Airborne particle size is the most important factor in determining the accuracy of a method for chemical analysis.

Chemical analysis of welding fume particles

https://depositonce.tu-berlin.de/bitstream/11303/7765/2/1-s2.0-S221282711400897X-main.pdf

Environmental and Social Life Cycle Assessment of Welding Technologies

Physicochemical properties, such as particle sizes, composition, and solubility of welding fumes are decisive for the bioaccessibility of manganese and thereby for the manganese cytotoxic and neurotoxic effects arising from various welding fumes. Because of the diverse results within the research on welding fume solubility, this article aims to review and discuss recent literature on physicochemical properties of gas metal arc welding, shielded metal arc welding, and flux-cored arc welding fumes, with focus on solubility properties. This article also presents a short introduction to the literature on arc welding techniques, health effects from manganese, and occupational exposure to manganese among welders.

/pdf/manganese-in-occupational-arc-welding-fumes-aspects-on-3mhobh4odb.pdf

Manganese in Occupational Arc Welding Fumes—Aspects on Physiochemical Properties, with Focus on Solubility

An improved fume chamber was constructed, and fume rates were measured with unprecedented precision for both steady- and pulsed-current weld- ing of mild steel using 92% argon/8% CO 2 shielding gas. Comprehensive fume maps were constructed depicting fume rates over a wide range of currents and voltages. Fume generation was generally lower under pulsed-current conditions. Theoretical arguments explaining this difference are presented. Accurate fume-generation data and a comprehensive fume formation model are necessary for more sophisticated fume control strategies. This paper in- cludes precise fume generation data for GMAW of mild steel using one shielding gas under steady- and pulsed-current conditions. A physical model introduced by Gray, Hewitt and Dare (Ref. 4) is em- ployed and amplified to explain our ob- servations. Although fume formation has been studied by many scientists, results are dif- ficult to reconcile from one researcher to another. Limited accuracy of some results is one problem, but interpretation and correlation are complicated because of the multitude of variables involved. Many types of welding exist with and without fluxes using a wide range of pos- sible shielding gases. Numerous different electrode and work materials or combi- nations are possible. Much of the prior work has been directed toward the solu- tion of immediate problems in the work- place. Often, fume generation studies in- volve so many variables results are almost impossible to use for theoretical purposes. Our research was designed to produce precise results for narrow con- ditions. Although limited to GMAW of mild steel with a single shielding gas, our fume typography is typical of profiles one should expect with other electrodes and shielding gases. It is hoped that similar re- sults for such systems will become avail- able in the future. Castner (Ref. 3) has provided what may be the most comprehensive study of a single system using the standard AWS fume chamber. Although a comparison of steady- and pulsed-current fume rates

Fume Formation Rates in Gas Metal Arc Welding A new fume chamber design improves the accuracy of fume generation data

The control of exposure to welding fume is necessary to meet health and safety obligations. The work reported here examines the fundamentals of welding-fume formation. A physical chemistry model of the metal vapour mechanism for fume formation has been developed for non short-circuiting transfer gas metal arc welding (GMAW). The model includes the important contribution made by direct condensation of metal vapour onto the weldpool and workpiece, in removing a substantial fraction of the fume. The model shows that droplet size and wire feed speed control the fine fume formation rate. The understanding developed so far, indicates that the smaller the detached droplet size, the lower the total fume formation rate. The physics behind this is explained. The model gives an insight into how process modification might be used to control fume at source. Control at source is believed to be the most cost-effective and energy-efficient technique for dealing with welding fume. It is anticipated that the understanding gained from this project will be applied to determine the practical limits for the control of welding fume at its source.

https://iopscience.iop.org/article/10.1088/0022-3727/33/11/320/pdf

A semi-empirical model of the fume formation from gas metal arc welding

An improved fume chamber was constructed, and fume rates were measured with unprecedented precision for both steady- and pulsed-current welding of mild steel using 92% argon/8% CO2 shielding gas. Compre- hensive fume maps were constructed de- picting fume rates over a wide range of currents and voltages. Fume generation was generally lower under pulsed-cur- rent conditions. Theoretical arguments explaining this difference are presented.

B. J. Quimby

Papers

Fume formation rates in gas metal arc welding