scholarly journals Extension of the Advanced REACH Tool (ART) to Include Welding Fume Exposure

2018 ◽  
Vol 15 (10) ◽  
pp. 2199 ◽  
Author(s):  
Aduldatch Sailabaht ◽  
Fan Wang ◽  
John Cherrie
Keyword(s):  
Power Level ◽  
Inhalation Exposure ◽  
Welding Process ◽  
Input Power ◽  
Welding Fumes ◽  
Welding Fume ◽  
Modifying Factors ◽  
Local Ventilation ◽  
The Impact ◽  
Welding Processes

The Advanced REACH Tool (ART) is a mechanistic higher tier model to estimate inhalation exposure to chemicals using a Bayesian approach. Currently the ART model does not include exposure to welding fumes within its applicability domain; it has only been calibrated for vapours, mists, and dusts. To extend the scope to metal fumes it is necessary to review the model structure to ensure that it is appropriate, and to calibrate the updated model using available welding fume exposure measurements. This paper provides a discussion of the key modifying factors (MFs) that should be considered to extend the ART model to include welding fume exposure. Based on our literature review, welding process type, input power level, shield gas, and welding electrodes have important impact on fume formation rates (FFRs). In addition, the convective dispersion of the fume away from the weld and the interaction of the welder with the fume plume should be incorporated into the ART model. Other aspects of the ART, such as the local ventilation, do not require modification to accommodate welding fume exposure. The ART does not include the impact of wearing personal protective equipment and so this is not included in our evaluation. Proposals are made for extending the scope of the ART to include welding processes.

scholarly journals Preliminary Study to Investigate the Distribution and Effects of Certain Metals After Inhalation of Welding Fumes in Mice

2022 ◽  
Author(s):  
Kővágó Csaba ◽  
Barbara Szekeres ◽  
Éva Szűcs-Somlyó ◽  
Kornél Májlinger ◽  
Ákos Jerzsele ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Mild Steel ◽  
Gma Welding ◽  
Inhalation Exposure ◽  
Glycogen Metabolism ◽  
Systemic Effect ◽  
Welding Fumes ◽  
Welding Processes ◽  
Mn Concentration ◽  
Sampling Times

Abstract The most important welding processes used are the Gas Metal Arc (GMA) welding, the Tungsten Inert Gas (TIG) welding, and the Manual Metal Arc (MMA) welding processes. The goal of our investigation was to monitor the distribution of iron (Fe), manganese (Mn), calcium (Ca) and magnesium (Mg) in the lung, spleen, liver, and kidney of mice after inhalation exposure of different welding methods using different steel base materials. The treatment groups were the following: MMA-mild steel, MMA-molybdenum-manganese (MoMn) alloy, TIG-mild steel, and TIG-stainless steel. The samples were taken 24- and 96 hours after the treatments.Most importantly, it was found that the Mn concentration in the lung’ samples of the MMA-mild steel and the MMA-MoMn groups was increased extremely at both sampling times and in the spleen’ samples also. In the TIG groups, the rise of the Mn concentration was only considerable in the lungs and spleens at 24h, and emerged concentration was found in the liver in 96h samples. Histopathology demonstrated emerged siderin content in the spleens of the treated animals and in siderin filled macrophages in the lungs mostly in all treated groups. Traces of high-level glycogen retention was found in the MMA groups at both sampling times. Similar glycogen retention in TIG-Ms and TIG stainless group’s liver samples and emerged number of vacuoles, especially in the hepatocytes of the TIG-stainless steel 96h group were also found.The mentioned results raise the consequence that there is a considerable difference in the kinetics of the Mn distribution between the MMA- and the TIG-fume treated groups. Hence, the result suggests that manganese has a particle-size dependent toxico-kinetics property. The anomaly of the glycogen metabolism indicates the systemic effect of the welding fumes. Also, the numerous vacuoles mentioned above show a possible liver-specific adverse effect of some components of the TIG-stainless steel welding fumes.

scholarly journals Forensic Engineering of Advanced Polymeric Materials—Part VII: Degradation of Biopolymer Welded Joints

