New Type Of Steel Research Articles

Producing Steels with Special Properties Using a Jet Heat Treatment System

The prospects of production of special properties steels in the Russian and global metal market are estimated. The necessity of using new types of steels is substantiated. The prospects of introducing steels with special properties developed by PJSC “Magnitogorsk Iron and Steel Company” to the market are determined. Evaluation of measures for the production of large volumes of products showed that there is a problem of a significant increase in the time of manufacturing and delivery of output products to the consumer. As measures to ensure the modernization of the technological complex of the steel enterprise and reduce the time for steel production, the system of jet heat treatment of metal is proposed. According to the results of comparative analysis of the MAGSTRONG H500 and HARDOX 500 alloys used in mining equipment under conditions of increased wear, it was revealed that the proposed method of heat treatment allows one to achieve high wear resistance properties, with high coefficients of tensile strength and toughness.

Flexural properties of new cold-formed thin-walled steel and concrete composite slabs

This paper presents a new type of steel and concrete composite slab, which is composed of cold-formed thin-walled steel C-sections, bars, concrete and polystyrene foam panels. Considering different filling quantities of the foam panel in the slab, two specimens (one three-hole slab and one two-hole slab) are made for flexural testing. Aimed at studying the bending performance and failure mode of the composite slab, the specimens are analyzed with respect to their flexural capacity, ductility ratio, concrete strain, reinforcement strain and C-section strain. Results show that the composite slab fails in a normal section of flexure while it has good bearing capacity and ductility in the test. The strain of concrete in the slabs is linearly distributed along the section height, which conforms to the plane section assumption. Mechanical performance of the three-hole slab is better than that of the two-hole slab. Together with finite element simulations, the numerical results of flexural capacity are compared to the test results; the comparison indicates that they are in good agreement, which lays a foundation for the subsequent parametric analysis.

Axial and transverse strengthening of R/C circular columns: Conventional and new type of steel and hybrid jackets using high-strength mortar

The basic subject of this primarily experimental research is the investigation of new techniques and methods to strengthen the axial and transverse load-carrying capacity and confinement of circular cross-section reinforced concrete columns. Column strengthening took place by construction of jackets composed of metal semi-pipe systems combined either with high-strength mortar or with spiral reinforcement and high-strength mortar. In the framework of the current research, nine test specimens modelling reinforced concrete columns of circular cross-section have been constructed and tested under either a transverse load or an axial load history. A new type of hybrid jacket for strengthening circular columns is proposed. Finally, an analytical investigation takes place, trying to correlate the experimental results with empirical equations, while also using the results from 39 specimens found in the international literature.

Study of a new-type of steel buckling-restrained brace

The rectangle core plate of all-steel buckling-restrained braces (BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a novel steel BRB is proposed. In this new-type steel BRB, two T-shaped steels are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar. Meanwhile, the ingot-iron material with low yielding strength and high elongation is applied to the steel core to study the mechanical properties of steel BRBs. To validate the theoretical requirements for the width-to-thickness ratio of the steel core and the thickness of angle steel, quasi-static tests of eight specimens were conducted. The tests focused on the energy dissipation capacity and failure modes of the proposed steel BRBs. Nonlinear finite element analysis was also carried out to validate the experimental results. Both the aforementioned results imply that appropriately designed steel BRBs can meet the performance requirements for BRB components.

Innovative accelerated construction method for Yushan Bridge, China

To overcome poor construction conditions, shorten construction time and improve project quality, the construction of Yushan Bridge in China is a fully industrialised, based on prefabrication of key components, site installation. The navigation span of the Yushan Bridge has a main span of 260 m and is the world's first segmented precast steel–concrete composite continuous-beam bridge. A new type of steel–concrete composite segment (a girder that connects the concrete box girders and the steel box girders) is used to ensure the bearing capacity and precision of closure. Thickened-edge U-shaped ribs and ultra-high-toughness concrete pavings are employed together to improve the durability of the orthotropic deck. A single-pile and single-column foundation is fully employed, with a maximum diameter of the steel composite pile (a pile that is outside is steel pipe, and the interior is filled with concrete) of 5 m. It is found that the construction time is reduced by 40%, the wave flow force is decreased by 80%, the scouring depth is decreased by 20% and the cost is reduced by 30% compared with group pilings. In addition, this method avoids durability problems of the pile cap due to group pilings. The use of a prefabricated exterior shell with cast-on-site concrete for the interior pier-top blocks of the 50 m non-navigation span solves the problems associated with the bearing force, durability, construction availability and quality control of the pier-top block.

