In the long-term use of automobile fuel tanks, cracks and leaks often occur due to vehicle bumps or corrosion. In addition to small crack damage and small stress, it can be blocked by soldering or bonding, and generally repaired by electric welding. However, when welding and repairing this container with petroleum products, we must strictly abide by the operating rules and strengthen safety protection measures, otherwise unimaginable consequences will occur. It is particularly important to note that the oil tank must be thoroughly cleaned before welding, because petroleum products (especially gasoline) have strong permeability, and it is difficult to remove petroleum gas molecules by random cleaning. When welding, the flame ignites the residual combustible mixed gas in the fuel tank, which will cause an explosion.

General cleaning methods of gasoline tank are:

1. Put off all the gasoline, remove the fuel tank, then fill the fuel tank with more than half of the water, and introduce the boiler steam into the water from the fuel filler with a conduit, so that the water in the fuel tank will boil for about 1 hour, and the colloid and dirt will float on the water surface and be washed away. This can be done twice in a row.

2. Wash the gasoline tank with hot water, then blow dry it with compressed air to remove the gasoline vapor inside, and finally put the gasoline tank into the water solution containing 10% sodium hydroxide for soaking and cleaning. After soaking, wash the inside and outside with clean water. If it is found to be rusty, brush it with a wire brush.

3. If the above conditions are not met, you can also flush the gasoline tank with clean water. The method is to insert the water pipe into the mouth of the oil tank, open the oil plug and float mouth, and rinse it continuously with pressure water for about 5 days until the smell of gasoline disappears, and then weld it. After cleaning the gasoline tank, check its tightness. The method is as follows: firstly, block all the orifices of the gasoline tank with rubber plugs, then immerse them in water, and input compressed air with the pressure of117.6 ~147 kpa into the oil tank from the pipe joint of the oil tank, and the place where the air emerges is the leakage position. Scrape the paint clean. If the leakage is not big, it can be welded. If it leaks too much, it needs to be patched up. When gas welding is used, the gasoline tank should be filled with cold water to prevent explosion. After welding, smooth the welding place with a trowel, then check the tightness of the gasoline tank with high-pressure air, and then load it for use after welding. This can not only ensure the production safety, but also ensure the welding quality of the gasoline tank.

The work site of automobile welders must be kept dry and clean, with good ventilation and natural light (or lighting), with an area of not less than 4 square meters; There shall be no inflammable and explosive articles on the wall and around, so as to reduce the fatigue of workers, improve labor efficiency and ensure safety in production. Attention should be paid to fire danger when welding. Splashes of molten metal and heated electrode tips may fall on combustible materials and cause combustion. When carrying out local welding repairs on automobiles, the gasoline tank should be removed or isolated first, so as to avoid accidents caused by sparks detonating fuel.

In order to prevent the danger of electric shock, automobile welders should be well protected during operation. Wear dry and clean work clothes and insulated shoes; The welding shell and weldment working in dry places must be grounded; When repairing welding equipment, the power switch must be cut off; Handle of cable and electrode holder shall be well insulated, and connecting bolts of cable and welding equipment shall be tightened; Dismantling or repairing the primary line of welding equipment shall be carried out by professional electricians, and shall not be disturbed at will.

The arc emits infrared rays, ultraviolet rays and strong light harmful to human body. People's eyes are exposed to infrared rays for too long, which will cause "lens cataract" eye disease, and in severe cases, they will be blind. Even short-term exposure to ultraviolet light can cause "photophobia" eye disease, which can cause severe pain and tears. Ultraviolet rays can also cause skin burns and even peeling. Strong visible light will dazzle people's eyes in a short time and weaken people's vision in a long time. In addition, during arc welding, it may be burned by splashes of molten metal. Therefore, before operation, welders must wear special leather gloves and special protective plates or masks for eye protection glass in addition to work clothes and insulating shoes. As an electric welder, we must realize the importance of safe production, be familiar with the knowledge of safety protection, observe the operating rules and ensure safe production.