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1167
Author(s):  
W. Sikorska ◽  
M. Zięba ◽  
M. Musioł ◽  
M. Kowalczuk ◽  
H. Janeczek ◽  
...  
Keyword(s):  
Degradation Products ◽  
Bond Cleavage ◽  
Hydrolytic Degradation ◽  
Welding Process ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Scanning Calorimetry ◽  
Forensic Engineering ◽  
The Impact ◽  
Welding Processes

Welding technology may be considered as a promising processing method for the formation of packaging products from biopolymers. However, the welding processes used can change the properties of the polymer materials, especially in the region of the weld. In this contribution, the impact of the welding process on the structure and properties of biopolymer welds and their ability to undergo hydrolytic degradation will be discussed. Samples for the study were made from polylactide (PLA) and poly(3-hydroxyalkanoate) (PHA) biopolymers which were welded using two methods: ultrasonic and heated tool welding. Differential scanning calorimetry (DSC) analysis showed slight changes in the thermal properties of the samples resulting from the processing and welding method used. The results of hydrolytic degradation indicated that welds of selected biopolymers started to degrade faster than unwelded parts of the samples. The structure of degradation products at the molecular level was confirmed using mass spectrometry. It was found that hydrolysis of the PLA and PHA welds occurs via the random ester bond cleavage and leads to the formation of PLA and PHA oligomers terminated by hydroxyl and carboxyl end groups, similarly to as previously observed for unwelded PLA and PHA-based materials.

scholarly journals Sex Hormones Levels in Male Welders in Nnewi, South-Eastern Nigeria

2020 ◽  
pp. 22-32
Author(s):  
C. H. Udeogu ◽  
I. S. I. Ogbu ◽  
A. N. Mbachu ◽  
M. C. Ugwu ◽  
O. F. Odo ◽  
...  
Keyword(s):  
Sex Hormones ◽  
Venous Blood ◽  
Test Group ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Welding Fumes ◽  
Welding Fume ◽  
Cross Sectional ◽  
Significant Difference ◽  
Welding Processes

Welding processes produce toxic fumes consisting of gaseous and aerosol by-products which pose a risk to the male reproductive systems. The rate of infertility has increased globally. This study therefore sought to assess the effects of welding fume inhalation on the sex hormones of welders in Nnewi. A site-by-site cross-sectional study of 45 welders (aged between 18 and 50 years) who were exposed to welding fumes (Test group) and 45 age-matched non-welders (Control group) was carried out. The ages of the Test and Control subjects, as well as the years of exposure of the Test subjects were obtained via questionnaire. A single non-fasting venous blood (about 5 mls) was collected from the ante-cubital space from the subjects via venipuncture between 8:00 AM and 11:00 AM. Serum was separated following clotting, and used for the investigation of the levels of male sex hormones: Testosterone (T), Progesterone (P), Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) among welders. Sex hormones were assayed by Enzyme Linked Immunosorbent Assay. The results showed that Testosterone (2.45±0.34 ng/ml) was significantly lower (p<0.05) in welders when compared to controls (4.94±0.81 ng/ml) and significantly increased (p<0.05) levels of Progesterone (0.54±0.09 ng/ml) and LH (7.47±1.56 mIU/L) were found in welders compared with controls Progesterone (0.45±0.08 ng/ml) and LH (5.53±1.05 mIU/L). There was no significant difference in the levels of FSH of the test when compared with the controls. This finding of altered hormone levels indicates a likelihood of reduced reproductive outcome. Exposure to welding fume may therefore interfere with testicular functions leading to disordered reproductive performance, delayed conception, and reduced fertility.

