What are the operation methods and precautions for gas welding and gas cutting?

The torch is the correct way to produce a gas flame to make the cut straight, and then spray oxygen to gas cut to form a cut, and the flame preheats the material to the ignition point at the starting point.

With acetylene gas. The cutting efficiency is the highest, so that the metal material is violently oxidized and burned, but the cost is high, the surface is smooth, and the generated oxide slag is blown away by the air flow, and the cutting heat energy is transmitted and adjusted; Combustible gas.

Acetylene gas, natural gas or coal gas are generally used.

The use of fast cutting nozzles can improve the cutting speed and better quality.

1 Oxyylene gas welding.

Gas cutting equipment is strictly forbidden to come into contact with grease and dust impurities.

2. If there are metal slag chips or other foreign objects or abnormal air lines during use, the operation should be stopped, and the foreign matter should be cleaned with a special welding nozzle or cutting nozzle, and the oxygen valve should be opened to blow out the foreign matter.

3. It is strictly forbidden to touch the contact working surface when the welding nozzle or cutting nozzle is working, so as not to block the pores, cause oxygen to flow backwards, and enter the acetylene system and cause accidents.

4. When the acetylene pressure reducer is in use, a qualified flashback arrestor must be installed to ensure safe and reliable operation.

5 oxygen cylinders.

It is forbidden to fall to the ground for use, and other items should be placed on the rack or pad, and the angle between the oxygen cylinder and the ground plane should be greater than 40°.

6 Use qualified oxygen pressure reducers and acetylene pressure reducers.

7. The safety distance between the oxygen cylinder and the acetylene cylinder should be greater than 5 meters.

8. Hold a certificate to work or have an experienced special operation certificate with a valid special operation certificate.

With the help of personnel guidance, oxyylene gas welding and gas cutting equipment are used.

The steps of gas welding are:

1. Pre-welding inspection: It is necessary to check whether the injection and suction performance is normal, and whether there is air leakage at the connecting parts of the welding torch and the needle valve of the adjusting handwheel. Gas welding must be done with a gas welding gun, and pay attention to safety before use.

2. Ignition: When ignition, you can open the acetylene handwheel first, ignite the acetylene and immediately open the oxygen regulating valve handwheel to adjust the flame, or you can open the oxygen adjustment handwheel slightly when ignition, and then open the acetylene adjustment handwheel and ignite immediately.

3. Preheating adjustment: After ignition, preheat for a period of time to slowly increase the oxygen concentration, and the flame will change from long to short, forming a neutral flame.

4. Welding: find the welding point, weld, cut and other operations on the object. Wear a protective shield to protect your eyes.

If flashback occurs during operation, turn off the oxygen regulating handwheel and then turn off the acetylene regulating handwheel in an emergency. After the tempering is extinguished, the welding nozzle is placed in water to cool, and then the oxygen is turned on to blow out the soot in the torch, and then the fire is re-ignited.

5. Flame-out: When the flame is out of use, the acetylene adjustment handwheel should be closed first to prevent backfire, and then the oxygen valve should be closed.

6. Post-welding cleaning: the welding torch should be hung in an appropriate place, or the hose should be removed and the torch should be stored in the toolbox.

Steps:

Gas welding ignition

For ignition, the oxygen valve of the torch is adjusted to a small oxygen flow rate, and then the acetylene gas is slowly turned on.

valve, ignite, and then adjust the flow of oxygen and acetylene gas until the flame is adjusted to the desired size, and the welding operation can be carried out.

The method of regulating the flame

According to the different mixing ratio of oxygen and acetylene, gas welding flame can be divided into: oxidation flame, neutral flame, and carbonization flame. The size of the flame during welding can be controlled and adjusted by adjusting the oxygen valve and acetylene gas valve to obtain an oxidizing flame, a neutral flame or a carbonization flame.

Adjustment method of neutral flame: after igniting the torch, gradually increase the oxygen flow, the flame changes from long to short, the color changes from light red to blue and white, when the contour of the flame core, inner flame and outer flame is quite clear, it is the standard neutral flame.

Adjustment method of carbonization flame: on the basis of neutral flame, increase the flow rate of acetylene gas, or reduce the flow rate of oxygen, so that the flame changes from short to long, and the color changes from blue-white to orange-yellow, the carbonization flame can be obtained.

Oxidation flame adjustment method: on the basis of the neutral flame, gradually increase the flow of oxygen, so that the length of the flame becomes shorter, straighter, and emitting a "hissing" sound to obtain the oxidation flame.

Carry out welding

Before ignition, it is necessary to check whether the injection and suction performance is normal, and whether there is air leakage at the connecting parts of the welding torch and the needle valve of the adjusting handwheel.

Gas welding flameout

When extinguishing the flame, the acetylene gas valve should be closed first, and then the oxygen valve.

There are 4 steps in the gas welding operation:

1. Ignition: Open the acetylene valve first, ignite the acetylene and open the oxygen regulating valve immediately.

2. Adjust the flame: The flame that starts to ignite is the carbonization flame, and then gradually opens the large oxygen valve to adjust it to a neutral flame.

