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1

Kinetyka absorpcji azotu przez topione łukowo spoiwa typu Fe-C-Mn

Gruszczyk Andrzej

Dozór Techniczny

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2019

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z. 3

22--31

PL

Poddano analizie wpływ warunków topnienia metodą TIG w atmosferach Ar+2%N2 i Ar+2%N2+0,2%O2 oraz zawartości tlenu w spoiwach na kinetykę absorpcji azotu przez spoiwa typu Fe-C-Mn. Proces badano w połączeniu z innymi zjawiskami występującymi w stopionych spoiwach. Absorpcja azotu przez topione łukowo spoiwa typu Fe-C-Mn została opisana kinetyczna reakcja I rzędu, dzieląca całkowitą powierzchnię stopionej próbki na obszar oddziaływania łuku elektrycznego i obszar kontaktu z chłodniejszym gazem osłonowym. Na podstawie tego modelu wyznaczono zależne od czasu zmiany zawartości azotu, a także współczynniki transportu masy i szybkości absorpcji azotu w różnych warunkach topnienia. Wykazano, że warunki absorpcji azotu przez topione łukowo spoiwa typu Fe-C-Mn różnią się znacznie od mechanizmu sugerowanego dla czystego Fe i rozwiązań w systemie Fe-O. Reakcja odtleniania węglem zachodząca w wysokich temperaturach jest czynnikiem ograniczającym absorpcje azotu przez topione łukowo spoiwa typu Fe-C-Mn. Wzrost szybkości absorpcji azotu i zawartości azotu, wynikający ze zmniejszenia prądu topnienia, związany jest ze zmniejszeniem intensywności odtleniania węglem i intensywności parowania manganu, a także z powstawaniem ciekłych tlenków, które zmniejszają desorpcję azotu z obszarów niepoddanych oddziaływaniu łuku elektrycznego.

2

The kinetics of nitrogen dissolution in levitation and arc-melted Fe-C-Mn filler metals

Gruszczyk A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 26, nr 2

115-122

EN

Purpose: The influence of melting method on the kinetics of nitrogen absorption by Fe-C-Mn filler metals has been analysed. The industrial heats of the Fe-C-Mn (SpG1) type welding filler metals were selected for own researches. Design/methodology/approach: The research of the nitrogen absorption kinetics was carried out in the levitation and TIG arc-melting conditions in the Ar+N2 atmosphere. The conditions of experiments were made possibly close to those existing in a molten metal drop in the welding processes. Findings: Based on the models of nitrogen absorption during levitation and arc melting of Fe-C-Mn filler metals, the time-dependent changes of nitrogen content were determined as well as the mass transfer coefficients b and the rates of nitrogen absorption. Nitrogen absorption rate decreases along with the increase of oxygen content in the Fe-C-Mn filler metals arc-melted in the Ar+N2 atmosphere. Research limitations/implications: Investigation of the Fe-C-Mn complex alloys with the specified amount of impurities makes the detailed analysis of the elementary stages of nitrogen dissolution more difficult, yet brings the experiment conditions closer to those occurring in the actual welding processes. Practical implications: Recognizing the mechanisms of nitrogen absorption under arc and non-arc melting to make possible the control of nitrogen level in the welds. Originality/value: Obtained results explain the influence of oxygen and melting conditions on kinetics of nitrogen dissolution in Fe-C-Mn alloys.

3

The microstructure and properties of a new Fe41Ni39P10Si5B5 glass forming alloy

Ziewiec K., Bryła K., Ziewiec A., Prusik K.

Archives of Materials Science and Engineering

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2008

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Vol. 34, nr 1

35-38

EN

Purpose: The aim of the work was to investigate the microstructure, thermal stability and some mechanical properties of a new Fe41Ni39P10Si5B5 glass forming alloy. Design/methodology/approach: A five component Fe41Ni39P10Si5B5 alloy was produced using arc melting in argon protective atmosphere from of pure elements 99.95 wt. % Fe, 99.95 wt. % Ni, 99,999 wt. % Si and Fe-P, Fe-B, Ni-P, Ni-B master alloys. The alloy was melt spun. The microstructure of the arc melted droplet is investigated in scanning electron microscope with EDS. The melt spun ribbon was investigated by X-ray diffraction, micro-hardness measurement, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and the microstructure of the melt spun ribbon at the beginning of crystallization process was observed using high resolution transmission electron microscope (HRTEM). Findings: The arc-melt alloy consisted of four phase constituents that provided amorphization during the melt spinning process. The alloy has relatively high hardness of 720HV and the elastic modulus on the level of 102 GPa. The elastic modulus is stable up to ca. 500 K and after it shows glass transition at 603 K. Crystallization causes temporary increase of the elastic modulus and finally causes brittleness of the sample. The crystallization was found to have the two stages and it begins with formation of bcc iron-base nano-metric crystals. Research limitations/implications: It has been shown that the multi-component Fe-Ni-P-Si-B system provides the multiphase composition and enables relatively easy amorphization of the Fe41Ni39P10Si5B5 alloy through the melt-spinning method. It is also possible to control the microstructure and the mechanical properties through the appropriate heat treatment. The existence of glass transformation in the alloy provides possibility of consolidation non-bulk material into a bulk sape. Practical implications: The work reports about the glass forming alloy of relatively good mechanical properties produced from a low-cost commercial purity precursors. The future investigations on the alloy can provide the basis to the processing and manufacturing soft-magnetic bulk parts of a very low coercivity. Originality/value: The study provides an original information about the primary structure of the arc-melt Fe41Ni39P10Si5B5 alloy as well as about the microstructure, mechanical properties and thermal stability of meltspun ribbon.