The occupational exposure and ventilation of welding workstations

2019 ◽  
Vol 571 (4) ◽  
pp. 10-14
Author(s):  
Tomasz Jankowski
Keyword(s):  
Occupational Exposure ◽  
Welding Process ◽  
Working Environment ◽  
Air Distribution ◽  
Welding Fumes ◽  
Metallic Materials ◽  
Fine Particulates ◽  
Basic Technology ◽  
Welding Processes ◽  
Concentration Of Air Pollutants

Welding is a basic technology for joining metallic materials and plastics. The high occupational exposure of welders results from the presence of various harmful factors that accompany welding processes, including the emission of a mixture of fine particulates (dust) and chemical substances (gases) into the working environment. Mechanical ventilation is the main way to reduce the concentration of air pollutants in the areas where welding works are carried. The article presents the characteristics of welding fumes, welding process parameters and methods of air distribution with ventilation devices and installations in rooms with welding workstations.

scholarly journals Oxidative Stress Biomarkers in Urine of Metal Carpentry Workers Can Be Diagnostic for Occupational Exposure to Low Level of Welding Fumes from Associated Metals

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3167
Author(s):  
Flavia Buonaurio ◽  
Maria Luisa Astolfi ◽  
Daniela Pigini ◽  
Giovanna Tranfo ◽  
Silvia Canepari ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Occupational Exposure ◽  
Oxidation Products ◽  
Control Group ◽  
Welding Fumes ◽  
Oxidative Stress Biomarkers ◽  
Limit Values ◽  
Stress Biomarkers ◽  
Specificity And Sensitivity ◽  
The Impact

Urinary concentrations of 16 different exposure biomarkers to metals were determined at the beginning and at the end of a working shift on a group of workers in the metal carpentry industry. Five different oxidative stress biomarkers were also measured, such as the oxidation products of RNA and DNA metabolized and excreted in the urine. The results of workers exposed to metals were compared to those of a control group. The metal concentrations found in these workers were well below the occupational exposure limit values and exceeded the mean concentrations of the same metals in the urine of the control group by a factor of four at maximum. Barium (Ba), mercury (Hg), lead (Pb) and strontium (Sr) were correlated with the RNA oxidative stress biomarker, 8-oxo-7, 8-dihydroguanosine (8-oxoGuo), which was found able to discriminate exposed workers from controls with a high level of specificity and sensitivity. The power of this early diagnostic technique was assessed by means of the ROC curve. Ba, rubidium (Rb), Sr, tellurium (Te), and vanadium (V) were correlated with the level of the protein oxidation biomarker 3-Nitrotyrosine (3-NO2Tyr), and Ba, beryllium (Be), copper (Cu), and Rb with 5-methylcytidine (5-MeCyt), an epigenetic marker of RNA damage. These effect biomarkers can help in identifying those workers that can be defined as “occupationally exposed” even at low exposure levels, and they can provide information about the impact that such doses have on their health.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Microstructure and mechanical property improvement of dissimilar metal joints for TC4 Ti alloy to Nitinol NiTi alloy by laser welding

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yan Zhang ◽  
DeShui Yu ◽  
JianPing Zhou ◽  
DaQian Sun ◽  
HongMei Li
Keyword(s):  
Tensile Strength ◽  
Laser Welding ◽  
Mechanical Performance ◽  
Niti Alloy ◽  
Welding Process ◽  
Ti Alloy ◽  
The One ◽  
Fusion Weld ◽  
Welding Processes ◽  
Cu Interlayer

Abstract To avoid the formation of Ti-Ni intermetallics in a joint, three laser welding processes for Ti alloy–NiTi alloy joints were introduced. Sample A was formed while a laser acted at the Ti alloy–NiTi alloy interface, and the joint fractured along the weld centre line immediately after welding without filler metal. Sample B was formed while the laser acted on a Cu interlayer. The average tensile strength of sample B was 216 MPa. Sample C was formed while the laser acted 1.2 mm on the Ti alloy side. The one-pass welding process involved the creation of a joint with one fusion weld and one diffusion weld separated by the remaining unmelted Ti alloy. The mechanical performance of sample C was determined by the diffusion weld formed at the Ti alloy–NiTi alloy interface with a tensile strength of 256 MPa.

scholarly journals Experimental studies on the possibility of using a pulsed laser for spot welding of thin metallic foils

