Carbon steel carabiners improvements for use in potentially explosive atmospheres

Abstract

In cases where an explosive atmosphere contains several types of inflammable and/or combustible gases, steams or powders, the protection measures must be appropriate to the highest possible danger. However, the employer must pay special attention to the workplace and to any factor that can influence the working conditions, especially to those related to the workers. Therefore, any device, tool or equipment used by the human operator must possess special properties. In addition to protective clothing, workers who work at heights must receive personal protective equipment against falling that includes multiple linking elements known as carabiners. The carabiners used in this equipment must be made of non-sparking material. The aim of this paper is to propose a spark characteristic improvement of carbon steel used in carabiners manufacturing by deposition of zinc phosphate coating.

Evaluation of the Corrosion Resistance of Phosphate Coatings Deposited on the Surface of the Carbon Steel Used for Carabiners Manufacturing

“…Although the phosphate coating by the immersion process takes longer, compared to the sputtering process, due to the uniform coverage of the material surface and taking into account the size, shape, and manufacturing process of the carabiner, this method was considered as the most suitable for depositing the phosphate layer [3,18].…”

“…In order to obtain a phosphate layer that will improve the corrosion resistance of carbon steel, as well as, a layer that can be used as a substrate for further coatings, three phosphating solutions were used, the first is a zinc-based solution (I-Zn), the second solution contains zinc and iron (II-Zn/Fe) and the third is a manganese-based solution (III-Mn) [18]. As can be seen in Figure 2, the morphology of the phosphate layer depends on the phosphate bath chemical solution.…”

“…The phosphating stage is followed by water neutralization in order to clean the phosphate salts from the surface of the sample. Finally, the samples are dried (drying) in a stove for 4 h at 120 • C [12,18]. The process parameters (time and temperature) for all the phosphate coatings, used in this study, are as follows: alkaline chemical degreasing for 10 min at 85 ± 1 • C; pickling for 20 min at room temperature (22 ± 2 • C); phosphating for 30 min at 90 ± 1 • C.…”

Phosphate Surface Treatment for Improving the Corrosion Resistance of the C45 Carbon Steel Used in Carabiners Manufacturing

“…The phosphating of the samples was performed by immersing the specimens in the phosphating solution for 30 min at a temperature of 95 ± 2 °C. The last stage of the phosphating process, drying, was performed at a high temperature of 120 °C for 4 h using a drying stove [ 11 ].…”

“…In this study, three phosphating solutions were used for immersion, with the main difference represented by the type of metal ions, as well as their amount dissolved in phosphoric acid (I-Zn-zinc-based solution, II-Zn/Fe-zinc-iron based solution and III-Mn-manganese-based solution). The phosphating of the samples was performed by immersing the specimens in the phosphating solution for 30 min at a temperature of 95 ± 2 • C. The last stage of the phosphating process, drying, was performed at a high temperature of 120 • C for 4 h using a drying stove [11].…”