scholarly journals Optimisation of chemical composition of high-strength structural steels for achieving mechanical property requirements

2021 ◽  
Author(s):  
Oleksandr Babachenko ◽  
Hanna Kononenko ◽  
Iryna Snigura ◽  
Nataliya Togobytska
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Chemical Composition ◽  
High Strength ◽  
Interatomic Interaction ◽  
Structural Steels ◽  
Integral Model ◽  
Model Parameters ◽  
National Academy Of Sciences ◽  
Iron And Steel

In addition to thermomechanical treatment, one of the main factors affecting the mechanical properties of steel is the chemical composition. The chemical composition may vary for a special high-strength low-alloy steel to meet certain mechanical property requirements. This work presents an approach, based on the method of physical-chemical modelling developed at the Z.I. Nekrasov Iron and Steel Institute of the National Academy of Sciences of Ukraine, to optimise the chemical composition of high-strength structural steels. The principle of this method is to describe the chemical composition of a melt by a complex of integral model parameters of interatomic interaction, characterising the chemical and structural state of the melt. The experimental data were analysed to obtain the regression model for mechanical properties based on the parameters of interatomic interaction. Finally, a multi-criteria optimisation method was applied to obtain an optimal set of microalloying elements which ensure the required mechanical properties.

scholarly journals The interrelation of the chemical composition and mechanical properties of constructional alloyed steels

2018 ◽  
pp. 328-335
Author(s):  
V.A. Lutsenko ◽  
E.V. Parusov ◽  
T.N. Golubenko ◽  
O.V. Lutsenko ◽  
O.V. Parusov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Relative Elongation ◽  
Interatomic Interaction ◽  
Alloying Elements ◽  
Structural Parameter ◽  
National Academy Of Sciences ◽  
Iron And Steel ◽  
European Standards

The aim of the work is to determine the content intervals of alloying elements in structural alloyed steels, which ensure the obtaining of mechanical properties and the conformity of rolled products to the requirements of European standards. The studies were conducted using a predictive model developed by the Iron and Steel Institute of the National Academy of Sciences of Ukraine, taking into account the full chemical composition of the steel. The regularities of changes in the interatomic interaction parameter on the number of alloying elements in the steel composition and its relationship with mechanical properties are revealed. The dependences of mechanical properties (tensile strength, relative elongation) on the chemical composition of steel are constructed through the physicochemical criterion – the average statistical distance between interacting atoms (structural parameter d). The interrelation between the chemical composition and mechanical properties of chrome-molybdenum structural steels has been established. It is shown that increasing the chromium content increases the tensile strength, and doping with molybdenum and vanadium increases the ductility of rolled products. It was determined that in order to guarantee compliance with the requirements of the ultimate strength (900-1100 MPa) and relative elongation (> 11%) for steel 31CrMoV9, the content of alloying elements should correspond to the following intervals: 2.42-2.62%Cr, 0.2-0, 23%Mo and 0.17-0.20%V. The results obtained make it possible to predict the mechanical properties of doped steel, depending on the actual chemical composition of the steel.

scholarly journals Physical and chemical models for expert evaluation of mechanical properties of structural steels

2018 ◽  
pp. 384-393
Author(s):  
A.A. Kononenko ◽  
A.V. Puchikov ◽  
O.V. Kuksa ◽  
A.N. Kuksa ◽  
I.R. Snigura
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Control Systems ◽  
Interatomic Interaction ◽  
Structural Steels ◽  
Expert Assessment ◽  
Iron And Steel ◽  
Chemical Models ◽  
Two Samples ◽  
The Matrix

