PPE

harm of argon arc welding to human body and personal protection

The harm degree of argon arc welding is bigger than that of shielded metal arc welding, but it is not so big as to be daunting. The infrared radiation is about 1-1.5 times of that of ordinary shielded metal arc welding, and the ultraviolet radiation produced by argon arc welding is about 5-20 times of that of shielded metal arc welding

when welding in a limited space, the concentration of ozone can increase to a dangerous level. 1n the welding process, harmful gases such as carbon dioxide, carbon monoxide and metal dust will be produced, which will cause certain harm to welders

therefore, we should do a good job in the welding process, choose electrode materials, and try to choose cerium tungsten with low radioactivity. Wear masks and gloves when grinding electrodes, and wash hands after work to minimize the harm

the harm of high frequency electromagnetic field

the frequency of high frequency oscillator is 200 ~ 500KHz, the voltage is 2500 ~ 3500v, and the electric field intensity is 140 ~ 190V / m. When arcing, the intensity of high frequency electromagnetic field is between 60-110v / m, which is several times higher than the reference health standard (20V / M)

high frequency oscillators are often used to excite the starting arc in the process of non consumable argon arc welding and plasma arc welding. Some AC argon arc welding machines also use high frequency oscillators to stabilize the arc. Under the action of high frequency electromagnetic field, human body can absorb certain radiation energy and produce biological effect, mainly thermal effect. The intensity of high frequency electromagnetic field is affected by many factors, such as distance, the closer the oscillator and oscillation circuit is, the higher the intensity is, and vice versa< 1n addition, it is related to the shielding degree of the high frequency part. Human body will produce biological effects under the action of high-frequency electromagnetic field. Welder's long-term exposure to high-frequency electromagnetic field can cause autonomic nerve dysfunction and neurasthenia. The symptoms included general discomfort, dizziness, headache, fatigue, loss of appetite, insomnia and low blood pressure if the high-frequency oscillator is used only for arc ignition, the influence is small due to the short time. 1f the high-frequency oscillator is used frequently or as an arc stabilizing device in the welding process, the high-frequency electromagnetic field can become one of the harmful factors< The thorium tungsten used in argon arc welding contains 1% - 1.2% thorium oxide. Thorium is a kind of radioactive element, which can radiate α,β,γ Three kinds of rays. During welding and contacting with thorium tungsten rod, it may be affected by radiation. Through a large number of investigations, the daily consumption of thorium tungsten rod is only 100-200mg, and the radiation dose is very small, which has little effect on human body. However, when welding in the container, the ventilation is not smooth, and the radioactive particles in the smoke may exceed the health standard secondly, the concentration of radioactive aerosol and radioactive dust can reach or even exceed the health standard when grinding and storing thorium tungsten rods. Radioactive substances into the body, can cause chronic radiation diseases, the formation of internal irradiation, mainly in the general functional state weakened, you can see obvious weakness, resistance to infectious diseases significantly reduced, weight loss and other symptoms Baidu Encyclopedia: radioactive aerosols are solid or liquid particles suspended in air or other gases containing radionuclides. A dispersion of solid or liquid radioactive particles suspended in air or gas. The basic characteristic of aerosols is instability. Particles smaller than 0.1 μ m make Brownian motion in the gas and do not settle due to gravity; The particles of 1-10 μ m settle slowly and stay in the air for a long time. The ionization effect of radioactive aerosol is high, the concentration is low, and the particle is easy to be charged (produced by radioactive decay). Radioactive aerosol is the main threat to human body harm of strong arc light welding arc radiation mainly includes visible light, infrared and ultraviolet. They act on the human body and are absorbed by the human tissue, causing thermal, photochemical or ionizing effects of the tissue, causing damage to the human tissue the luminosity of the visible light is about 10000 times greater than that of the naked eye. When the visible light radiates into the eyes, it will cause pain and can’t see clearly. 1t is usually called “dazzling”, and it will lose the ability to work in a short time the main harm of infrared rays to human body is the thermal effect of tissues. 1n the process of welding, the eyes are exposed to strong infrared radiation, and they will immediately feel strong burns and burning pain, resulting in flash hallucination. Long term exposure may cause infrared cataract, vision loss, and even blindness ultraviolet radiation (UV), also known as ultraviolet, refers to the electromagnetic wave with the wavelength of 100-400nm. The right amount of ultraviolet radiation can have a beneficial effect on the human body, but excessive exposure will cause adverse effects on the human body (such as welding ultraviolet radiation). The main harm of ultraviolet to human body is photochemical action, which causes damage to human skin and eyes. After the skin is exposed to intense ultraviolet radiation, it can cause dermatitis, diffuse erythema, sometimes small blisters, exudates, burning and itching when the effect is strong, it is accompanied by systemic symptoms: headache, dizziness, fatigue, nerve excitement, fever, insomnia, etc. Ultraviolet excessive irradiation of human eyes can cause acute cornea and conjunctivitis, namely electro-optic ophthalmia. The