Papers by Keyword: Deposited Metal (DM)

Abstract: The fatigue crack growth of longitudinal SAW welds of a API 5L X42 steel pipe was evaluated using curved three point bend test specimens, where the radius of curvature of the specimens was equal to the pipe radius, so that no extensive machining or flattening was required. The fatigue crack growth tests were done in a servohydraulic closed loop machine under load control, in air at room temperature. The da/dN vs ∆K plots and Paris’s equation constants were obtained for the base metal, deposited metal and heat affected zone in the CR orientation, which corresponds to the short transverse direction of the pipe. The greater resistance to fatigue crack growth was the base metal, whereas the deposited metal showed the least resistance to the fatigue crack propagation. The deposited metal and the heat affected zone behaved according to Paris’s law, unlike the base metal, that showed a high dispersion of the fatigue crack growth rates. This behavior was due to the propagation of the crack in the direction transverse to the banded microstructure. Furthermore, the differences in fatigue crack growth rates among each zone were also related to the roughness of the fracture surfaces and fracture toughness.

Abstract: Consistent patterns for transfer of chromium and carbon from the electrode coating into the fused metal, impact of their amounts on transfer of other alloying elements into the alloy are considered. Respective compositions of electrode coatings are made so, that Cr content in coated layers would change from 2 % up to 40 % (content of C ~ 3 %). At research of transfer of carbon patterns, the compositions of electrode coatings are made so, that C content in coated layers would change from 0.1 % up to 4 % (content of chromium in this case is approximately 20 %). In both cases the content of other alloying elements remain in a settled level (Si ~ 2 %, Mn ~ 1.1 %, Ti ~ 0.5 %, B ~ 0.6 %).

Abstract: The wire for high strength and toughness TMCP steels of submerged arc welding was developed. The low carbon and micro-alloying with Ti-B system was adopted to obtain the acicular ferrite dominated deposited metals. Experimental results show that the carbon equivalent (Pcm) should be higher than 0.17, which can ensure the high strength and high toughness of the deposited metals. In the alloy system, Oxygen and Nitrogen contents, micro-alloyed elements (C, Mn) and its mixture ratio are the key factors that affect the deposited metals toughness. With increasing C, Mn content, the acicular ferrite is increased and toughness is improved. Oxygen and Nitrogen are deleterious to the toughness of deposited metals.