scholarly journals A METHOD FOR OPTIMIZING CHEMICAL COMPOSITION OF STEELS TO REDUCE RADICALLY THEIR ALLOY ELEMENTS AND INCREASE SERVICE LIFE OF MACHINE COMPONENTS

2017 ◽  
Vol 1 ◽  
pp. 3-12
Author(s):  
Nikolai Kobasko
Keyword(s):  
Chemical Composition ◽  
Service Life ◽  
Alloy Element ◽  
Steel Grades ◽  
Computer Calculations ◽  
Increase Service Life ◽  
Quenched Steel ◽  
Chemical Composition Of Steel ◽  
Compressive Residual Stresses ◽  
Strength And Ductility

A method for optimizing chemical composition of steel is proposed and a correlation is established to reduce cardinally alloy elements in existing steel grades that results in high compressive residual stresses at the surface of intensively quenched steel parts and increasing strength and ductility of material due to super- strengthening phenomenon. The algorithm of optimization consists in reducing alloy elements in existing alloy steel in 1.5 – 2 times and then lowering step-by-step content of steel, beginning from the most costly alloy element and ending the most cheaper one, until established correlation is satisfied. The range of reduction is minimal and during computer calculations can be chosen as 0,001wt%. The proposed approach can save alloy elements, energy, increase service life of machine components and improve environmental condition. The method is a basis for development of the new low hardenability (LH) and optimal hardenability (OH) steels.

The Influence of Chemical Composition of Steel on Steel Desulphurization

2011 ◽  
Vol 56 (3) ◽  
pp. 605-609 ◽  
Author(s):  
B. Bulko ◽  
J. Kijac ◽  
T. Borovský
Keyword(s):  
Chemical Composition ◽  
Distribution Coefficient ◽  
Manganese Content ◽  
Ladle Furnace ◽  
Optimal Parameters ◽  
Similar Chemical ◽  
Wide Range ◽  
Steel Grades ◽  
Reducible Oxides ◽  
Chemical Composition Of Steel

The Influence of Chemical Composition of Steel on Steel Desulphurization The steel desulphurization in ladle furnace depends on temperature, oxygen and sulphur content in the steel, but mainly on chemical composition and physical properties of slag. Necessary requirement for effective desulphurization is also minimum content of easily reducible oxides in the slag. There are many correlations for expression of slag desulphurization capability, where their functional dependency on each other can be found, mainly between sulphur distribution coefficient, optical basicity, basicity, sulphide capacity, desulphurisation potential of slag and also calcium - aluminate ratio of oxides in slag or content of easily reducible oxides in slag. This work presents statistical and graphical correlation between manganese and slag parameters using the set of approximately 768 heats and based on these, the optimal parameters for slag desulphurization capability are expressed especially for steel grades internally marked as OR1, OR3 in Železiarne Podbrezová, a.s. Steel grades OR1 and OR3 were chosen because of difference in manganese content with similar chemical composition of other elements. The MnO content in the slag is one of the most important parameters. Despite the higher scatter of obtained values, the distribution coefficient of sulphur (Ls) is one of the wide range of parameters for whom exists very close dependence on MnO content in slag.

Increase of resistance of piercing mill mandrels at seamless pipes production of 13Cr grade martensite class stainless steel at line ТПА 159‒426 of JSC VTZ

2020 ◽  
Vol 76 (12) ◽  
pp. 1259-1264
Author(s):  
I. I. Lube ◽  
N. V. Trutnev ◽  
S. V. Tumashev ◽  
A. V. Krasikov ◽  
A. G. Ul’yanov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Oil And Gas ◽  
Cobalt Content ◽  
Pipe Plant ◽  
Piercing Mill ◽  
Steel Strength ◽  
New Material ◽  
Chemical Composition Of Steel ◽  
Technical Solutions ◽  
Grade Steel

