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1

Effect of the degree of cold work and sensitization time on intergranular corrosion behavior in austenitic stainless steel

Ławrynowicz Zdzisław

Advances in Materials Science

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2019

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Vol. 19, nr 1(59)

32--43

EN

Present paper deals with the influence of a wide range of cold rolling (5, 10, 15 and maximum 40% cold deformation) and the sensitization time (aging at 700oC for 0.12, 0.5, 1, 4, 16 and 32 hours) on intergranular corrosion (IGC). Intergranular corrosion of commercial stainless steel type X6CrNiTi18-10 (1.4541, AISI 321) is frequently observed in several process environments. These localized attacks are normally attributed to the carbide precipitation and concomitant depletion of chromium near grain boundary due to steel exposure to sensitization temperature. Such undesirable microchemistry is expected to be changed further if the material undergoes deformation prior to sensitization. The consequences of deformation on IGC have been investigated by using EN ISO 3651-1methods (Huey test – Corrosion test in nitric acid medium by measurement of loss in mass). Introducing deformation to the investigated stainless steel seems to change the kinetics of carbide precipitation M23C6 and thereby changes it resistance to IGC. Cold deformation before sensitization reduces the intensity of intergranular corrosion of this steel. The deformed structure created during the cold work process, numerous slip planes and the twins boundaries are just like the grain boundaries and the places where the chromium carbides preferentially precipitates. Due to the more evenly occurring precipitation processes within the whole deformed grains, there is no phenomenon of local grain boundary carbide precipitation, and thus there is no decrease in the resistance of this steel to intergranular corrosion. The assessment of the degree of intergranular corrosion was based on the measurement of mass loss and observation of corroded surfaces on optical and electron transmission and scanning microscopes.

2

Ultrasonic testing of grain distortion direction in cold formed aluminium profile

Keran Z., Mihaljević M., Runje B., Markučič D.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 2

375--381

EN

Cold deformation process of metals causes distortion of crystalline structure. When a material is formed, the grains are usually distorted and elongated in one or more directions which make the material anisotropic. Anisotropy can be defined as a difference in a material's physical or mechanical properties in different directions of taking of testing samples. In exploitation, it is very important to recognize the direction of grain elongation so that the best orientation of working part can be chosen. For that purpose ultrasonic testing is used. The ultrasonic velocity of the material is determined by using a digital oscilloscope under condition that thickness of the material is known. Testing shows the difference in wave velocity for different orientations of grain structure. In order to determine whether there is a significant difference in the ultrasonic velocity, the measurement results were statistically analyzed and graphically presented. The results are verified by performing the same measurement procedure on annealed homogenous testing samples. The result of this work leads to a non-destructive, simplified way of anisotropy recognition, without more expensive, destructing, testing by cutting out a large number of testing samples.

3

Kinetics of precipitation and recrystallisation of titanium copper

Konieczny J., Labisz K., Rdzawski Z., Polok-Rubiniec M., Włodarczyk-Fligier A.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 67, nr 2

53--57

EN

Purpose: The main aim of this work is to investigate effect of cold working following supersaturation of alloy copper in change in electrical conductivity of the finally aged CuTi4 alloy. Next, plots were worked out describing the kinetics of precipitation and recrystallisation from titanium copper, based on results of the electric conductivity measurements using the KJMA (Kolmogorov, Johnson, Mehl, Avrami) relationship. Design/methodology/approach: The energy of the nucleation activation, precipitation, and grain growth was calculated by approximating the segments of the straight lines shown in the plots. Findings: As a result of the electrical conductivity tests, the energy of the nucleation activation, growth, and precipitation of new particles during the ageing, was calculated for the two different variants of CuTi4 alloy processing. Research limitations/implications: As a result of the electrical conductivity tests, and using the KJMA (Kolmogorov, Johnson, Mehl and Avrami) relationship, the energy of the nucleation activation, precipitations, and growth of new particles during the ageing, was calculated for two treatment variants. Practical implications: It was found that the activation energy of nucleation of crystal nuclei is lower for the alloy treated according to variant 1st (supersaturation, ageing), while the activation energy of the precipitation and grain growth is lower for the alloy treated according to variant 2nd (supersaturation, cold working Z=50%, ageing). Originality/value: Article presented the energy of the nucleation activation, growth, and precipitation of new particles during the ageing, was calculated for the two different variants of CuTi4 alloy processing, based on the results of measurement of electrical conductivity.

