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PL
W artykule omówiono wpływ mikrododatku boru na strukturę i właściwości stali oraz przedstawiono wyniki badań wpływu tego pierwiastka na hartowność żeliwa sferoidalnego z przemianą izotermiczną.
EN
Impact of boron microadditive on steel structure and properties and the research results of the influence of this element on the hardenability of ductile iron with isothermal transformation have been discussed in the paper. Experimental results are presented and analyzed.
PL
Wykonano stop niklu typu Inconel 740 w próżniowym piecu indukcyjnym średniej częstotliwości. W trakcie wytopu stosowano atmosferę gazu obojętnego (argon). Metal zalewano do formy ceramicznej z krzemianem etylu jako spoiwem. Modelami były wałki o średnicy 20 mm i długości 300 mm. Wykonane odlewy stanowiły materiał badawczy do oceny struktury w stanie odlanym i po obróbce cieplej oraz do oceny właściwości mechanicznych. Określono wpływ parametrów temperaturowo-czasowych procesu starzenia stopu typu Inconel 740 na proces jego umacniania wydzieleniowego i roztworowego.
EN
The Inconel 740 type nickel alloy was melted in a vacuum, medium frequency induction furnace. During melting the inert gas (argon) atmosphere was used Metal was poured into a ceramic mould based on ethyl silicate. Models were 300 mm long rods of 20 mm diameter. Castings were used as a test material to evaluate the structure in as-cast state and after heat treatment and to determine the mechanical properties. The effect of time-temperature parameters of the aging process of an Inconel 740 type alloy on the process of the precipitation and solution hardening was investigated.
PL
Omówiono rolę pierwiastków międzywęzłowych (azotu i boru) w procesie krystalizacji żeliwa sferoidalnego i w procesie obróbki cieplnej odlewów. Hartowanie z przemianą izotermiczną żeliwa sferoidalnego ma na celu otrzymanie ausferrytycznej struktury osnowy. Jest to obróbka cieplna polegająca na chłodzeniu stopu z temperatury austenityzacji i wychładzaniu go w specjalnej kąpieli solnej w stałej temperaturze. We wstępnych pracach badawczych stwierdzono pozytywny wpływ mikrododatków boru na proces zwiększenia intensywności przemiany izotermicznej żeliwa sferoidalnego. Wykonano następujące gatunki żeliwa: skład podstawowy (ozn. 1/ADI), żeliwo z dodatkiem azotu (ozn. 2/N1 i 4/N2), boru (ozn. 3/B1 i 5/B2) oraz azotu i boru (ozn. 6/NB). Dokonano analizy termicznej odlewanych stopów oraz określono ich strukturę i twardość. Próbki pobrane z wlewków odlanych z tych stopów poddano obróbce cieplnej. Zastosowano dwa warianty hartowania izotermicznego: w temperaturze 275°C i 350°C. Przeprowadzono badania wytrzymałościowe (Rm, A5, KV, HB) oraz mikrostruktury po obu rodzajach obróbki cieplnej. Analiza uzyskanych wyników pozwoliła określić wpływ mikrododatków boru i azotu na strukturę wyjściową badanego żeliwa oraz po jego izotermicznej obróbce cieplnej, a także na wybrane właściwości mechaniczne.
EN
The role of interstitial elements, i.e. nitrogen and boron, in the process of ductile iron solidification and heat treatment of castings was discussed. Austempering of ductile iron aims at obtaining an ausferritic matrix structure. Austempering is the kind of heat treatment that consists in cooling the alloy from the austenitising temperature, first, followed by further cooling in a salt bath at a constant temperature. The initial research studies proved favourable effect of boron microadditions on an increased rate of the ductile iron isothermal transformation process. The following cast iron grades were made: basic composition (designation 1/ADI), cast iron with an addition of nitrogen (designations 2/N1 and 4/N2), cast iron with an addition of boron (designations 3/B1 and 5/B2), and cast iron with additions of nitrogen and boron (designation 6/N B). The cast alloys were subjected to thermal analysis, their structure was examined, and hardness measurements were taken. The specimens cut out from ingots cast from the above mentioned alloys were subjected to heat treatment. Two austempering variants were applied, i.e. at temperatures of 275°C and 350°C. Mechanical tests were carried out (Rm, A5, KV, HB) and microstructure was examined after both heat treatment variants. The analysis of the obtained results enabled determination of the effect of boron and nitrogen microadditions on the as-cast and austempered structure of the examined iron; the effect on selected mechanical properties was established as well.
