HSLA100 steels: Influence of aging heat treatment on microstructure and properties (original) (raw)
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International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/comparison-of-mechanical-properties-and-weld-joint-strength-of-high-strength-low-alloy-steels-with-low-carbon-steels https://www.ijert.org/research/comparison-of-mechanical-properties-and-weld-joint-strength-of-high-strength-low-alloy-steels-with-low-carbon-steels-IJERTV4IS010458.pdf In automotive industry, the high strength steels have been used since many years but in recent years a new range of steels have been introduced known as high strength low alloy steels which can sustain high stresses more than 600N/mm and known as high strength low alloy steels. While the use of these steels lowers the overall weight of the vehicle its joint weldability and performance are the main area of concern. This paper deals with the Resistance welding of HSLA steels and modifications that are to be made in welding techniques and also compares HSLA steels with low carbon steels properties. Keywords-HSLA steels, microstructure and mechanical properties, dual phase steels.
Today getting high thermal efficiency in thermal and nuclear power plant is a big challenge. Many new material are developed. SA 335 grade 91 steel is modified high chrome-moly martenstitic steel. This material is having excellent toughness and high temperature creep strength. During welding, this material is having tremendous change in its microstructure and hence mechanical property. Many research works were done in this area. This paper discusses weld ability of P91 material. Effect of different welding process, type of filler wire, its chemical composition and type of flux is discussed in this paper. PWHT is necessary after welding of P91 steel. PWHT temperature and its duration affects phase transformation and mechanical properties of weld metal, HAZ and parent metal. Major focus is given on hardness, creep resistance and notch toughness.
Influence of tempering on the microstructure and mechanical properties of HSLA-100 steel plates
Metallurgical and Materials Transactions A, 2001
The influence of tempering on the microstructure and mechanical properties of HSLA-100 steel (with C-0.04, Mn-0.87, Cu-1.77, Cr-0.58, Mo-0.57, Ni-3.54, and Nb-.038 pct) has been studied. The plate samples were tempered from 300 ЊC to 700 ЊC for 1 hour after austenitizing and water quenching. The transmission electron microscopy (TEM) studies of the as-quenched steel revealed a predominantly lath martensite structure along with fine precipitates of Cu and Nb(C, N). A very small amount of retained austenite could be seen in the lath boundaries in the quenched condition. Profuse precipitation of Cu could be noticed on tempering at 450 ЊC, which enhanced the strength of the steel significantly (yield strength (YS)-1168 MPa, and ultimate tensile strength (UTS)-1219 MPa), though at the cost of its notch toughness, which dropped to 37 and 14 J at 25 ЊC and Ϫ85 ЊC, respectively. The precipitates became considerably coarsened and elongated on tempering at 650 ЊC, resulting in a phenomenal rise in impact toughness (Charpy V-notch (CVN) of 196 and 149 J, respectively, at 25 ЊC and Ϫ85 ЊC) at the expense of YS and UTS. The best combination of strength and toughness has been obtained on tempering at 600 ЊC for 1 hour (YS-1015 MPa and UTS-1068 MPa, with 88 J at Ϫ85 ЊC). S.K. DHUA, Principal Research Manager, and D. MUKERJEE, Deputy formed at the martensite lath boundaries. General Manager, are with the Research and Development Centre for Iron The present investigation is mainly aimed at a study of and Steel, Steel Authority of India Limited, Ranchi-834 002, India. D.S. the evolution of the microstructure of the HSLA-100 steel SARMA, Professor, is with the Department of Metallurgical Engineering, that occurs on tempering and its effect on the steel's mechani
Advanced Technologies & Materials, 2019
The effect of Post Weld Heat Treatment (PWHT) on the microstructure, mechanical and corrosion properties of low carbon steel have been investigated. The welding process was conducted on butt joint using Manual Metal Arc Welding (MMAW) techniques at a welding voltage of 23 V and welding current of 110 A with the use of E6013 and 3.2 mm diameter as filler material. Heat treatment through full annealing was carried out on the welded low carbon steel. The mechanical properties (hardness, impact toughness and tensile properties) of the AW and PWHT samples were determined. The microstructure of the AW and PWHT samples was characterized by means of an optical microscopy. Corrosion behavior of the sample was studied in3.5 wt.% NaCl environment using potentiodynamic polarization method. The results showed that the AW samples has good combination of mechanical and corrosion properties. The microstructure revealed fine grains of pearlite randomly dispersed in the ferrite for the AW base metal (BM) sample while agglomerated and fine particle of epsilon carbide or cementite randomly dispersed on the ferritic phase of the heat affected zone (HAZ) and weld metal (WM), of the AW, respectively. The PWHT samples shows that the annealing process allow diffusion and growth of the fine grains into partial coarse grains of ferrite and pearlite which did not encourage improvement of the properties. Therefore, it was concluded that the welding parameters put in place during welding of the low carbon steel are optimum for quality weld.
