Helio Goldenstein

Helio Goldenstein
University of São Paulo | USP · Metallurgical and Materials Engineering Department, Escola Politécnica

Doutor em Engenharia Metalúrgica, Livre Docente

About

208
Publications
57,184
Reads
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1,534
Citations
Additional affiliations
March 1976 - September 2017
University of São Paulo
Position
  • Professor (Full)
January 1976 - September 2016
University of São Paulo
Position
  • Professor (Full)
January 1974 - November 1974
Instituto de Pesquisas Tecnológicas
Position
  • engenheiro junior (recém formado)
Description
  • Bibliography research, retrieval and summarizing on a FINEP / IPT project that lead to the publication of a book (manual) on "Materials for Tool Machines"; the main editors were Professor Alberto de Albuquerque Arantes and Prof. Renato Rocha Vieira.

Publications

Publications (208)
Article
Twin-disc tests were carried out between two discs of rail steel (fully pearlitic and spheroidized microstructures) to investigate the effect of the flash-butt welded rail HAZ microstructure. The spheroidized cementite micro-structure was obtained by heat-treating simulating the HAZ softer region. Ten tests were performed for each condition, consid...
Preprint
Full-text available
The development of new fire-resistant steels represents a challenge in materials science and engineering of utmost importance. Alloying elements such as Nb and Mo are generally used to improve the strength at both room- and high-temperatures due to, for example, the formation of precipitates and harder microconstituents. In this study we show alter...
Article
Full-text available
Simulations using the finite element method (FEM) were done to understand the effects of heating/cooling rates on the distribution of residual stresses. Two material parameters from rails were used while the boundary conditions remained constant: heat-affected zone size, maximum temperature and heating extraction rate. To complement the analysis, a...
Article
Full-text available
A novel combined process of Cold Stamping (CS) and Hot Stamping (HS) with Quenching and Partitioning (Q&P) treatment applied to advanced TRIP-assisted steel has been conducted by thermomechanical simulation to evaluate the influence of CS or HS in the Q&P processing. With this purpose, Q&P, CSQ&P, and HSQ&P cycles were designed to obtain multiphase...
Thesis
Full-text available
Os aços de construção mecânica são amplamente empregados na indústria, sendo que o SAE 4340 possui aplicações específicas na fabricação de eixos, engrenagens, mangas e cilindros devido à sua boa resistência à fratura e elevada resistência à fadiga. Entender a usinabilidade de um material como este, é de suma importância para a metalurgia, por c...
Article
The current paper aimed to introduce a new heat treatment regarding the quenching and partitioning (Q&P) processing of tailoring desirable complex microstructure to obtain a good strength-ductility combination. First, change in length under heating and cooling of commercial eutectoid steel was studied using dilatometry to understand the kinetics of...
Article
AlN compacts with different CaO–Y2O3–C mixtures were sintered between 1100 and 1850 °C to understand the effects of the in situ formed reducing atmosphere on the densification behavior and evolution of the second-phases. AlN with Y2O3 densified at 1750 °C, but the addition of C changed the second-phases evolution towards Y-rich phases that delayed...
Article
Understanding the kinetics of microstructural degradation during the event of a fire is of major relevance to future optimization of fire-resistant steels (FRS). In this work, we use in situ synchrotron X-ray diffraction to assess the rapid thermally-assisted degradation of different starting microstructures, such as (i) ferrite + pearlite; (ii) ba...
Article
Full-text available
The possibility of improving the mechanical and wear performance of steel rails with conventional compositions, near-eutectoid and without special alloying elements, using a two-step heat treatment was investigated. The heat treatment involved a first step involving quenching to a low temperature, near the Ms, maintaining at this temperature for a...
Article
Hydrogen-Induced Cracking (HIC) is a primary failure mechanism of pipeline-welded joints in the absence of external loading in the oil and gas exploration industries. Three different cooling rates after austenitization were used to simulate in the laboratory different regions of the heat-affected zone (HAZ) formed when welding an API X80 pipeline s...
Article
Full-text available
The effect of the austenitization route on the bainitic reaction kinetics of an alloyed (3.2C-2.8Si-1.8Ni-1.4Cu-0.4Mn-0.2Mo-0.1Cr) austempered ductile iron was studied. Two-step, conventional and rapid austenitization heat treatments were employed to produce different austenite grains sizes (94, 39, and 15 um, respectively) and, in one case, second...
Article
A concept of plasma treatment for enhancing pre-textured surfaces of components made in pearlitic gray cast iron is proposed. It consists of a plasma nitriding at low temperatures and short times, to increase the hardness of the surface employing a shallow depth nitride formation in the surface of the iron. As a result, the roughness pattern of a p...
Article
Purpose The purpose of this study is to develop a lower bainite structure consists of a dispersion of fine carbide inside plates of bainitic ferrite from chemical composition unmodified conventional pearlitic steel under bainitic transformation and to investigate its effect on tensile properties and wear resistance. Design/methodology/approach A c...
