QUANTITATIVE PHASE ANALYSIS OF ARMOUR STEEL WELDED JOINT BY X-RAY DIFFRACTION
| Autor: | Cvetinov, Miroslav, Čabrilo, Aleksandar, Gerić, Katarina, Stojanović, Maja, Klisurić, Olivera |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Issue: 1 36-40 The Eurasia Proceedings of Science Technology Engineering and Mathematics |
| ISSN: | 2602-3199 |
| Popis: | Ultra-high tensile strength ischaracteristic of armour steel and in order to preserve this strength itswelding process is of paramount importance. Austenitic filler material istraditionally used for welding of armour steel, yet it has lower mechanicalproperties than the base material, i.e. the filler material is the weakestpoint of the welded joint. Moreover, due to the plastic deformation at thecrack tip austenitic filler material gets transformed into martensite duringfatigue crack propagation. An amount of austenite transformed into martensiteis directly related to crack growth resistance in the weld metal.In order to quantify martensitephase formed during the crack propagation under the effect of fatigue load, weemployed method of X-ray diffraction. Diffractograms were recorded inBrag–Brentano θ:2θ reflection geometry on a Philips PW 1820/30 X-ray diffractometeremploying monochromatic CuKαradiation (30 kV, 30 mA) in the range 40°-60° 2θ. For the quantitative phase analysis RIR method was subsequentlyemployed.From the obtained data,martensite to austenite ratio was calculated for the fracture surface.Thereafter the 0.05 mm thick layer was removed from specimen surface and thediffraction patern was recorded again. This procedure was repeated till 25% ofthe martensite remained in two-phase mixture. α´ martensite was detected atdistances up to 0.25 mm under the fracture surface. The greatest transformationof austenite into α´ martensite was 55%, seen on the fracture surface. Theamount of α´ martensite declines with a distance by an average of ≈5%/0.05 mm,in the depth perception tests. At the distance of 0.25 mm, the amount oftransformed austenite fell to 24%. |
| Databáze: | OpenAIRE |
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