4
Content available remote Nitrogen hardening of creep-resistant G-NiCr28W alloy
EN
In the group of creep-resistant materials, most important are heat-resistant nickel-based alloys. The G-NiCr28W alloy subject to detailed examinations was observed to have two different austenite-like phases. In the interdendritic spaces of alloy matrix, the presence of another phase, also characterised by paramagnetic properties, was detected. Inside this interdendritic phase, local areas of a lamellar structure, composed of both of the above mentioned phases, were present. Nitrogen treatment was observed to raise the microhardness of both these phases. The presence of nitrogen made the regions of a lamellar structure disappear completely. Their place was occupied by precipitates dispersed in the matrix, and occasionally forming large clusters. It has been observed that cold work can harden the G-NiCr28W alloy to a very small degree only, in spite of the fact that hardness is increasing systematically with the increasing degree of cold work. The said alloy, when enriched with nitrogen added as an alloying element, is characterised by hardness higher than the hardness of its nitrogen-free counterpart. The value of hardness is increasing even more under the effect of low-degree cold work, although increasing further the degree of cold work seems to have no effect on hardness increase. The problem faced in nickel-based materials is the possibility of making defect-free castings from alloys with high nitrogen content. Alloys investigated in the present study were remelted, cast and subject to solidification under high nitrogen pressure in the furnace chamber. However, melting carried out under these conditions could not prevent the occurrence of non-metallic inclusions which, while being unable to pass to a riser, formed local clusters or even thin films, resulting in numerous microcracks or discontinuities encompassing large regions of the casting. This problem seems to be of major concern and is the first one to require prompt solution in the currently executed large research project.
PL
Przedstawiona praca stanowi część badań przemysłowych (stosowanych) wykonanych w ramach projektu celowego ROW-II-403/2008 realizowanego w MAGNUS-NORD w Toruniu. Celem pracy było dobranie obróbki cieplnej zapewniającej uzyskanie założonych wartości udarności staliwa GS-20Mn5 w temperaturze -30°C oraz -55°C. W artykule nakreślono problem związany z przejściem stopów w stan kruchy przy obniżeniu temperatury eksploatacji. Ze względu na charakter produkcji odlewów w zakładach "Magnus-Nord" w Toruniu praca dotyczyła możliwości uzyskania, w warunkach tej odlewni, staliwa konstrukcyjnego niskostopowego z przeznaczeniem na wybrane odlewy pracujące w temperaturze poniżej -20°C. Przeprowadzono wytopy staliwa GS- 20Mn5, a następnie dobrano parametry obróbki cieplnej tego stopu umożliwiające osiągnięcie odpowiedniej udarności w temperaturze -30°C (20-50 J) i temperaturze -55°C (20-30 J).
EN
The study formed a part of industrial (applied) research executed under Target Project ROW-II-403/2008 at MAGNUS-NORD in Toruń. The aim of the study was to select the heat treatment parameters ensuring the required impact resistance values of GS-20Mn5 cast steel when operating at-30°C and -55°C. The study outlines the problem of alloy embrittlement when operating at low temperatures. Considering the production profile of "Magnus-Nord" Toruń, the study mainly regarded the possibilities of manufacturing under the conditions of this specific Foundry, the structural low-alloyed steel for castings operating at temperatures below -20°C. Consequently, the GS-20Mn5 steel was melted and, as a next step, parameters of the heat treatment of this alloy were selected to satisfy the requirements to obtain the required impact resistance at temperatures of -30°C (20-50J) and -55°C (20-30).