Studies on damped hybrid outrigger systems of composite walls and steel bracings

Both experimental and numerical investigations were conducted on a new type of steel–concrete hybrid outrigger system developed for high-rise building structures. The steel bracing is embedded in the reinforced concrete outrigger wall, and the steel bracing and concrete outrigger wall work together to enhance the overall structural performance of tower structures under extreme loads. At the same time, metal dampers of a low-yield steel material are used as a ‘fuse’ device between the hybrid outrigger and the column. The damper is engineered to be ‘sacrificed’ and yield first in moderate to severe earthquakes to protect the structural integrity of important structural components of the hybrid outrigger system. Thus, brittle failures are unlikely to occur due to severe cracking in the concrete outrigger wall. A comprehensive experimental research programme was conducted to examine the structural performance of this new type of hybrid outrigger system. Finite-element models were also proposed and verified to be able to conservatively predict the structural performance of the hybrid outrigger system in both elastic and non-linear plastic stages. The key component and overall system tests were examined, which reveal the detailed structural response under various levels of static and cyclic loads.

Experimental Study on Seismic Behavior of New Steel Box Bridge Piers with Embedded Energy Dissipation Shells

An investigation was conducted to evaluate the seismic behavior of a new type of steel box-section bridge piers with embedded energy dissipation shell plates. In this study, two sets of the new steel box-section bridge piers were designed and pseudo-static tests were carried out on ten steel box bridge piers under constant axial force, with a horizontal cyclic load on top of the piers. The change regularities of the failure mode, the patterns of local buckling, the load–displacement hysteresis curve and its curve skeletons, and the load-strain hysteresis curves of the specimens were analyzed. The rules of horizontal stiffener spacing on embedded shell plates, the axial compression ratio, the embedded shell strength, and the layout of longitudinal ribs in the box-section wallboards were obtained to evaluate their influence on the seismic behavior of the new-type steel piers. The test results indicated that, after installing the embedded shells, the deformation ability of steel box-section bridge piers was enhanced and their ductility was improved. The effects of axial compression ratio and the space of transverse stiffeners in embedded shells on the seismic behavior of the new steel piers were significant. When the space of the horizontal stiffeners on the embedded shells and the axial compression ratio become smaller, the bearing capacity and ultimate displacement capability of the specimens would be greater, the descent segment of the curve skeleton would be more gradual, and the deformability and ductility of the new-type steel piers would be better. The effects of setting longitudinal stiffening ribs and enhanced embedded shell strength on the bearing capacity and ductility of the steel box bridge piers were relatively small. Based on the experimental results, calculation equations were established for stable bearing capacity and maximum deformation of the new-type steel piers, under the constant axial force and horizontal cyclic loading, in order to promote their seismic design.

Seismic performance of new-type box steel bridge piers with embedded energy-dissipating shell plates under tri-directional seismic coupling action

Accurate numerical models are necessary to evaluate the seismic performance and load-bearing mechanism of new-type box steel bridge piers with embedded energy-dissipating shell plates under tri-directional seismic coupling action. Numerical simulations of seismic performance under six types of tri-directional seismic coupling action was conducted. The effects of this stress on the seismic performance of the new-type steel bridge piers was evaluated through analysis of damage mode, hysteresis curve, skeleton curve, stiffness and strength degradation characteristic, and energy-dissipating capacity. This study also compared the numerical analysis with experimental results in order to validate the accuracy of the proposed finite element model. Based on this model, the range of relevant parameters expanded and 88 numerical specimens were analysed for seismic performance, producing further information about the influence of thickness and curvature of the embedded shell plate, spacing of transverse stiffening ribs of the shell, axial compression ratio, and slenderness ratio. Results showed that tri-directional seismic coupling action significantly affects the specimen’s deformation capacity; the embedded shell plate effectively improves the piers’ load-carrying and deformation capacity; and the thickness of the embedded shell plate, width-to-thickness ratio of the wall plate, axial compression ratio, and slenderness ratio significantly affect the seismic performance of the new-type steel bridge piers. To promote the ease of seismic design of new-type box steel bridge piers, this study used theoretical analysis and numerical simulation to calculate equations for the minimum height of the energy-dissipating zone of the bottom embedded shell plate. Finally, formulas were also established to calculate the relevant stability bearing capacity and displacement ductility factor of the new-type steel bridge piers under tri-directional seismic coupling action in order to improve their seismic design.