The aim of the study is to develop an adapted methodology for assessing the influence of the chemical composition on the properties of multicomponent steels and finished rolled products. An approach to predicting the mechanical properties of structural steels with regard to heat treatment parameters, based on the concept of a directed chemical bond in the description of interatomic interaction in the melt, is presented. The physico-chemical models of the structure of the melts, which interconnect their composition, structure, and properties, were developed in the Iron and Steel Institute of NAS Ukraine. The representation of the element-by-element composition of multicomponent steels in the integral parameters of the interatomic interaction makes it possible to reduce the parametricity of the models. The role of various pairing interactions of alloying, microalloying and impurity elements in the formation of properties of steels and alloys was evaluated. A factor analysis has been carried out, the chemical composition of the steel has been structured into various subsystems. It is shown that the most significant subsystems are the matrix m (C, Si, Mn) and microalloying ml (Cr, Mo, V, Ni, Ti, Nb). For two samples of structural steels with significant technological differences and features (1-st group - low alloyed steels: St3sp, VSt3sp, VMSt3sp; 2-nd group: 09Г2ФБ, 10ХСНД, 15ХСНД, 14Г2САФ, 14Г2АФ, 16Г2АФ) dependencies of the type are obtained: σВ (σ0,2, δ5) = f (interatomic interaction parameters, Vcool). It is shown that the most important parameters for calculating the σB, σ0.2 and δ5 matrix subsystem m are the integral parameters of the interatomic interaction d and ZY, dm and tgαm, and for the microalloying subsystem ml - ZYml and dml, as well as the cooling rate Vcool for both subsystems. The developed semi-empirical models are recommended for expert assessment of the mechanical properties of structural steels and for use in automated control systems and automated process control systems.

scholarly journals Forecasting the physical and chemical and thermophysical properties of nickel-containing ferroalloys

2018 ◽  
pp. 336-348
Author(s):  
A.F. Petrov ◽  
O.V. Kuksa ◽  
L.A. Golovko ◽  
N.E. Khodotova
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Interatomic Interaction ◽  
Model Parameters ◽  
Melting Points ◽  
National Academy Of Sciences ◽  
Iron And Steel ◽  
Nickel Chromium ◽  
Composition Structure

The aim of the work is to study the possibility of using integral and partial model parameters of interatomic interaction for the systematic study of the most important consumer properties of nickel ferroalloys used for alloying steel and alloys. In the work, a new approach developed at the Iron and Steel Institute of the National Academy of Sciences of Ukraine was used to solve the problems of predicting the properties of alloys, connecting the composition, structure and properties of melts. Using experimental data on the heat of melting, heat capacity, thermal conductivity, thermal diffusivity of ferronickel, ferroboron, ferromolybdenum, ferro-tungsten, ferrozirconium and other ferroalloys, equations were obtained which made it possible to estimate these properties in advance. Analysis of the experimental data showed that the density of liquid iron-nickel-chromium alloys and their melting points are closely related to the interatomic interaction parameters. Using the parameters of interatomic interaction and experimental data, equations were obtained to describe the dependence of the crystallization temperature, specific density, specific heat capacity, thermal conductivity of nickel-chromium-containing ferroalloys on the parameters of interatomic interaction. Using the above equations, model melting points and ferronickel densities (FN-5M) were estimated using model prediction. The developed semi-empirical models can be used to predict the properties of standard grades of ferroalloys both within a single grade and the entire range of ferroalloys. This allows you to evaluate the effectiveness of the use of ferroalloys at the main stages of steelmaking.

Microstructure and Mechanical Properties of High Strength Low Alloy Steel Q550D

2021 ◽  
Vol 1035 ◽  
pp. 424-429
Author(s):  
Fang Po Li ◽  
Ning Li ◽  
Xian Lin Wang ◽  
Ming Hua Liang
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Oil And Gas ◽  
High Strength ◽  
Service Performance ◽  
Low Alloy Steel ◽  
Micro Structure ◽  
Gas Drilling ◽  
Drilling Equipment ◽  
Equipment Manufacture

