Study on Non-Metallic Inclusions in Laser-Welded TRIP-Aided Nb-Microalloyed Steel

Grajcar, A.; Różański, Maciej; Kamińska, Małgorzata; Grzegorczyk, B.

doi:10.2478/amm-2014-0203

Cited by 27 publications

(21 citation statements)

References 7 publications

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“…Since the AHSS contain a high alloying content their weldability should also be affected by the presence of non-metallic inclusions. Different sulphide and oxide particles have been identified by M. Amirthalingam et al 11 and A. Grajcar et al 12 in different types of TRIP steels containing Mn, Si and Al additions. It is well known that brittle oxides and ductile manganese sulphides affect the fatigue endurance limit, the fatigue-crack propagation rate, the fracture toughness, the anisotropy of the tensile properties with respect to the rolling direction and the weld quality, too.…”

Section: Introductionmentioning

confidence: 99%

“…It is well known that brittle oxides and ductile manganese sulphides affect the fatigue endurance limit, the fatigue-crack propagation rate, the fracture toughness, the anisotropy of the tensile properties with respect to the rolling direction and the weld quality, too. 13,14 Recently, A. Grajcar et al 12 analysed various types of non-metallic inclusions in laser-welded Fe-1.5Mn-0.9Si-0.4Al TRIP steel. Numerous oxide-type particles have been revealed in the fusion zone formed under air conditions.…”

Section: Introductionmentioning

confidence: 99%

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Effect of gas atmosphere on the non-metallic inclusions in laser-welded trip steel with Al and Si additions

Grajcar¹,

Różański²,

Kamińska³

et al. 2016

Mater. Tehnol.

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The present study aims to characterize the weldability of a multiphase, automotive steel containing Al and Si additions from the point of view of its tendency to form non-metallic inclusions. Laser welding tests of 2-mm-thick sheets were performed using the keyhole-welding mode and a solid-state laser. The tests were carried out in air and with the use of an argon atmosphere. The distribution, type and chemical composition of the non-metallic inclusions formed in the base metal and fusion zones were analysed. The effect of applying the protective gas on the type and amount of non-metallic inclusions was determined using light and scanning electron microscopy. The chemical composition of the identified particles was assessed using the EDS method. It was found that a protective gas has a beneficial effect on reducing the non-metallic inclusions, but only to a limited extent. The boundary between the complex oxides and the pure aluminium oxides was determined to be 2-3 μm. Keywords: TRIP steel, laser welding, non-metallic inclusions, protective gas, Ar atmosphere, oxidation Namen te {tudije je opredeliti varivost s stali{~a tvorbe nekovinskih vklju~kov v ve~faznem jeklu, ki vsebuje Al in Si, za avtomobilsko industrijo. Izvedeni so bili varilni preizkusi z laserjem na 2 mm debelih plo~evinah z V zarezo. Preizkusi so bili izvedeni na zraku in v za{~itni atmosferi argona. Analizirana je bila razporeditev, vrsta in kemijska sestava nekovinskih vklju~kov v osnovnem materialu in v coni zlivanja. Vpliv uporabe za{~itnega plina na vrsto in koli~ino nekovinskih vklju~kov je bil dolo~en s pomo~jo svetlobne in vrsti~ne elektronske mikroskopije. Kemijska sestava najdenih delcev je bila ugotovljena z metodo EDS. Ugotovljeno je bilo, da ima za{~itni plin ugoden vpliv na zmanj{anje nekovinskih vklju~kov le v omejenem obsegu. Meja med kompleksnimi oksidi in~istimi oksidi aluminija je bila dolo~ena kot 2-3 μm.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of gas atmosphere on the non-metallic inclusions in laser-welded trip steel with Al and Si additions

Grajcar¹,

Różański²,

Kamińska³

et al. 2016

Mater. Tehnol.

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“…[6][7][8] The HAZ ductility is significantly improved by Ti 2 O 3 particles, which are more stable than TiN particles and insoluble even at higher temperatures and act as nucleii by the nucleation of fine-lamellar ferrite. [9][10][11] Fine-lamellar ferrite within austenite grains increases the HAZ ductility. The HAZ microstructure of a multi-run welded joint depends on the chemical composition of the steel, heat source intensity and the number of runs.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and properties of the high-temperature (HAZ) of thermo-mechanically treated S700MC high-yield-strength steel

Górka

2016

Mater. Tehnol.