EFFECT OF METASTABLE AUSTENITE ON MECHANI-CAL PROPERTY AND MECHANISM IN CRYOGENICSTEEL APPLIED IN OCEANEERING

With the development of marine resources and its emerging markets, the marine equipments such as offshore drilling platform, subsea oil and gas transportation pipeline, and storage equipment of oil and gas are developing actively. It is urgent to develop a new type of steel with low cost and excellent toughness to satisfy the demand of marine equipment. In this work, the morphology of austenite and phase transition process in medium manganese steel during quenching and tempering (QT) and quenching, lamellarizing and tempering (QLT) heat treatments were investigated by using EBSD, HRTEM and thermal dilatometer. The results show that the discrepancy of stability in austenite caused by its shape, size and location leads to the more excellent toughness during QLT heat treatment compared to QT. It has been found from thermodynamical and dynamical viewpoint that the formation rates of reverted austenite during QLT heat treatment are significantly larger relative to QT due to the partition process of C and Mn elements in the lamellarizing stage. Moreover, two growth models of film-type reverted austenite are distinct during two heat treatments: the unidimensional two-sided growth mode during QT and unidimensional one-sided growth mode during QLT.

Development of accelerated wet–dry cycle corrosion test in marine environment for weathering steels

There is great interest in the steel industry of incorporating new products that go beyond the properties of existing ones. Among these properties, corrosion resistance is extremely important for countries that, like Chile, have an extensive ocean coastline. In costal zones, the chloride ions in air produce corrosion that reduces the service life of structures. For this reason, it is of utmost importance to study the influence of different alloying elements such as nickel, which lead to improve steel's resistance to marine corrosion. In this context the development of new types of steel is hindered if the evaluation of their corrosion resistance takes very long times. This paper presents a methodology based on accelerated wet–dry cycle corrosion experiences to simulate the behaviour of steel over time in a marine environment. The results of the proposed methodology allow adequate prediction of corrosion thickness in ASTM A242 and A588 steels exposed for years to a specific marine environment.

Studies on the Corrosion Properties of High-Mn Austenitic Steels

Institute of Materials Science at Silesian University of Technology since 6 years conducts researches to learn about the new dedicated for automotive, railway and military industries. Some of these materials belong to the group of AHS steels, characterized by the twinning induced plasticity (TWIP) effect. It is a new type of steel possessing both a high strength and a great plastic elongation, and an ideal uniform work hardening behaviour. It is therefore a good candidate for deep drawing applications in the automobile and railway industries. In the paper the of the three grades of high-manganese steels of was studied in 3.5% NaCl solution and in an “acid rain” solution with pH=3.5 environments using polarization experiments. The results of corrosion tests and analysis of show that a higher polarisation resistance and lower values of corrosion current density are observed for all studied steels in 3.5% NaCl solution. Spontaneous passivation ability has been shown only for one grade of high-manganese steel in 3.5% NaCl.

