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FEM simulation of open die forging of a plate from material NIMONIC 80A in DEFORM 3D

Polakova I., Duchek M., Malecek L.

Archives of Materials Science and Engineering

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2014

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Vol. 66, nr 1

31--36

EN

Purpose: This article presents results of a three-dimensional FEM-simulation of open die forging of a plate from material NIMONIC 80A. The FEM-simulation was carried out in DEFORM 3D Multiple Operation. Design/methodology/approach: The open die forging simulation contains many sequence operations, each single stroke and displacement of dies had to be modelled. The FEM-simulation of the open die forging process was set in accordance with real process conditions. Findings: The main effect on the crack initiation was the decrease in temperature on a edge of the plate. The real forgings show transverse cracks on the surface which starts on edges of the plate during forging. A good agreement between the simulation and experiment results was observed. Research limitations/implications: The plastic behaviour of material NIMONIC 80A was defined by means of strain hardening data which was obtained on the basis of measured data from Rastegaev compression test. The desired final thickness of the plate was reached by two procedures to study the effect of an amount of a reduction. The first procedure comprised 8 reduction passes with three reheatings, and second procedure comprised 10 reduction passes with four reheatings. The data evaluation of crack initiation in the FEM-simulation was carried out by tensile tests on the specimens. Originality/value: This article describes the FEM-simulation of open die forging process that was set in accordance with real process conditions. The aim of this simulation was to analyze the effect of an amount of a reduction on crack initiationon a real plate and to suggest the optimization of the process.

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About heat treatment and properties of Duplex Stainless Steels

Rosso M., Peter I., Suani D

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 59, nr 1

26--36

EN

Purpose: of this paper is to review the effect of heat treatments and of strain hardening on microstructure and properties of superduplex stainless steels. Design/methodology/approach: Annealing and strain hardening treatments influences microstructures and properties. Findings: The characteristics and the properties of the industrially employed superduplex grade has been discussed, moreover the presence and the precipitation of sigma phase has been highlighted through ageing treatments. Research limitations/implications: : Based on the up to date achieved outcomes, it appears that a quite homogeneous and good mechanical properties can be obtained controlling the composition and the heat treatment and strain hardening parameters. Practical implications: The major implication is related to the transfer toward the proper choice of correct parameters for working the duplex grades. Originality/value: to supply deeper information with respect to those available in literature, which does not clearly indicate what amount of secondary phases existing in duplex stainless steel microstructure can be acceptable.

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Wymiarowanie konstrukcji spawanych wykonanych z umocnionych zgniotowo stopów aluminium

Gwóźdź M.

Przegląd Spawalnictwa

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2009

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R. 81, nr 2

5-9

PL

Stan normalizacji obliczeń spawanych konstrukcji aluminiowych nie jest w Polsce zadowalający. Przedstawiono zasadnicze zmiany, jakie wystąpiły we współczesnych metodach obliczeń konstrukcji budowlanych, wykonanych z umocnionych zgniotowo stopów aluminium. Przytoczono procedury obliczeniowe wg Eurocode 9, które uwzględniają postęp, jaki się dokonał w zakresie oceny bezpieczeństwa konstrukcji aluminiowych. Jakościowe zmiany w analizie nośności są szczególnie widoczne dla spawanych konstrukcji aluminiowych, w których ujawnia się destrukcyjny dla właściwości mechanicznych efekt penetracji termicznej w strefach wpływu ciepła. Są to zjawiska specyficzne dla większości stopów aluminium, nieznane dla spawanych konstrukcji stalowych.

EN

The progress in standardisation of aluminium welded structure calculations leaves much to be desired. The article presents fundamental evolution of advanced methods of calculation of the building structures made of strain-hardened aluminium alloys. It contains calculation procedures consistent with Eurocode 9, which account for the actual development of aluminium structural safety. Qualitative advancement in the analysis of load-bearing capacity is explicitly visible in the area of welded aluminium structures that display the thermal penetration effect in the zones exposed to heat; this phenomenon has a destructive impact on mechanical properties of the structure. The said effects are typical of the majority of aluminium alloys and do not happen in the case of welded steel structures.

4

Umocnienie zgniotowe hartowanej stali o różnej strukturze osnowy

Berkowski L., Borowski J., Rybak Z.

Journal of Research and Applications in Agricultural Engineering

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2009

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Vol. 54, nr 2

9-14

PL

Duże znaczenie mają technologie inżynierii powierzchni kojarzące zabiegi obróbki cieplnej objętościowej i obróbek powierzchniowych. W pracy przedstawiono możliwość łączenia zabiegów obróbki cieplnej, wpływającej na tworzenie struktur o osnowie martenzytycznej i austenitycznej, z procesem nagniatania. Badania wykazały, że proces obróbki plastycznej powierzchniowej niewiele wpływa na własności wyrobów zahartowanych na martenzyt. Natomiast wpływ nagniatania na stal o osnowie austenitycznej jest znaczący. Umocniona zgniotowo warstwa wierzchnia miała twardość większą od stali zahartowanej na martenzyt. Wykazano ponadto, że austenit otrzymany po zahartowaniu stali z wysokiej temperatury jest trwały, a umocnienie warstwy wierzchniej o takiej strukturze zostaje częściowo zachowane po czterogodzinnym odpuszczaniu w temperaturze 480 C.

EN

More important processes of surface engineering technology is combination of classical volume heat treatment and surface deformation, burnishing. The paper presents the mean of the combination of two technologies of NCHLVsteel: heat treatment with different of austenityzation temperature (result two structures after hardening - martensite and austenite) and burnishing. The burnishing of the steel contains martensiting structure of the matrix had not effects, but burnishing of austenite changes properties of the NC11 LV steel evidently. The hardness after burnishing was larger, then hardness of the steel after classical hardening, contains martensiting structure. The research show, that austenit - result of the heat treatment from high austenitization temperature - after hardening during deformation, after tempering (480°C, 4 h) partially remain.