What problems should be paid attention to in electric welding? Can it be firmly welded without false

Proper welding current, broken arc welding.

The types of welding rods are different, the diameters are different, and the welding electrode packaging box has a description of the scope of welding current.

Even if the thin workpiece is welded, the welding current should not be too small, otherwise there will be slag inclusion, no fusion, no penetration, sticking electrode and even burning out the welding machine.

The welding current is too large, it is easy to burn through, the weld grain is coarse, the heat affected zone is too wide, and the weld has no strength at all.

Broken arc welding, then the base metal ignites the arc to form a solder joint, lifts the arc to extinguish, observes the weld pool with a welding cap to cool to the diameter of the welding rod, and then arc welding. Thin iron welded solder joints can lap 1 2.

It is the four major elements of welding.

What they say about the environment where there are weldments that put p.

The real four elements are .

Not soldered. There is no breakdown weldment.

Undissolved. That is, the electrode is not fully dissolved in the weldment.

Inclusion. In some places, it is called slag inclusion. It is the coating in the weld bead pool.

Bubble. It's that there are air bubbles in the weld meat.

The above are the requirements for top welders. Because a good welder has to take a picture of a seam after welding.

That's the Achilles' heel of welders. There have always been words. That's not a good welder.

.Although I would be theoretical. But I'm just a little welder. Wish.

To weld firmly, then the two sides of the workpiece should be fused well, the power supply can fully open the molten pool, there can be no slag inclusion, the thin iron plate is suitable for the power supply spot welding is completed, and the welding rod is selected with a small diameter

current, voltage, and welding speed. The diameter of the electrode should be thin. Welding firmly looks at the weld pool, which requires experience.

First set the current according to the material, and then do a good job of self-protection. Evenly, you should put yourself in a good posture to withstand loneliness, maintain the welding speed of the welding rod angle, and when you think of yourself as a welding machine, you can weld evenly without too many distractions. If you want not to burn through, pay attention to the welding current, angle, speed, and welding technique.

Don't use too much current; The angle should be positive, not burned, and more thick materials should be burned; The second is to be fast; Then there are the most critical methods, reciprocating, circle, serrated crescent, spot welding, these methods can effectively avoid burn-through. Do more experiments and summarize by yourself, think more about why, and soon you will be very good.

1. In order to ensure the stable combustion of the welding arc and the surface forming of the weld, after the arc is ignited, the welding rod should move in three directions

1) The electrode is continuously fed into the weld pool.

2) The electrode moves forward along the welding direction.

3) The electrode swings horizontally.

When the electrode moves, it should be at an angle of 70-80 degrees to the forward direction, and push the melted metal and slag to the rear, otherwise the slag flows to the front of the arc, which will cause slag inclusion defects.

Second, the method of transport. In order to obtain a wide weld seam, the electrode also has to make the necessary oscillation during feeding and moving. The usual shipping method is as follows:

1) Linear transport strip method.

2) Straight line reciprocating transport method.

3) Zigzag transport method.

Pay attention to the size of the current and the speed of welding, and it will not burn through. If you want to weld evenly, you can only practice more, and there is no other way.

No welding wire welding must be the workpiece welding joints together, if you leave even if only it is difficult to weld, first spot welding, when welding, the welding speed should be uniform, no welding wire, the current is not about 20A, from the middle to both sides of the welding.

The key point of not deforming after welding is that the plate butt is dense, at least 1 cm a point, and it is best to add copper lining under the conditional plate, and the point to be welded can also be on the platform or as a fixture. The speed must be fast, the slower it is, the more deformed.

On the basis of the principle of ordinary arc welding, the protection of argon on metal welding consumables is used, and the welding consumables are melted into a liquid state on the welded substrate to form a molten pool through high current, so that the welded metal and the welding consumables can achieve metallurgical combination.

Of course, no, the self-melting of TIG welding is only suitable for thin parts.

No, the weld will be dented, that is, there is a lack of meat.

There are two main reasons why electric welding iron plates are easy to penetrate:

1. The plate wall is thin and the current is too large.

2. The technique is wrong. That is to say, the angle between the electrode and the board is wrong, generally 45°.

3. The current of the iron plate can not exceed 30 times the diameter of the welding rod. That is, if you use the case of electrode, the current cannot exceed 75A.

It is impossible to weld too thin iron plate (less than 1 mm) electrode without burn-through.

In our country, welding operations need to be licensed, welders are the type of work that belongs to the access category, in the professional qualifications of skilled personnel, only five of the 81 types of work in the access category, welders are one of them, and the actual situation is that most of the industry practitioners are unlicensed operations. With the continuous standardization of technology and the relevant requirements of the industry, more and more people want to take a welding certificate, the advantage of the certificate is still very large, first of all, the salary of the certificate and the non-certificate are very different, often able to reach more than double or higher level. Therefore, the issue of short-term welder training has naturally become a concern for practitioners.

