Rolled Sections Research Articles

Energy-saving potential and process optimization of iron and steel manufacturing system

SUMMARY Thermodynamic models for iron and steel manufacturing system are established to analyze the equilibriums of mass and energy and the characteristics of energy consumption. Based on the analysis of theoretical and practical energy consumptions, energy-saving potentials of the processes are obtained. Thermo-analysis software for iron-making process is developed and used to investigate the theoretical mechanisms and practical effects of some focused energy-saving technologies. For steel-making section, thermodynamic models of hot metal pretreatment, converter steel-making, secondary refining, and ladle transporting are established to simulate temperature and composition of liquid metal. Energy-saving measures are summarized by analyzing the effects of the operating parameters on energy-consuming process in the section. An integrated scheduling model of slab hot rolling section is established, which concerns the processes of slab transmitting, slab heating, and hot rolling. Production scheduling software and furnace control system are developed. As a result of practical application, the number of rolling units and energy consumption of reheating furnaces are minimized through the systematic optimization. Based on the physical model of dynamic ordered production, simulation platform of production and network model of energy flow are developed for iron and steel manufacturing system. The optimal operating parameters and energy distribution scheme of the main processes are obtained by using the platform and the model. Copyright © 2013 John Wiley & Sons, Ltd.

Theoretical and experimental analysis of RHS/CHS K gap joints

This work presents a study of welded K joints with gap, formed by a structural steel hot rolled hollow section, having rectangular hollow sections at the chords and circular hollow sections in the others members. The study developed theoretical and numerical analyses for the joints, experimental tests in full scale prototypes. Theoretical analyses were performed using code standards for K joints. The results in terms of behavior, ultimate load and collapse mode were analyzed and compared with numerical (finite elements) and theoretical models. The theoretical analysis was carried out from the code regulations. The joints tested indicated the failure mode of Plastic failure of the chord face (mode A). The results showed that the loads using code regulations and the ones from the numerical analysis had good agreement for the K joint.

Influence of cold bending on the resistance of wide flange members

Cold rolling is used for bending straight members with hot rolled wide-flange sections to create arches. Extensive studies have shown that the influence of residual stresses due to hot rolling on the resistance of wide-flange steel sections is nonnegligible. On the contrary, the residual stress pattern due to roller bending has been only recently identified. Its effects on the elasto-plastic behavior of curved members have not been studied sufficiently. In this paper, an in-depth study of the influence of such residual stresses is performed. Considering the residual stress pattern due to cold bending, interaction diagrams and buckling curves for cold bent steel arches are developed. The results are quantified and compared with those for hot-rolled and stress free members. This allows designers to appreciate the available margins of safety when using standard interaction equations and buckling curves for cold bent members. Furthermore, the results suggest the necessity for the development of buckling curves for cold bent members including initial imperfections.

Numerical Evaluation of Steel Columns Stability under Various Cases of Thermal Loads

This paper presents the results of a simulation study of fire tests of restrained (fixed-hinged) hot rolled steel column sections subjected to axial compression in addition to constant and variable thermal loads. Finite element computer software is utilized to study steel columns stability under thermal loads using three approaches; non-linear buckling analysis, thermal structural-Load Transfer Method (LTM) analysis, and Direct Coupled Field analysis. The finite element results are in good agreement with experimental results found in literature. The Direct Coupled Field analysis is also used to study a non-uniform temperature distribution on one side of the steel column. The LTM shows the best capabilities in studying such problems compared to the other two approaches

Minimum Weight Design of Pre Engineered Steel Structures Using Built-up Sections and Cold Formed Sections

In the past few decades most of the efforts were made to achieve minimum weight of the steel structures by satisfying all the design requirements imposed by various latest building codes and this idea lead towards the concept of pre-engineered steel buildings (PEB). In current research work, minimum weight buildings are targeted with simple fabrication process and easy erection to have maximum structural efficiency. Minimum weight of structure is proportional to the minimum cost and hence lowers seismic and gravitational forces. To achieve above mentioned objectives and to verify the suitability and applicability of concept of PEB, a sample steel industrial building is first analyzed and designed by using conventional steel hot rolled sections and then by using pre-engineered tapered and cold formed sections. Results of analysis were compared in terms of weight and response of structures which clearly indicated that PEB structures are of less weight and structurally more efficient than conventional steel structures.

Structure and mechanical properties of ingots and rolled sections of aluminum alloy based on the Al-Mg-Mn system

Commercial ingots and hot-pressed rolled sections of Al-Mg-Mn alloy doped with zinc, scandium, zirconium, chromium, and vanadium have been studied using optical microscopy, thermal analysis, electron microscopy, and electron-probe microanalysis. The compositions of the phase constituents and aluminum matrix of the alloy are determined. The sensitivity of the alloy to the formation of complex intermetallic compounds during solidification is revealed. The mechanical properties of ingots and rolled sections are determined.