4

The investigation of Microstructures and Properties of High Speed Steel HS6-5-2-5 after Laser Alloying

Bonek M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1647--1651

EN

This paper presents the results of the influence of laser alloying on structure and properties of the surface of HS6-5-2-5 high speed steel, carried out using a high power diode laser (HPDL). WC, VC, TiC, SiC, Si3N4 and Al2O3 particles powder was used for alloying. It was found out that remelting and laser alloying with hard particles result in structure refinement across the entire investigated laser power range. Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, EDX, X-ray microanalysis results. Fine grained, dendritic structures occur in the remelted and alloyed zone with the crystallization direction related to the dynamical heat movement from the laser beam influence zone. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. Micro-hardness changes depend up in the effects of the laser beam on the treated surface, and especially in the alloyed layer. The outcome of the research provides better understanding of the structural mechanisms accompanying laser remelting and alloying. Laser technique features the especially promising tool for solving the contemporary surface engineering problems thanks to the physical properties of the laser beam, making it possible to focus precisely the delivered energy in the form of heat in the surface layer.

PL

W pracy przedstawiono wyniki badań laserowego stopowania na strukturę i własności warstwy wierzchniej stali szybkotnącej HS6-5-2-5, przetapianej za pomocą lasera diodowego dużej mocy (HPDL). Jako materiał stopujący użyto proszków WC, VC, TiC, SiC, Si3N4 i AI2O3. Stwierdzono, że do przetopienia i stopowanie laserowe twardymi cząstkami powoduje poprawę własności warstwy wierzchniej w całym zakresie mocy lasera. Odpowiedni dobór warunków pracy lasera jak również jakość wiązki ma wpływ na wyniki przetopienia co potwierdzono badaniami twardości, mikrotwardości, mikroanalizy rentgenowskiej i rentgenowskie analizy fazowej. W strefie przetopionej i stopowanej stwierdzono występowanie drobnoziarnistej oraz dendrytycznej struktury z kierunkiem krystalizacji związanym z dynamicznym przepływem ciepła ze strefy oddziaływania wiązki laserowej. Drobnoziarnista struktura martenzytu jest odpowiedzialna za wzrost twardości warstwy stopowanej. Zmiany mikrotwardości ściśle zależą od efektów oddziaływania wiązki laserowej na obrabianą powierzchnię. Wyniki badań pozwalają na lepsze zrozumienie mechanizmów strukturalnych towarzyszących przetapianiu i stopowaniu laserowemu. Laserowa obróbka powierzchniowa stanowi szczególnie obiecujące narzędzie do rozwiązywania problemów inżynierii powierzchni dzięki wykorzystaniu własności fizycznych wiązki lasera umożliwiających precyzyjną obróbkę cieplną w warstwie wierzchniej.

5

Physical Modelling of the Plastic Working Processes of Zirconium Alloy Bars and Tubes in Thermomechanical Conditions

Kawałek A., Dyja H., Gałkin A. M., Ozhmegov K.V., Sawicki S.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 3

935--940

EN

The article presents results of physical modelling of processes of plastic working of the modified Zr-1%Nb zirconium alloy, obtained using different methods of the plastometric testing. The „Gleeble 3800”‚ metallurgical process simulator, a DIL805 A/D dilatometer with a plastometric attachment, and a „Setaram‚ plastometer were used for testing. Based on the obtained testing results, the values of the yield stress and limiting plasticity of the tested alloy were determined for wide ranges of temperature variation (T=20÷950°C) and strain rate variation (ε=0.1÷15.0 s-1) under continuous loading conditions. It was found that by using different testing methods, different alloy properties, characteristic for a given plastic working process, could be obtained.

PL

W artykule przedstawiono wyniki modelowania fizycznego procesów przeróbki plastycznej modyfikowanego stopu cyrkonu Zr-1%Nb, otrzymane za pomocą różnych metod badań plastometrycznych. Do badań zastosowano symulator procesów metalurgicznych „Gleeble 3800”‚ dylatometr DIL805 A/D z przystawką plastometryczną i plastometr „Setaram‚. Na podstawie otrzymanych wyników badań określono wartość naprężenia uplastyczniającego i plastyczności granicznej stopu dla szerokiego zakresu zmian temperatury (T=20÷950°C) i prędkości odkształcenia (ε=0.1÷15.0 s-1), w warunkach obciążania ciągłego. Stwierdzono, że stosując różne metody badawcze można uzyskać inne własności stopu, charakterystyczne dla danego procesu przeróbki plastycznej.