PL
Badano wpływ obróbki cieplnej na strukturę i właściwości mechaniczne stopu B1044 (CuAl10Fe4Ni4). Zawartość aluminium, żelaza i niklu powoduje występowanie struktury stopu badanego w układzie granicznym między obszarami α + α[sub]2 + β' oraz β' + β[sub]1' + α[sub]2 i obecnością fazy γ[sub]2 z przemiany eutektoidalnej, co odbija się na właściwościach mechanicznych. Stosowano przed hartowaniem nagrzewanie (przesycanie) przez 2 h w 950°C i wariantowe chłodzenie: w wodzie, oleju i na powietrzu. Ponadto część próbek hartowanych starzono w temperaturze 500 lub 700°C przez 6 h z wariantowym chłodzeniem z piecem i na powietrzu. Uzyskano interesujące właściwości mechaniczne, tak wytrzymałościowe (R[sub]m, R[sub]0,2) jak i plastyczne (A, Z). W badaniach w stanie stałym posłużono się dylatometrem i kalorymetrem różnicowym.
EN
The effect of heat treatment on structure and mechanical properties of B1044 (CuAl10Fe4Ni4) alloy was investigated. In the examined alloy, the content of aluminium, iron and nickel results in the formation of structure comprised in a boundary system between the regions of α + α[sub]2 + β' and β' + β[sub]1' + α[sub]2 with the presence of γ[sub]2 phase formed due to eutectoid transfomation, affecting the level of mechanical properties. Before quenching, the specimens were preheated (solutioning heat treatment) for 2 h at 950°C, and different variants of cooling in water, oil and air were applied next. Some quenched specimens were also subjected to ageing from 500 or 700°C after 6 h heating and cooling with furnace and in the air. Very interesting results were obtained regarding both mechanical (R[sub]m, R[sub]0,2) and plastic (A, Z) properties. Tests in the solid state were carried out using a dilatometer and differential calorimeter.
EN
In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI). Melts were conducted with ironnickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.
PL
W drugiej części pracy, opisującej rolę mikrododatków wanadu i boru w procesie kształtowania się struktury grubościennych odlewów z żeliwa ADI, omówiono wyniki przeprowadzonych badań własnych. W ramach pracy wykonano dwie serie wytopów żeliwa sferoidalnego wprowadzając mikrododatki tych pierwiastków zarówno do niestopowego żeliwa sferoidalnego, jak też do żeliwa zawierającego zwiększoną zawartości niklu i miedzi (skład typowego żeliwa ADI). Wytopy prowadzono stosując zaprawy żelazowo-niklowo-magnezowe. Przeprowadzono analizę termiczną procesu krzepnięcia odlewanych wlewków, wykonano obróbkę cieplną otrzymanych stopów, a następnie oceniono wpływ wprowadzanych dodatków boru i wanadu na hartowność badanego żeliwa.
EN
The theoretical part of the study discloses the genesis of the research which originated from a possibility of replacing the so far used expensive machine parts with parts cheaper and yet offering similar quality and performance life. A short characteristic of the machine was given where the main operating parts made so far from steel were replaced with parts made from cast iron. The equipment and its main applications were described. In the research part of the study several types of alloys were proposed. Their use is expected to ensure the required performance life of parts combined with price reduction. A short characteristic of the proposed material was given. A technology of making moulds for the said machine parts was developed. Using this technology, the respective moulds were made and poured next with three cast alloys. One of the proposed materials was subjected to four types of the heat treatment, two alloys used as reference materials were left in as-cast state. The castings were fettled and weighed. The hardness of the cast materials was measured. The working (turning) parts were delivered for operation to a sewage-treatment plant where, after assembly in a turning machine, the performance tests were conducted.
9
Content available remote Tests and studies on improved innovativeness of sand reclamation units
EN
The aim of the present study was raising the innovativeness of sand reclamation units through application of a new material - austempered ductile iron (ADI) - for elements exposed to abrasion wear and impacts. Methods used for casting of ADI blades for disk-type reclamation units were described along with the results of tests and measurements of the obtained hardness, strength and microstructure. The ready ADI castings of blades were next subjected to performance tests to compare them with the conventionally made cast steel blades operating under industrial conditions. The obtained results of the tests confirmed high properties and numerous benefits offered by ADI respetive of cast steel used as a material for elements of sand reclamation units.
10
Content available remote Microadditions of boron and vanadium in ADI. Part 2. Own investigations
EN
In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI). Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.