Article
Purpose The purpose of this paper is to present the results of a metallurgical, mechanical and tribological characterization of the weld and heat-affected zone (HAZ) of aluminothermic welding of premium rails used in heavy haul, looking into the origins of the squat defects associated with rail wear. Design/methodology/approach A full factorial de...
Article
Full-text available
Heavy haul railways are increasingly being subjected to operating conditions that demand better performance of the materials, with speeds of operation and loads increasing to comply with the large demand for transportation. For joining of rails, the Flash Butt Welding (FBW) process stands out due to the higher quality of the joint with respect to t...
Article
The Heavy-Haul railroad wheels started to use higher wear resistance steels microalloyed with niobium, vanadium, and molybdenum [1]. During continuous cooling, these elements depress the temperature of the pearlite formation, producing smaller interlamellar spacing that increases the hardness of the steel, besides to favor the precipitation hardeni...
Article
Full-text available
Despite the experimentation of bainitic and martensitic microstructures in wheel-rail steels, pearlitic microstructure remains dominant in railway track. The wear resistance behavior of bainitic and pearlitic microstructures is still a matter of controversy. In this study, pin-on-disc sliding wear tests were performed to analyze the effects of the...
Article
The rail, as the most important component in railways, needs to be routinely checked to maintain proper service conditions to prevent catastrophic accidents by any premature failure of the rail. The severe plastic deformation of rails due to cyclic wheel/rail contact forces forms a superficial deformed layer, referred to as the white etching layer,...
Article
Full-text available
Although several studies have been conducted on the mechanism of the formation of white layer by cyclic large shear deformation, and its effect on rolling contact fatigue, limited research has been carried out to find a correlation between sub-superficial layer of running contact surface and the crystallographic orientation, microstructural changes...
Article
Full-text available
The modification of the matrix of ductile cast irons by heat treatments has been of interest of researchers for many years. Among these treatments, in the last years the Quenching & Partitioning (Q&P) process has emerged as a viable way to produce microstructures containing controlled amounts of martensite and retained austenite, providing a good c...
Article
Full-text available
Improvement of wear resistance and mechanical performance of rails used in heavy-haul railway are essential to reduce railroad maintenance costs. A novel heat treatment based on quenching and partitioning (Q&P) processing was proposed to improve the wear resistance of a hypereutectoid pearlitic rail. 50% of austenite was transformed into martensite...
Article
Wheel-rail contact is in the spotlight of Railway Engineering and its specific conditions are highly dependent on railroad characteristics, such as load, speed, track design and materials used, among others. To understand wear mechanisms for typical contact conditions of a railroad with many tight curves, sliding-wear tests were performed on pin-on...
Article
Full-text available
Heavy haul transportation (load over 30 tons/axle), as well as the axle load, has been more and more used in Brazil and worldwide. The stress generated in the wheel-rail contact with loads up to 30 tons/axle is around 760 MPa, which causes premature wear and cracks of conventional wheels (AAR (Association of American Railroads) class C). Microalloy...
Article
Full-text available
In this work a DP 600 Dual Phase steel, conventionally treated in order to obtain 40 to 60% austenite at the intercritical temperatures, called reference sample, was compared to samples from the same steel, initially fully austenitized and quenched to 100% martensitic structure and subsequently intercritically tempered once (one step) or twice, (tw...
Article
Full-text available
Welds in heavy haul rails are usually associated with accelerated wear and are a common source of defects, justifying a careful study of their characteristics. Heat-affected zones usually present hardness loss, corresponding to a spheroidized cementite region. The literature acknowledges that this is a consequence of the welding heat input but with...
Thesis
Full-text available
This is Izabela's master thesis, I am only the advisor. The URL is: http://www.teses.usp.br/teses/disponiveis/3/3133/tde-30012019-091915/pt-br.php
Article
Failure analysis studies were carried out on a used rail with head check defects to characterise the effect of microstructural features (i.e. microstructure and crystallographic orientation) on fatigue crack nucleation and propagation. The morphological differences of the pearlitic structure were analysed using secondary electron microscopy and ele...
Article
Full-text available
RESUMEN Los aceros multifásicos son una familia de materiales con propiedades mecánicas excepcionales que incluyen alta resistencia mecánica, excelente ductilidad e índice de endurecimiento y buena conformabilidad. Estas propiedades están relacionadas con la microestructura, que puede ser desde combinaciones de ferrita y martensita (aceros dúplex)...
Article