6

Influence of cold working on microstructure and properties of annealing CuTi4 alloy

Konieczny J., Rdzawski Z.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

331--338

EN

Purpose: The aim of this study was to investigate the effect of cold plastic deformation of the supersaturation on the structure and properties of the CuTi4 alloy after aging. Design/methodology/approach: CuTi4 alloy of supersaturation temperature of 900°C after heating for 1 hour. After solutioning alloy was processed in two ways: first aged in the temperature range 450-600°C and the second stage rolling reduction with Z=50%, and then aged in the temperature range 450-600°C. Findings: The results confirmed that the temperature within the range 500-600°C, the hardness increases with increasing aging time until reaching the maximum, but then with increasing aging time the hardness decreases. By using methods of electron microscopy (SEM, EDS, EBSD, TEM) after aging at 550°C after 1 minute of modulated microstructure was observed - characteristic for the spinodal transformation and lamellar, formed by nucleation and growth. Research limitations/implications: A widely used method for increasing the strength properties of metal alloys, in addition to cold plastic deformation, is the strengthening of new phases separated particles during aging. The effect of cold rolling operation between solutioning and aging on microstructure and properties of alloyed copper CuTi4. Further examination also included the effect of time and aging temperature. Practical implications: On the basis of conductivity, the influence of cold plastic deformation and subsequent aging on the hardness and electrical conductivity of the alloy CuTi4. It was found that with increasing aging time and with increasing aging temperature increases electrical conductivity of the alloy. On the basis of X-rays can be concluded that in alloyed copper containing 4% Ti and precipitation hardening metastable phase β’-Cu4Ti is separated, which occurs both in the previously deformed and undeformed cold worked alloy.

7

Experimental and numerical research on radial extrusion of parts such as "rod with head

Kalpin U. G., Petrov P. A., Pertrov M. A.

Computer Methods in Materials Science

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2007

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Vol. 7, No. 3

347-351

EN

New technological process of manufacturing of parts such as "rod with head" was investigated experimentally and numerically. The process is based on two operations of forming: upsetting and radial (transverse) extrusion. The tool set was developed for experimental research of the mentioned process. The experimental trials allowed to investigate the metal flow during the extrusion. The numerical modelling was also carried out. Commercial code QFORM-2D was used for simulation of the process. Good compatibility between the results of experiments and numerical simulation was obtained. Some practical recommendations are given in the conclusions.

PL

Nowy technologiczny proces wyciskania promieniowego elementów typu "pręt z główką był analizowany doświadczalnie i numerycznie. Ten proces opiera się na dwóch operacjach plastycznej przeróbki metali, spęczaniu i promieniowym wycis-kaniu. Zaprojektowano zestaw narzędzi do badań doświadczal-nych tego procesu. Badania doświadczalne pozwoliły prześledzić schemat płynięcia metalu w procesie wyciskania. Następnie wykorzystano komercyjny QFORM-2D do symulacji numerycznej procesu. Otrzymano dobrą zgodność między wynikami symulacji i doświadczeniem. Good compatibility between the results of experiments and numerical simulation was obtained. We wnioskach przedstawiono rekomendacje dla projektowania analizowanego procesu.

8

Badania strukturalne mechanizmu odkształcenia na zimno stali przez zgniatanie obrotowe

Stępień J.

Archiwum Technologii Maszyn i Automatyzacji

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2007

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Vol. 27, nr 1

169-177

PL

Zgniatanie obrotowe na zimno stali niskowęglowej Cr-Mn-Mo-V stosuje się w celu uzyskania w wyrobie gotowym bardzo drobnej struktury. Uzyskanie bardzo drobnej struktury pozwala na podwyższenie właściwości wytrzymałościowych wyrobu gotowego przy bezpiecznym poziomic wydłużenia A5 powyżej 10%. Zgniatanie obrotowe wykonano na dwóch stanowiskach: na stanowisku doświadczalnym FPS Bolechowo, stosując stal wytapianą z zastosowaniem pozapiecowej obróbki próżniowej VAD, i na stanowisku produkcyjnym niemieckiej firmy MSR, stosując stal przetapianą elektrożużlowo EŻP. Stwierdzono, że mikrostruktura stali EŻP jest bardziej jednorodna i bardziej drobnoziarnista niż stali VAD, zarówno po ulepszaniu cieplnym jak i po zgniataniu obrotowym na zimno. Niskowęglowa stal Cr-Mn-Mo-V po hartowaniu z temperatury 970°C i odpuszczaniu w temperaturze ok. 660°C ma wydłużenie A5 od 12,0 do 12,9% przy Rm od 1114 do 1154 MPa i spełnia założone kryteria: przy Rm = 1080 + 1280 MPa A5≥ > 10. Po odkształceniu na zimno wytrzymałość tej stali wzrasta do ok. 1500 MPa.