4

The kinetics of nitrogen dissolution in levitation and arc-melted Fe-C-Mn filler metals

Gruszczyk A.

Archives of Materials Science and Engineering

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2008

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Vol. 31, nr 2

109-112

EN

Purpose: The influence of melting method on the kinetics of nitrogen absorption by Fe-C-Mn filler metals has been analysed. The industrial heats of the Fe-C-Mn (SpG1) type welding filler metals were selected for own researches. Design/methodology/approach: The research of the nitrogen absorption kinetics was carried out in the levitation and TIG arc-melting conditions in the Ar+N₂ atmosphere. The conditions of experiments were made possibly close to those existing in a molten metal drop in the welding processes. Findings: Based on the models of nitrogen absorption during levitation and arc melting of Fe-C-Mn filler metals, the time-dependent changes of nitrogen content were determined as well as the mass transfer coefficients b and the rates of nitrogen absorption. Nitrogen absorption rate decreases along with the increase of oxygen content in the Fe-C-Mn filler metals arc-melted in the Ar+N₂ atmosphere. Research limitations/implications: Investigation of the Fe-C-Mn complex alloys with the specified amount of impurities makes the detailed analysis of the elementary stages of nitrogen dissolution more difficult, yet brings the experiment conditions closer to those occurring in the actual welding processes. Practical implications: Recognizing the mechanisms of nitrogen absorption under arc and non-arc melting to make possible the control of nitrogen level in the welds. Originality/value: Obtained results explain the influence of oxygen and melting conditions on kinetics of nitrogen dissolution in Fe-C-Mn alloys.

5

The microstructure and mechanical properties of Ni78Ag2P20 alloy

Ziewiec K., Dutkiewicz J., Ziewiec A., Kąc S.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 11

657-660

EN

Purpose: The aim of the work was to investigate the influence of silver as a modifying constituent on structure formation in Ni-P based glass forming matrix and to characterize mechanical properties of the alloys. Design/methodology/approach: Nickel-silver-phosphorus Ni78Ag2P20 alloy was produced using arc melting in argon protective atmosphere from commercial powders. The alloy was melt spun. The microstructure of the arc melted droplet is investigated in scanning electron microscope with EDS and micro-hardness tester and the melt spun ribbon is investigated using light microscope and transmission electron microscope. Then the mechanical properties are evaluated with use of micro-hardness measurements. Findings: A strong tendency for demixing of Ni-P-rich and Ag-rich liquids is observed leading to formation of the primary structure consisting of slightly hypo-eutectic Ni-P-rich regions and Ag rich regions. The melt spinning process produced the amorphous Ni-P and Ag-rich crystalline structure. The alloys hardness and elasticity modulus were characterized. The melt spun ribbons are slightly softer than the crystalline Ni-P regions. In case of the melt spun ribbons, a softening influence of silver was observed giving the lower hardness for Ni78Ag2P20 than Ni80P20. The alloy constituents in a bulk crystalline state present the higher values of elasticity modulus when compared to the melt spun ribbons. Research limitations/implications: It has been shown that the criterion of a high positive values of mixing enthalpies can be applied to design the materials that should separate before the solidification to form a hard glassy matrix/soft crystalline composite. The amorphization of the crystalline Ni-P-based alloys can lead to formation of more flexible materials with a lower elasticity modulus and lower hardness. Practical implications: The main limits for application of the glassy alloys are the high prices of the materials used for alloying and the low plasticity of the amorphous metals. Therefore, the work provides the alloy produced from a low-cost commercial purity precursors that are able to form a glassy matrix composite with a crystalline soft particles included. The future works on the development of the idea can lead to a successful manufacturing of a hard and ductile metallic composite parts. Originality/value: The work delivers a new information on possibility of amorphous/crystalline composite formation starting from Ni Ag P system. This includes the original microstructural and mechanical characteristics of the arc melt and melt spun alloy. The information could be used by researchers for future works on development of Ni-P based composites complementary to the electroless coatings.

6

Absorpcja azotu przez topione łukowo spoiwa typu Fe-C-Mn

Gruszczyk A.

