Wyniki wyszukiwania - BazTech

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Model numeryczny zjawisk hartowania stali narzędziowej do pracy na gorąco

Kulawik A., Wróbel J., Bokota A.

Modelowanie Inżynierskie

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2017

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T. 33, nr 64

38--46

PL

W pracy przedstawiono kompleksowy model hartowania stali narzędziowej do pracy na gorąco. Pola temperatury otrzymuje się z rozwiązania metodą elementów skończonych zagadnienia przewodzenia ciepła. Model szacowania udziałów faz oparto na wykresach ciągłego nagrzewania i ciągłego chłodzenia (CTPa i CTPc). Udział fazy powstałej podczas ciągłego nagrzewania lub chłodzenia (austenit, perlit lub bainit) wyznacza się równaniem Johnsona-Mehla i Avramiego (JMA). Obliczanie udziału tworzącego się martenzytu realizowane jest zmodyfikowanym równaniem Koistinena i Marburgera (KM). W modelu zjawisk mechanicznych uwzględniono odkształcenia cieplne, strukturalne, plastyczne oraz odkształcenia indukowane przemianami fazowymi. Wielkości termofizyczne występujące w zagadnieniu termosprężysto-plastyczności uzależniono od temperatury i składu fazowego. Założono, że materiał charakteryzuje się wzmocnieniem izotropowym.

EN

In the paper the complex quenching model of the hot-work tool steel is presented. The temperature fields are determined based on the solving of the heat transfer equation using the finite element method. Model of estimation of phase fractions is based on the continuous heating diagram (CHT) and continuous cooling diagram (CCT). Phase fractions which occur during the continuous heating and cooling (austenite, pearlite or bainite) are described by Johnson-Mehl-Avrami (JMA) formula. To determine of the formed martensite the modified Koistinen-Marburger (KM) equation is used. In the model of mechanical phenomena the thermal, structural, plastic strains transformation induced plasticity are taken into account. Thermophysical properties occurring in the thermo-elastic-plasticity model depended on the temperature and phase composition of the material. It was assumed that the material is characterized by isotropic hardening.

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Microstructure and properties of the hot work tool steel gradient surface layer obtained using laser alloying with tungsten carbide ceramic powder

Jonda E., Labisz K., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 73, nr 2

214--221

EN

Purpose: The aim of the paper is to present the innovatory investigation results of the impact of laser treatment consisting of multiple remelting and alloying using tungsten carbide ceramic powder on the microstructure and properties of hot work tool steel X40CrMoV5-1 surface layer. Design/methodology/approach: Laser heat treatment allows the production of gradient surface layer with a thickness reaching from of tenths of a millimetre even to few millimetres with specific functional properties, including high hardness and abrasion resistance, while maintaining the properties of the substrate material. Findings: Preliminary investigations of the effects of laser radiation on steel surface have showed, that in the surface layer there occur changes concerning the microstructure as well as in the chemical composition different from those occurring during conventional heat treatment. Research limitations/implications: There was determined the effect of laser power on the remelting depth, the depth of the heat affected zone and the width of the laser tray face. There was also measured and compared to the hardness and roughness of the steel processed by remelting with different process parameters. Practical implications: The current application areas for hot work tool steels are constantly growing, and the intensive development of techniques requires the use of new technologies, what leads to production of specific surface layer on materials, in order to meet the extremely difficult working conditions of modern tools. Originality/value: The effect of a HPDL laser melting on the hot work tool steel, especially on their structure and hardness has been studied.

3

Badania odporności na ścieranie warstw napawanych i stali narzędziowych na matryce kuźnicze

Turek J., Okoński S., Piekoszewski W.

Obróbka Plastyczna Metali

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2012

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T. 23, nr 1

39-44

PL

W artykule przedstawiono wyniki badań odporności na zuSycie ścierne stali narzędziowych do pracy na gorąco X37CrMoV5-1 i 55NiCrMoV7 i warstw napawanych materiałami UTOP-38, F-812 i F-818. Badania wykonano na urządzeniu T11 produkcji ITE Radom w temperaturze 250 oC. Najlepsze wyniki uzyskano dla stali X37CrMoV5-1 i 55NiCrMoV7 oraz dla materiału F-818.

