.17 S; 0.01 P. The building-up mode selected. Samples wear tests were carried out at machine 2070 СМТ-1. Chemical composition of the built-up metal was determined at spectrometer ДФС-71. The hardness of built-up layers was measured by hardness meter МЕТ-ДУ. The estimation of nonmetallic inclusions was made as per GOST 1778– 70 by optical microscope Olympus GX-51.Quality indices studied and coefficients of manganese recovery at different proportions of components calculated. Statistical processing of the study results was made, statistical curves of influence of component compositions on properties of built-up layer constructed.

Effect of Heat Treatment and of Primary Austenite Grain Size on the Minimum Size of Detectable Defect on 26NiCrMoV11.5 High Strength Steel

2013 ◽  
Vol 16 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Silvia Barella ◽  
Andrea Gruttadauria ◽  
Carlo Mapelli ◽  
Davide Mombelli ◽  
Claudia Lisiane Fanezi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
High Strength Steel ◽  
High Strength ◽  
Minimum Size ◽  
Austenite Grain Size ◽  
Primary Austenite ◽  
Austenite Grain

The Nitrogen Content Effect on Carbonitride Coagulation in 40Cr8 Steel with Micro-Additions V and V + Al

2013 ◽  
Vol 58 (2) ◽  
pp. 607-611 ◽  
Author(s):  
E. Głowacz ◽  
H. Adrian ◽  
W. Osuch
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Grain Size ◽  
Nitrogen Content ◽  
Grain Growth ◽  
Metallographic Analysis ◽  
Coagulation Rate ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Austenite Grain Growth

The work examines the effect of nitrogen and micro-additions V and V+Al on the austenite grain size and the coagulation of carbonitride precipitates in 40Cr8 steel. The analyzed materials underwent heat treatment consisting in holding the material at 1200ºC for 1h, which was next exposed to furnace cooling down to 820ºC and maintained at this temperature for 20hrs, and subsequently quenched in water. With the application of electron microscopy, the microstructure and the formed carbonitride precipitates were examined. The SigmaScanPro software was used to perform the quantitative metallographic analysis of the precipitates. The study demonstrated that increase in the content of nitrogen inhibits the coagulation rate of carbonitrides, whereas aluminium favours the tendency for coagulation and efficiently inhibits the austenite grain growth.

scholarly journals A New Systematic Approach Based on Dilatometric Analysis to Track Bainite Transformation Kinetics and the Influence of the Prior Austenite Grain Size

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 324
Author(s):  
David San-Martin ◽  
Matthias Kuntz ◽  
Francisca G. Caballero ◽  
Carlos Garcia-Mateo
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Prior Austenite ◽  
Bainitic Transformation ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

This investigation explores the influence of the austenitisation heat treatment and thus, of the prior austenite grain size (PAGS), on the kinetics of the bainitic transformation, using as A case study two high-carbon, high-silicon, bainitic steels isothermally transformed (TIso = 250, 300, 350 °C), after being austenised at different temperatures (γTγ = 925–1125 °C). A methodology, based on the three defining dilatometric parameters extracted from the derivative of the relative change in length, was proposed to analyse the transformation kinetics. These parameters are related to the time to start bainitic transformation, the time lapse for most of the transformation to take place and the transformation rate at the end of the transformation. The results show that increasing the PAGS up to 70 µm leads to an increase in the bainite nucleation rate, this effect being more pronounced for the lowest TIso. However, the overall transformation kinetics seems to be weakly affected by the applied heat treatment (γTγ and TIso). In one of the steels, PAGS > 70 µm (γTγ > 1050 °C), which weakly affects the progress of the transformation, except for TIso = 250 °C, for which the enhancement of the autocatalytic effect could be the reason behind an acceleration of the overall transformation.

scholarly journals Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1988
Author(s):  
Tibor Kvackaj ◽  
Jana Bidulská ◽  
Róbert Bidulský
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Strength Steel ◽  
Single Phase ◽  
Hsla Steel ◽  
High Strength ◽  
Strength Properties ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Steel Grades

This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.

The effect of austenite grain size on deformation mechanism of Fe–17Mn steel

2021 ◽  
Vol 809 ◽  
pp. 140972
Author(s):  
Jin-Young Lee ◽  
Jin-Sung Hong ◽  
Seok-Hyeon Kang ◽  
Young-Kook Lee
Keyword(s):  
Grain Size ◽  
Deformation Mechanism ◽  
Austenite Grain Size ◽  
Austenite Grain

Austenite Grain Evolution Mechanism of High Carbon Rail Based on Thermal Technology

2020 ◽  
Vol 837 ◽  
pp. 74-80
Author(s):  
Jun Yuan ◽  
Zhen Yu Han ◽  
Yong Deng ◽  
Da Wei Yang
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Rail Steel ◽  
Heating Temperature ◽  
Great Influence ◽  
Stable Operation ◽  
High Carbon ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Austenite Grains

In view of the special requirements of rails to ensure the safe and stable operation of Railways in China, the formation characteristics of austenite grains in high carbon rail are revealed through industrial exploration, the process of industrial rail heating and rolling is simulated, innovative experimental research methods such as different heating and heat treatment are carried out on the actual rails in the laboratory. Transfer characteristics of austenite grain size, microstructures and key properties of high carbon rail during the process are also revealed. The results show that the austenite grain size of industrial produced U75V rail is about 9.0 grade. When the holding temperature is increased from 800 C to 1300 C, the austenite grain size of high carbon rail steel decreases, the austenite grain are gradually coarsened, and the tensile strength increases slightly. The tensile strength is affected by the heating temperature. With the increase of heating temperature, the elongation and impact toughness of high carbon rail decrease. The heating temperature of high carbon rail combined with austenite grain size shows that the heating temperature has a great influence on austenite grain size, and has the most obvious influence on the toughness of high carbon rail.

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