Application of acetylene. Welding with acetylene

To understand where acetylene is used, it is necessary to study and understand what it is. This substance is a combustible colorless gas. Its chemical formula is C₂H₂. The gas has an atomic mass equal to 26.04. It is slightly lighter than air and has a pungent odor. The production and use of acetylene is carried out only in industrial conditions. This substance is obtained from calcium carbide by decomposing the component in water.

What is dangerous is acetylene

The use of acetylene is limited by its extraordinaryproperties. This gas is self-igniting. This occurs at a temperature of 335 ° C, and its mixture with oxygen at a temperature of 297 to 306 ° C, with air at a temperature of 305 to 470 ° C.

It is worth noting that acetylene is explosive technical. This happened when:

Increasing the temperature to 450-500 ° C, and also at a pressure of 150-200 kPa, which is equal to 1.5-2 atmospheres.
A mixture of acetylene and oxygen at atmospheric pressure is also dangerous, if acetylene contains 2.3-93% of it. The explosion can occur from strong heating, open flame and even from a spark.
Under similar conditions, an explosion of the air mixture with acetylene occurs if it contains 2.2-80.7% acetylene.
If the gas is in contact for a long time with copper orsilver object, then acetylenic explosive silver or copper can be formed. This substance is very dangerous. The explosion can occur from a strong impact or as a result of an increase in temperature. Work with gas should be carefully.

Features of the substance

Acetylene, the properties and application of which to the endnot studied, as a result of the explosion can lead to an accident and severe destruction. Here are some data. In the explosion of one kilogram of this substance, 2 times more thermal energy is released than with the explosion of the same amount of TNT, and one and a half times more than in the explosion of one kilogram of nitroglycerin.

Areas of application of acetylene

Acetylene is a combustible gas that is usedat gas welding. Often it is used for oxygen cutting. It is worth noting that the combustion temperature of a mixture of oxygen and acetylene can reach 3300 ° C. Due to this property, the substance is most often used in welding. Acetylene is usually replaced by natural gas and propane-butane. The substance provides productivity and high quality welding.

Supply of gas for cutting and welding canbe carried out from an acetylene generator or from cylinders with acetylene. To store this substance, white containers are usually used. As a rule, they have the inscription "Acetylene", painted with red paint. It is worth considering that there is GOST 5457-75. According to this document for processing metals used technical dissolved acetylene grade B or the substance in a gaseous form.

Acetylene welding: verification

The technology of welding with this gas is quite simple. However, when working with the substance requires patience and attention. For welding, special burners are used, with the marking 0-5. Its choice depends on the thickness of the parts to be welded. It should be noted that the larger the burner size, the higher the consumption.

Acetylene welding is carried out only afterHow the equipment will be checked and adjusted. In doing so, note the tip number and the number of the gas injector, which is located near the handle of the burner under the nut. Also check all seals.

Welding process

The use of acetylene in welding shouldbe carried out carefully and in accordance with certain rules. To start, the burner should be flushed with gas. This should be done until the smell of acetylene appears. After that, the gas is ignited. At the same time, oxygen should be added until the flame becomes more stable. From the reducer at the outlet, the acetylene pressure should be from 2 to 4 atmospheres, and oxygen from 2 atmospheres.

For the welding of ferrous metals, a neutralflame. It has a clearly defined crown and can be divided into three bright parts: the core is bright blue with a greenish tint, the restored flame is a pale blue tint, the flame of the flame. The last two zones are workers.

Before you start, all parts must be cleaned, andthen adjust to each other. When working with the burner, the left and right methods are also used. In the latter case, the joint slowly cools. The filler material, as a rule, moves behind the burner. With the left method, the elasticity and strength of the seam increases. In this case, the flame is sent from the welding location. The filler material should only be added to the weld pool after the burner has moved to the next position.

Safety regulations

The use of acetylene without skills and experience is prohibited. There are several rules that should be observed when working with a substance:

The content of acetylene in a room in the airmust be constantly monitored. To do this, use special automatic devices that are able to alert you of excess gas concentrations. This indicator should not be more than 0.46%.
Areas of application of acetylene are completely different,but most often it is used for welding. Care should be taken when working with cylinders filled with this particular gas. It is forbidden to place containers near open flames or near heating systems. In addition, it is prohibited to work with cylinders that are in a horizontal position, and also if they are not fixed and defective.
When working with acetylene, use only non-sparking tools, electrical equipment and explosion-proof lighting.
If leakage of acetylene from the cylinder occurs, the valve of the container should be quickly closed. To do this, you can use a non-sparking special key. Determine the leakage can only be by sound or smell.

What to do if there is a fire

Incorrect use of acetylene can lead to unfortunate consequences. This gas explodes and causes severe destruction. What to do if there is a fire?

When a fire occurs, it should immediatelyRemove all containers filled with acetylene from the danger zone. Those cylinders that have remained should be constantly cooled with ordinary water or with a special composition. Containers must completely cool down.
If the gas that comes out of the cylinder is ignited, then immediately close the container. To do this, use a non-sparking key. After that, the container must be cooled.
In case of severe fire, extinguishing the fire shouldonly from a safe distance. In such a situation it is worth using fire extinguishers filled with a composition containing a phlegmatizing nitrogen concentration of 70% by volume, also carbon dioxide of 75% by volume, sand, water jets, compressed nitrogen, asbestos cloth and so on.