Papers by Keyword: Cored Wires

Abstract: The use of cored wire - shielding gas (gas mixture) pair, during mechanized Metal Active Gas - MAG welding, leads to the formation of gas emissions (CO₂, CO, NO_x, NO, O₃ etc) which is harmful for the welder’s health. The paper addresses the experimental method applied to establish the gas emissions developed during MAG welding when rutile cored wires (standard and low fume emissions) and metal powder cored wires (standard and low fume emissions) are used. Carbon dioxide and the shielding gas mixture are investigated, too. Four types of cored wires were comparatively analysed, when three wire speed values were applied. The experimental results have revealed that using rutilic cored wires and increasing the speed feed, an augmentation of CO (ppm), constant values of O₂ (%), insignificant constant values of NO (ppm) and NO_x (ppm) and absence of CO₂ (%) are achieved. Using metal cored wires and increasing the speed feed, increase of CO (ppm), insignificant values of NO (ppm) and NO_x (ppm), and constant values of CO₂ (%) and O₂ (%) are noticed.

Abstract: Use of cored wire - shielding gas (gas mixture) pair, during mechanized MAG welding, causes the microparticles formation which is harmful for the welder’s health. The paper presents the experimental method for determining the concentration of the microparticles generated during MAG welding when rutile cored wires (standard and low fume emission) and metal powder cored wires (standard and low fume emission) are used. Carbon dioxide and the shielding gas mixture are investigated, too. Four types of cored wires were comparatively analysed, when three wire speed values were applied. The research of the microparticles concentration was conducted after each welding bead deposition, at the upper part of the welding enclosure, using MicroDust Pro particulate monitor. After each weld bead was deposited, the metal frame of the welding enclosure was removed, and, the fumes and gases, produced during the welding process, were eliminated through two fans, positioned inside and outside of the equipment. Using rutile cored wire with low fume emission, a decrease of microparticles concentration up to 30% is noticed in comparison with standard rutile cored wire. Using metal powders cored wire with low fume emission, the microparticles concentration is diminished with 12.5% comparing with standard metal powders cored wire.

Abstract: In this article, the working conditions and the failure mechanism of the four tubes in Boiler have been studied. On the base of these researches, a new kind of Fe-based/Cr3C2/B-Fe cored wire was designed. And arc spraying technology was used to produce coatings which had high performance and price ratio. The results of test show that the cored wire was easy sprayed with arc spray equipment. The coatings have dense microstructure, good bond with substrate, and excellent wear-resistance and corrosion-resistance at high temperature.This coating can prolong the using life of heated tubes of circulating fluidized bed boiler effectively and is worthy to be widely used in industry.

Abstract: A Fe-Al/WC composite coating was fabricated by using high velocity arc spraying (HVAS) and cored wire. The elevated temperature erosion behaviors of the coating were investigated with a grit blasting type erosion tester. The coating microstructure and eroded surface morphologies were analyzed by energy dispersion spectroscope (EDS), X-ray diffraction (XRD), scanning electron microscope (SEM) , transmission electron microscope (TEM) and image analyzer. The effects of incidence angle and test temperature on the erosion behavior were determined.

Abstract: Cored wires and high velocity arc spraying (HVAS) technologies have been applied to produce Zn-Al-Mg-RE coating on A3 steels. The durability of coating in terms of corrosion resistance is the focus of this paper. The detailed degradation mechanism has been investigated using electrochemical-monitoring techniques supported by precise pre-test and post-test microscopical examination using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Zn-Al-Mg-RE coating shows a typical aspect of layered heterogeneous structure, the existing of ZnAl2O4 and MgAl2O4 implies the good anti-corrosion feature. The polarization curves showed that Zn-Al-Mg-RE coating exhibits passive behavior at 0.5h and 16h immersion, but at 600h, it begins to dissolute. In contrast, the anti-corrosion performance isn’t cut down. The corrosion potential moves to the noble direction step by step, along with the current density drops gradually. After corrosion, it has been observed that the coating surface is jointed by flaky lamellar products and dense without obvious defects and pores. It is postulated that with the addition of RE, the porosity of the coating is reduced, meanwhile, the stability of the products layer can reinforce the self-sealing effect of the coating distinctively.