At production of pipes of type 13Cr grade steel used at development of oil and gas deposits in areas with aggressive environment, intensive wear of instrument takes place, first of all, piercing mill mandrels. Factors, influencing the resistivity of the piercing mandrels considered, including chemical composition of the material, the mandrel is made of and its design. Based on industrial experience it was shown, that chrome content in the mandrel material practically does not affect on the increase of its resistivity, since the formed thin protective oxides having high melting temperature, are quickly failed and practically are not restored in the process of piercing. To increase the resistivity of piercing mandrels at production of casing tubes of type 13Cr grade steel, a work was accomplished to select a new material for their manufacturing. The chemical composition of steel presented, which was traditionally used for piercing mandrels manufacturing, as well as a steel grade proposed to increase their resistivity. First, molybdenum content was increased, which increases the characteristics of steel strength and ductility at high temperatures and results in grain refining. Second, tungsten content was also increased, which forms carbides in the steel resulting in an increase of its hardness and “red resistivity”, as well as in preventing grains growth during heating. Third, cobalt content was also increased, which increases heat resistivity and shock loads resistivity. The three elements increase enabled to increase the mandrels resistivity by two times. Results of mandrel test of steel 20ХН2МВ3КБ presented, the mandrel having corrugation on the working cone surface, which enabled to reach the resistivity growth to 12 passes without significant change of instrument cost. Microstructure of mandrels made of steels 20Х2Н4МФА and 20ХН2МВ3КБ shown. Application of the centering pin of special design was tested, which provided forming of a rounding edge on the front billet ends, eliminated undercut of mandrel external surface in the process of secondary billet grip and increase the service life of the piercing mill mandrels. At production of seamless pipes of martensite class type 13Cr stainless steels having L80 group of strength, an increase of piercing mandrel resistivity was reached by more than four times, which together with other technical solutions enabled to increase the hourly productivity of the hot rolling section of Volzhsky pipe plant ТПА 159-426 line by more than two times.

FORCE CONDITIONS OF TRANSITION TO ONE-ZONE PROCESS OF BACKWARD SLIP DURING COLD ROLLING OF STRIPS

2020 ◽  
pp. 45-53
Author(s):  
L.S. Kokhan ◽  
◽  
A.V. Aldunin ◽  
Keyword(s):  
Service Life ◽  
Cold Rolling ◽  
Considerable Decrease ◽  
Steel Strips ◽  
Increase Service Life

Results of analytical researches of power parameters of cold rolling of thin and average steel strips with a back tension are presented. Considerable decrease in average relative tension on a surface of contact with rolling rolls upon transition is established from two-zonal to one-zonal rolling of lag. It allows to increase service life of rolling rolls.

Microstructure Optimization in δ-TRIP Steels with Al and Nb

2018 ◽  
Vol 930 ◽  
pp. 501-506
Author(s):  
Eustáquio de Souza Baêta Júnior ◽  
Ramón Alves Botelho ◽  
Leonardo Sales Araújo ◽  
Luiz P. Brandão ◽  
Sergio Neves Monteiro
Keyword(s):  
Chemical Composition ◽  
Alloying Elements ◽  
Eutectoid Temperature ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Plasticity Effect ◽  
Δ Ferrite ◽  
Areas Of Interest ◽  
Thermocalc Software ◽  
Strength And Ductility

δ-TRIP steel is a recent concept and has been developed over the last ten years aiming to combine good mechanical strength and ductility. This class of steels is multiphase and contains δ and α ferrites, as well as austenite, bainite and/or martensite. The TRIP (Transformation Induced Plasticity) effect is influenced by those phases proportion, which depends on alloying contents. This paper investigates a chemical composition that allows adequate proportion among the phases, optimizing the microstructures by means of computational methods. These microstructures are designed to contain between 10 to 50% austenite, 10 to 70% α-ferrite and 20 to 80% δ-ferrite at the eutectoid temperature. The ThermoCalc Software [1] was used to predict the fractions of the microconstituents, producing graphs describing areas of interest of microconstituents as function of alloying elements variations that leads to the desired microstructure. Results indicate that the designed volume of the phases can be found for certain proportions among the alloying elements, higher concentrations of Al and Nb combined with C allow or not the occurrence of carbides and other phases in smaller quantities.

scholarly journals Cooling process optimization during hardening steel in water polyalkylene glycol solutions

2021 ◽  
Vol 6 (1(62)) ◽  
pp. 27-35
Author(s):  
Nikolai Kobasko
Keyword(s):  
Residual Stresses ◽  
High Surface ◽  
Heat Treating ◽  
Steel Part ◽  
Water Solutions ◽  
Inconel 600 ◽  
Polyalkylene Glycol ◽  
Cooling Intensity ◽  
Chemical Composition Of Steel ◽  
Compressive Residual Stresses

