Fumes from Shielded Metal Arc Welding Electrodes PDF Download

Author: J. F. McIlwain
Publisher:
ISBN:
Category : Mineral industries
Languages : en
Pages : 28

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Author: J. F. McIlwain
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

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Author: William Astleford
Publisher:
ISBN:
Category : Fume control
Languages : en
Pages : 132

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Author: William James Astleford
Publisher:
ISBN:
Category : Fume control
Languages : en
Pages : 132

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Author: National Institute for Occupational Safety and Health
Publisher:
ISBN:
Category :
Languages : en
Pages : 136

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Author: J. F. McIlwain
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 24

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Author: Charles Chadim
Publisher:
ISBN:
Category : Welding
Languages : en
Pages : 158

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Book Description
Electric arc welding is the most prevalent welding type in industry. It creates two main groups of health hazards for workers; fumes and gases, and radiant energy. Shielded Metal Arc (SMA) welding is the most widely used welding method in industrial plant welding shops. The main chemical health hazards associated with this type of welding are fumes. Fumes are particles formed when the electrode and base metal constituents are vaporized and condensed in the welding area. Potential health problems can be anticipated by measuring the concentration of fumes in the welding space and comparing these data to established exposure standards. If high concentrations of these fumes are present, control measures should be undertaken to reduce the potential toxic effect to workers. Most of the studies have been done on mild (carbon) steel welding where it is generally necessary to monitor only the total amount of fumes. Stainless steel welding differs from carbon steel welding in that it generates considerable fume concentrations of chromium and nickel, which are suspected human carcinogens. The first part of this study evaluated the health risks posed to workers exposed to chromium and nickel fumes from routine stainless steel welding procedures. All the welding was performed in an industrial plant welding shop by one experienced welder. The welded piece was a three-part stainless steel cylinder. The whole period of welding lasted almost three weeks, although the actual welding was done in eleven days during that period. All sampling was performed with filter cassettes connected to personal air pumps. Sampling was performed in welder's breathing zone, in the general area (background sample), and at conveniently located points outside the breathing zone for evaluation of ratios of chromium and nickel to total fumes. The results indicated that at this particular industrial plant, exposure levels did not exceed the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs) and the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs). The results also indicated that it was not necessary to monitor the general area because of very low concentrations of chromium and nickel fumes. Rather, it is suggested that the monitoring focuses on the welder's breathing zone where it is important to sample hexavalent chromium (chromates) because of its proven carcinogenic effect and therefore very low TLV. Also, it was found that if TLV for chromates is not exceeded, then levels of total chromium and nickel are also likely to be below limits. The second part of the study sought to devise a simplified method of monitoring of welding operations. The results suggested that it is not always necessary to sample for all the components (total fumes, total chromium, chromates, and nickel) when estimating worker's exposure. Rather, it is possible to simplify the process by establishing the ratios of fume constituents during a period of heavy welding, thus enabling the industrial hygienist to make a reasonable estimate of exposure that occurs at other times. The estimate can be made by sampling either the main constituent (chromates) or total fumes, and predicting the exposure to remaining constituents of interest from these data. In addition, and in contrast to previous studies, it has been concluded that when fume concentrations are low, a welder's helmet does not provide any additional protection against fumes. Additional protection can be provided with the use of proper local ventilation, such as with a flexible hose, to reduce exposure well below suggested limits.

Author: National Institute for Occupational Safety and Health. Division of Standards Development and Technology Transfer
Publisher:
ISBN:
Category : Brazing
Languages : en
Pages : 258

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Author: Paul Kah
Publisher: Elsevier
ISBN: 0128239069
Category : Technology & Engineering
Languages : en
Pages : 430

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Book Description
Advancements in Intelligent Gas Metal Arc Welding Systems: Fundamentals and Applications presents the latest on gas metal arc welding which plays a significant role in modern manufacturing industries and accounts for about 70% of welding processes. The importance of advancements in GMAW cannot be underestimated as they can lead to more efficient production strategies, resource savings and quality improvements. This book provides an overview of various aspects associated with GMAW, starting from the theoretical basis and ending with characteristics of industrial applications and control methods. Additional sections cover processes associated with welding and welding control, such as fuzzy logic, artificial neural networks, and others. Provides an up-to-date overview of recent GMAW developments Includes insights into intelligent welding automation Describes real-world, industrial cases of welding automation implementation

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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It is the intention of this paper to document that certain types of welding fumes have little or no effect on the effectiveness of the carbon filter air filtration efficiency when directly exposed to a controlled amount of welding fumes for a short-term period. The welding processes studied were restricted to shielded metal arc welding (SMAW), flux cored arc welding (FCAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) processes. Contrary to the SMAW and FCAW processes, the GTAW (or TIG) and the GMAW (or MIG) welding processes do not require the use of flux as part of the overall process. Credit was taken for these processes occurring in inert gas environments and producing minimal amount of smoke. It was concluded that a study involving the SMAW process would also envelop the effects of the TIG and MIG welding processes. The quantity of welding fumes generated during the arc welding process is a function of the particular process, the size and type of electrode, welding machine amperage, and operator proficiency. For this study, the amount of welding for specific testing was equated to the amount of welding normally conducted during plant unit outages. Different welding electrodes were also evaluated, and the subsequent testing was limited to an E7018 electrode which was judged to be representative of all carbon and stainless steel electrodes commonly used at the site. The effect of welding fumes on activated charcoal was tested using a filtration unit complete with prefilters, upstream and downstream high efficiency particulate air (HEPA) filters, and a carbon adsorber section. The complete system was field tested in accordance with ANSI N510 standards prior to exposing the filters and the adsorber bed to welding fumes. The carbon samples were tested at an established laboratory using ASTM D3803-1989 standards.