Towards the problem of dispersity and morphology of particles in welding aerosols

Abstract

The hard component of welding aerosol is one of the main hazards, which are encountered by those working with welding and related technologies. The investigations on this subject have been carried out for more than half a century. The size and dispersity of the particles are of particular interest among the properties and peculiarities of structure of hard component of welding aerosol, as these parameters define the ways of penetrating into a living organism. The present study examines dispersity of particles of hard component of welding aerosol by means of several types of equipment, involving different analysis principles. It was shown that the technique of preparation of a sample for analysis and peculiarities of equipment greatly influence the results. The morphology of particles was also examined. 20 Ref., 5 Figures. K e y w o r d s : welding aerosol, hard component, dispersity, morphology, nanoparticle, agglomerate, laser granulometry, diffusion spectrometerFor more than half a century, welding aerosol has been one of the main objects of investigation of negative factors affecting human organism in the process of welding. Nowadays these investigations are of extreme importance in view of new data in medicine and toxicology.Welding aerosol is a by-product of welding process and consists of hard and gassy components, predetermined by its formation processes. Under high-temperature heating during welding, the components of coating undergo thermal destruction, and some part of base and electrode materials evaporates. As a result of blowing out of the formed gas-vapor mixture into relatively low-temperature environment, condensation of vapor phase occurs and the small hard particles are formed [1]. The primary object of investigation is the hard component of welding aerosol (HCWA), as it contains main hazardous constituents.The HCWA influence on a living organism (toxicity) is a complex characteristic and depends on many factors, namely size and morphology of single particles or their agglomerates, total quantitative distribution by sizes (dispersity), chemical composition, content of highlytoxic compounds, solubility. Each of these factors should be analyzed separately and in combination with others.

Methodological aspects of assessing the emission of nanosized fractions of the welding aerosol solid component forming during welding with coated electrodes

“…До останніх можна віднести дисперсність частинок твердої 1(54) '2018 ОРИГІНАЛЬНІ СТАТТІ складової зварювальних аерозолів (ТСЗА), їхні структурні параметри, розчинність окремих сполук. Концентрація пилу ЗА у повітрі робочих приміщень більшості збірнозварювальних виробництв не від повідає гігієнічним регламентам, при цьому провідна фракція ЗА представлена наночастинками [3,4]. Як відомо, в останні роки накопичено достатньо експе риментальних даних, які свідчать на користь того, що речовинам в нанодіапазоні властива більш вели ка біологічна активність і пошкоджувальна дія [5].…”

“…В основному вони згрупо вані в агломерати, що налічують від кількох до тисяч частинок, які, згідно з даними рентгеноспект рального мікроаналізу, складаються переважно зі сполук лужних металів, силікатів і оксидів заліза. При цьому інтегральний хімічний склад нанороз мірних частинок ТСЗА суттєво залежить від виду електродного покриття [3].…”

Identifying patterns of aerosols formation during contact butt fusion welding

“…However, in the case of CBFW, the intensity of WA release is almost 100 times higher than, for example, in the case of mechanized welding under a flux. At the same time, it should be taken into account that WA can be represented by solid particles smaller than 100 nm in the form of agglomerates with a volume of several to thousands of particles [2]. Therefore, there is the task of determining the quantitative and dispersed composition of WA for the development of effective filter ventilation equipment and other measures to protect welders specifically for the processes of CBFW.…”