The analysis of possible changes in the chemical composition of steel grade L555 with respect to its weldability

2013 ◽  
Vol 28 (12) ◽  
pp. 923-925
Author(s):  
Andrzej Klimpel
Keyword(s):  
Chemical Composition ◽  
Steel Grade ◽  
Chemical Composition Of Steel

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.

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.

scholarly journals Study on the Deformation behaviour of Non–Hardenable Ferritic Stainless Steel (grade X6Cr17) by Hot Torsion Tests

2020 ◽  
Vol 14 (2) ◽  
pp. 239-244
Author(s):  
Imre Kiss ◽  
Vasile Alexa
Keyword(s):  
Stainless Steel ◽  
Chemical Composition ◽  
Ferritic Stainless Steel ◽  
Deformation Behaviour ◽  
Industrial Process ◽  
Steel Grade ◽  
Deformation Resistance ◽  
Practical Significance ◽  
Friction Forces ◽  
Hot Torsion

The knowledge about the characteristics of deformability (deformation resistance and plasticity) has for the technologist, as well as for the designer and researcher, a great practical significance, because they are important elements in establishing a correct technological process. The change of deformation conditions existing in the industrial process, such as the temperature and rate of deformation, are difficult to consider for correcting the deformability determined by testing. The chemical composition of the material influences the plasticity and its deformation resistance both by the nature and distribution of the alloying elements and by the phase transformations they produce. In this paper, through "deformability", we cover all properties characterizing the deformation behaviour of alloys. In this sense, "deformation resistance" is expressed through the unit strain required to produce a certain degree of plastic deformation, under the conditions of a particular diagram of tensions, deformations and deformation rates, in the absence of external friction forces. Plasticity, being the ability of metallic materials to deform plastic under the action of external forces, is influenced by a number of material characteristics (chemical composition, structure) and other factors characteristic of the deformation (temperature, degree and speed of deformation, applied mechanical scheme). Plasticity is characterized, in the torsion test, by the number of rotations made by the specimen until breakage. A number of methods have already been used for the study of deformability. This study includes the results of hot torsion tests conducted to find the plasticity and deformability characteristics of ferritic stainless steel (non–hardenable stainless steel, grade X6Cr17), which is a flexible grade of the stainless steel family with properties closely matching those of the more popular and expensive austenitic grade.

Algorithm for Controlling Mechanical Properties of Hot Rolled Steels Using Bayesian Network Model

2012 ◽  
Vol 706-709 ◽  
pp. 1444-1447
Author(s):  
Oleg S. Khlybov ◽  
Igor V. Dubinin
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Probability Distribution ◽  
Bayesian Network ◽  
Control Method ◽  
Steel Production ◽  
Steel Grade ◽  
Rolling Temperature ◽  
Joint Probability Distribution ◽  
Coiling Temperature

The work presents a control method for on-line adjustment of mechanical properties of as rolled steels produced at hot strip mills. The key idea of the method is a probabilistic causal (Bayesian) network which represents in a form of a directed acyclic graph the joint probability distribution of mechanical properties, chemical composition and temperature–strain parameters acting during hot rolling. As a slab moves along the mill the distribution is used for continuous recalculating the posterior probability of all mechanical properties conditioned by chemical composition and all other process parameters which become known to the moment of recalculating. Finally, when a strip is just before the finishing group we evaluate the probability distribution of finishing rolling temperature and coil temperature given the strip has the target mechanical properties. It generates new setups for these temperatures A pilot version of the method has been just implemented at CSP–line at Vyksa, Russia, United Metallurgical Company’s steel production site The adjustment is realized through appropriate correction of finish rolling temperature or/and coiling temperature setups of the mill automatic control system after the last chemical analysis of the current heat is made at the start of casting. Only “cautious” corrections of the temperatures are permissible so far (deviation from predefined level not more than ±30 degrees for each temperature) and the main aim of them is to set off the influence of chemistry variations on mechanical properties scatter of a given steel grade. The results of using the algorithm show that even these limited but interconnected actions reduce approximately twice the standard deviation of the mechanical properties inside a steel grade.

Modified Tartagli Method for Calculation of Jominy Hardenability Curve

2008 ◽  
Vol 575-578 ◽  
pp. 892-897 ◽  
Author(s):  
Wojciech Sitek ◽  
Jacek Trzaska ◽  
Leszek Adam Dobrzański
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Chemical Composition ◽  
Network Models ◽  
Steel Grade ◽  
Regression Coefficients ◽  
Neural Network Models ◽  
The Neural Network ◽  
The Neural Networks ◽  
Hardenability Curve

Basing on the experimental results of the hardenability investigations, which employed Jominy method, the model of the neural networks was developed and fully verified experimentally. The model makes it possible to obtain Jominy hardenability curves basing on the steel chemical composition. The modified hardenability curves calculation method is presented in the paper, initially developed by Tartaglia, Eldis, and Geissler, later extended by T. Inoue. The method makes use of the similarity of the Jominy curve to the hyperbolic secant function. The empirical formulae proposed by the authors make calculation of the hardenability curve possible basing on the chemical composition of the steel. However, regression coefficients characteristic for the particular steel grade must be known. Replacing some formulae by the neural network models is proposed in the paper.

Investigation of consequences of violation of technology of manufacture of individ-ual elements of BMP-2 track tape

2021 ◽  
pp. 61-68
Author(s):  
R. Kuzmenko ◽  
М. Kovba ◽  
O. Popovchenko ◽  
Т. Kovbasiuk ◽  
S. Shvachko
Keyword(s):  
Heat Treatment ◽  
Spectral Analysis ◽  
Chemical Composition ◽  
Materials Science ◽  
Density Measurement ◽  
Science Research ◽  
Steel Grade ◽  
Military Equipment ◽  
Steel Grades ◽  
The Military

The operation of the BMP-2 infantry fighting vehicle was accompanied by periodic failures of the tracked belts. This is due to the breakage of the fixing bolts of the track pins fastening bracket, and thus the military equipment became stationary. Establishing the causes of the destruction of the bolt fixing the staple of the track fingers of the tracked belt of military equipment was carried out using a complex of instrumental materials science research. In particular, the chemical composition of the material from which the bolts and staples were made was determined by the spectral analysis; the fracture surface of the fixing bolt was investigated by the macroanalysis; the microstructure of the bolts was examined using optical microscopy; the microhardness and density of the bolt material was measured. The bolts were made from steel grades 30XM and 33XC, and not from the recommended steel grade 38XC. The macrostructure of the broken bolt corresponds to the shearing structure. The microstructure showed rolling and heat treatment defects. Density measurement confirmed the presence of heat treatment defects. The imperfection of the applied heat treatment was confirmed by measuring the microhardness. A complex of metallurgical research has established the main cause of the destruction of the bolts. It consists in an unsuccessful design of bolts and brackets, an incorrectly selected steel grade with defects in rolling and heat treatment.

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