symptoms are high shyness, tears, foreign body sensation, tingling, eyelid redness and swelling, spasm, headache and visual phantom burning harm of welding dust a large amount of metal welding dust will be produced in the welding process. The diameter of the metal powder produced by welding is very small, which is easy to absorb into the lung. Because the diameter is very small, it is difficult to discharge out of the body, so pathological changes occur. The higher the welding current intensity is, the higher the dust concentration is. 1n the case of high concentration of welding dust and without corresponding dust removal measures, long-term exposure to welding dust can cause occupational diseases such as welder’s pneumoconiosis, manganese poisoning and metal heat< 1n recent 10 years, some researches on the reproductive toxicity of electric welding have been carried out at home and abroad, mainly involving the semen quality of male workers, reproductive outcomes and damage mechanism of female workers. The results showed that the menstrual volume increased, menstrual cycle shortened, menstrual period prolonged, leucorrhea increased, spontaneous abortion, premature birth, dysmenorrhea, menstruation rate of female welders were higher than those of the control group. The semen of male workers with manganese poisoning showed uniform gray white appearance with normal pH value, and the average liquefaction time was longer than that of the control group< The results showed that the average amount of ejaculation, total sperm count, sperm survival rate and motile sperm rate of male workers with manganese poisoning were lower than those of the control group, and the sperm deformity rate of male workers with manganese poisoning was significantly higher than that of the control group. 1t is considered that manganese can affect the spermatogenic system of male workers, has direct toxic effect on the development of sperm, and can kill sperm, thus causing changes in the quality of male semen. 1t was also reported that the sex hormone secretion of welding workers changed and sperm quality decreased, but there was no effect on the sex ratio of offspring harm of harmful gases under the action of welding arc high temperature and strong ultraviolet, a variety of harmful gases are formed around the arc, including ozone, nitrogen oxides, carbon monoxide and hydrogen fluoride. Ozone is a pungent toxic gas, light blue. When the concentration is high, it gives off a fishy smell; High concentration of ozone is slightly sour the main harm of ozone to human body is that it has a strong stimulating effect on the suction tract and lung. 1t often causes cough, chest tightness, loss of appetite, fatigue and weakness, dizziness, general pain, etc., and even bronchitis and pulmonary edema when it is serious nitrogen oxides are irritating toxic gases. Nitrogen dioxide is reddish brown and has a special odor. The main harm of nitrogen oxides to human body is the stimulation of lung tissue. After being sucked into the airway, it gradually reacts with water in the alveoli to form nitric acid and nitrous acid, causing strong stimulation and corrosion to the lung tissue, causing poisoning the main symptoms of chronic poisoning are neurasthenia, such as insomnia, headache, loss of appetite and weight loss. High concentration of nitrogen oxides can cause acute poisoning, in which mild toxicity, only acute bronchitis; Severe poisoning can cause severe cough, dyspnea, collapse, weakness and other symptoms the effect of nitrogen oxides on human body is also reversible. With the increase of time away from work, its adverse effects gradually reduce or eliminate. 1n T1G welding, if ventilation measures are not taken, its concentration is often more than ten times or even dozens of times higher than the health standard. The hygienic standard of nitrogen oxide (converted to nitrogen dioxide) in China is 5mg / m3. 1n the welding process, ozone and nitrogen oxides usually exist at the same time, so they are more toxic. 1n general, two kinds of toxic gases exist at the same time, which is 15-20 times more harmful than a single toxic gas protective measures (1) ventilation measures argon arc welding work site should have good ventilation device to discharge harmful gas and smoke. 1n addition to the ventilation of the workshop, several axial flow fans can be installed in the place where the welding workload is heavy and the welding machines are concentrated to exhaust. 1n addition, the harmful gas around the arc can be removed by local ventilation measures, such as the use of open arc smoke hood, smoke welding gun, portable small fan, etc< (2) radiation protection measures cerium tungsten electrode with extremely low radiation dose should be used as far as possible. When processing thorium tungsten electrode and cerium tungsten electrode, sealed or exhaust grinding wheel should be used for grinding. Operators should wear masks, gloves and other personal protective equipment, and wash hands and face after processing. Thorium tungsten electrode and cerium tungsten electrode should be stored in aluminum box< 1n order to prevent and weaken the influence of high frequency electromagnetic field, the following measures are taken: 1) the workpiece is well grounded, and the welding torch cable and ground wire should be shielded by metal braided wire; 2) Reduce the frequency appropriately; 3) Try not to use high frequency oscillator as arc stabilizing device to reduce the action time of high frequency electricity (4) other personal protective measures when argon arc welding, due to the strong effect of ozone and ultraviolet, it is advisable to wear non cotton work clothes (such as acid resistant cloth, tussah silk, etc.). 1n the case of welding in the container and local ventilation can not be used, personal protective measures such as air helmet, air mask or gas mask can be used

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