EN

Microstructure low-carbon Cr-Mn-Mo-V electro-slag remelted (ESR) steel was more homogenous and more fine-grained than vacuum argon decarburization (VAD) steel. The same was found after quenching and tempering and after cold rotary extrusion. Also, ESR steel has more lower banding structure introduced by segregation of chemical composition (major C and Mn). After cold rotary extrusion on the experimental stand of FPS and industry stand of MSR, both VAD and ESR steels had a fine-structure, witch was composed of thin lath tempered martensite. In the structure deformation bands appeared arranged in space in different directions and carbides of chromium and molybdenum type M6C (this carbides often were found in the VAD steel) and carbides vanadium type MC. The fine laths of martensite received in the ESR steel were deformed on the industry stand MSR. The low-carbon Cr-Mn-Mo-V steel after quenching from 970°C and tempering at about 660°C has elongation A5 = from 12.6 to 12.9% and strength Rm = from 1114 to 1154 MPa and fulfils criteria of standards: Rm - from 1080 to 1280 MPa, A5 ≥ 10. After cold rotary extrusion strength incrased to about 1500 MPa.

9

Weryfikacja doświadczalna wybranych właściwości odkształcanych metalicznych materiałów porowatych

Galanty M.

Rudy i Metale Nieżelazne

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2002

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R. 47, nr 5

242-246

PL

Przedstawiono uwagi na temat właściwości materiałów porowatych otrzymywanych na bazie proszków metali podczas ich odkształcania na zimno. Omówiono możliwości oceny stopnia zagęszczenia i porowatości na przykładzie rozpylanego proszku aluminium RALI. Pod uwagę wzięto różne fazy procesu od momentu zasypywania do matryc, poprzez wstępne prasowanie i dalej wyciskanie na zimno bez stosowania środków poślizgowych.

EN

The author calls the reader's attention to the properties of porous materials obtained on the base of metal powders, during their cold deformation. The possibility of evaluation of the consolidation degree and porosity are described on example of sprayed aluminium powder RAL1. Several phases of the process are taken into consideration, from the moment of filling the matrix, through pre-pressing and further cold extrusion, without application of lubricants.

10

Tekstura i struktura stali ferrytyczno-austenitycznej typu duplex po odkształceniu plastycznym na zimno.

Ryś J., Ratuszek W., Woźniak J., Chruściel K.

Inżynieria Materiałowa

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1999

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R. XX, nr 6

601-609

PL

Badania dotyczyły rozwoju tekstury i struktury w dwufazowej stali ferrytyczno-austenitycznej 00H18N6Mo3 poddanej walcowaniu na zimno w zakresie od 85% odkształcenia. Obserwacje zmian struktury ze wzrostem odkształcenia przeprowadzono opierając się na badaniach metalograficznych. Badania rentgenowskie obejmowały analizę fazową oraz pomiar trzech figur biegunowych dla każdej z faz, na podstawie których obliczano funkcje rozkładu orientacji (FRO). Rozwój tekstury analizowano w warstwach powierzchniowej i środkowej walcowanych blach niezależnie dla każdej z faz. W przybliżeniu jednakowe zmniejszanie się szerokości pasm ferrytu i austenitu (tzw. struktura "pancake") wskazuje, że obie fazy ulegają odkształceniu plastycznemu w trakcie walcowania stali duplex. Pasma odkształcenia widoczne w obszarach ferrytu począwszy od 40% odkształcenia oraz charakterystyczne pofalowanie pasmowej struktury ferrytu i austenitu przy wyższych stopniach deformacji (powyżej 75%) wskazują na niejednorodny charakter odkształcenia.

EN

The investigations concerned the texture and structure development in duplex type austenitic-ferritic steel 00H18N6Mo3 cold-rolled within the range up to 85% of deformation. The X-ray investigations carried out in the course of deformation included the phase analysis and the measurements of pole figures. The orientation distribution functions (ODFs) were calculated from three experimental pole figures in the case of each phase. The texture development of ferrite and austenite was analysed within the surface and centre layers of rolled sheets and the structure changes were studied by means of optical metallography. Approximate reductions in width of ferrite and austenite bands forming so-called pancake structure indicate that both phases were plastically deformed during rolling of duplex steel. Deformation bands within the ferrite areas observed starting from 40% of strain and corrugated shape of ferrite-austenite pancake structure at higher degrees of deformation (above 75%) reflect the nonhomogeneous character of deformation.