Welding workers suffer from various occupational health threats

I. Major hazards in welding operations
1. Hazard of metal fumes The composition of welding fumes varies depending on the welding rod used. The electrode consists of a core and a coating. In addition to a large amount of iron, the core contains carbon, manganese, silicon, chromium, nickel, sulfur, and phosphorus. The inner material of the core consists of marble, fluorite, rutile, pure salt, water glass, and ferromanganese. During arc welding, the arc discharge produces a temperature of 4000°C to 6000°C. At the same time of melting the electrode and the weldment, a large amount of smoke and dust is generated. Its composition is mainly iron oxide (mainly mainly triiron trioxide, accounting for 36%-76%). ), Manganese oxides, silicon dioxide, silicates, fluorides, ozone, nitrogen oxides, etc., soot particles are diffused in the operating environment and can easily be inhaled into the lungs. Long-term inhalation can cause fibrous lesions in lung tissue, which is called welder pneumoconiosis, and is often accompanied by Mn poisoning, fluorosis, and metal fume fever. Welders have a slow onset of pneumoconiosis mainly manifested as chest tightness, chest pain, shortness of breath, cough, sputum and other respiratory symptoms, accompanied by headaches, general malaise and other illnesses, but they are mild and generally do not affect work. Early lung function impairment is not obvious, and late pulmonary function can be impaired. When combined with pulmonary infection symptoms and signs tend to be obvious. The onset of illness is mostly 7-23 years, with an average of about 20 years. Chest X-ray findings: Small irregular shadows in the early stages, mostly in the middle and lower lung areas. There are a variety of small round shadows, and have a wide distribution, low density characteristics; some are mainly small round shadows, and high density, individual cases can see block large shadows late. Humps generally do not increase, rarely pleural adhesions and emphysema. After leaving the operation, little progress has been made.

2. Hazard of toxic gases Under the effect of high temperature and strong ultraviolet rays generated by welding arcs, a large amount of toxic gases such as carbon monoxide and nitrogen oxides will be generated around arc regions.

(1) Ozone is a colorless, harmful gas with a special pungent odor. It has a strong irritating effect on respiratory mucosa and lungs. Short-term inhalation of low concentrations (0.4mg/m3) of ozone can cause cough, dry throat, chest tightness, loss of appetite, fatigue and other symptoms, long-term inhalation of low concentrations of ozone can cause bronchitis, emphysema, lung Hardening and so on.

(2) Carbon monoxide, a colorless, odorless, non-irritating gas, is easily combined with hemoglobin that transports oxygen in the human body and is extremely difficult to separate. Therefore, when a large amount of hemoglobin is combined with carbon monoxide, oxygen is lost. The opportunity to combine with hemoglobin causes the human body to transport and utilize oxygen to function as obstacles, resulting in the loss of oxygen in human tissues and necrosis.

(3) Nitrogen oxides are toxic gases with pungent odors, and the nitrogen oxides that are often exposed are mainly nitrogen dioxide. It is a reddish-brown gas with a special odor. When inhaled, it enters the alveoli through the upper respiratory tract and gradually reacts with water to form nitric acid and nitrous acid. It produces intense irritative and corrosive effects on the lung tissue and causes pulmonary edema. .

3. Harm of arc light radiation The arc light produced by welding mainly includes infrared rays, visible light and ultraviolet rays. Infrared rays can cause local skin temperature rise, blood vessels dilate, erythema reaction occurs, and repeated exposure to pigmentation. Short-wave infrared light and visible light are converted to thermal energy through refraction of the interstitial substance, resulting in visual choroidal burns. The short-wave infrared light can be absorbed by the cornea to cause thermal damage to the cornea and can damage the iris through the cornea. If the length of service is longer, the iris pigment absorbs infrared rays and turns into heat energy, indirectly damaging the crystal, or because the anterior segment tissue, such as the cornea, iris, and the crystal itself absorbs infrared heat energy, increases the amount of heat in the anterior segment and promotes the hydrolyzed deformation of the crystalline protein. Solidification, leading to cataracts. Infrared cataracts typically show vacuolar degeneration in the posterior pole of the suboccipital sac, which is spidery and gradually develops into a dish with turbidity and clear boundaries. Regular follow-up treatment of early infrared cataract workers can severely affect vision and can be removed surgically. Electromagnetic waves in the wavelength range of 100-400nm are called ultraviolet radiation, also known as ultraviolet radiation. Ultraviolet rays appear when the object temperature reaches 1200°C or more, and the wavelength of the ultraviolet rays becomes shorter as the temperature increases, and the intensity becomes greater. Ultraviolet rays mainly cause harm to the human body through photochemical effects. It damages the eyes and exposed skin and causes keratoconjunctivitis (electrooptic ophthalmia) and cutaneous erythema. Mainly manifested as patients with eye pain, shyness, tearing, redness and swelling of the eyelids, the skin after UV exposure can appear significantly edematous erythema, severe blisters, exudate and edema, and there is a clear burning sensation. Electro-optic ophthalmia is the most common kind of electromagnetic radiation injury in ophthalmology. Its clinical manifestation is that the attack requires a certain incubation period, and the length of the incubation period depends on the irradiation direction, radiation intensity, and irradiation time. Usually 6-8 hours, it often occurs at night or early morning.

Second, the protection of occupational hazards of welding operations

1. Improve welding technology, improve welding process and materials By improving the welding technology, the welding operation will be mechanized, automated, and the human and welding environment will be isolated from each other, and the harm of the welding operation to the human body will be fundamentally eliminated. By improving the welding process, such as rationally designing the structure of the welding vessel, adopting a single-side welding, double-sided forming new process, to avoid welders welding in poorly ventilated containers, thereby greatly improving the welder's working conditions; another example is the use of welding Smoke dust ionically inhibits CO in-situ technology. Protecting the welding process allows 80% to 90% of the welding fumes to be suppressed on the work surface, to achieve in-situ purification of dust, and to reduce welding fume pollution. Because the harm caused by welding is mostly related to the coating ingredients of the welding rod, it is also an effective measure to reduce the welding hazard by improving the welding rod material and selecting non-toxic or low-toxicity welding electrodes.

2. Improve the ventilation conditions in the workplace The ventilation methods can be divided into natural ventilation and mechanical ventilation. Mechanical ventilation relies on the pressure generated by the fan to ventilate the air. The effect of dust removal and detoxification is better. Therefore, the interior is poorly ventilated and closed. When welding in a container, mechanical ventilation must be provided.

3. Strengthen personal protection measures Strengthen personal protection to prevent the harm of toxic gases and dust generated during welding. Workers must use appropriate protective glasses, face masks, masks, gloves, white protective clothing, insulated shoes, and must not wear short-sleeve clothing or roll up sleeves. If they work in closed containers with poor ventilation, they must wear it. Air performance protective helmet.

4. Reinforce labor protection propaganda and education and on-site tracking and monitoring. Electric welding operators should carry out necessary occupational safety and health education, improve their self-prevention awareness, and reduce the incidence of occupational diseases. At the same time, the monitoring of dust hazards in electric welding workplaces and the medical work of electric welders should also be strengthened to promptly identify and resolve problems.

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