11
Content available remote Microadditions of boron and vanadium in ADI. Part 1. Literature review
EN
The first part of this study describes the methods of obtaining a bainitic structure in ferrous alloys. The TTT diagrams were characterised along with the run of cooling curves for ductile iron in its alloyed, unalloyed and low-alloyed variations. Next, the effect of alloying additions on the hardenability of ferrous alloys was discussed. A formula was given to determine the temperature of the beginning of bainitic transformation with examples of the diagrams illustrating the effect of some selected alloying additions on the hardenability factor. Special attention was paid to a complex role played by boron and vanadium.
PL
Przedstawiono prace nad uruchomieniem produkcji żeliwa sferoidalnego do pracy w temperaturze - 20°C do 40°C. Opracowano technologię produkcji żeliwa EN-GJS-350-22-LT i 400-18-LT. Uruchomiono piec do obróbki cieplnej współpracując z firmą C.C&T. Wykonano próbne odlewy i obróbkę cieplną. Wykonano serię armatury, która przeszła pozytywnie badania i próby szczelności.
EN
The works on the putting into industrial practice the ductile iron for application in low temperatures (-20°C to - 40°C) has been presented. The technology of manufacturing the EN-GJS-350-22-LT iron and the EN-GJS-400-18-LT iron has been worked out. Cooperating with C.C.& T firm, the annealing furnace has been worked out and put in motion. The experimental castings and the heat treatment of the castings have been made. The batch of fittings, which passed all tests (leak proof test too) has been made.
PL
Podsumowano badania zmierzające do poprawy odporności staliwa Cr26Ni5Mo3 na zużycie erozyjno-korozyjne, zwracając szczególnie uwagę na znaczenie pierwiastków międzywęzłowych jako dodatków stopowych. W części pierwszej zdefiniowano podstawowe pojęcia związane z procesem niszczenia powierzchniowego, a następnie omówiono spotykane w literaturze metody badań odporności na zużycie erozyjne i na tym tle przedstawiono urządzenie własnej konstrukcji. W części drugiej scharakteryzowano stopy dwufazowe oraz wytypowano materiał do badań własnych. Opisano problemy związane z otrzymywaniem staliwa o zwiększonej zawartości pierwiastków międzywęzłowych, głównie azotu. Następnie przedstawiono sposoby oszacowania ilości ferrytu w strukturze staliwa chromowo-niklowego na podstawie zawartości pierwiastków stopowych. Porównując obliczenia teoretyczne z wynikami pomiarów zamieszczono własne rozważania w tym zakresie. Następnie omówiono znaczenie węgla, azotu i boru w procesie kształtowania się struktury badanego staliwa. W części trzeciej natomiast wykazano istotny wpływ tych dodatków na takie własności użytkowe staliwa Cr26Ni5Mo3, jak odporność na zużycie korozyjne i erozyjno-korozyjne w środowisku jonów chlorkowych. Część czwarta traktuje o obróbce cieplnej staliwa chromowo-niklowo-molibdenowego; przedstawiono w niej wpływ zabiegów obróbki cieplnej w trakcie stopu oraz na jego zużycie erozyjne.
EN
Investigation aiming at the improvement of the resistance of the cast steel Cr26Ni5Mo3 to the erosive and corrosive wear paying special attention to the significance of interstitial elements as alloy additions is summed up. In the first part the basic terms connected with the process of the superficial destruction are defined, and then the methods of testing the erosive wear cited in the literature are discussed and against this background the device of the authors' own design is presented. In the second part the two-phase alloys are characterized and the material for the authors' own investigation is selected. The problems connected with obtaining cast steel with an increased content of interstitial elements, mainly nitrogen, are described. Next the methods of estimation of the amount of ferrite in the structure of the chromium-nickel cast steel on the basis of the content of alloying additions are presented. When comparing the theoretical computations with the measurement results, the authors' own considerations in this range are given. Then the consequence of carbon, nitrogen and boron in the process of structure shaping of the invesitigated cast steel is discussed. In the third part the vital effect of these additions on such utilization properties of the cast steel Cr26Ni5Mo3, as: resistance to the corrosive and erosive-corrosive wear in the medium of chloride ions is proved. The fourth part deals with heat treatment of the chromium-nickel-molybdenum cast steel. The effect of heat treatment on the alloy structure and on its erosive wear is presented.
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