Key Issues of Using High Strength Steels in Seismic Structures and some Recent Progress

2012 ◽  
Vol 166-169 ◽  
pp. 2444-2452 ◽  
Author(s):  
Guo Qiang Li ◽  
Yan Bo Wang ◽  
Su Wen Chen ◽  
Fei Fei Sun
Keyword(s):  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Constructional Steel ◽  
Research Progress ◽  
Work Related ◽  
Key Issues ◽  
Increasing Demand ◽  
Future Work ◽  
Tongji University

Since recent advances of technology in material science and increasing demand for high strength steel, Q460 high strength steel has been applied to several landmark buildings and major projects. However, the application of high strength steel in seismic structures is limited by the relative worse ductility, which is usually decreasing with the increasing on yield strength. For this purpose, key issues of using high strength steels in seismic structures are discussed and two design methodologies are proposed. Recent research progress on application of high strength constructional steel achieved at Tongji University is introduced. Finally, future work related to the application of high strength steels are recommended.

Research Progress for High Strength Structural Steel and Key Issues of Application in Seismic Zone

2014 ◽  
Vol 989-994 ◽  
pp. 379-382
Author(s):  
Li Xia Ji ◽  
Teng An
Keyword(s):  
Structural Steel ◽  
High Strength Steel ◽  
Mechanical Performance ◽  
Research Work ◽  
High Strength ◽  
Hysteretic Behavior ◽  
Research Progress ◽  
Seismic Zone ◽  
Steel Columns ◽  
Key Issues

A review of recent research on mechanical performance of high strength structural steel (HSSS) in the level of both materials and members is presented, including the static material performance, toughness and mechanical property under cyclic loadings of HSSS, buckling and hysteretic behavior of high strength steel columns (HSSC), the ductility and resistance of bolted connection with high strength steel slices etc. Previous research work shows that the application of high strength steel (HSS) is limited in seismic zone .Finally, two design methods of using HSS in seismic zone are proposed based on current seismic design philosophy.

Study of the Prospects of the Use of High-Strength Steel Shapes

2013 ◽  
Vol 475-476 ◽  
pp. 1253-1256
Author(s):  
Valentina Parlashkevich ◽  
Oleg Tsyba
Keyword(s):  
Comparative Analysis ◽  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Structural Elements ◽  
Steel Shapes ◽  
Economic Indices

The prospects of the use of rolled shapes made of high-strength steels in steel structural elements are considered. A comparative analysis of strength values and economic indices of steel structural elements is done for their work in compression, tension and bending.

Structural Performance Evaluation of Built-Up Stub Steel Column with Various Steel Grades under Concentric Loading

2015 ◽  
Vol 764-765 ◽  
pp. 127-131
Author(s):  
Yang Yang ◽  
Kang Min Lee ◽  
Keun Yeong Oh ◽  
Sung Bin Hong
Keyword(s):  
Tensile Strength ◽  
High Strength Steel ◽  
Local Stability ◽  
Experimental Studies ◽  
High Strength Steels ◽  
High Strength ◽  
Design Criteria ◽  
Stability Criteria ◽  
Steel Grades ◽  
Concentric Loading

The current local stability criteria (KBC2009, AISC2010) are enacted through theoretical and experimental studies of ordinary steels, but the mechanical properties of high strength steels are different from ordinary steels. The high strength steel in the applicability of design criteria should be needed to review because of increasing market demanding for high strength steel in the high-rise and long span buildings. In this study, stub columns of H-shaped and box section with various steel grades subjected to concentric loading were investigated, and these steels were checked to the applicability of current local stability criteria. The difference between the ordinary steel and high strength steel was compared. As a result of comparison with various steel grades, most specimens were satisfied with the design criteria, but some specimens with lower tensile strength were not reached the required strength. It is considered that the uncertainty of material was the higher when the tensile strength of material was the lower.

Study on Micro-Mechanism of Crack Initiation and Propagation Induced by Inclusion in Ultra-High Strength Steel

2007 ◽  
Vol 353-358 ◽  
pp. 1185-1190 ◽  
Author(s):  
Yan Ping Zeng ◽  
Hong Mei Fan ◽  
Xi Shu Wang ◽  
Xi Shan Xie
Keyword(s):  
Crack Initiation ◽  
High Strength Steel ◽  
Harmful Effect ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Ultra High Strength Steel

Specially designed SEM in-situ tensile and fatigue tests have been conducted to trace the entire process of crack initiation and propagation till fracture in an ultra-high strength steel MA250. TiN is a typical inclusion and its average size is in the range of 8~10μm in MA250 steel. The micro-mechanism of the effect of TiN inclusion on crack initiation and propagation at tensile and fatigue tests both have been studied in detail. Experimental results show the harmful effect of TiN on tensile and fatigue properties both. This work is helpful to establish the practical life prediction model for the characteristic inclusion parameters in ultra-high strength steel components. It also enlightens us to eliminate TiN in the further development of ultra-high strength steels.

