What are the main harmful substances produced during the welding process of metal materials?

What are the main harmful substances produced during the welding process of metal materials?

1. Arc radiation

During arc discharge, high heat is generated on the one hand, and arc radiation is also generated at the same time. Arc radiation mainly includes visible rays, infrared rays and ultraviolet rays. It acts on the human body and is absorbed by the tissues in the body, causing thermal, photochemical or ionization effects on the tissues, causing acute or chronic damage to the human tissues.

2. Noise

During the plasma arc welding and cutting process, friction occurs due to the high-speed jetting of plasma flow, resulting in noise. When the noise intensity exceeds the health standards, it is harmful to the human body. The most sensitive part of the human body to noise is the hearing organ. Without protection, strong noise can cause hearing impairment, noise-induced trauma, deafness and other symptoms. Long-term exposure to noise can also cause disorders in the central nervous system and blood system, leading to symptoms such as boredom, irritability, elevated blood pressure, and tachycardia.

3. Radioactive materials

The thorium in the thorium tungsten rod electrode used in argon arc welding, plasma arc welding and cutting is a natural radioactive substance that can emit three types of rays: α, β and γ. Radioactive substances act on the human body in two forms: one is external irradiation, and the other is during welding operations. Smoke and dust containing thorium and its decay products enter the human body through the respiratory and digestive systems and are difficult to be expelled from the body, forming internal irradiation. Internal exposure is more harmful. If the human body is exposed to a dose exceeding the allowable dose for a long time, or radioactive substances often enter and accumulate in the body in small amounts, it can cause pathological changes and cause diseases of the central nervous system, hematopoietic organs and digestive system. In severe cases, radiation sickness may occur.

4. High frequency electromagnetic field

In non-melting electrode argon arc welding and plasma arc welding, high-frequency oscillators are commonly used to stimulate the arc. Some AC argon arc welding machines also use high-frequency oscillators to stabilize the arc. The human body will produce biological effects under the action of high-frequency electromagnetic fields. Long-term exposure of welders to high-frequency electromagnetic fields can cause plant dysfunction and neurasthenia, manifesting as symptoms such as general discomfort, dizziness, headache, fatigue, loss of appetite, insomnia, and low blood pressure. According to measurements, during manual tungsten arc welding, the high-frequency electromagnetic intensity received by all parts of the welder exceeds the standard. Among them, the intensity of the hand is the highest, which exceeds the health standard by more than five times.

Labor protection measures for welding and cutting operations

The so-called protection means to isolate the human body from dangerous and toxic factors in production and create a safe, hygienic and comfortable working environment to ensure safe production. Safety production includes two aspects: first, to prevent the occurrence of work-related accidents, that is, electric shock, fire, explosion, metal splash, mechanical injury, etc.; second, to prevent the hazards of occupational diseases, such as dust protection, virus protection, radiation protection, noise protection, etc. . This article mainly discusses protective measures against harmful factors.

Welding smoke first originates from the evaporation of metal during the welding process. This is because the temperature of the welding arc is above 3000°C, and the arc center temperature is higher than 6000°C. Such high temperatures will inevitably cause the evaporation and oxidation of metal elements. The second is the metal oxide produced by the oxidation reaction between the oxygen decomposed under the high temperature of the arc and the liquid metal in the arc zone. In addition to causing defects such as slag inclusions in the weld, they may also spread to the work site. It is mainly a mixed dust composed of iron oxide, manganese oxide, fluoride and silica.

The dangers of welding fumes

When welding ferrous metal materials, the main components of the smoke are iron, silicon, and manganese. When welding other different materials, there are aluminum, zinc oxide, molybdenum, etc. in the smoke, among which manganese is the most toxic. Although iron and silicon are not very toxic, their dust particles are below 5 microns and stay in the air for a long time. They can easily enter the lungs through the respiratory tract and form pneumoconiosis. Iron oxide, manganese oxide particles and fluoride enter the peripheral bronchioles and alveoli through the upper respiratory tract, and then enter the body, which can easily cause metal heat in welders. Welders are exposed to such metal fume for a long time. If the protection is not good and excessive fume is inhaled, it will cause headaches, nausea, tracheitis, pneumonia, and even the risk of welder pneumoconiosis, metal fever and manganese poisoning.