Energy and environment, challenges and driving forces for the future heat treatment and surface engineering

exploration, which is heavily dependent on heat treatment and surface engineering. The paper has clearly demonstrated with statistical data how stabilising and improving product quality as the result of the improvement of scientific, technical and management level of HT during the last decade in the petroleum machinery manufacturing industry in China has raised the equipment utilisation rate and reduced the energy consumption. We hope it may trigger a series of studies on various important industrial branches. In general, any scientific achievements in materials science in HT and SE, as well as technical innovations and upgrading in process efficiency, energy efficiency, furnace design and construction, measurement and process control, etc. contribute to the solution of energy-environment problems. In this relatively ‘old’ field of HT, many interesting and practically important effects still need to be reinvestigated and clarified, such as those presented in the paper by Dong and Zhu 2 . Energy and environment are, from the optimistic viewpoint, the external driving forces for the future of HT and SE. No doubt, clean energy generation and supply systems require not only upgrading of conventional HT and SE, but also new materials and methods for their processes. The energy transition may not be realised without innovation of new types of steels and highly developed steel processing. For example, the offshore wind power station demands high corrosion resistant steels for its foundations and towers. The efficiency of thermal power plant may be much improved when its pressure and temperature are raised, which may only be possible with new high-performance alloys. Recently the 2 nd International Conference on Energy and the Future of Heat Treatment and Surface Engineering 3 organised by Chinese Heat Treatment Society (CHTS) took place in Beijing. Following its predecessors the conference addresses the main themes of energy management in HT and SE and the HT and SE in the manufacture of clean energy generation and supply systems. In the coming IHTSE issues we will introduce selectively most interesting papers to our readers.

Milling Force Modeling and Experimental Research of 300M Ultra High Strength Steel

300M ultra high strength steel, a new type of steel with broad prospects for development, has good mechanical properties, and is widely used for manufacture of aircraft landing gear. In order to reveal influence law of cutting parameters on milling force of 300M ultra high strength steel, the influence law of feed rate, milling width, and depth of cut and spindle speed on milling force is firstly studied through the single factor experiments in this paper. Secondly, the influence level of experimental factors is compared by orthogonal experiment. Finally, combined with orthogonal test data and the least square method, the multiple linear regression model of milling force in 300M ultra high strength steel milling is built. The accuracy of the model has been verified well by experimental verification, which has the guiding significance to reveal the milling mechanism and actual production.

Experimental study on concrete filled elliptical/oval steel tubular stub columns under compression

A concrete filled elliptical/oval steel tubular (CFEST) member consists of elliptical/oval steel tube and in-filled concrete. The CFEST member is a new type of steel–concrete composite member and is part of a family of concrete filled steel tubular members known as CFT. The present study aims to investigate, experimentally, the characteristics of CFEST stub columns under centric loading. The main test parameters selected are diameter-to-thickness and diameters ratios of elliptical/oval steel tube. From the results, local buckling of the elliptical/oval steel tube associated with shear failure of in-filled concrete could be observed. Axial loading capacity decreased as diameter-to-thickness ratio increased. Whereas, those capacities normalized by the summation of the individual strengths, namely the elliptical/oval steel tube and in-filled concrete strengths, are regulated in case the diameter-to-thickness ratio becomes larger. Finally, a method to predict the axial loading capacity induced by confinement effects of the in-filled concrete is proposed.

High Manganese TWIP Steel - Technological Plasticity and Selected Properties

Over the last few years national as well as international research centres conducting research on the development of high-manganese steels. Some of these materials belong to the group of AHS steels, are characterized by the twinning induced plasticity (TWIP) effect which is a new type of steel possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. It is therefore a good candidate for deep drawing applications in the automobile and railway industry. The article presents the results of researches of TWIP-type austenitic steel in case of determination some of the more important parameters for continuous casting simulation process and the results of tests regarding the influence of strain parameters on sensitivity to plastic forming and deformation strengthening. It has been shown that the researched steel reaches a zero plasticity temperature at 1250°C. The deformation tests indicate its good workability of hot processing within the temperature range of 1100 ÷ 800°C. The relation between yield stress and strain during the hot deformation is typical for the presence of dynamic recrystallization processes. The tested steel has good formability and high mechanical properties, especially when being deformed at a high strain rate. Analysis of the substructure of researched steel was indicate presence of mechanical twinning.