Drilling equipment is the key of oil and gas drilling development. Its manufacturing quality and service performance have important influence on oil and gas drilling development safety. The application of high strength grade steel plays an important role in improving drilling equipment manufacturing level and service performance. In this paper, the chemical composition, microstructure, tensile properties, impact properties and hardness of TMCP Q550D and Q-T Q550D high-strength low-alloy steel were tested and compared, and the application feasibility for drilling equipment manufacture was analyzed comprehensively. The experimental results show that the mechanical properties of Q550D by two different methods were obviously higher than the requirement of national standard. Q550D steel had excellent plasticity and toughness, which meets the requirement of drilling equipment manufacture. The main difference between different steel lied in their chemical composition and micro-structure. Carbon content of TMCP Q550D steel plate was lower than that of QT Q550D, and TMCP Q550 was mainly depend on TMCP technology and micro-alloy elements, whose micro-structure was mainly granular bainite. Q-T Q550D was mainly depend on Q-T technology, and its microstructure was tempered sorbite with obvious banded structure and slightly low toughness.

Spun Steel Pipes for the Offshore Industry

1983 ◽  
Vol 105 (1) ◽  
pp. 97-102 ◽  
Author(s):  
A. Royer ◽  
B. Dumas ◽  
M. Gantois
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Centrifugal Casting ◽  
High Strength ◽  
Controlled Rolling ◽  
Climatic Conditions ◽  
Casting Technique ◽  
Steel Pipes ◽  
Potential Applications ◽  
Offshore Industry

Many parts either for sea-line pipes as “buckle” or “crack arrestor,” or for structures may require the use of wall tubular products with high mechanical properties. Such heavy-wall pipes may be produced by centrifugal casting. Two Mn-Mo steels have been developed for medium-wall pipes (e≤35 mm) to be used under very severe climatic conditions: an acicular ferritic steel, a pearlite reduced steel produced by controlled rolling techniques [1, 2, 3]. More alloyed chemical composition and heat-treatments are needed to produce heavy-wall pipes. Then, production of such pipes is more difficult and sometimes impossible. Observations made on controlled-rolled Mn-Mo steel led to a better understanding of the influence of metallurgical structures and chemical composition on steel characteristics. Similar metallurgical structures can only be reached via other routes, for example centrifugal-casting of steel associated with heat-treatment, lead to the production of heavy-wall pipes with high strength and suitable transition temperature. After a brief description of the centrifugal casting technique, we introduce the grades developed for heavy-wall pipes with yield strength up to 100,000 psi. The mechanical properties, Battelle, fatigue, static bending, C.O.D., weldability, etc., of Centrishore II are given and compared to other materials. Possible offshore applications and other potential applications of parts produced by centrifugal casting are described.

Relationships between Strength and Microstructure for Cement-Based Materials: an Overview

1984 ◽  
Vol 42 ◽  
Author(s):  
Sidney Mindess
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
High Strength ◽  
Pore Geometry ◽  
Precise Form ◽  
Cement Based Materials ◽  
Very High

AbstractThe mechanical properties of cement-based materials must be controlled by the microstructure, pore geometry and chemical composition of the cement, by the properties of the aggregate, and by the nature of the cement-aggregate bond. While the precise form of the strength vs. microstructure relationship is as yet only imperfectly understood, enough is known to permit us to predict what alterations in the microstructure are required for the production of materials with very high strengths. There are also techniques available for reducing the brittleness that is often a characteristic of high-strength materials. The present paper presents an overview of the strength vs. microstructure relationships that can be used to predict the properties of high strength cement-based materials, and a brief review of some of the methods for achieving high strengths.