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The aim of the study was to determine the properties and microstructure of the high-temperature heat affected zone (HAZ) of S700MC steel heated to a temperature of 1250°C and cooled at different speeds. The simulation of the thermal cycles was performed using a welding thermal cycles simulator. Samples with a cross-section 10 mm × 10 mm × 55 mm were submitted to metallographic analysis, impact tests, hardness measurements and tensile tests. Welding thermal cycles with cooling times t8/5 = (3, 5, 10, 15, 30, 60 and 120) s and a maximum temperature cycle temperature of Tmax = 1250°C were used. The welding thermal thermomechanical processing cycles differ significantly, especially with high rates of heating and cooling in the SWC, short time holding at the maximum temperature and frequent overlap of two or more cycles during the multi-layer welding. One of the elements in the evaluation of steel weldability is the analysis of the austenite phase transformation during cooling. Steel hardness tests on simulated HAZ regions cooling times increasing from 3 s to 120 s, showed reductions by approximately 40 HV, while, regardless of the length of the cooling time t8/5, the impact resistance was very low, at the level of a few J/cm 2 . The tensile strength, hardness and toughness indicates a secondary role of austenite in the control of welded joints transformation strength and plastic properties, the analysis of the g-a phase transition not shown to be a reliable basis for assessment of the weldability of this steel group. Keywords: TMCP steel, welding thermal cycles, HAZ, high yield strength, impact resistance Namen {tudije je bil dolo~iti lastnosti in mikrostrukturo visokotemperaturne toplotno vplivanega obmo~ja zvara (HAZ) v jeklu S700MC, segretem na temperaturo 1250°C in ohlajenem pri razli~nih hitrostih. Simulacija procesa toplotnih ciklov je bila izvedena z uporabo simulatorja toplotnih ciklov pri varjenju. Vzorci s presekom 10 mm × 10 mm × 55 mm so bili metalografsko pregledani, izveden je bil udarni preizkus, izmerjena je bila trdota in izvedeni so bili natezni preizkusi. Uporabljeni so bili toplotni cikli pri varjenju s~asi ohlajanja t8/5 = (3, 5, 10, 15, 30, 60 in 120) s in maksimalna temperatura toplotnega cikla je bila Tmax = 1250°C. Pri varjenju se cikli varilno termi~nega in termomehanskega procesiranja precej razlikujejo, predvsem pri veliki hitrosti ogrevanja in ohlajanja v SWC, kratkotrajnem zadr`anju na maksimalni temperaturi in pogostem prekrivanju enega ali ve~ciklov pri ve~plastnih zvarih. Eden od elementov pri ocenjevanju varivosti jekla, je analiza premene avstenita med ohlajanjem. Pri preizkusih trdote simuliranih HAZ podro~ij, se le ta, s pove~anjem~asa ohlajanja od 3 s na 120 s, zmanj{a za okrog 40 HV, medtem ko je`ilavost zelo nizka in na nivoju nekaj J/cm 2 ne glede na~as ohlajanja t8/5. Natezna trdnost, trdota iǹ ilavost ka`ejo drugotno vlogo pri kontroli trdnosti in plasti~nosti transformiranega avstenita zvarjenih spojev. Analiza faznega prehoda g-a ni zanesljiva osnova za ugotavljanje varlj...

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“…The newest high-manganese steels, such as TRIP, TWIP, or MBIP, are different than conventional steels by their contents of alloying elements deciding about the microstructure stability and strength properties. In particular, this refers to carbon, which affects hardening of solid solution and is an effective austenite stabiliser; aluminium limiting the deformation-induced γ → ε → α transformation, stabilising austenite and forming fine precipitations with high dispersion, effectively reducing the size of the austenite grains [4][5][6][7][8][9][10]. Additionally, Al increases the value of stacking fault energy (SFE) and corrosion resistance by formation of passive layers; it also decreases the density of steel.…”

Section: Introductionmentioning

confidence: 99%

The Effect Of Strain Rate On The Mechanical Properties And Microstructure Of The High-Mn Steel After Dynamic Deformation Tests

Jabłońska¹,

Śmiglewicz²,

Niewielski³

2015

Archives of Metallurgy and Materials

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The paper presents results of dynamic tensile investigations of high-manganese Fe -20 wt.% Mn -3 wt.% Al -3 wt.% Si -0.2 wt.% steel. The research was carried out on a flywheel machine, which enables to perform dynamic tensile tests and impact bending with a linear velocity of the enforcing element in the range of 5÷40 m/s. It was found that the studied steel was characterized by very good mechanical properties. Strength of the tested materials was determined in the static tensile test and dynamic deformation test, while its hardness was measured with the Vickers hardness test method. The surface of fractures that were created in the areas where the sample was torn were analyzed. These fractures indicate the presence of transcrystalline ductile fractures. Fractographic tests were performed with the use of a scanning electron microscope. The structure was analyzed by light optical microscopy. Substructure studies revealed occurrence of mechanical twinning induced by high strain rates. A detailed analysis of the structure was performed with the use of a transmission scanning electron microscope STEM.Keywords: high-manganese steel, dynamic deformation test, strain rate, impact strength, mechanical twinning, structure W pracy przedstawiono wyniki wstępnych badań dynamicznego rozciągania wysokomanganowej stali gatunku X20MnAlSi16-3-3. Badania przeprowadzono na młocie rotacyjnym, który posiada możliwość realizacji prób dynamicznego rozciągania i udarowego zginania w zakresie prędkości liniowej elementu wymuszającego od 5÷40 m/s. Badana stal charakteryzuje się bardzo dobrymi właściwościami mechanicznymi. Wyniki badań uzyskano na podstawie statycznej próby rozciągania, próby dynamicznego rozciągania na młocie rotacyjnym oraz pomiaru twardości metodą Vickersa. Przeanalizowano powierzchnie przełomów powstałych w miejscu zerwania podczas prób rozciągania, które wskazują na obecność przełomów transkrystalicznych ciągliwych. Badania strukturalne wykonano z wykorzystaniem techniki mikroskopii świetlnej, skaningowej mikroskopii elektronowej i skaningowej transmisyjnej mikroskopii elektronowej. Przeprowadzone badania substruktury ujawniły obecność mechanizmu bliźniakowania mechanicznego, indukowanego w warunkach dużych prędkości odkształcenia.

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Study on Non-Metallic Inclusions in Laser-Welded TRIP-Aided Nb-Microalloyed Steel

Cited by 27 publications

References 7 publications

Effect of gas atmosphere on the non-metallic inclusions in laser-welded trip steel with Al and Si additions

Effect of gas atmosphere on the non-metallic inclusions in laser-welded trip steel with Al and Si additions

Microstructure and properties of the high-temperature (HAZ) of thermo-mechanically treated S700MC high-yield-strength steel

The Effect Of Strain Rate On The Mechanical Properties And Microstructure Of The High-Mn Steel After Dynamic Deformation Tests

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