Design and experimental verification of an innovative steel–concrete composite beam

This paper deals with the design method and the experimental verification of a new type of steel–concrete composite beam under static and fatigue loading. The connection is an alternative solution for steel–concrete composite bridges suitable for prefabrication and fast erection, while guaranteeing durability. The composite action of the beam is established through an innovative shear connection by adhesion, interlocking and friction. The resistance of the connection to longitudinal shear is based on the development of shear stresses in the confined interfaces that form the connection. The interfaces include a steel–cement grout interface and a rough concrete–cement grout interface. Confinement is provided by the reinforced concrete slab that encloses the connection. A composite beam was designed according to the design method for such type of composite beams in order to resist cyclic loading and to guarantee in the sequence its bearing capacity at ultimate limit state. The beam was initially subjected to cyclic loading and did not present signs of important damage after five million cycles. The damage on such type of connections is expressed by the development of a small residual slip in the interface which with the appropriate design stabilizes with the number of cycles. Finally the composite beam was statically loaded up to failure. The results show the capability of such a composite beam to develop its plastic moment at ultimate limit state.

Improving the crashworthiness of reinforced wooden road safety barrier using simulations of pre-stressed bolt connections with failure

During the development process of a new type of steel reinforced wooden road safety barrier parametric computational simulations were used to simulate the experimental vehicle impact certification tests as prescribed by the standard EN 1317. First a detailed study of pre-stressed bolt connection behavior between the guardrail and the guardrail connector was performed using parametric computational simulations of which results were later used in a large scale vehicle impact simulations. A novel, simplified approach to the modeling of barrier wooden parts was introduced to achieve reasonable simulation times in parametric study of the barrier behavior under vehicle impact. The wooden parts of the road safety barrier were modeled indirectly through a modified contact definition. The developed safety barrier design was later successfully experimentally certified in a full scale crash test according to the standard EN 1317. Experimental results were in a good agreement with the results of the full scale crash test simulations, which validates the proposed computational safety barrier model and thus justifies the use of the simplified modeling approach of the wooden safety barrier parts.

A new type of steel–concrete composite channel girder and its preliminary experimental study

A new type of steel–concrete composite beam that is specifically applicable to railway bridges is presented. The beam is featured with a channel shaped section. For such a section, the U-section steel beam is prefabricated with steel plates and the interior side of the channel is cast with concrete. The steel plates and concrete are integrated through shear stud connectors and work together to distribute loads. This type of structure not only inherits the characteristics of traditional concrete channel beams but also possesses its own unique attributes, such as advantageous mechanical performances, facilitating construction process, and low maintenance cost etc. To develop a design method for this new type of structures, and based on some FEM analysis, a static test of four-point symmetric bending was designed on a simply supported steel–concrete composite channel beam model with 1/3 sectional scale and 1/4 length scale. Preliminary research was conducted on its bending capacity, stiffness, stress distribution, crack diagram etc. Experimental results revealed that the steel plates and the concrete slab integrated through shear stud connectors can work well together and the channel beam model presented a bending failure mode. The flexural load carrying capacities and deformations of the composite channel beam were also analyzed by the Section analysis method, and the results agreed well with those from the test.

형상을 개선한 강섬유보강 숏크리트의 현장 적용성에 관한 기초적 연구

This paper presents the fundamental study on the field applicability of new-type steel fiber improved the existing shape. In this study, the theoretical reviews and the laboratory test programs were carried out to evaluate the mechanical characteristic of the new-type of steel fiber. The steel fiber sticking coefficient of new-type steel fiber was estimated from the test results. The laboratory scaled shotcrete rebound tests were also performed to analysis the field applicability of New-type steel fiber shotcrete and the mechanical behaviour of New-type steel fiber shotcrete were compared with that of the existing steel fiber shotcrete. It was found that the strength characteristic of New-type steel fiber shotcrete was increased.

Shaving and Masculinity in Eighteenth‐Century Britain

AbstractHow did new technologies inform conceptions of masculinity in Enlightenment Britain? This article explores the practice and material culture of shaving as an expression of polite masculinity. The eighteenth‐century masculine ideal was clean‐shaven. New types of steel meant sharper and more durable razors, in turn affecting the practice of shaving. Men at this time increasingly began to shave themselves rather than visit a barber. But razor‐makers advertised their wares using carefully constructed discourses, linking razors – and shaving – to a broader male interest in science. Razors were thus simultaneously a product of, and a vector for, Enlightenment ideas.