Manufacture Technique and Mechanical Properties of Kevlar/PET Composite Fabrics

2014 ◽  
Vol 910 ◽  
pp. 206-209 ◽  
Author(s):  
Jia Horng Lin ◽  
Mei Chen Lin ◽  
An Pang Chen ◽  
Ching Wen Lou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
Melting Point ◽  
High Strength ◽  
Nonwoven Fabric ◽  
Air Permeability ◽  
Kevlar Fiber ◽  
Composite Nonwoven ◽  
Composite Fabrics

With the advancement of industry, the utilization of cushion package to apply on the products of civilian, sports, electric, precise equipment increases extensively, which are brittle and vulnerable that need to be protected. In the research, the Recycled High Strength PET fiber, Recycled Kevlar fiber and low melting PET fiber are selected as materials, which the content of Recycled Kevlar fiber is stationary. The composite nonwoven fabric was manufactured by non-woven processing and subsequently estimated its stab-resistant strength and air permeability. The composite nonwoven fabric was being heat treatment which can make low melting point PET fiber bonding with other fibers in order to enhance the mechanical property of composite nonwoven fabric.

scholarly journals Technological pecularities of producing cast iron with spherical graphite using a fast-cooled copper-magnesium ligature

2020 ◽  
pp. 15-21
Author(s):  
A. G. Slutsky ◽  
I. L. Kulinich ◽  
V. A. Sheinert ◽  
V. A. Stefanovich ◽  
R. E. Trubitsky ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Chemical Composition ◽  
Magnesium Alloys ◽  
High Strength ◽  
Favorable Effect ◽  
Maximum Effect ◽  
Spheroidal Graphite ◽  
Graphite Phase ◽  
Spherical Graphite

Various modifiers are used for non-furnace processing of cast iron. Some of them are designed for inoculating modification, which improves mechanical properties and eliminates the appearance of whiteness in castings, while others are designed for spheroidizing processing, in particular for producing cast iron with spherical and vermicular graphite. Some have both spheroidizing and inoculating properties. The main part of inoculating and spheroidizing modifiers is made on iron-silicon, Nickel and copper bases.In addition to the chemical composition, the size of the modifier particles, as well as their shape, are of great importance for modification. The optimal size of the fraction depends significantly on the non-furnace processing technology. Thus, for the larger the bucket and the longer the casting the longer the modification effect is required. One of the methods to achieve this is to increase the particle size of the modifier to 50 mm. When intraform processing of cast iron with spherical and vermicular graphite, magnesium-containing modifiers have strict limits on the upper size (4...5 mm), and in addition, the content of small fractions (less than 0.6...1 mm) is not allowed.The use of «heavy» magnesium-containing ligatures for spheroidizing modification of cast iron in order to obtain higher physical and mechanical properties has scientific and practical interest. Numerous studies show that for maximum effect the formation of the structure of the spheroidal graphite, dispersed pearlite metallic base of SGI (spheroidal graphite iron) relevant question is not only selection of the chemical composition of magnesium alloys, but also of the fractional composition, as well as effective method of input into the liquid melt.The purpose of this work was to study the technological features of obtaining cast iron with spherical graphite by bucket modification of copper-magnesium ligature.The researchers used a Leo–1420 scanning microscope, a Polam l-213 optical microscope, and a VEGA II LMU electron microscope with an INCA ENERGY 350 microanalyzer. High-speed induction melting plant, a set of equipment for analyzing the technological and mechanical properties of high-strength cast iron were used.Earlier experimental studies have shown the real possibility of obtaining in the laboratory a «heavy» copper-magnesium alloys as the alloying of magnesium metal with copper, followed by rapid cooling with use of rolling and plastic deformation of powder alloys. Analysis of test results of samples of such alloys showed that it depends on the value of its additives into liquid iron in the structure of formed graphite phase in compacted and globular form. At the same time, the metal base of cast iron is additionally alloyed with copper, which has a favorable effect on the strength characteristics of SGI.However, an urgent problem is the possibility of the appearance of a cementite phase in the structure of high-strength cast iron as a result of its increased supercooling due to the process of spheroidization of the graphite phase. This phenomenon is compounded by the fact that the copper-magnesium ligature, in contrast to the «light» ligature, does not contain silicon active graphitizer. This feature must be taken into account when obtaining high-strength cast iron of high grades.

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