3. Carry out welding.

4. Flameout: When the workpiece is extinguished after welding, the acetylene valve should be closed first and then the oxygen valve should be closed to avoid tempering and reduce smoke and dust.

If it is found that the acetylene and oxygen pressure or flow rate changes during the operation, and cannot meet the work requirements and needs to be adjusted, the welding must be stopped, the flame must be extinguished, and the ignition must be re-ignited after treatment. It is forbidden to adjust the treatment with flame to prevent backfire caused by fluctuations in generator pressure and flow.

The role of acetylene in gas welding and gas cutting is to melt the metal by burning the hole roughly. In the traditional welding process, acetylene is used as a fuel gas in gas cutting, gas nano welding for a long time, and the traditional process is the use of calcium carbide.

Chemical reaction of carbon-calcium compounds with water.

Acetylene gas is produced.

Characteristics of acetylene in gas welding and gas cuttingGas welding and gas cutting is the flame produced by the mixing of oxygen and acetylene, which is divided into neutral flame carbonization flame and oxidation flame, oxygen and acetylene gas are flammable and explosive gases, oxygen and acetylene gas are stored and used as upright and separated, there are no flammable and explosive materials around, acetylene emits a lot of heat when burning, so the alkyne oxygen flame formed by the mixed combustion of acetylene and oxygen can reach several thousand degrees Celsius.

It can be used for gas cutting.

Acetylene uses pure oxygen to support combustion, compared with the empty stool potato gas, can greatly increase the flame temperature of about 3000 or more, it is compared with arc welding, the temperature of the gas welding flame is low heat dispersion, the heating speed is slow, so the productivity is low, the workpiece deformation is serious, the heat affected zone of welding is large, and the quality of the welded joint is not high.

Gas cutting and gas welding is a processing process for metal fracture and joining, which is usually used in metal cutting, welding, repair and other fields. The process usually consists of the following steps:

1.Preparation: Prepare the metal materials that need to be processed, clean the surface of impurities and grease, choose the right welding materials and pneumatic equipment.

2.Make a plan: according to the type, thickness, shape and other conditions of the metal materials to be processed, formulate the corresponding processing plan, and determine the type and use method of welding materials.

3.Ignition preheating: Ignite the nozzle with a lighter to start preheating the work area so that the welding material can adhere and melt better. It is usually necessary to preheat the work area at both ends and in the middle, respectively, until the temperature reaches the melting point of the welding material.

4.Start machining: When the preheating is complete, you can start gas cutting and gas welding. The ratio of oxygen and acetylene is controlled by the wild repentance operating handle, and the high-temperature flame generated by the combustion is sprayed into the working area, melting or cutting the metal material.

5.Adjust the flame: In the process of processing, it is often necessary to adjust the size and shape of the flame according to the situation of the processing object to ensure that the metal material can be melted or cut evenly and stably.

6.Complete the processing: When the processing is completed, the nozzle needs to be cleaned, the valves for oxygen and acetylene need to be closed, and the workbench and equipment need to be cleaned for the next use.

It should be noted that gas cutting and gas welding is a dangerous processing process, and it is necessary to strictly abide by the full operation procedures before the safety cover, wear the corresponding labor protection equipment, and ensure that the equipment runs normally to avoid accidents. In addition, it is also necessary to pay attention to the type and quality of the welding material, and operate in strict accordance with the processing plan to obtain the best processing effect.

The gas cutting process of metal is a continuous process of preheating, combustion, and slag blowing, which is essentially the process of metal combustion in pure oxygen, rather than the melting process. Heat the start point with a preheated flame (at this point hyperbaric oxygen.

The air valve is closed), the preheating time should be determined by the temperature of the metal, heated to the surface of the workpiece close to melting (the surface is orange-red.

At this time, gently open the high-pressure oxygen valve and start gas cutting.

If the preheating place can not be cut, it means that the preheating temperature is too low, the high-pressure oxygen should be turned off to continue preheating, the front end of the flame core of the preheating flame should be 2 4mm away from the surface of the workpiece, and at the same time, it should be noted that there should be a certain angle between the torch and the workpiece, when the workpiece with a thickness of 5 30mm is cut by gas, the cutting torch should be perpendicular to the workpiece; When the thickness is less than 5mm, the torch can be tilted back 5 10°.

If the thickness exceeds 30mm, the torch can be tilted forward by 5 10° at the beginning of gas cutting, and when it is cut through, the cutting torch can be perpendicular to the workpiece until the gas cutting is completed. If the preheated area is cut off, continue to increase the amount of high-pressure oxygen to increase the depth of the incision until it is completely cut through.

Gas welding. To operate, hold the welding moment in your right hand and place your thumb at acetylene.

At the switch, the index finger is located at the oxygen switch to facilitate the adjustment of the gas flow at any time. Hold the welding moment handle with the other three fingers, and hold the wire in your right hand The basic operations of gas welding are: ignition, flame adjustment, welding and flame out.