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1

Analysis of the Possibilities of Using Forging Heat in Isothermal Annealing Processes for AISI 4140 Alloy

Zwierzchowski M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

951--958

EN

Production processes of hot forging most often look similar [1-3]. Forging in several operations, usually in three or four. Most often the first operation is upsetting or flattening (sometimes rolling). The last operation is finishing forging. This applies to the production of steel forgings for the automotive, agricultural and other similar industries. Typical production proceeds as follows: the forgings are cleaned (shot-blasted) and then heat treatment is performed. It can be normalization, hardening and tempering, etc. After the heat treatment, forgings are checked and subjected to strength and microscopic tests, hardness tests, impact tests. The type of tests depends on the recipient. The process described in the work takes place in three operations. The heat treatment used so far is hardening and tempering. An attempt was made to change the heat treatment technology for a selected product made of 42CrMo4 steel (1.7225) (4140). An isothermal annealing test was carried out at different temperatures and for different times. The possibility of using heat from the forging process in heat treatment processes for the described product has been confirmed.

2

Kinetics of static recrystallization in the coarse-grained Fe–40 at.%Al–Zr–B alloy

Schindler I., Kopeček J., Kawulok P., Jabłońska M., Hadasik E., Jóźwik P., Opěla P., Hanus P., Polkowski W., Bojar Z.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

816--826

EN

The aim of works was to describe mathematically the kinetics of static recrystallization of the alloy type Fe–40 at.%Al–Zr–B (with 24.6 Al–0.01 B–0.18 Zr–0.01 C in wt.%) with the coarse-grained structure. The microstructure of the laboratory castings made of this extremely brittle alloy was homogenized by hot rolling of the material in the protective capsules and by the long-term annealing at 1200 °C. An initial microstructure with average grain size 0.77 ± 0.27 mm was obtained. Based on the isothermal plastic deformation tests and EBSD analysis, the static recrystallization kinetics of the prepared coarse-grained B2 iron aluminide after strain 0.20 was mathematically described. Recrystallized fraction depends on deformation/annealing temperature (900–1100 °C) as well as on annealing time. The activation energy of static recrystallization was calculated as 255 kJ mol−1. Competition between dynamic recovery and static recrystallization was proved after strain 0.35 and annealing temperature 1100 °C. Static recrystallization starts relatively easily in the studied alloy, but a very long-term annealing is quite necessary for the complete course of recrystallization. The mean size of recrystallized grains falls with the decreasing annealing temperature (0.47 ± 0.15 mm for temperature 1100 °C, and 0.22 ± 0.04 mm for 900 °C). Even at a temperature of 1200 °C the annealing after deformation should last approx. 1 min for obtaining the fully recrystallized microstructure. That is why the standard hot forming technologies should be combined by an interpass annealing in order to refine sufficiently the coarse grains.

3

Influence of hot rolling and isothermal annealing on microstructure and mechanical properties of high carbon steel

Aniołek K., Herian J., Cieśla M.

Inżynieria Materiałowa

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2014

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Vol. 35, nr 2

72--74

EN

The paper presents the results of morphological shaping of pearlite and carbon-manganese steel (R 260) properties after a hot rolling process and isothermal annealing. The obtained structures of steel after isothermal annealing had pearlite colonies reduced in size, smaller interlamellar distances and smaller thickness of cementite lamellae in relation to the microstructure obtained in the hot rolling process. The lowering of the pearlitic transition-point resulted in an increase in hardness and tensile strength of the rail steel. The morphology of steel pearlite after hot rolling and thermal treatment was subjected to a quantitative evaluation by measuring the thickness of cementite lamellae and the distance between them on images from an electron scanning microscope. The findings confirm that these methods can be effectively used for shaping the pearlitic structure and properties of steel and thus, the abrasive wear resistance and operational durability of rail sections.

PL

W pracy przedstawiono wyniki kształtowania morfologii perlitu węglowomanganowej stali (R 260) w procesach walcowania na gorąco i wyżarzania izotermicznego. Otrzymane struktury po wyżarzaniu izotermicznym charakteryzowały się rozdrobnionymi koloniami perlitu, mniejszą odległością między płytkami cementytu oraz mniejszą grubością płytek w porównaniu z mikrostrukturą uzyskaną po walcowaniu na gorąco. Obniżenie temperatury przemiany perlitycznej powoduje zwiększenie twardości i wytrzymałości na rozciąganie stali szynowej. Ocenę ilościową morfologii perlitu materiału po walcowaniu na gorąco i obróbce cieplnej, polegającą na pomiarze grubości płytek oraz odległości między płytkami cementytu, wykonano na obrazach zarejestrowanych na skaningowym mikroskopie elektronowym. Otrzymane wyniki potwierdzają, że metody te mogą być skutecznie wykorzystywane do kształtowania morfologii perlitu i właściwości stali, a tym samym pozwalają uzyskać zwiększoną odporność na ścieranie i trwałość eksploatacyjną kształtowników szynowych.