Zeszyty Naukowe. Mechanika / Politechnika Śląska

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1999

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z. 132

1-103

PL

Praca w sposób syntetyczny ujmuje zagadnienia dotyczące absorpcji azotu przez ciekłe stopy na osnowie żelaza. Do badań własnych wybrano przemysłowe wytopy spoiw spawalniczych typu Fe-C-Mn (SpGl) o zbliżonej zawartości azotu i zróżnicowanej zawartości tlenu i węgla. Podstawowe badania kinetyki absorpcji i desorpcji azotu przeprowadzono w warunkach topienia łukowego metodą GTA w atmosferach Ar, AT+N2, Ar+-N2+02. Dla porównania przeprowadzono również podobne badania z zastosowaniem topienia metodą indukcyjną lewitacyjną. Warunki termodynamiczne i kinetyczne prowadzenia eksperymentów z łukowym topieniem spoiw SpGl starano się maksymalnie zbliżyć do istniejących w kropli ciekłego metalu łukowych procesów spawania. Analizowano wpływ tlenu zawartego w spoiwach oraz warunków topienia (składu atmosfer ochronnych, natężenia prądu topienia metody GTA) na kinetykę absorpcji azotu. Proces absorpcji azotu analizowano na tle innych reakcji metalurgicznych zachodzących w topionych spoiwach, szczególną uwagę zwrócono na reakcję odtleniania węglem. Wykazano, że warunki absorpcji azotu przez topione łukowo spoiwa Fe-C-Mn są bardziej złożone niż w modelach proponowanych dla czystego Fe i roztworów w układzie Fe-O. Absorpcję azotu przez topione indukcyjnie i łukowo spoiwa Fe-C-Mn opisać można wyrażeniami kinetycznymi I rzędu. Wskazuje to, że ogniwem limitującym przebieg absorpcji jest transport azotu w fazie ciekłej. W modelu matematycznym absorpcji azotu w czasie topienia łukowego całkowitą powierzchnię kropli rozdzielono na obszar oddziaływania łuku elektrycznego i obszar kontaktujący się z chłodniejszym gazem osłonowym. W oparciu o wymienione modele wyznaczono czasowe przebiegi zawartości azotu, współczynniki transportu masy ß i szybkości absorpcji azotu dla różnych warunków topienia. Wykazano, że czynnikiem ograniczającym absorpcję azotu przez topione łukowo spoiwa Fe-C-Mn jest zachodząca w wysokich temperaturach reakcja odtleniania węglem. Wynikający z obniżenia natężenia prądu topienia metody GTA wzrost szybkości absorpcji i zawartości azotu wiąże się z ograniczeniem intensywności odtleniania węglem i parowania manganu oraz tworzeniem ciekłych tlenków ograniczających desorpcję azotu z obszarów nie podlegających oddziaływaniu łuku elektrycznego. Uzyskane wyniki wskazują ponadto, że na zwiększenie intensywności absorpcji azotu przy topieniu łukowym wpływają, obok często podkreślanych w literaturze procesów aktywowania azotu w łuku elektrycznym, zjawiska związane z transportem azotu w ciekłym metalu. Wzrostowi współczynników transportu azotu podczas topienia łukowego sprzyjają wysoka temperatura i warunki dynamiczne ciekłego metalu.

EN

In the work, there are some issues of nitrogen absorption by iron-based liquid alloys dealt synthetically. For the author's own investigation, industrial heats of welding fillers of the type Fe-C-Mn (SpGl), similar in nitrogen content but diversified in that of oxygen and carbon, have been selected. The basic investigation into the kinetics of nitrogen absorption and desorption was carried out in GTA melting circumstances under Ar, Ar+N2 and Ar+N2+02 shields. For comparison purposes, similar research with use of induction-levitation melting method was carried out. Thermodynamic and kinetic conditions of experimentation of arc melting of SpGl filler metals were attempted to be made alike, as much as possible, to those existing in liquid metal drops in arc welding processes. It was analysed the influence of oxygen entrapped in fillers as well as that of melting conditions (shielding atmosphere composition, welding current in GTA method) on nitrogen absorption kinetics. The process of nitrogen absorption was analysed on the background of another metallurgical reactions running in the fillers being melted, a special attention has been paid on the reaction of carbon deoxidation. It has been shown that the conditions of nitrogen absorption by Fe-C-Mn fillers being arc melted are more complex than those in the models preasumed in case of pure iron and Fe-0 solutions. Nitrogen absorption by induction and arc molten Fe-C-Mn fillers can be described by first order kinetic reactions. It denotes that nitrogen transfer in liquid phase is the factor limiting the absorption run. In mathematical model of nitrogen absorption in arc melting the whole drop surface has been divided into the electric arc interaction range and that where a contact with cooler shielding gas occurs. On the basis of mentioned model it has been determined the changes of nitrogen content in time, mass transfer coefficient ß and nitrogen absorption rate coefficient for various melting conditions. It has been shown that carbon deoxidation reaction running at high temperatures is the factor limiting nitrogen absorption by arc molten Fe-C-Mn fillers. An increase in nitrogen absorption rate and its content resulting from a decrease in melting current of GTA method is connected with a reduction in intensity of carbon deoxidation and manganese evaporation as well as with formation of liquid oxides which reduce nitrogen desorption from the regions not subject to electric arc interaction. The achieved results show, moreover, that the increase in nitrogen absorption intensity during arc melting, is affected (apart from nitrogen activation processes in electric arc, mentioned often by other authors) by phenomena connected with nitrogen transfer in liquid metal. High temperature and dynamic conditions of liquid metal are conducive to the increase of nitrogen transfer coefficients in arc melting.