The Role of Niobium in Lightweight Vehicle Construction

2007 ◽  
Vol 537-538 ◽  
pp. 679-686 ◽  
Author(s):  
Hardy Mohrbacher ◽  
Christian Klinkenberg
Keyword(s):  
Grain Refinement ◽  
High Strength Steel ◽  
Mechanical Performance ◽  
High Strength Steels ◽  
High Strength ◽  
Interstitial Free ◽  
Niobium Microalloying ◽  
Hsla Steels ◽  
Steel Grades ◽  
Different Characteristics

Modern vehicle bodies make intensive use of high strength steel grades to improve the weight and the mechanical performance simultaneously. A broad range of medium and extra high strength steel grades is available. These steel grades have different characteristics concerning strength, formability and weldability. For many steel grades microalloying by niobium is the key to achieve their characteristic property profile. In HSLA steels niobium enhances the strength primarily by grain refinement. In interstitial free high strength steels niobium serves as a stabilizing element and also assists in obtaining the bake hardening effect. Some modern multiphase steels rely on niobium to achieve additional strength via grain refinement and precipitation hardening. Microstructural control provides a way to further optimize properties relevant to automotive processing such as cutting, forming and welding. The relevance of niobium microalloying in that respect will be outlined.

scholarly journals Post-fire mechanical properties of high strength steels

2018 ◽  
Author(s):  
Ben Young ◽  
Hai-Ting Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Ambient Temperature ◽  
High Strength Steel ◽  
Elevated Temperatures ◽  
Weight Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Predictive Equations ◽  
Retention Factors

High strength steels are becoming increasingly attractive for structural and architectural applications due to their superior strength-to-weight ratio which could lead to lighter and elegant structures. The stiffness and strength of high strength steels may reduce after exposure to fire. The post-fire mechanical properties of high strength steels have a crucial role in evaluating the residual strengths of these materials. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed high strength steels. A series of tensile coupon tests has been carried out. The coupon specimens were extracted from cold-formed square hollow sections with nominal yield stresses of 700 and 900 MPa at ambient temperature. The specimens were exposed to various elevated temperatures ranged from 200 to 1000 °C and then cooled down to ambient temperature before tested to failure. Stress-strain curves were obtained and the mechanical properties, namely, Young’s modulus, yield stress (0.2% proof stress) and ultimate strength, of the cold-formed high strength steel materials after exposure to elevated temperatures were derived. The post-fire retention factors that obtained from the experimental investigation were compared with existing predictive equations in the literature. New predictive equations are proposed to determine the residual mechanical properties of high strength steels after exposure to fire. It is shown that the proposed predictive equations are suitable for both cold-formed and hot-rolled high strength steel materials with nominal yield stresses ranged from 690 to 960 MPa.

Fiber Augmented Steel Technology Pipe (FAST-Pipe™): An Alternative to High Strength Steel

2010 ◽  
Author(s):  
Mamdouh M. Salama
Keyword(s):  
High Strength Steel ◽  
Life Cycle Cost ◽  
High Strength Steels ◽  
Performance Testing ◽  
High Strength ◽  
Proof Of Concept ◽  
Long Distance ◽  
Steel Technology ◽  
Technological Advances ◽  
Bending Load

A key imperative to the transportation of natural gas for long distance is the continued technological advances to reduce the development and life cycle cost of high pressure gas pipeline while maintaining the required high level of safety, reliability and environmental stewardship. Therefore, advances in high strength steels such as X100 and X120 have been pursued by several companies. This paper presents an alternative solution namely FAST-Pipe™ (Fiber Augmented Steel Technology - Pipe). The FAST-Pipe™ Concept involves wrapping a conventional strength steel pipe (X70) whose thickness is selected to satisfy axial and bending load requirement with dry fiberglass to achieve the pressure load requirement. The FAST-Pipe™ offers several technical and economical advantages over High strength steel concepts. The paper presents the results of the proof of concept validation program that included cost analysis and performance testing. The paper also summarizes the results of the rigorous qualification program that was implemented subsequent to the successful results of the proof of concept phase.

scholarly journals Experimental Studies of Different Strength Steels MIG Brazed Joints

2018 ◽  
Author(s):  
Miklós Berczeli ◽  
Zoltán Weltsch
Keyword(s):  
Motor Vehicle ◽  
Experimental Studies ◽  
High Strength Steels ◽  
High Strength ◽  
Small Degree ◽  
Dead Load ◽  
Brazed Joints ◽  
Key Issues ◽  
Increased Strength ◽  
The Given