Experimental and theoretical behaviour analysis of steel suspension members subjected to tension and bending

Steel suspension members subjected to tension and bending offer an economical and efficient alternative for many structural problems. This paper is concerned with the elastic and elastic-plastic behaviour of suspension members with bending stiffness subjected to vertical point and uniformly distributed loads. An experimental study is described which focuses on the response of three suspension members with various T-shaped steel hot rolled sections and geometric configurations. The tests enable direct assessment of the influence of a key parameter such as the sag-to-span ratio on the response of suspension members. Detailed nonlinear finite-element models are generated to provide a tool for theoretical analyses and to facilitate further understanding of the behaviour. Results demonstrate that experimentally obtained responses can generally be closely predicted numerically because there are relatively good agreements between finite element and tests results. The results and observations of subsequent numerical parametric studies offer an insight into the key factors that govern the behaviour of suspension members with bending stiffness in the elastic-plastic range.

Experimental investigation on flexural behaviour of HSS stud connected steel-concrete composite girders

In this paper, experimental investigations on high strength steel (HSS) stud connected steel-concrete composite (SCC) girders to understand the effect of shear connector density on their flexural behaviour is presented. SCC girder specimens were designed for three different shear capacities (100%, 85%, and 70%), by varying the number of stud connectors in the shear span. Three SCC girder specimens were tested under monotonic/quasi-static loading, while three similar girder specimens were subjected to non-reversal cyclic loading under simply supported end conditions. Details of casting the specimens, experimental set-up, and method of testing, instrumentation for the measurement of deflection, interface-slip and strain are discussed. It is found that SCC girder specimen designed for full shear capacity exhibits interface slip for loads beyond 25% of the ultimate load capacity. Specimens with lesser degree of shear connection show lower values of load at initiation of slip. Very good ductility is exhibited by all the HSS stud connected SCC girder specimens. It is observed that the ultimate moment of resistance as well as ductility gets reduced for HSS stud connected SCC girder with reduction in stud shear connector density. Efficiency factor indicating the effectiveness of high strength stud connectors in resisting interface forces is estimated to be 0.8 from the analysis. Failure mode is primarily flexure with fracturing of stud connectors and characterised by flexural cracking and crushing of concrete at top in the pure bending region. Local buckling in the top flange of steel beam was also observed at the loads near to failure, which is influenced by spacing of studs and top flange thickness of rolled steel section. One of the recommendations is that the ultimate load capacity can be limited to 1.5 times the plastic moment capacity of the section such that the post peak load reduction is kept within limits. Load-deflection behaviour for monotonic tests compared well with the envelope of load-deflection curves for cyclic tests. It is concluded from the experimental investigations that use of HSS studs will reduce their numbers for given loading, which is advantageous in case of long spans. Buckling of top flange of rolled section is observed at failure stage. Provision of lips in the top flange is suggested to avoid this buckling. This is possible in case of longer spans, where normally built-up sections are used.

Wear and rolling contact fatigue of PEEK and PEEK composites

Wear and rolling contact fatigue were investigated on unfilled PEEK and on three PEEK short fiber reinforced composites. For this aim, roller-shaped specimens were subjected to rolling contact tests at different contact pressure levels. Wear rate-pv product and contact pressure-life diagrams were obtained, depending on material hardness. Microscopic observations of rolling contact surfaces and sections of the rollers highlighted damages at two different scales, surface and bulk, leading independently to wear and rolling contact fatigue. These damages were also of different typology for unfilled PEEK and composites: micro-pitting and deep transversal cracks occurred on unfilled PEEK rollers, while delamination and spalling phenomena where found on composite rollers.

Study, test and designing of cold formed section as per AISI code

Use of hot rolled steel member in structures is a well known practice in construction industry. But, in case of light and moderate loaded structures, the usage of hot rolled steel section leads to overweight and uneconomical. To overcome this deficiency a new form steel known as cold formed steel (CFSS) has come into practice. Cold Formed steel product such as Z-purlin has been commonly used in metal building industry more than 40 year in unites state due to their wide range of application, economy, ease of fabrication and high strength-to-weight ratios. Z- purlins are predominantly used in light load and medium span situations such as roof systems. Literature review details the review of the literature on local buckling, torsional bucking buckling, Distortional buckling, Channel section with Stiffened Lip and Channel section with unstiffened Lip formed members. For tensile test a test specimen of Z-section fabricated according to the IS1608-2005. The design of cold formed section is also explained with numerical example.