2020 ◽  
Vol 10 (1) ◽  
pp. 674-680
Author(s):  
Piotr Sęk
Keyword(s):  
Experimental Studies ◽  
Pulsed Laser ◽  
Welding Process ◽  
Pulse Mode ◽  
Weld Strength ◽  
Spot Welds ◽  
Butt Welding ◽  
Strength Tests ◽  
Metallic Foils ◽  
The Impact

AbstractThe purpose of the experiment was to study the influence of the laser beam in pulse mode on metallic foils in order to obtain a spot weld. The welding process was carried out using the overlap weld method, using spot welds in various quantities. The Nd - YAG BLS 720 pulsed laser was used to conduct the experiment. The impact of the number of spot welds on the value of force needed to break the sample was examined. A number of measurements were carried out to determine the best process parameters. Butt welding and overlap welding were also performed using a continuous weld consisting of spot welds. Weld strength tests were performed to select the most appropriate parameters for the process under consideration.

scholarly journals RF Small and large signal characterization of a 3D integrated GaN/RF-SOI SPST switch

2021 ◽  
pp. 1-6
Author(s):  
Frédéric Drillet ◽  
Jérôme Loraine ◽  
Hassan Saleh ◽  
Imene Lahbib ◽  
Brice Grandchamp ◽  
...  
Keyword(s):  
Power Level ◽  
Coplanar Waveguide ◽  
Average Power ◽  
Input Power ◽  
Capacitive Coupling ◽  
Rf Switch ◽  
Large Signal ◽  
Waveguide Transmission ◽  
Signal Characterization

Abstract This paper presents the radio frequency (RF) measurements of an SPST switch realized in gallium nitride (GaN)/RF-SOI technology compared to its GaN/silicon (Si) equivalent. The samples are built with an innovative 3D heterogeneous integration technique. The RF switch transistors are GaN-based and the substrate is RF-SOI. The insertion loss obtained is below 0.4 dB up to 30 GHz while being 1 dB lower than its GaN/Si equivalent. This difference comes from the vertical capacitive coupling reduction of the transistor to the substrate. This reduction is estimated to 59% based on a RC network model fitted to S-parameters measurements. In large signal, the linearity study of the substrate through coplanar waveguide transmission line characterization shows the reduction of the average power level of H2 and H3 of 30 dB up to 38 dBm of input power. The large signal characterization of the SPST shows no compression up to 38 dBm and the H2 and H3 rejection levels at 38 dBm are respectively, 68 and 75 dBc.

Advanced submerged arc welding processes for Arctic structures and ice-going vessels

2016 ◽  
Vol 232 (1) ◽  
pp. 114-127
Author(s):  
Pavel Layus ◽  
Paul Kah ◽  
Viktor Gezha
Keyword(s):  
Case Studies ◽  
Arc Welding ◽  
Oil And Gas ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
The Arctic ◽  
Correct Selection ◽  
Advantages And Disadvantages ◽  
Welding Processes ◽  
Submerged Arc

The Arctic region is expected to play an extremely prominent role in the future of the oil and gas industry as growing demand for natural resources leads to greater exploitation of a region that holds about 25% of the world’s oil and gas reserves. It has become clear that ensuring the necessary reliability of Arctic industrial structures is highly dependent on the welding processes used and the materials employed. The main challenge for welding in Arctic conditions is prevention of the formation of brittle fractures in the weld and base material. One mitigating solution to obtain sufficiently low-transition temperatures of the weld is use of a suitable welding process with properly selected parameters. This work provides a comprehensive review with experimental study of modified submerged arc welding processes used for Arctic applications, such as narrow gap welding, multi-wire welding, and welding with metal powder additions. Case studies covered in this article describe welding of Arctic steels such as X70 12.7-mm plate by multi-wire welding technique. Advanced submerged arc welding processes are compared in terms of deposition rate and welding process operational parameters, and the advantages and disadvantages of each process with respect to low-temperature environment applications are listed. This article contributes to the field by presenting a comprehensive state-of-the-art review and case studies of the most common submerged arc welding high deposition modifications. Each modification is reviewed in detail, facilitating understanding and assisting in correct selection of appropriate welding processes and process parameters.

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