Pollution and prevention control of CO2 gas shielded welding
2018-11-16 14:01:38
China's CO2 welding technology is a welding method developed in the last 20 or 30 years. It has the advantages of good welding quality, small welding deformation, high welding efficiency, energy saving, low welding cost and easy automation. Generally attached. However, from the current situation of CO2 gas shielded welding in China, the pollution hazard has not been fully understood. This paper aims to analyze the pollution of CO2 gas shielded welding from the classification and causes of CO2 gas shielded welding pollution. Hazard, combined with the experience of our company, propose corresponding control methods.
CO2 gas shielded welding is a processing method that uses electric energy to heat and promote the partial or near liquid state of the metal to be welded, so as to form a firm and non-detachable unit. It is a very common machining process in industrial enterprises.
1. Pollution of CO2 gas shielded welding area
The pollution in the CO2 gas shielded welding area is divided into two categories: chemical pollution and physical pollution.
Chemical pollution
Chemical pollution refers to the harmful gases and fumes generated during the CO2 gas shield welding process. When performing CO2 gas shielded welding, some harmful substances are generated around the arc in the welding area. See Tables 1 to 3.
The harmful substances produced by CO2 gas shield welding can be divided into two categories, one is harmful gases, mainly carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3). One type is soot, and its main components are ferric oxide (Fe2O3), silicon dioxide (SiO2), and manganese oxide (MnO). These harmful substances, except for carbon dioxide, are used to protect the arc and the molten pool. They are sprayed from the welding torch. The welding is not used up and remains around the welding area. The remaining harmful substances are generated from the welding arc and the weld pool. Therefore, the closer the welding arc is, the higher the concentration of harmful substances, the stronger the energy used for welding, the greater the concentration of harmful substances, the longer the welding time, and the more harmful substances are produced, the greater the concentration. Obviously, the more enclosed the welding environment, the worse the ventilation conditions and the higher the concentration of harmful gases.
2. Physical pollution
Physical pollution mainly includes: CO2 gas shielded welding arc light.
Second, the impact of CO2 gas shielded welding area pollution on the human body
1. The effect of CO2 gas on the human body
Welding work is a task of heavy physical labor. Under normal circumstances, welders need to have enough air in the welding environment. Although CO2 gas is non-toxic, the content in the air is too high, which is harmful to the human body. When the concentration of CO2 gas in the air is too high, people may have difficulty breathing. When the concentration is > 5%, the person will be in a coma. Until the suffocation dies. CO2 gas shielded welding, there is no problem in the air in a smooth space, but in the container or in a poorly ventilated space, it should be paid full attention to prevent welders from dizziness, coma and suffocation.
2. The effect of CO on the human body
The air does not contain CO, and the CO in the weld zone is generated during the chemical reaction. When CO2 gas shielded, a large amount of CO can be generated, because the high temperature of the arc decomposes CO2 and generates CO. At the same time, the chemical reaction between the liquid metal in the weld pool and CO2 also generates CO. When CO enters the lungs through the human respiratory tract, CO poisoning can occur. CO mild poisoning manifests as headache, dizziness, vertigo, tinnitus, and symptoms such as nausea and vomiting. When inhaled fresh air, the symptoms can disappear immediately. Moderate poisoning in addition to mild symptoms of poisoning, gait instability, confusion and other symptoms can occur; severe poisoning can cause inhalers to lose their lives.
3. The effect of nitrogen oxides on the human body
Under the high temperature of the arc, the nitrogen molecules in the air are oxidized to form nitric oxide (NO). The NO is unstable, and after encountering light and heat, it will continue to oxidize to form stable nitrogen dioxide (NO2). Nitrogen dioxide can become nitric acid or nitrous acid when exposed to water, which has a strong stimulating effect. After inhalation, it can cause acute asthma.
CO2 gas shielded welding is a processing method that uses electric energy to heat and promote the partial or near liquid state of the metal to be welded, so as to form a firm and non-detachable unit. It is a very common machining process in industrial enterprises.
1. Pollution of CO2 gas shielded welding area
The pollution in the CO2 gas shielded welding area is divided into two categories: chemical pollution and physical pollution.
Chemical pollution
Chemical pollution refers to the harmful gases and fumes generated during the CO2 gas shield welding process. When performing CO2 gas shielded welding, some harmful substances are generated around the arc in the welding area. See Tables 1 to 3.
The harmful substances produced by CO2 gas shield welding can be divided into two categories, one is harmful gases, mainly carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3). One type is soot, and its main components are ferric oxide (Fe2O3), silicon dioxide (SiO2), and manganese oxide (MnO). These harmful substances, except for carbon dioxide, are used to protect the arc and the molten pool. They are sprayed from the welding torch. The welding is not used up and remains around the welding area. The remaining harmful substances are generated from the welding arc and the weld pool. Therefore, the closer the welding arc is, the higher the concentration of harmful substances, the stronger the energy used for welding, the greater the concentration of harmful substances, the longer the welding time, and the more harmful substances are produced, the greater the concentration. Obviously, the more enclosed the welding environment, the worse the ventilation conditions and the higher the concentration of harmful gases.
2. Physical pollution
Physical pollution mainly includes: CO2 gas shielded welding arc light.
Second, the impact of CO2 gas shielded welding area pollution on the human body
1. The effect of CO2 gas on the human body
Welding work is a task of heavy physical labor. Under normal circumstances, welders need to have enough air in the welding environment. Although CO2 gas is non-toxic, the content in the air is too high, which is harmful to the human body. When the concentration of CO2 gas in the air is too high, people may have difficulty breathing. When the concentration is > 5%, the person will be in a coma. Until the suffocation dies. CO2 gas shielded welding, there is no problem in the air in a smooth space, but in the container or in a poorly ventilated space, it should be paid full attention to prevent welders from dizziness, coma and suffocation.
2. The effect of CO on the human body
The air does not contain CO, and the CO in the weld zone is generated during the chemical reaction. When CO2 gas shielded, a large amount of CO can be generated, because the high temperature of the arc decomposes CO2 and generates CO. At the same time, the chemical reaction between the liquid metal in the weld pool and CO2 also generates CO. When CO enters the lungs through the human respiratory tract, CO poisoning can occur. CO mild poisoning manifests as headache, dizziness, vertigo, tinnitus, and symptoms such as nausea and vomiting. When inhaled fresh air, the symptoms can disappear immediately. Moderate poisoning in addition to mild symptoms of poisoning, gait instability, confusion and other symptoms can occur; severe poisoning can cause inhalers to lose their lives.
3. The effect of nitrogen oxides on the human body
Under the high temperature of the arc, the nitrogen molecules in the air are oxidized to form nitric oxide (NO). The NO is unstable, and after encountering light and heat, it will continue to oxidize to form stable nitrogen dioxide (NO2). Nitrogen dioxide can become nitric acid or nitrous acid when exposed to water, which has a strong stimulating effect. After inhalation, it can cause acute asthma.
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