Wyniki wyszukiwania - BazTech

1

Effect of Element Addition, Microstructure Characteristics, Mechanical Properties, Machining and Welding Processes of the Hadfield Austenitic Manganese Steel

Zellagui Rihab, Hemmouche Larbi, Ait-Sadi Hassiba, Chelli Amel

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

863--868

EN

High manganese steel, also called Hadfield steel, is an alloy essentially made up of iron, carbon, and manganese. This type of steel occupies an important place in the industry. It possesses high impact toughness and high resistance against abrasive wear and hardens considerably during work hardening. The problem with this kind of steel is the generation of carbides at the grain boundaries after the casting. However, heat treatment at the high-temperature range between 950°C and 1150°C followed by rapid quenching in water is proposed as a solution to remove carbides and obtain a fully austenitic structure. Under the work hardening effects, the hardness of Hadfield steel increases greatly due to the transformation of the austenite γ to martensite ε or α and mechanical twinning, which acts as an obstacle for sliding dislocations. Hot machining is the only solution to machine Hadfield steel adequately without damage of tools or changing the mechanical characteristics of the steel. The choice of welding parameters is important to prevent the formation of carbides and obtain welded steel with great characteristics. This paper aims to give an overview about Hadfield steel, element addition effect, microstructure, heat treatments, work hardening, machinability and welding processes.

2

Wpływ twardości warstwy wierzchniej na odporność staliwa Hadfielda na ścieranie

Bolanowski K.

Problemy Eksploatacji

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2013

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nr 1

127--139

PL

Staliwo Hadfielda cechuje się dobrymi właściwościami mechanicznymi. Po zadaniu dużego zgniotu twardość warstwy zgniecionej może osiągać wartość dochodzącą do ok. 850 HV0,1. W artykule przedstawiono ogólną charakterystykę stali Hadfielda oraz wybrane wyniki badań mikrostruktury i próby ścieralności uzyskane na próbkach pobranych z odlewów młotków kruszarek urobku skalnego. Uzyskane wyniki wskazują na silną zależność pomiędzy mikrostrukturą osnowy austenitycznej staliwa i jego odpornością na ścieranie. Staliwo Hadfielda z ukształtowaną pod wpływem udarów warstwą eksploatacyjną wykazuje dużą odporność na ściernie, porównywalną z odpornością, jaką cechuje się hartowana stal łożyskowa gatunku ŁH15.

EN

This paper deals with Hadfield steel, known to have unique mechanical properties. After work hardening, the outer layer of the material may reach a hardness of 850 HV0.1. The paper presents general characteristics of Hadfield steel, and it also discusses the results of a microstructural analysis and abrasion resistance tests obtained for samples of castings to be used in rock crusher hammers. The experiments performed under laboratory conditions indicated that the abrasion resistance of Hadfield steel was largely dependent on the microstructure of the austenitic matrix. The high abrasion resistance of Hadfield steel after work hardening was comparable with that of ŁH15 bearing steel subjected to quenching.

3

Flash butt weldability of austenitic high strength steels

Schmidova E., Svanda P., Konecny M.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 2

477-482

EN

This paper deals with specific changes in the structure of crossings made of Hadfield's steel, caused by heat and mechanical stress during the welding process, and of rails made of carbon steel. Experiments were undertaken to analyze the sources of damage to the weld joint, established by a post-weld capillary test after machining the weld joints. The analysis demonstrated the presence of welding defects consisting of a phosphide phase and of carbides as a secondary phase. The distribution and amount of this undesirable phase was given by the technical welding parameters employed. It was established that the material is prone to hot tearing only in a very narrow zone inside the heat-affected zone where comprehensive reaustenitization takes place. Initiation of the defects is related to the presence of a phosphide eutectic. A further growth of cracks takes place along the carbide border line; this means that the main factor limiting the use of such welds is attainment of structural degradation. Reducing the thermal effect on the welded components is thus essential for further use of the investigated samples

4

Comparison of experimental and simulation results of 2D-draw-bend springback

Da Sisva Botelho T., Bayraktar E., Inglebert G.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

275--278

EN

Purpose: This paper presents the results of experimental, analytical and numerical studies of draw-bend springback on the response of steel blank strips. Design/methodology/approach: Springback, the elastically-driven change of shape of a part after forming, has been simulated with 2-D plane strain finite elements model (ABAQUS). Springback simulations compared with experimental test results under some test conditions and also sidewall curls were further discussed in this paper. Findings: The results validate the finite element approach as a trustworthy tool for predicting the springback parameters for a given set of stamping conditions and material properties. Research limitations/implications: This model is a simple and an efficient way to take apart the responsibilities of the steel maker for the selection of steel to be used and sheet stamping designer for the selection of the forming conditions to work in a safety zone in order to increase the reliability of the stamped structures. Originality/value: Experimental and finite element analyses have been conducted on blank strips of Hadfield steel (high strength steel) and Mild steel with similar operational conditions.

5

Możliwość usuwania azotu i tlenu podczas argonowania stali Hadfielda

Głownia J., Sobula S., Sierant Z., Furgał G., Pietrzak A., Tęcza G.

Przegląd Odlewnictwa

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2003

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Vol. 53, nr 9

319-325

PL

Stosowanie żywic i utwardzaczy do mas formierskich zwiększa stężenie gazów w odlewach wskutek występowania reakcji metal - forma; to samo dotyczy wprowadzania złomu obiegowej wytopów odzyskowych. Wprowadzenie argonowania stali Hadfielda w kadzio pojemności 7 t ograniczyło stężenie gazów w odlewach poniżej warości ktytycznej, przy której występują nakłucia, porowatości gazowe i skurczowe. Opracowane warunki argonowania zapewniły w odlewach pochodzących z wytopów odzyskowych końcowe stężenia tlenu i azotu odpowiednio poniżej 60 ppm i 380 ppm w odlewach o ciężarze 5,5 t.

EN

Using the resin or sodium-silicate-bonded sand mixtures increases the gas contents in castings owing to the chemical penetration between molten steel and a mould or owing to using of return scrap during the melting process. Argon stirring of Hadfield steel in the ladle with the capacity of 7 t eliminated the critical gases contents in castings, at which gas porosity, micro-shrinkages and needles are observed. The argon stirring conditions observed in these investigations, assured oxygen content below 6 ppm and nitrogen content below 380 ppm in Hadfield castings with the weight of 5.51.