Nowadays the stakeholders of vehicle industry are focusing on making materials and technologies for motor-vehicle bodies that satisfy the newest requirements. Reduction of the manufactured vehicle’s dead load - while the important material properties of proper functioning only change in a small degree – is such a requirement. There exist many solutions to satisfy this requirement. One of them is when the materials are in the same group, but the material with higher strength is used with less thickness. Reducing mass should be searched in recent high strength steels. Evidently, to reduce dead load, manufacturers use steels with different strength, depending on the function of the given structural component. The advantages of steels with increased strength is the reduced cost of manufacturing and to make the hybrid material couplings cheaper as well. However, malleability is one of the key issues of manufacturing body components, so common use of basic and increased strength steels is necessary. The connection between the standard (DC) and increased strength (DP) steels design is one way for the binding established by brazing, which has several advantages over welding. In this paper MIG brazing is formed between the DC-DP steel pairs and examine changes in the surface properties and the interfacial layer. The results shows there are differences between the DC and DP side of the joint.

The Influence of Mismatch Effect on the High Cycle Fatigue Resistance of High Strength Steel Welded Joints

2018 ◽  
Vol 1146 ◽  
pp. 73-83 ◽  
Author(s):  
Ádám Dobosy ◽  
Marcell Gáspár ◽  
János Lukács
Keyword(s):  
Fatigue Resistance ◽  
Welded Joints ◽  
High Cycle Fatigue ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Cycle Fatigue ◽  
Matching Problem ◽  
Work Related ◽  
Base Materials

The objective of this article is to present the newest results of our research work related to the high cycle fatigue resistance of advanced high strength steels. In order to determine and compare the fatigue resistance, high cycle fatigue (HCF) tests were performed on two strength categories (S690 and S960) of high strength steels including quenched and tempered (Q+T) and thermomechanical (TM) types. During the HCF tests base materials and their welded joints were investigated at different mismatch conditions (matching, undermatching, overmatching). Measured and analysed data about base materials and welded joints were compared and discussed. Statistical approach was applied during the preparation and the evaluation of the investigations, which increased their reliability. The parameters of the HCF design curves were calculated based on the Japanese testing method (JSME S 002-1981) which uses 14 specimens. During the evaluation the results were compared with each other and with literary data. According to the presented examinations the HCF resistance of the base materials is more advantageous than the welded joints. The TM steel indicated better fatigue resistance than the quenched and tempered one of the same category. The matching problem had influence on the HCF resistance of high strength steels, depending on the strength category and the steel type.

Basic Investigations of Non-Pre-Punched Joining by Forming of Aluminium Alloy and High Strength Steel with Shear-Clinching Technology

2014 ◽  
Vol 611-612 ◽  
pp. 1413-1420 ◽  
Author(s):  
Marion Merklein ◽  
Gerson Meschut ◽  
Martin Müller ◽  
Réjane Hörhold
Keyword(s):  
Impact Load ◽  
Lightweight Design ◽  
High Strength Steels ◽  
High Strength ◽  
Joining By Forming ◽  
Forming Technology ◽  
Process Reliability ◽  
Mechanical Clinching ◽  
Increasing Demand ◽  
The One

Facing a decreasing amount of resources on the one hand and an increasing demand for comfort on the other, more and more attention is being paid to sustainability and care for the environment. Particularly in the automotive sector, lightweight design principles continue to prosper rapidly. As a result, adjusted materials for different applications were developed. Due to the formation of intermetallic phases, most multi-material mixes cannot be welded and require adapted joining technologies. Mechanical joining technologies such as self-piercing riveting and mechanical clinching have proven effective methods of joining lightweight materials like aluminium and ductile steels. New high-strength steels are increasingly used in crash-sections, where limited deformation under impact load is required. These hot stamped steels have a very low elongation at break and therefore a low formability. Currently there is no joining by forming technology without pre-punching available using these grades of steels on die-side. The newly developed shear-clinching process is one possible method of joining this kind of material without additional elements. The fundamental idea of shear-clinching is a single-stage process in which pre-punching of the die-side material is performed by indirect shear-cutting and subsequent forming of the upper layer into this hole. This would immensely enlarge the application segment of mechanical clinching even if hot stamped steels are positioned on die-side. Fundamental studies are required to ensure process reliability and it is necessary to break down the joining process into fragments, like pre-punching and clinching with pre-punched sheet, and superpose them to form the combined procedure shear-clinching. This paper presents a detailed investigation of the sub-process clinching with pre-hole.

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