4

The structure and properties of steel with different pearlite morphology and its resistance to abrasive wear

Herian J., Aniołek K.

Archives of Materials Science and Engineering

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2008

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Vol. 31, nr 2

83-86

EN

Purpose: The analyse of pearlite morphology changes as a result of hot rolling process and isothermal annealing. Design/methodology/approach: Physical modelling of isothermal annealing for a transition point of 520-620°C was carried out using a Gleeble simulator. A scanning electron microscope was used for a quantitative evaluation of the microstructure. Findings: The obtained test results confirm that these methods can be effectively used in shaping the pearlitic structure and properties of the steel. During numerical simulation of a ride of a rail-vehicle through a switch, the load acting on a block section being part of the vehicle structure was determined. The load values were used in simulation of the resistance to abrasive wear, which was carried out in physical simulation. Practical implications: In physical modelling of tests of resistance to abrasive wear for the steel grade R260 after hot rolling and isothermal annealing it has been proved that this feature is a function of the steel structure and properties in the given operation conditions (load and slide magnitude). Abrasive wear of the rail steel is the more intensive, the larger the load at a constant slide is. Originality/value: An advantageous pearlitic morphology of steel (block sections) with interlamellar distance in the order of 0.12-0.13 μm, ensuring hardness of about 340-350 HB, is facilitated by a hot rolling process combined with isothermal annealing.

5

Wybrane aspekty kształtowania mikrostruktury stali szynowej oraz jej wpływ na odporność na zużycie ścierne

Herian J., Aniołek K.

Hutnik, Wiadomości Hutnicze

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2007

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Vol. 74, nr 5

251-255

PL

Przeprowadzono ocenę jakości walcowanych kształtowników klockowych ze stali gat. R260, które stosowane są w rozjazdach kolejowych. Przedstawiono związki pomiędzy odpornością na zużycie ścierne a morfologią perlitu i warunkami eksploatacyjnymi dla perlitycznej stali szynowej. ocenę ilościową morfologii perlitu przeprowadzono dla stanu stali po gorącym walcowaniu i po fizycznym modelowaniu proces wyżarzania izotermicznego. Stwierdzono, że w badanych procesach można uzyskiwać strukturę perlityczną o znacząco zróżnicowanej morfologii. Badania odporności na ścieranie w zależności od czynników eksploatacyjnych określono dla stanu po gorącym walcowaniu. Wykazano, że ze wzrostem obciążenia i poślizgu następuje zużycie ścierne stali.

EN

There was estimated a quality of block rolled sections from steel of R260 grade, which are used in turnouts. It was presented a dependence of resistance to abrasive wear of pearlite rail steel from pearlite morphology and exploational conditions. The quantity evaluation of pearlite morphology was realized for steel state after hot rolling and after a manual modelling of isothermal annealing process. It was stated that in research processes it can be obtain the pearlite structure with a significantly diversified morphology. Research of the resistance to abrasion in dependence of exploational factors were defined for state after hot rolling. It was proved that with a growth of load and spin follow an intensive abrasive wear of steel.

6

Effect of heat treatment on the microstructure and mechanical properties of Ti-6Al-2Mo-2Cr-Fe alloy.

Szkliniarz W., Chrapoński J.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

896-899

EN

The paper presents the results of investigations concerning the effect of heat treatment consisting in isothermal annealing performed according to three different schemes, on changes of the microstructure and strength properties of a two-phase coarse-grained titanium alloy. It has been found that a change of the primary phase a form into one similar to spheroidal leads to a considerable improvement of the alloy's plasticity, with simultaneous maintaining of the strength properties which are comparable to the initial state.

PL

W pracy przedstawiono wyniki badań dotyczące oddziaływania obróbki cieplnej, polegającej na izotermicznym wyżarzaniu, prowadzonym wg trzech różnych schematów, na zmiany mikrostruktury i właściwości mechanicznych gruboziarnistego, dwufazowego stopu tytanu. Stwierdzono, że uzyskana w wyniku długotrwałego wyżarzania zmiana postaci pierwotnej fazy a z płytkowej na zbliżoną do sferoidalnej prowadzi do znacznej poprawy plastyczności stopu, przy zachowaniu właściwości wytrzymałościowych porównywalnych do stanu wyjściowego.

7

Nanocrystalline Al-based alloys.

Latuch J., Kokoszkiewicz A., Matyja H.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

556-559

EN

The structure and mechanical properties determined by microhardness measurements of nanocrystalline Al86Y5Ni5TM4 (x = 4 at. %) alloys, where TM = Cu, Fe, were examined. The effect of replacement of Ni by TM elements on structure of the alloys obtained by rapid solidification and by isothermal annealing of initially fully amorphous alloys was investigated. This replacement extended the temperature region in which the A1 phase precipitates. The control of cooling rate and changes of annealing temperature caused the formation of nanoscale fcc-Al particles embedded in an amorphous matrix. The volume fraction of the nanophase particles and average size of Al-phase were calculated. The hardening effect induced by nanocrystallization was observed.