Structural evaluation of FRP Pultruded Sections in overhead transmission line Towers

This paper presents experimental investigation carried out on modular X-braced panels of a transmission line tower made from FRP pultruded structural profiles subjected to transverse and vertical loading. The modular elements are light weight, can be easily assembled for structural support of an overhead transmission lines. The member stresses were monitored using strain gauges during full scale testing. Mathematical model of 3-Dimensional panel were generated using standard FEM software to study the analytical correlation with the experiments. The results from this study illustrates the light weight FRP structural profiles is an alternate sections to the conventional rolled steel angle sections used in power transmission line towers.

Performance of intermediate and long links in eccentrically braced frames

Recent researches about the performance of eccentrically braced frames have shown that some of the intermediate-length links do not meet the requirements of AISC2005. Further investigations on the current AISC 2005 provisions and also assessing the effect of involved parameters on the behavior of this type of links have been carried out in this research. Moreover, to cover the shortages of previous researches conducted on the performance of long links compared to short ones, some flexural links are also put into the study. By analyzing the links made of European-standard rolled shape sections, validity of the provisions for these types of links, which fewer investigations about them are available, is also examined. The Finite element analysis employing 3D solid elements is implemented to model a total of 68 links. Results of the study imply some design suggestions for these types of links. Also, the slenderness ratio of the web as well as the specification of the stiffeners is discerned as important parameters impacting on the performance of the intermediate links.

Study on Model and Method for Production Scheduling on Hot Rolling Section

According to the technical demand of hot-rolling production in steel plant, a production scheduling mathematical model was proposed with the aim of reducing the production cost and optimizing the product quality. The scheduling of reheating furnaces which was summed up as the Boolean satisfiability problem was involved in rolling scheduling optimization which was summed up as the multiple traveling salesman problem with uncertain traveling salesman number, and a two-stage genetic-tabu algorithm was designed to solve the problem. It was shown that, the model could fully meet the demand of hot-rolling production. Compared to the human-computer method, the results had better performance on high production and energy efficiency.

Composite Steel Stud Blast Panel Design and Experimental Testing

Based on Federal Aviation Authority (FAA) requirements, project specific blast loads are determined for the design of a new airport traffic control tower. These blast loads must be resisted by exterior wall panels on the control tower, protecting building occupants from intentional explosives attack scenarios. Such blast resistant walls are typically constructed of thick reinforced concrete panels or composite steel plate and rolled sections, as conventional building cladding systems have relatively low blast resistance. While these more robust design approaches are valid, the additional cladding mass they represent will significantly increase the base shear and overturning demand in seismic zones. This paper investigates the use of a light structural system comprised of a steel stud wall assembly partially embedded in a thin layer of concrete to obtain composite action. Fiber reinforced polymer (FRP) composites are also included to increase the blast resistance and aid in keeping the panel weight to a minimum. Two full-scale composite steel stud walls are designed, constructed, and tested dynamically in the BakerRisk shock tube. The stud walls consist of back-to-back 150 mm deep, 14 gauge (1.8 mm thick), cold-formed steel studs spaced at 610 mm on center. Both specimens have a 50 mm thick normal weight concrete layer, reinforced with welded wire mesh that is welded to the stud compression flanges to achieve composite action. Two layers of Tyfo® SEH-51A fiber reinforced composites are used on the tension flange of the steel studs. A single layer of Tyfo® SEH-51A composites is used on the tension face of the concrete layer between the studs for one of the specimens. Web stiffeners are used at the bearing support to prevent premature web crippling shear failure of the specimens. The stud walls are analyzed using single-degree-of-freedom (SDOF) models. A non-linear moment-curvature relationship, accounting for actual material constitutive properties, is used for determining the resistance function of the walls. Blast pressure and impulse data from the shock tube tests is used to compare analytical predictions to the measured displacement-time response. Analytical predictions of panel response for both tests are within ten percent of the observed response based on displacement.

Finite Element Analysis and Comparison of Castellated and Cellular Beam

The solid I section beam with creating hexagonal cavities (openings) has numerous advantages over conventional rolled sections. As they are light weight, strong, cheap and elegant. The opening in the web simplifies the work of the installer and the electrician, since taking pipes across beams presents no problems. A cellular beam (circular openings) is the modern version of the traditional castellated beam. The beam comprises pronouncedly asymmetric cellular tees, to provide a wide bearing for either pre-cast units or a profiled metal deck. The elastic finite element analysis of castellated beam and cellular beam is carried out to understand its behaviour under load. The failure pattern and stresses developed under same loading condition are studied. Based on the various modes of failure, the applicable methods of analysis are studied which includes plastic analysis, mid post yielding and buckling analysis. From the previous experimental results, one beam is selected and analyzed. Then the no of openings is varied as 2, 4 and 6 in selected beam. The shape of opening is considered as hexagonal and circular of same cross sectional area. The support conditions are considered as fixed, hinged and roller. Overall 18 cases are studied for same central point load and span with change of spacing of openings. The maximum Deflection and the maximum VonMises stress are worked out. The comparative study is carried out using software for finite element analysis ANSYS.

