scholarly journals MAIN DIRECTIONS OF MODERN DEVELOPMENT OF STEEL CONSTRUCTIONS FOR BUILDINGS AND STRUCTURES

2021 ◽  
pp. 5-12
Author(s):  
Bilyk S.І. ◽  
◽  
Bilyk А.S. ◽  
Keyword(s):  
High Strength Steels ◽  
Steel Structures ◽  
High Strength ◽  
Structural Systems ◽  
Metal Structures ◽  
Term Operation ◽  
Design Solutions ◽  
The Creation ◽  
Welding Processes

The development of technologies for the manufacture and design of steel structures, together with the development of computer technologies, makes it possible to increase productivity in the building industry. The analysis and generalization of such factors made it possible to identify the main trends and directions of the creation and improvement of metal structures, taking into account the automation of their manufacturing processes and the use of BIM technologies. The highlighted tendencies make it possible to show both new directions for the development of scientific research and directions for the development of practical methodologies for determining the regularities of the stress-strain state of structural systems using steel. Among the main trends, the following are highlighted: digitalization of the metal construction industry; automation and robotization of the manufacturing and assembling processes; science intensity of design and production processes; greening production, evaluating design solutions from the standpoint of environmental safety; complex optimization of design solutions. The authors highlight the next important tasks and prospects for the development of the creation of effective metal structures: the creation and use of high-strength steels C960 and more, the improvement of automated and robotic welding processes for ultra-high-strength steels with various metal thicknesses; development and improvement of the theory of calculation of thin-walled and composite structures, determination of the actual resource of metal structures after long-term operation; introduction into the practice of creating new structures of rational and optimal design approaches with the requirements of long-term operation and life cycle, including progressive collapse, reduction in the cost of fire and anti-corrosion covers for steel structures; improvement of building codes and rules for the design of metal structures; implementation of leading foreign standards and experience; training of modern professional engineers and technicians; development of experimental and theoretical studies of full-scale samples of structures on the basis of creating high-precision information models of structural systems.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Favourable Steel Structures using High Strength Steels

ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 1530-1536
Author(s):  
Fengyan Gong ◽  
André Dürr ◽  
Jochen Bartenbach
Keyword(s):  
High Strength Steels ◽  
Steel Structures ◽  
High Strength

Metallurgical Study of Friction Stir Welded High Strength Steels for Shipbuilding

2014 ◽  
Vol 783-786 ◽  
pp. 2798-2803 ◽  
Author(s):  
Marion Allart ◽  
Alexandre Benoit ◽  
Pascal Paillard ◽  
Guillaume Rückert ◽  
Myriam Chargy
Keyword(s):  
Cubic Boron Nitride ◽  
High Strength Steels ◽  
High Strength ◽  
High Yield ◽  
Friction Stir ◽  
Polycrystalline Cubic Boron Nitride ◽  
Recent Developments ◽  
Metallurgical Study ◽  
Welding Processes ◽  
Pcbn Tools

Friction Stir Welding (FSW) is one of the most recent welding processes, invented in 1991 by The Welding Institute. Recent developments, mainly using polycrystalline cubic boron nitride (PCBN) tools, broaden the range of use of FSW to harder materials, like steels. Our study focused on the assembly of high yield strength steels for naval applications by FSW, and its consequences on the metallurgical properties. The main objectivewas to analyze the metallurgical transformations occurring during welding. Welding tests were conducted on three steels: 80HLES, S690QL and DH36. For each welded sample, macrographs, micrographs and micro-hardness maps were performed to characterize the variation of microstructures through the weld.

Durable Architectural and Decorative Powder-Activated Concrete Using Waste-Crushing Stone Rocks

2019 ◽  
Vol 802 ◽  
pp. 1-15
Author(s):  
Sergey Victorovich Daletsky ◽  
Yuri Mikhailovich Kolitievsky ◽  
Victor Vasilievich Nikonov ◽  
Nikolay Nikolaevich Sirotin ◽  
Vladimir Vladimirovich Yudaev
Keyword(s):  
High Strength ◽  
High Density ◽  
Term Operation ◽  
Fine Grained ◽  
Concrete Mixtures ◽  
Technical Properties ◽  
Fine Grained Sand

The article consists in the development of compositions of self-compacting powder-activated fine-grained (sand) concrete mixtures, including color ones, for the production of high-density, high-strength and durable architectural and decorative concretes, which do not lose their architectural appeal during long-term operation, on the basis of multi-tonnage waste of stone crushing of various rocks, without the use of expensive mineral reactive components and the study of their physical and technical properties.