Materials Science and Engineering: A, 2019
The direct quenching of low-carbon steels after thermomechanical processing on hot strip mills is able to produce both strong and tough coiled plate without the need for subsequent tempering. The process is energy and time efficient with relatively low emissions when compared to conventional reheating, quenching and tempering. For some applications, however, it is desirable to combine direct quenching with tempering, and, bearing in mind the form of the semi-finished product, it is of interest to study the effect of tempering whole coils in a bell furnace. Here, the effects of boron, carbon, titanium, vanadium and tempering temperature on the microstructure, crystallography and mechanical properties of direct-quenched steels has been studied with the aid of simulated bell furnace heating and cooling cycles. All steels contained (in wt.%) 0.2Si-1Mn-1Cr-0.65Mo-0.03Al, while there were two levels of C (0.095 /0.140), V (0 /0.08), Ti (0 /0.025) and B (0 /0.0015). Tempering was performed with peak temperatures at 180 and 570°C. The paper reveals several possible alloying and processing routes to strong and tough low-C steel. Carbon controls the strength and toughness, while titanium and boron affects the grain size of coarsest grains (d 90%), Vanadium has a strong effect on strength retention during tempering at 570°C: an addition of 0.08 wt% vanadium increases yield strength by 70 MPa and ultimate tensile strength by 100 MPa. The removal of boron from the steel is shown to have a huge impact not only on the microstructure but also on the impact toughness.
2015
In automotive industry, the high strength steels have been used since many years but in recent years a new range of steels have been introduced known as high strength low alloy steels which can sustain high stresses more than 600N/mm and known as high strength low alloy steels. While the use of these steels lowers the overall weight of the vehicle its joint weldability and performance are the main area of concern. This paper deals with the Resistance welding of HSLA steels and modifications that are to be made in welding techniques and also compares HSLA steels with low carbon steels properties.
of High Strength Steel Weld Metals
2012
The effects of variations in alloying content on the microstructure and mechanical properties of high strength steel weld metals have been studied. Based on neural network modelling, weld metals were produced using shielded metal arc welding with nickel at 7 or 9 wt. %, manganese at 2 or 0.5 wt. % while carbon was varied between 0.03 and 0.11 wt. %. From mechanical testing, it was confirmed that a large gain in impact toughness could be achieved by reducing the manganese content. Carbon additions were found to increase strength with only a minor loss to impact toughness as predicted by the modelling. The highest yield strength (912 MPa) in combination with good impact toughness (over 60 J at-100 o C) was achieved with an alloying content of 7 wt. % nickel, 0.5 wt. % manganese and 0.11 wt. % carbon. Based on thermodynamic calculations and observed segregation behaviour it was concluded that the weld metals solidify as austenite. The microstructure was characterised using optical, transmission electron and high resolution scanning electron microscopy. At interdendritic regions mainly martensite was found. In dendrite core regions of the low carbon weld metals a mixture of upper bainite, lower bainite and a novel constituent-coalesced bainite-formed. Coalesced bainite was characterised by large bainitic ferrite grains with cementite precipitates and is believed to form when the bainite and martensite start temperatures are close to each other. Carbon additions were found to promote a more martensitic microstructure throughout the dendrites. Mechanical properties could be rationalised in terms of microstructural constituents and a constitutional diagram was constructed summarising microstructure as a function of manganese and nickel contents.
Study of the mechanical properties of low carbon content HSLA steels
Revista de Metalurgia, 2009
Two high strength low alloy steels (HSLA) with the same bulk composition and slight microalloying content differences were studied. The main purpose of the study was to determine the effect of different heat treatments and the influence of vanadium (V) on the microstructure and mechanical properties of the bainite present in each steel. For that purpose, standard tests were conducted to determine the hardness, toughness, tensile and yield stress of the different bainite-acicular ferrite structures found in both steels. The results show how the V content promoted the formation of acicular ferrite, resulting in a decrease in hardness and tensile strength while improving toughness.