Badania wstępne bezszwowych drutów proszkowych przechowywanych w ekstremalnych warunkach

In this paper, we describe the preliminary experimental studies of flux-cored wires moisturized under controlled conditions. Three seamless wires of different grades have been placed in an environmental chamber and moisturized in extremely adverse conditions (temperature T = 60°C, relative humidity H = 90%) for 240 hours. During this time, measurements of weight gain as well as surface observations of the wires have been carried out. Also, the amount of diffusible hydrogen in deposited metal was determined by the mercury method for one of the moisturized wires. A significant increase in the level of hydrogen was observed (from H5 to H10). Further research will aim to determine the effect of storage conditions on the hydrogenation of deposited metal and quality of flux-cored wires.Praca dotyczy badań drutów proszkowych nawilżanych w kontrolowanych warunkach. Trzy gatunki drutów bezszwowych umieszczono w komorze klimatycznej i nawilżano w niekorzystnych warunkach (temperatura T = 60°C, wilgotność względna H = 90%) przez 240 h. Badania polegały na pomiarze nasiąkliwości i ocenie stanu powierzchni badanych drutów. Ponadto dla jednego z nawilżanych drutów oznaczono metodą rtęciową zawartość wodoru dyfundującego w stopiwie. Stwierdzono znaczny wzrost poziomu wodoru (z H5 do H10). Dalsze badania powinny zmierzać do ilościowego ustalenia wpływu warunków przechowywania na nawodorowanie stopiwa i jakość badanych drutów

Weldability of high strength steels in wet welding conditions

In this paper are characterized problems of high strength steel weldability in underwater wet welding conditions. Water as a welding environment intensifies action of unfavourable factors which influence susceptibility to cold cracking of welded steel joints. The susceptibility to cold cracking of S355J2G3 steel and S500M steel in wet conditions was experimentally estimated (by using Tekken test). It was concluded that the steels in question are characterized by a high susceptibility to formation of cracks in welds. Usefulness of the proposed Temper Bead Welding technique (TBW) was experimentally verified as a method for improving weldability of the steels in the analyzed conditions

Zawartość wodoru dyfundującego w stopiwie wielościegowych złączy spawanych

This article describes the manufacturing technology of multilayer joints in terms of controlling the diffusible hydrogen content. The diffusible hydrogen content in deposited metal for multilayer welded joints made of covered rutile electrodes or covered cellulosic and basic electrodes was determined. It was found that, after four beads, the diffusible hydrogen content decreases from 36 m l/100 g to 18 ml/100 g in the ca se of the first technology, and about 40 ml/100 g to a level of 12 ml/100 g in the second. The explanation of the mechanisms responsible for this phenomenon and direction s for further study have been proposed.W artykule scharakteryzowano technologię wytwarzania złączy wielościegowych w aspekcie kontroli ilości wodoru dyfundującego. Oznaczono zawartość wodoru dyfundującego w stopiwie dla wielościegowych złączy spawanych wykonanych dwoma technologiami: za pomocą elektrod o otulinie rutylowej oraz celulozowej i zasadowej. Ustalono, że po wykonaniu czte- rech ściegów ilość wodoru dyfundującego spada w przypadku pierwszej technologii z poziomu36 ml/100 g do 18 ml/100 g, natomiast w drugim z około 40 ml/100 g do poziomu 12 ml/100 g. Wyjaśniono mechanizmy odpowiedzialne za to zjawisko i zasugerowano kierunki kontynuacji badań

Oznaczanie ilości wodoru dyfundującego w stopiwie elektrod rutylowych metodą glicerynową

The presence of diffusible hydrogen in welded joints is one of the causes of formation the welding imperfections. Improvement of weldability can be achieved by reducing the hydrogen amount in welded joints. This requires, among others, the finding of sources of hydrogen. For high hydrogen processes the commonly used method of determining the diffusible hydrogen amount is the glycerin method. This paper concerns issues related to the test procedure and the possibility to control the diffusible hydrogen amount in deposited metal.Obecność wodoru dyfundującego w złączach spawanych jest jedną z przyczyn powstawania niezgodności spawalniczych. Poprawę spawalności stali można osiągnąć przez zmniejszenie nawodorowania złączy. Wymaga to m.in. wyznaczenia źródeł wodoru. W procesach wysokowodorowych często stosowaną metodą oznaczania ilości wodoru dyfundującego jest metoda glicerynowa. Praca dotyczy zagadnień związanych z procedurą badawczą i możliwością sterowania ilością wodoru dyfundującego w stopiwie

Study on Microstructure-Property Relationship of Inconel 617 Alloy/304L SS Steel Dissimilar Welds Joint

Welding of Inconel 617 (IN617) alloy and austenitic 304L SS steel has been attempted using the autogenous Laser Beam Welding (LBW) process. Characterization of dissimilar weldments was performed on either side of the fusion boundaries. The metallographic results showed that the inhomogeneous microstructure formation for weld metal contained columnar and cellular dendrites near the interface, whilst the columnar, cellular, and equiaxed types of dendrites were in the weld center. The energy dispersive spectroscopy (EDS) and electron probe microanalysis (EPMA) studies revealed the white layer near the interface on both sides of the fusion line, as well as a significant change in the concentration of alloying elements (Fe, Cr, Ni, Co, and Mo). The weld metal accompanied by Cr, Ti, and Mo precipitates evolved in the inter-dendritic spaces. The Cr and Mo-rich M23C6 and Mo-rich M6C phases in IN617 heat-affected zone (HAZ) were found in SEM/EDS and EPMA studies. The 304L SS side showed a distinct HAZ, whilst, on the IN617 side, no distinct HAZ was seen. Samples were prepared from the dissimilar weldments to evaluate their mechanical properties, such as tensile strength and hardness. The microhardness plot showed the non-uniformity in hardness along the weldments. The weld metal hardness was 253 ± 10 HV. The tensile test of the welded joint results was compared with the base metals. The tested results exhibited that the failure of the specimen from 304L SS base metal (BM) or from weld metal with tensile strength was marginally lower than the Inconel 617 base metal but significantly higher than the 304L SS BM. The fracture surface study revealed the presence of Mo and Cr segregation in inter-dendritic spaces, which impoverished the tensile properties. The order of impact toughness was measured as follows: 304L SS BM > 304L SS HAZ > IN617 BM > weld metal > IN617 HAZ. The IN617 HAZ was recognized as the weakest area of the weldments in terms of impact strength. The welded joint was considered safe for AUSC application because the stress-rupture properties were evaluated in between base metals data