Measurement of Critical Dimensions of Cold Roll Formed Sections Using Digital Image Processing

A research investigation is presented which discusses the practicality of using several image processing and knowledge based techniques for the measurement and classification of cold rolled steel sections. Image analysis techniques can be applied to many different applications and assessing the quality and the accuracy of cold roll formed steel sections is no exception. The operations detailed within this paper are both traditional image processing methods and novel neural network based techniques which are combined together to give a bespoke alternative to the manual processing currently employed to test these sections. The results show the suitability of using image analysis and image processing to aid in the quality control of cold steel roll forming and initial tests have demonstrated great potential for this work.

A simple steel beam design curveWork upon which this paper is based was presented at the 2008 CSCE Annual Conference in Quebec City on 11 June 2008.

A simple alternative equation for the calculation of the strength of laterally unbraced structural steel beams is presented herein. This equation uses a format similar to the present steel column design curve in the Canadian structural steel design standard, CAN/CSA-S16-09, and is proposed as a replacement for the existing three part curve for beam strength by a one part equation with a continuous derivative. A reliability analysis of the new equation indicates that the equation provides safety levels very close to those of the current formula for classes 1 and 2 rolled sections. It also provides the desired level of safety for welded beams, whereas the current equations tend to over-estimate their strength. The alternative equation also provides adequate safety for class 3 beams. The concept of maximum unbraced length for braced beam design (Lu) is revisited herein and a simple calculation for this length is also proposed.

Parameteric Study of Castellated Beam

“Castellated beam” is a name commonly used for type of expanded beam. Castellated beams combine beauty, versatility, economy in steel design. These are fabricated from standard rolled section and are engineered to save time of construction, enabling saving in steel and reducing building costs. These are mainly designed to reduce weight and at the same time increase the efficiency in structural performance. The principal advantage of castellation is the increase in vertical bending stiffness castellated beams have proved to be efficient for moderately loaded longer spans where the Design is controlled by moment capacity or deflection. In this paper a steel beam is selected and Finite Element Analysis is done for constant loading and support condition by using ANSYS software. The deflection pattern at the center of castellated beam is studied for different parametric conditions by changing depth of hexagon to the depth of web ratio and also by changing the position of hexagon along the length of the beam. A comparison is done for various conditions.

Design and Costs for Simple-Made-Continuous Rolled Steel Girder Bridges: Literature Survey

The method of simple-made-continuous for steel bridges is becoming more popular throughout the United States because it enables significant cost savings. Specifically, the method allows one to avoid steel bridge girder splices and design the steel sections for the self weight and the weight of the slab as simply supported and then the addition of live load and remaining dead loads as continuous. This balances the moments between the positive and negative regions allowing for a prismatic section and even adds speed of construction since the field splices are not needed. In 2006, the Colorado DOT sponsored a study to (1) review current approaches to simple-made-continuous using standard rolled sections and (2) develop design charts for rapid sizing of steel bridge beams and cost estimation for simple-made-continuous. This paper presents a state-of-the-art review up until 2007 for this type of construction and focuses on several of the most recent and successful transportation department projects.

Experimental investigation of residual stresses in roller bent wide flange steel sections

Residual stresses in straight hot rolled wide flange sections are well documented and have been investigated in the recent past. However, to the knowledge of the authors, residual stress measurements have not been published on roller bent wide flange sections. Straight sections are curved into roller bent ones at ambient temperatures by means of the roller bending process. Since roller bent sections underwent severe plastic deformation during the forming process, the well-known residual stress patterns from hot rolling may not be appropriate for the roller bent steel. Roller bent sections can be applied in halls, roofings and bridges, thereby acting as structural arches and it is important that a realistic residual stress pattern is implemented when assessing their load carrying capacity. An experimental program has been carried out to investigate the residual stresses in roller bent wide flange sections bent about the strong axis. Residual stresses were measured with the sectioning method. The experimental technique was investigated with respect to possible temperature influence and repeatability of the measurements. Experimental values revealed that the residual stress pattern and magnitude in roller bent sections is different when compared to their straight counterparts.