Application of Copper as Stabiliser in Aluminium Assisted Transfer of Titanium in Submerged Arc Welding of Carbon Steel

The element transfer of Ti from molten flux to the weld metal is limited to less than 310 ppm Ti in the submerged arc welding of carbon steel. This limitation is due to the high oxygen partial pressure prevailing at the molten flux-weld pool interface. Our previous study illustrated that the use of Al powder in combination with Ti powder improves the transfer of Ti to the weld metal to 4% Ti, whilst maintaining 509 ppm O in the weld metal. The weld metal ppm O should be controlled at 200 to 500 ppm O to maintain weld metal toughness. In this study, the addition of Cu powder with Ti and Al powder is applied to illustrate the stabiliser effect of Cu in the weld pool. The role of Cu as weld pool stabiliser is due to its decrease of the temperature required to melt Ti into the weld pool, so increasing the quantity of metal powder melted into the weld pool. The weld metal composition improved to 5.1% Ti, 3.6% Cu, and 371 ppm O. Thus, the role of Al in controlling the partial oxygen pressure at the molten flux-weld pool interface is maintained in the presence of Cu powder.

Reactions at the molten flux-weld pool interface in submerged arc welding

In submerged arc welding (SAW) of chromium (Cr) containing steels, Cr is usually added to the weld metal from the weld wire, and not from the welding flux. Manufacturing of weld wires of specific compositions is expensive and time consuming and cannot closely match all the desired alloy compositions. Therefore, the weld wire chemistry is usually over matched to the base plate composition. Better matching between the weld metal and base plate is possible if the weld metal incorporates Cr from Cr containing metal powder, instead of sourcing Cr from weld wire of limited Cr content. Because Cr is easily oxidised, the oxygen partial pressure in SAW must be controlled. This work illustrates the control of the oxygen potential at the molten flux-weld pool interface by using aluminium (Al) powder addition. The controlled oxygen potential at the molten flux-weld pool interface ensures increased Cr powder transfer into the weld pool, without interfering with oxygen transfer from the plasma arc to the weld pool. The objective of this work is to use targeted powder additions to better control Cr reactions in SAW to improve Cr metal transfer to the weld metal and maintain an acceptable level of oxygen in the weld metal.

Trends in Rare Earth Thiophosphate Syntheses: Rb3Ln(PS4)2 (Ln = La, Pr, Ce), Rb3-xNaxLn(PS4)2 (Ln = Pr, Ce; x = 0.50, 0.55), and RbEuPS4 Obtained by Molten Flux Crystal Growth

Single crystals of new rubidium rare earth thiophosphates with the formulas Rb3Ln(PS4)2 (Ln = La, Pr, Ce), Rb3-xNaxLn(PS4)2 (Ln = Pr, Ce; x = 0.50, 0.55), and RbEuPS4 were crystallized...

A Series of Rb4Ln2(P2S6)(PS4)2 (Ln = La, Ce, Pr, Nd, Sm, Gd) Rare Earth Thiophosphates with Two Distinct Thiophosphate Units [PVS4]3- and [PIV2S6]4-

A series of rubidium rare earth thiophosphates with the formula Rb4Ln2(P2S6)(PS4)2 (Ln = La, Ce, Pr, Nd, Sm, and Gd) was synthesized using the high temperature molten flux crystal growth...

High-temperature wettability study of mineral waste added CaO–CaF2–SiO2 and CaO–TiO2–SiO2-based electrode coating for offshore welds

This paper investigates the high-temperature wettability property of the mineral waste red ochre added CaO–CaF2–SiO2 and CaO–TiO2–SiO2-based electrode coating mixture for offshore welding. The extreme vertices design method was applied to formulate 21 coating compositions. The pellets made from developed electrode coating compositions were exposed to a high temperature of 1250℃ on the substrate of super duplex stainless steel of 2507 grade. The molten flux has been characterized for contact angle, surface tension, adhesion energy and spreadability. The regression analysis has been used to estimate the effect of individual components and their interactions on the wettability property parameters. The developed regression models have been optimized using multiresponse optimization to achieve optimum flux composition. Structural analysis of flux mixture has been done using X-ray diffraction and Fourier transformation spectroscopy.