Here are some related knowledge: 1: the arc temperature of argon arc welding is generally between plasma arc and manual arc welding, with the arc temperature of 9000- 10000K, plasma arc 16000-32000K, manual arc 5000-6000K and MIG welding arc temperature of 65438. Colchicine myopia caused by welding arc light; Noise causes hearing loss. 2. Electric welding is the difference (positive or negative) between the workpiece and covered electrode power supply. The instantaneous contact between covered electrode and the workpiece ionizes the air to generate an arc, and the arc temperature is relatively high, about 5000-6000K, which melts the surface of the workpiece to form a molten pool. After melting, the coated covered electrode metal is coated on the surface of the workpiece to form metallurgical bonding. 3. "Oxyacetylene Flame" refers to acetylene in oxygen (acetylene is commonly known as calcium carbide gas, which reacts with water). In this reaction, a lot of heat is released, so that the temperature of oxyacetylene flame can reach above 3000℃, and steel will melt soon when it comes into contact with oxyacetylene flame. Using this characteristic, oxyacetylene flame is often used to weld or cut metal in production, which is usually called gas welding and oxyacetylene cutting. Gas welding; It uses the high temperature of oxyacetylene flame to fuse two metals together. The key is to prevent metals at high temperature from being oxidized by oxygen in the air. Therefore, it is necessary to control the amount of oxygen, which will make acetylene burn insufficiently. In this way, the flame is reducible because it contains carbon monoxide and hydrogen produced by incomplete combustion of acetylene. This kind of flame makes the metal parts and covered electrode to be welded not be oxidized to change their composition when melting, and the weld will not be polluted by oxides ... 4. Water welding should be a welding process under special conditions. 5. The temperature of oxyhydrogen flame can be as high as 2500~3000℃, not to mention the high melting point (melting point: 17 15℃) can be melted under oxyhydrogen flame combustion. Therefore, oxyhydrogen flame can be used to process timely finished products. The application of C2H2 flame and HO flame is different. O of HO flame is highly oxidizing. In some cases, HO flame is not needed to prevent metal from being oxidized during welding. On the contrary, C with valence of-1 in C2H2 is reducible. C2H2 flame can be used not only for welding metal, but also as a protective gas to prevent O in the air from oxidizing the welding metal. Covered electrode: E43 and E50 series welding machines are commonly used: The working principle of ordinary welding machines is similar to that of transformers, and they are step-down transformers. At both ends of the lifting coil are the welded workpiece and the coated electrode, which ignite the arc and melt the gap between the workpiece and the coated electrode at high temperature of the arc. Welding transformer has its own characteristics, that is, the voltage drops sharply. Covered electrode voltage drops after ignition; When the covered electrode is short-circuited due to adhesion, the voltage also drops sharply. The reason for this phenomenon is the iron core characteristics of welding transformer. The working () voltage of electric welding machine can be adjusted not only by a 220/380 voltage conversion, but also by the secondary winding tap. At the same time, it can be adjusted by iron core. With the intervention of the iron core, the magnetic circuit will be shunted, and the more involved, the lower the welding voltage. The working schematic diagram is similar to that of transformer, so it is not drawn here. Suggestions on becoming an excellent welder: 1. First of all, there are more than 100 welding methods. The first one is manual welding (that is, the one that burns covered electrode); Resistance bump welding; Gas shielded welding (carbon dioxide and argon arc welding, etc. ); Flame welding; Ultrasonic welding, friction welding, etc. Commonly used welding technologies are argon arc welding, carbon dioxide welding and manual welding. You need to go through formal welding training and obtain a welder's certificate before you can take up your post. 3。 Due to certain technical and skill requirements, the effect and quality of products welded by different degrees of welders are quite different. The salary of a truly high-level welder (national level) is very high. The minimum income of welders in Guangdong is around 1500 yuan, and the piece rate may be higher. Welders should have good occupational protection measures when operating, such as gloves, masks, shoes, aprons, underwear, glasses, etc. So there is no need to worry about danger. As long as you follow the rules, it is safe. Welder is a good skill, but to be a good welder, you really need to study and practice hard. -Manual arc welding process operation method, welding medium carbon steel

I. Custody of covered electrode:

1, all kinds of covered electrode must be stored in different brands to avoid clutter. At the same time, it should be stored in a dry and well-ventilated warehouse, and placed at a place not less than 300 mm away from the ground and walls to prevent moisture deterioration.

2. Because the coating is easy to be affected with damp, the process performance of covered electrode becomes worse after being affected with damp, and the hydrogen in the moisture is easy to cause pores and cracks in the weld, so covered electrode must be dried before use to reduce the hydrogen content of covered electrode, which is generally 350 ~ 450&; Ordm, keeping the temperature for 65438 0 ~ 2 hours, and drying.

Second, the operation:

1. After the workpieces are connected, they should be spot-welded firmly before welding. The width-height ratio of the weld is 2~3, and the width of the weld is generally 1.5~2 times. The initial weld refers to the part that has just started welding. After arcing, the arc should be slightly lengthened, the welding end should be preheated, and then the arc length should be appropriately shortened for normal welding.

2. Sweep welding means that after a weld is completed, the arc pit at the sweep welding place should be filled. If the arc is broken immediately during arc sweeping, an arc pit lower than the surface of the weldment will be formed, which will weaken the strength of the weld arc sweeping and lead to cracks. Therefore, arc pits are not allowed to exist when sweeping the tail, and the arc pits should be filled in.

3. Due to the limitation of the length of covered electrode, it is sometimes impossible to finish welding with covered electrode. The starting point of the weld required to be welded first is slightly lower. When connecting, start arc striking slightly in front of the starting point of the weld, lengthen the arc slightly, lead the arc to the starting point, and cover the end point of the previous weld. After the weld at the starting point is leveled, it will move along the welding target.

4. Generally speaking, zigzag or crescent-shaped strip conveying method is used for the width of weld. This method has the advantages of high weld strengthening, good metal melting, long heat preservation time, gas evolution and slag floating to the surface easily, which is beneficial to improve weld quality.

Welding thickness: the first layer of weld and other layers of weld.

Covered electrode Diameter Welding Current (A)

≥6 4 160~2 10 4 160~2 10 5220~280

When welding the second layer, the slag of the first layer should be removed first, and then the welding should be carried out with a larger diameter covered electrode and a larger welding current. In order to ensure quality and prevent deformation, the welding targets between layers should be opposite and the welded joints should be staggered. The verbal expression of welding skills is not clear, so you have to manually operate face to face, so as to understand the welding operation skills. If the operation is not good, the welding interface will be irregular, there will be many bubbles, the welding things are different, the skills and methods are different, and the selection of covered electrode and voltage is also very particular! First of all, be careful of colchicine. That job is difficult to do.

Then use both hands and use your brain.

Finally, what is to be welded together is considered successful as if there is no welding (Editor: admin).