The localized wear within a four-cylinder automotive spark-ignition internal combustion engine was investigated using a dynamometer durability test. The test engine was equipped with flexible fuel technology, popularly known as “Flex-Fuel”, capable of operating under any mixture of gasoline and ethanol in the fuel. A 2-D profilometer analysis was c...
Article
Full-text available
The possible effects of crystallographic orientation and grain boundary distributions on fatigue crack initiation and propagation were studied in used pearlitic rail steels. Microstructure and hardness variation along the depth distance showed the effect of strain accumulation on microstructure modification. Although no evidence was shown of a corr...
Conference Paper
Full-text available
The paper compares Hydrogen Induced Cracking (HIC) resistance and Hydrogen Permeation (HP) results for two API X65 microalloyed steels, with different contents of Mn and Nb: one containing low Mn and high Nb (L-Mn) and the other, high Mn and low Nb (H-Mn). The main objective is to correlate the microstructural differences between these steels with...
Article
AlN with 0.5-8. wt% CaO was pressureless sintered between 1100. °C and 1800. °C. The results of density, second-phases, microstructure, and weight loss were used to identify the possible mechanisms that may cause a significant delay on the densification of AlN with CaO additive. It was observed that the additive content is the main parameter contro...
Article
Full-text available
In the present study the microstructural evolution and kinetics of carbon redistribution during the partitioning step of the Quenching and Partitioning process are investigated by means of a modeling approach that simultaneously considers the martensite-austenite carbon partitioning and the decomposition of austenite into bainitic ferrite. The deve...
Conference Paper
Full-text available
THE INFLUENCE OF PEARLITE LAMELLAR DISTANCE ON HARDNESS, MAGNETIC SATURATION AND MAGNETIC BARKHAUSEN NOISE Abstract Research about rail transport in Brazil has been intensified recently due the need to improve the wheel-rail performance, considering the demand of increasing axle load aiming for a transportation cost reduction. Changes in the materi...
Conference Paper
Full-text available
Increased requirements for low fuel consumption and improved safety in the automotive industry have stimulated the development of new generations of high strength steels. To reduce fuel consumption, weight reduction of the steel car body is required by using thinner and therefore stronger but not less ductile materials. With this purpose, the prese...
Conference Paper
Full-text available
The increasing in the ratio load per wagon has been a fundamental subject to reduce the costs in railway transportation, requiring wheels with a higher strength and toughness. One of the strategies is to add small amounts of alloys (<0,5% in weight) of niobium and/or vanadium, wich in solid solution on austenite retards its decomposition increas...
Article
The thermal stability of nanocrystalline Ni due to small additions of Mo or W (up to 1 at%) was investigated in computer simulations by means of a combined Monte Carlo (MC)/molecular dynamics (MD) two-steps approach. In the first step, energy-biased on-lattice MC revealed segregation of the alloying elements to grain boundaries. However, the condit...
Article
Biased Metropolis Monte-Carlo is employed to build a carbon Cottrell atmosphere around an edge dislocation. A novel method involving only local minimisation during the Metropolis scheme allows to deal with a million-atom system within a reasonable computation time. In this study, it is discovered that (i) the carbon atoms occupy interstitial sites...
Article
The stability of the body- and face-centered cubic lattices corresponding to the α and γ phases of Fe, respectively, as well as the transformation of one phase to the other were investigated by atomistic simulations. Two interatomic potentials were used: the embedded atom method (EAM) potential of Meyer and Entel and the bond order potential (BOP)...
Conference Paper
Full-text available
The Austempering heat treatment is a well-known solution to improve the mechanical properties of ductile cast irons, therefore being referred as 'ADI' (Austempered Ductile Iron). The improved mechanical properties of ADI's with respect to conventional ductile iron is attributed to its resulting microstructure, which contains mainly carbide-free bai...
Article
Full-text available
Duplex stainless steels have a structure normally composed of austenite and ferrite in approximately equal proportions. In order to attain control of its fabrication processes and performance, it is important to understand its microstructural evolution, due to the formation of intermetallic phases such as sigma (σ) and chi (χ), which may cause a se...
Article
Thermomechanical simulation of quenching, hot stamping, and quenching and partitioning processes of a high-strength TRIP-assisted steel were carried out in a Gleeble®3S50 thermo-mechanical simulator, coupled to the synchrotron X-ray diffraction line. The microstructures and mechanical properties were analyzed using Field Emission Gun Scanning Elect...
Conference Paper
Full-text available
In this work, the kinetics of austenite decomposition during the application of the novels thermomechanical treatments of Quenching and Partitioning (Q&P) and Hot Stamping + Q&P on a ductile cast iron and a TRIP-assisted steel, and also duirng the application of tensile stress in a metastable austenitic steel were studied by means of in situ synchr...