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The degree of harm of argon arc welding is relatively greater than that of electrode arc welding, but it is not so daunting. The infrared radiation is about 1 to 1.5 times that of ordinary electrode arc welding, and the ultraviolet radiation generated by argon arc welding is about It is 5-20 times that of electrode arc welding. Professional Manufacturer of nylon bearings
When welding in a limited space, the concentration of ozone can increase to a dangerous level. During the welding process, harmful gases such as carbon dioxide, carbon monoxide and metal dust will also be produced, which will cause certain harm to the welder.
Therefore, we must take good care of the protection during the welding process, choose the electrode material, and try to choose the radioactive cerium tungsten. When grinding electrodes, wear masks and gloves, and wash your hands after work to minimize the harm. Professional Manufacturer of nylon bearings
Prevent damage from high-frequency electromagnetic fields
- The generation and hazards of high-frequency electromagnetic fields
In tungsten argon arc welding and plasma arc welding, a high-frequency oscillator is often used to excite the arc starting, and some AC argon arc welding machines also use a high-frequency oscillator to stabilize the arc. The frequency of the high-frequency oscillator usually used in welding is 200-500 thousand cycles, the voltage is 2500-3500 V, the high-frequency current intensity is 3-7 mA, and the electric field intensity is about 140-190 V/m.
Long-term exposure of welders to high-frequency electromagnetic fields can cause autonomic dysfunction and neurasthenia. It is manifested as general malaise, dizziness, dreaminess, headache, memory loss, fatigue, loss of appetite, insomnia and low blood pressure. Click to receive 10G CNC programming tutorial for free
The reference health standards for high-frequency electromagnetic fields stipulate that the allowable radiation intensity for 8 hours of exposure is 20 volts/meter.
According to measurement, the high-frequency electromagnetic field intensity of all parts of the welder during manual argon tungsten arc welding exceeds the standard. Among them, the strength of the hand is the highest, which exceeds the health standard by more than 5 times. If the high-frequency oscillator is only used for arc ignition, the time is short and the impact is small, but long-term exposure is also harmful, and effective protective measures must be adopted. Professional Manufacturer of nylon bearings
- Protective measures against high-frequency electromagnetic fields
⑴The arc ignition and stabilization measures of argon arc welding try to use transistor pulse device instead of high-frequency oscillation device, or only used for arc ignition. After the arc is ignited, immediately cut off the high-frequency power supply.
(2) Reduce the oscillation frequency, change the capacitor and inductance parameters, reduce the oscillation frequency to 30 thousand cycles, and reduce the impact on the human body.
⑶ Shielded cables and wires, using thin copper braided flexible wires, sheathed outside the cable hose (including the wires inside the welding torch and the wires leading to the welding machine), and grounded them.
⑷Because of the high voltage of the high-frequency oscillation circuit, there must be good and reliable insulation.
The thorium tungsten used in argon arc welding contains 1% to 1.2% thorium oxide. Thorium is a radioactive element that can emit three kinds of rays: α, β, and γ. During the welding process and the contact process with the thorium tungsten rod, it may be affected by radiation. Through a large number of investigations, the daily consumption of thorium tungsten rods is only 100-200mg, and the radiation dose is very small, which has little effect on the human body. However, when welding in the container, the ventilation is not smooth, and the radioactive particles in the smoke may exceed the hygienic standard;
The second is that the concentration of radioactive aerosol and radioactive dust can reach or exceed the sanitary standard when the thorium tungsten rod is ground and where the thorium tungsten rod is stored. The intrusion of radioactive materials into the body can cause chronic radiation diseases and form internal radiation, which is mainly manifested in the weakening of the general functional state. You can see obvious weakness, significantly reduced resistance to infectious diseases, and weight loss.
Baidu Encyclopedia: Radioactive aerosol, solid or liquid particles containing radionuclides suspended in the air or other gases. A dispersion system of solid or liquid radioactive particles suspended in air or gas medium. The basic characteristic of aerosol is that it is unstable. The particles smaller than 0.1 micron make Brownian motion in the gas and do not settle due to gravity; the particles of 1-10 microns 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 particles are easily charged (produced by radioactive decay). Radioactive aerosol is the main threat to human body exposure.
The harm of strong arc light
Welding arc radiation mainly includes visible light, infrared rays and ultraviolet rays. They act on the human body and are absorbed by human tissues, causing thermal, photochemical, or ionization of the tissues, causing damage to human tissues.
The luminosity of visible light is about 10,000 times greater than the normal luminosity of the naked eye. When visible light radiates human eyes, it will cause pain and make people unable to see things clearly. It is usually called “dazzling” and loses the ability to work in a short time. .
The main hazard of infrared rays to the human body is the heat effect of the tissue. During the welding process, the eyes receive strong infrared radiation, and they will immediately feel strong burns and burning pain, and flash hallucinations occur. Long-term exposure may cause infrared cataracts, loss of vision, and blindness in severe cases.
