Epoxidized Vegetable Oil as a Sustainable Ingredient in Welding Electrode Coatings

Abstract

Welding with coated (covered) electrodes is a manual process in which an electric arc is generated between the electrode and work piece to melt the metals at the welding point whereby they are joined. Among the several ingredients that constitute the electrode coating, there is the binder, which is usually sodium or potassium silicate. Recently, studies were conducted where the usual binders were successfully replaced by hydrophobic polymers in solution, making the electrode waterproof, therefore of very low diffusible hydrogen content, and eliminating the need for a drying step during the preparation of the electrode. In the present work, the use of epoxidized vegetable oils as binders was evaluated in order to minimize negative environmental impacts since the binders are produced from a renewable source. The epoxidized vegetable oils were prepared from a variety of vegetable oils using acetic acid and hydrogen peroxide as reagents and an acidic ion exchange resin as catalyst. The prepared resins were dully characterized and used as a binder in the formulation for coating of basic-type electrodes. The produced electrodes were evaluated for the quality of the weld.