Objects of investigations are water solutions of polyalkylene glycol (PAG) which are used as the quenchants in the heat-treating industry. They are tested by standard cylindrical probe made of Inconel 600 material. The main and not solved yet is the problem of transition from data achieved for standard probe to data suitable for any form and size of real steel part. It opens possibility to make predictable calculations. Taken this into account, it has been investigated water solutions of PAG of different concentration. It is underlined that cooling intensity of quenchant can be evaluated by Kondratiev number Kn. The mentioned number Kn varies within 0≤Kn≤1 when generalized Biot Biv number varies within 0≤Biv≤∞. As a main achievement of investigation is established correlation between standard Kn number and Kn number of real steel part. In many cases, when film boiling is absent, the established correlation is a linear function. It allows optimizing quenching processes: obtain high surface compressive residual stresses, save alloy elements and improve environment condition. All of this is achieved by tolerating chemical composition of steel with size and form of quenched object as it is proposed by UA Patent No. 114174. Also, the number Kn allows interruption of quench process when surface compressive residual stresses are at their maximum value that essentially improves the quality of steel components. Moreover, interrupted cooling prevents quench crack formation, decreases distortion of quenched steel parts. The results of investigations can be used by engineers in the heat-treating industry and scientists for further research.

Hartwalzen von Lagerringen zur Lebensdauersteigerung/Hard rolling of bearing rings to increase service life

2020 ◽  
Vol 110 (06) ◽  
pp. 368-374
Author(s):  
Kirk Jahnel ◽  
Sebastian Hähnel ◽  
Tim Grunwald ◽  
Thomas Bergs
Keyword(s):  
Service Life ◽  
Rolling Process ◽  
Rolling Bearings ◽  
Development Fund ◽  
European Regional Development Fund ◽  
Compressive Stresses ◽  
Fraunhofer Institute ◽  
Increase Service Life ◽  
Bearing Rings ◽  
European Regional

Zur Steigerung der Lagerlebensdauer von Hybridwälzlagern hat das Fraunhofer Institut für Produktionstechnologie IPT gemeinsam mit Cerobear GmbH, Hegenscheidt-MFD (A Member of the NSH-Group) und Schmitz-Metallographie GmbH an der Qualifizierung und Implementierung des Verfahrens Hartwalzen in die Prozesskette zur Herstellung von Hybridwälzlagern gearbeitet. Durch die Induzierung von Druckeigenspannungen in die Lagerlauffläche konnte die Lebensdauer nachweislich erhöht werden. Die Arbeiten wurden im Rahmen des geförderten Forschungsvorhabens „Hartwalzen von Lagerringen“ durchgeführt, das aus Mitteln des europäischen Fonds für regionale Entwicklung (EFRE) gefördert wurde.   To increase the service life of hybrid rolling bearings, the Fraunhofer Institute for Production Technology IPT together with Cerobear GmbH, Hegenscheidt-MFD (A Member of the NSH Group) and Schmitz-Metallographie GmbH successfully qualified and implemented the hard rolling process in the process chain for manufacturing hybrid rolling bearings. By inducing residual compressive stresses in the bearing running surface, the service life has been demonstrably increased. The work was carried out as part of the funded research project „Hard Rolling of Bearing Rings“, which was supported by the European Regional Development Fund (EFRE).

scholarly journals Welding materials used to increase service life of agricultural machinery processing soil

2018 ◽  
Vol 244 ◽  
pp. 01002
Author(s):  
Petr Hrabě ◽  
Viktor Kolář ◽  
Abraham Kabutey ◽  
Aleš Sedláček
Keyword(s):  
Service Life ◽  
Abrasive Wear ◽  
Soil Treatment ◽  
Agricultural Machinery ◽  
Wear Resistant ◽  
Welding Material ◽  
Increase Service Life ◽  
Materials Used ◽  
Welding Materials

Intensive abrasive wear occurs in soil-treatment machines. This article is focused on increasing the service life of ploughs by the welding material. The welding material is applied at a 45° angle to the tool. This material is abrasive wear resistant. The welding material was applied parallel to the head of ploughshares with spacing of 60 mm. Carbide materials were used (SK 258 TiC-O, SK 900-O, SK A43-O, SK 299- O, SK A45-O, OK TUBRODUR 15.82, SK 258 TiC-O). The tested ploughshare variants were wearing the same when were used the welding material and the standard.

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