EN

The article features an analysis of the resistance to abrasive wear of X37CrMoV5-1 and 55NiCrMoV7 hot-work tool steels and of padding welds overlaid with UTOP-38, F-812 and F-818 materials. The analysis was conducted at the temperature of 250 oC on the T11 testing machine produced by ITE Radom. The best outcome was achieved for X37CrMov5-1 and 55NiCrMoV7 steels and for F-818

4

Comparison of the secondary hardness effect after tempering of the hot-work tool steels

Mazurkiewicz J., Dobrzański L. A., Hajduczek E.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 2

119-122

EN

Purpose: of this paper was to examine of the secondary hardness effect after tempering of the developed complex hot-work tool steel 47CrMoWVTiCeZr16-26-8 in relation to standard hot-work tool steel X40CrMoV5-1. Design/methodology/approach: The investigations steels were made using the specimens made from the experimental steel, for which the working 47CrMoW-V-TiCe-Zr16-26-8 denotation was adopted, similar to the ones used in the ISO Standard on using the standard alloy hot-work tool steel X40CrMoV5-1. Both investigated steels were melted in a vacuum electric furnace. Specimens made from the investigated steels were heat treated with austenitizing in salt bath furnaces for 30 minutes in the temperature range of 970-1180 degrees centigrade with gradation of 30 degrees centigrade. Next, the specimens were tempered twice in the temperature range of 450-660 degrees centigrade for 2 hours. Findings: The secondary hardness effect after tempering from temperature of 540 degrees centigrade in the 47CrMoW-V-Ti-CeZr16-26-8 steel and from temperature of 510 degrees centigrade for the X40CrMoV5-1 steel, which is caused by the carbides M4C3 and M7C3 in the 47CrMoWVTiCeZr16-26-8 steel and M7C3 in the X40CrMoV5-1 steel. Practical implications: The developed complex hot-work tool steel 47CrMoWVTiCeZr16-26-8 can be used to the hot work small-size tools which requires higher strength properties at elevated temperature. Originality/value: The obtained results show the influence of the chemical compositions on the secondary hardness effect after tempering in the hot-work tool steel. The secondary hardness effect after tempering determined structure and mechanical properties in this kinds of steels group.

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Możliwości podwyższania właściwości eksploatacyjnych stali narzędziowych przy wykorzystaniu procesów nawęglania

Babul T., Nakonieczny A., Senatorski J.

Inżynieria Powierzchni

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2006

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nr 2

3-8

PL

W artykule przedstawiono wyniki pomiarów zużycia przez tarcie stali narzędziowych do pracy na gorąco 4H5W2FS, AMS 6437E oraz stali do pracy na zimno ASTM A681, Ch12FS z umocnioną warstwą wierzchnią przez zastosowanie technologii nawęglania (Carbo). Proces nawęglania prowadzono w proszkach w czasie 6h przy zastosowaniu różnych temperatur procesu. Badania zużycia prowadzono stosując metodę trzy wałeczki-stożek. Prędkość tarcia wynosiła 0,58 m/s, stosowano obciążenia 50 MPa i 400 MPa, drogę tarcia 3470 m. W trakcie badań dozowano olej SAE30 w ilości 30 kropli na minutę. Badania obejmowały również: budowę warstwy, jej grubość, rozkład mikrotwardości oraz skład fazowy.

EN

The paper presents results of wear tests of hot-work steels 4H5W2FS, AMS 6437E and cold- work steels ASTM A681, Ch 12FS, with surface hardened by Carbo carburizing process. The carburizing process was carried out in powder pack during for 6 h. Wear tests were made by the three cylinders-cone method. Wear velocity was 0.58 m/s, unit bad was 50 MPa and 400 MPa, wear path was 3470 m. SAE30 oil was applied at the rate of 30 drops per minute. Investigated factors were: morphology, depth and microhardness of obtained cases, their microstructure, as well as phase composition.