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Effect of Solution Treatment on Age-Hardening Behavior of Al-12Si-1Mg-1Cu Piston Alloy with Trace-Zr Addition

Kaiser M. S.

Journal of Casting & Materials Engineering

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2018

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Vol. 2, no. 2

30--37

EN

The influence of a solution treatment with a trace zirconium addition on the precipitation behavior of a cast Al-12%Si-1%Mg1%Cu piston alloy has been reported. The alloys were prepared by controlled melting and casting. The cast alloys were given an age-hardening treatment having a sequence of homogenization, T6 solutionizing, quenching, and aging. Both the cast and solutionized samples were naturally aged for 58 days, isochronally aged for 60 minutes at different temperatures (up to 350°C), and isothermally aged at various temperatures (up to 225°C) for different periods of time (ranging from 15 to 360 minutes). The hardness values of the differently processed alloys were measured to understand the aging behavior of the alloys. Electrical resistivity changes with aging time and temperature were measured to understand the precipitation behavior of the alloys. It is observed that significant hardening takes place in the aged alloys due to the formation of GP zones as well as the formation of metastable phases. The solutionizing treatment improves the hardness because some alloying elements are re-dissolved during solution treatment to produce a solute-rich solid solution. The trace-added Zr hinders the softening due to the precipitation of Al3Zr, which is very stable against coarsening and the re-dissolution of precipitates. Electrical resistivity decreases due to stress relieving, the dissolution of the metastable phase, and precipitation coarsening. The resistivity of the solutionized alloys decreases more due to the higher concentration of elements in the solid solution. A microstructural study of the alloys reveals that the solution treatment improves the distribution of the silicon grains. It is also observed that the alloys attained an almost fully re-crystallized state after aging at 350°C for 90 minutes.

2

Solutionizing of IN 519 superalloy after long-term exposure

Jasiński W.

Advances in Manufacturing Science and Technology

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2008

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Vol. 32, nr 1

69-80

EN

Hydrogen used for ammonia synthesis in chemical plants is received as a result of endothermic thermal-catalytic decomposition of methane with water steam. The process is carried out in reformer pipes made from austenitic cast steel with nickel catalyst under pressure up to 4.0 MPa and temperature up to 900 °C [1]. The mechanical properties and phase composition of these tubes changed during a long service. The precipitation of intermetallic phases in alloyed austenite matrix and at grain boundaries are spheroidizated. The stable dendritic microstructure disappears. This results in a decrease of mechanical properties of the pipe material as well as in the intensification of creeping. In order to regenerate the tube material a solution heat treatment was applied. The author presents results of LMA, XRD and mechanical property investigation of IN 519 samples taken from a centrifugal cast pipe which worked in a catalytic reformer for 120760 hours and was solutionized.

PL

Wodór do syntezy amoniaku w zakładach chemicznych uzyskuje się w endotermicznym procesie cieplno-katalitycznego rozkładu metanu parą wodną pod ciśnieniem do 4 MPa w temperaturze do 900 stopni C. Proces prowadzi się w reformerze wykonanym z nadstopu IN 519 z rur odlewanych odśrodkowo i wypełnionych katalizatorem niklowym. Długotrwała eksploatacja powoduje przemiany fazowe i strukturalne w austenitycznej osnowie nadstopu: sferoidyzację wydzieleń faz międzymetalicznych oraz w eutektyce na granicach ziarn. Odlewnicza mikrostruktura dendrytyczna ulega zanikowi. Następuje koagulacja wydzieleń faz międzymetalicznych, powodując zmiany właściwości mechanicznych nadstopu IN 519, także intensyfikując proces pełzania. W celu regeneracji materiału rury (IN 519) prowadzono jego przesycanie. W pracy przedstawiono wyniki badań właściwości mechanicznych, metalograficznych i rentgenograficznych nadstopu IN 519 pobranego z rury po 120760 h eksploatacji i przesycaniu.

3

Solutionizing of IN 519 superalloys after long-term service.

Jasiński W.

Advances in Manufacturing Science and Technology

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2006

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Vol. 30, nr 4

41-48

EN

The hydrogen to ammonia synthesis in the chemical plants is received in process of endothermic thermal-catalytic decomposition of methane with water steam. The process is carried out in reformer pipes made from austenitic cast steel with nickel catalyst under pressure up to 4.0 MPa and temperature up to 900 degrees C [1]. The long-lasting influence of raised temperature causes structural and phase changes, spheroidization precipitation of the intermetallic phases in alloyed austenite matrix and at grain boundaries. The dendritic microstructure disappears [2]. This results in a decrease of mechanical properties of the pipe material as well as in the intensification of the creeping. In order to regenerate tube material the solution heat treatment was applied. The author presents results of LMA, XRD and mechanical property investigation of IN 519 material from centrifugal cast pipe which worked in catalytic reformer for 120760 hours and was solutionized.

PL

Wodór do syntezy amoniaku w zakładach chemicznych otrzymuje się w endotermicznym procesie cieplno-katalitycznego rozkładu metanu parą wodną pod ciśnieniem do 4 MPa w temperaturze do 900 stopni C. Proces jest prowadzony w reformerze, w odlewanych odśrodkowo rurach z austenitycznego staliwa wypełnionych katalizatorem niklowym. Długotrwała eksploatacja powoduje przemiany fazowe i strukturalne, sferoidyzację wydzieleń faz międzymetalicznych w osnowie austenitycznej i w eutektyce na graniach ziarn. Stabilna odlewnicza mikrostruktura dendrytyczna ulega zanikowi. Następuje koalescencja i koagulacja wydzieleń faz międzymetalicznych powodująca zarówno zmiany właściwości mechanicznych wysokostopowego staliwa, jak również intensyfikację procesu pełzania. W celu regeneracji materiału rury prowadzono przesycanie. Autor przedstawia wyniki badań właściwości mechanicznych, mikrokrystalicznych i rentgenowskich nadstopu IN 519 pobranego z rury po 120760 h eksploatacji i przesycaniu.