Ultraviolet radiation (UV), also known as ultraviolet, refers to electromagnetic waves with a wavelength of 100-400nm. Appropriate amount of ultraviolet radiation can have a beneficial effect on the human body, but excessive radiation can cause adverse effects on the human body (such as welding ultraviolet radiation). The main harm of ultraviolet rays to the human body is photochemical action, which causes damage to human skin and eyes. After the skin is exposed to strong ultraviolet radiation, it can cause dermatitis, diffuse erythema, sometimes small blisters, exudate, burning sensation, and itching;
When the effect is strong, there are systemic symptoms: headache, dizziness, fatigue, nerve excitement, fever, insomnia, etc. Excessive exposure of ultraviolet rays to human eyes can cause acute keratitis and conjunctivitis of the eyes, namely electrophthalmitis. The symptoms are high levels of shame in the eyes, tearing, foreign body sensation, tingling, red and swollen eyelids, cramps, headache and blurred vision.
The hazards of welding fumes
A large amount of metal welding dust will be produced during the welding process. The metal powder produced by welding has a small diameter and is easier to suck into the lungs. Because of its small diameter, it is difficult to be discharged from the body, so pathological changes occur. The higher the welding current intensity, the higher the dust concentration. In the case of high welding dust concentration and no corresponding dust removal measures, long-term exposure to welding dust can cause occupational diseases such as welder’s pneumoconiosis, manganese poisoning and metal fever.
Reproductive toxicity. In the past 10 years, some studies on reproductive toxicity of electric welding have been carried out at home and abroad, mainly involving the quality of male workers’ semen, female workers’ reproductive outcome and damage mechanisms. Studies have shown that the menstrual volume of female electric welding workers increased, the cycle shortened, the menstrual period prolonged, the vaginal discharge increased, spontaneous abortion, premature delivery, and dysmenorrhea were all higher than those of the control group. The semen of men with manganese poisoning was uniformly grayish white, the PH value was normal, and the average liquefaction time was longer than that of the control group.
The test results proved that the average ejaculation volume, total number of sperm, sperm survival rate and motile sperm rate of men with manganese poisoning were lower than those in the control group, and the rate of sperm deformity in men with manganese poisoning was significantly higher than that of the control group. It is believed that metal manganese can affect the spermatogenesis system of male workers, has a direct toxic effect on the development of sperm, and can kill sperm, thereby causing changes in the quality of male semen. There are also reports abroad that the secretion of sex hormones in electric welding workers has changed, and the quality of sperm has decreased, but it has no effect on the sex ratio of the offspring.
Harm of harmful gases
Under the action of the high temperature of the welding arc and strong ultraviolet rays, a variety of harmful gases are formed around the arc, including ozone, nitrogen oxide, carbon monoxide and hydrogen fluoride. Ozone is an irritating and toxic gas with a light blue color. When the concentration is high, it gives off a fishy smell; high concentration ozone also has a slightly sour taste.
The main hazard of ozone to the human body is a strong stimulating effect on the respiratory tract and lungs. It often causes cough, chest tightness, loss of appetite, fatigue, dizziness, and body pain. In severe cases, it can also cause bronchitis and pulmonary edema.
Nitrogen oxides are irritating and toxic gases. Nitrogen dioxide is reddish brown and has a special smell. The main harm of nitrogen oxides to the human body is the stimulating effect on lung tissue. After being inhaled into the respiratory tract, it gradually interacts with water in the alveoli to form nitric acid and nitrous acid, which have a strong stimulus and corrosive effect on lung tissues, 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. Among them, the mild ones will only cause acute bronchitis; when severe poisoning, it will cause symptoms such as intense coughing, difficulty breathing, collapse, and general weakness.
The effect of nitrogen oxides on the human body is also reversible, and as the time of separation from work increases, its adverse effects are gradually reduced or eliminated. In the case of argon tungsten arc welding, if ventilation measures are not taken, its concentration often exceeds the health standard by ten times or even dozens of times. The sanitary standard of nitrogen oxides (converted into nitrogen dioxide) stipulated by our country is 5mg/m3. In the welding process, ozone and nitrogen oxides are usually present at the same time, so they are more toxic. Under normal circumstances, the simultaneous presence of two toxic gases is 15-20 times more harmful than a single toxic gas.
(1) Ventilation measures
The argon arc welding work site must have a good ventilation device to exhaust harmful gases and smoke. In addition to ventilation in the workshop, several axial fans can be installed to exhaust air in places where the welding workload is heavy and the welding machines are concentrated. In addition, local ventilation measures can also be used to remove harmful gases around the arc, such as open arc fume hoods, fume exhaust welding torches, and portable fans.
(2) Protective measures
Use cerium tungsten electrode with extremely low radiation dose as much as possible. When thorium tungsten electrode and cerium tungsten electrode are processed, sealed or exhausted grinding wheel should be used for grinding. Operators should wear masks, gloves and other personal protective equipment, and wash hands and faces after processing. Thorium tungsten electrodes and cerium tungsten electrodes should be stored in aluminum boxes.
(3) Measures to protect high frequency
In order to prevent and weaken the influence of high-frequency electromagnetic field, the measures taken are: 1) The workpiece is well grounded, and the welding torch cable and ground wire should be shielded with metal braided wire; 2) The frequency should be reduced appropriately; 3) Try not to use high-frequency oscillators as The arc stabilizing device reduces the time of high-frequency electric action.
(4) Other personal protective measures
During argon arc welding, due to the strong effects of ozone and ultraviolet rays, it is advisable to wear non-cotton work clothes (such as acid-resistant cloth, tussah silk, etc.). In the case of welding in the container and local ventilation cannot be used, personal protective measures such as ventilation helmets, ventilation masks or gas masks can be adopted.
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