Influence of Predetermined Surface Defect to the Bendability of Ultra-High-Strength Steel

2012 ◽  
Vol 504-506 ◽  
pp. 901-906 ◽  
Author(s):  
Antti Määttä ◽  
Antti Järvenpää ◽  
Matias Jaskari ◽  
Kari Mäntyjärvi ◽  
Jussi A. Karjalainen
Keyword(s):  
Surface Defects ◽  
High Strength Steels ◽  
Steel Structures ◽  
High Strength ◽  
Crack Size ◽  
Critical Crack ◽  
Bending Radius ◽  
Ultra High Strength Steels ◽  
Materials Used ◽  
Critical Crack Size

The use of ultra-high-strength steels (UHS) has become more and more popular within last decade. Higher strength levels provide lighter and more robust steel structures, but UHS-steels are also more sensitive to surface defects (e.g. scratches). Practically this means that the critical crack size decreases when the strength increases. The aim of the study was to study if the formula of critical crack size is valid on forming processes of UHS-steels. Surface cracks with different depths were created by scratching the surface of the sheet by machining center. Effect of the scratch depth was determined by bending the specimens to 90 degrees. Bents were then visually compared and classified by the minimum achieved bending radius. Test materials used were direct quenched (DQ) bainitic-martensitic UHS steels (YS/TS 960/1000 and 1100/1250). Results from the bending tests were compared to the calculated values given by the formula of critical crack size.

scholarly journals STUDYING THE IMPROVEMENT OF TENSILE STRENGTH OF LOW ALLOY HIGH STRENGTH STEEL WELDS USING AN ECONOMICAL TECHNIQUE

2018 ◽  
Vol 18 (3) ◽  
pp. 498-505
Author(s):  
Abdul Sameea J Jilabi
Keyword(s):  
Tensile Strength ◽  
Weld Joint ◽  
Copper Wire ◽  
High Strength Steels ◽  
High Strength ◽  
Low Alloy Steels ◽  
Joint Efficiency ◽  
Comparison Results ◽  
Alloy Steels ◽  
Welding Processes

Low alloy steels are particularly used in manufacturing several parts in the heavyengineering industries, agricultural equipment and dies which may be subject to servicefailure, and thus may need to be repaired by one of the welding processes. The weldabilityof steels is determined by their sensitivity to cracks that can be prevented by the use ofspecial welding procedures which are often expensive and difficult to use. Manual metal arcwelding of low alloy high strength steels was done firstly, using a cheap electrode (OK46.00), followed by the use of an economical technique which depends on coiling copperwires with different diameters around the cheap electrode. The expensive electrode (OK73.68) was also used for comparison. Results showed an increase in the tensile strength (712MPa) and weld joint efficiency (83.8%) when the expensive iron powder low hydrogencovering electrode (OK 73.68) was used. On the other hand, the tensile strength wasdecreased to (206 MPa) and the weld joint efficiency to (24.2%) when the cheap electrode(OK 46.00) was used. Coiling a (0.6 mm) dia. copper wire around the (OK 46.00) electrodeincreased the tensile strength and weld joint efficiency to (510 MPa) and (60%) respectively.

scholarly journals The Assessment of Selected Properties of Welded Joints in High-Strength Steels

2020 ◽  
pp. 73-79
Author(s):  
Lechosław Tuz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Welded Joints ◽  
Heat Input ◽  
Structural Changes ◽  
High Strength Steels ◽  
High Strength ◽  
High Quality ◽  
Treatment Processes ◽  
Welding Processes

The use of technologically advanced structural materials entails the necessity of adjusting typical welding processes to special requirements resulting from the limited weldability of certain material groups. Difficulties obtaining high-quality joints may be the consequence of deteriorated mechanical properties and structural changes in materials (beyond requirements of related standards). One of the aforementioned materials is steel characterised by a guaranteed yield point of 1300 MPa, where high strength is obtained through the addition of slight amounts of carbide-forming elements and the application of complex heat treatment processes. A heat input during welding may worsen the aforesaid properties not only in the weld but also in the adjacent material. The tests discussed in the article revealed that the crucial area was that heated below a temperature of 600°C, where the hardness of the material decreased from approximately 520 HV to 330 HV.

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