Welding as an industrial "tailor" is a very important means of processing in industrial production, the quality of welding has a decisive impact on the quality of the product, so what is the future development of welding technology?

Industry outlook. With the development of production, welding is widely used in aerospace, aviation, nuclear industry, shipbuilding, construction and machinery manufacturing and other industrial sectors, in China's economic development, welding technology is an indispensable means of processing. After entering the 21st century, welding is an important part of the manufacturing industry, and the rapid development of the welding industry has brought unprecedented development opportunities.

At present, China consumes 300 million tons of steel every year (about tons of welded structure), and needs about 750,000 welding machines, and the welding industry will continue to grow in the next 8 10 years.

1. Quality problems and phenomena.

The length of the weld is not enough, the surface of the weld is uneven, there are large depressions, welding nodules, undercuts in the weld, the welding rod is unqualified, the welding skin is not knocked off, and the axis of the two joint steel bars is inconsistent.

2. Cause analysis.

1) The welder is not skilled and has not obtained the welder examination certificate.

2) The length of the inflatable mandrel weld is not measured after the welding is completed.

3) The welding rod is unqualified, or the specification of the selected welding rod is incorrect.

4) After the welding is completed, no attention is paid to knocking off the inflatable core die welding skin.

5) Two welded steel bars with no pre-bending at the lap ends.

3. Precautionary measures.

1) Before the welding of the inflatable core mold steel bar, the test welding must be carried out according to the construction conditions, and the welder must have the examination certificate.

2) When the rebar joint of the inflatable mandrel is welded or arc welded, it should be made into a double-sided weld as much as possible.

3) When lap arc welding is used for the reinforcing steel joint of the inflatable core mold, the lap end of the two reinforcing bars should be folded to one side in advance, so that the axis of the two joint reinforcing bars is consistent.

4) The length of the double-sided weld of the joint should not be less than 5d, and the length of the single-sided weld should not be less than 10d.

5) When the steel bar joint is arc welded, the steel bar should be of the same level as the main reinforcement, and its total cross-sectional area should not be less than the cross-sectional area of the welded steel bar. The length of the strip, such as double-sided weld, should not be less than 5d, such as single-sided weld should not be less than 10d.

6) The performance of the welding rod used should meet the relevant provisions of the welding electrode standard for low carbon steel and low alloy steel.

7) The welding of stressed steel bars should be set at a place with small internal force and staggered arrangement.

8) The distance between the arc welding and the bending place of the steel bar should not be less than 10 times the diameter of the steel bar, and it should not be located at the maximum bending moment of the component.

9) When welding, the welding site should have appropriate windproof, rain, snow and cold facilities, and technical measures should be taken when the ambient temperature is 5-20; Below -20 feed, not suitable for welding.

10) After the welding is completed, the welding skin should be knocked off in time.

Before welding stress and steel bar welding, the welding part should be removed from rust, slag, oil stain, etc.; Welding between imported steel bars from different countries or between imported steel bars and domestic steel bars should be avoided as much as possible.

1.The power supply is equipped with vertical external characteristics, and the positive polarity (welding wire is connected to the negative electrode) is used in the case of DC

2.Generally, it is suitable for the welding of thin plates below 6mm, and has the characteristics of beautiful weld forming and small welding deformation.

3.The shielding gas is argon and the purity is. When the welding current is 50"At 150A, the argon flow rate is 8"10l min, when the current is 150"At 250A, the argon flow rate is 12"15l/min。

4.The tungsten electrode protrudes from the gas nozzle to 4"5mm is preferred, and 2 is in areas with poor opacity such as fillet welding"3mm, 5 in the place where the groove is deep"6mm, the distance from the nozzle to the working is generally not more than 15mm.

5.In order to prevent the appearance of welding pores, the welding parts must be cleaned if there is rust and oil stains.

6.The length of the welding arc, when welding ordinary steel, is 2"4mm is preferred, while when welding stainless steel, take 1"3mm is preferred, too long will not have a good protection effect.

7.In order to prevent oxidation of the backside of the bottom weld bead, gas protection is also required on the backside of the bottom weld bead during butt priming.

8.In order to make argon well protect the weld pool and facilitate the welding operation, the center line of the tungsten electrode and the workpiece at the weld should generally be kept at 80"85° angle, the angle between the filler wire and the surface of the workpiece should be as small as possible, generally about 10°.

9.Wind protection and ventilation. In windy areas, it is important to take measures to block the screen, and appropriate ventilation measures should be taken indoors.

Key points and precautions for stainless steel MIG welding.

1.The flat characteristics are used for welding power supply, and the reverse polarity (welding wire is connected to the positive electrode) is used for DC

2.Generally, pure argon gas (purity of or ar 2%O2, flow rate of 20"25L min is appropriate.

3.The arc length, MIG welding of stainless steel, is generally welded under the condition of jet transition, and the voltage should be adjusted to the arc length of 4"6mm degree.

4.Wind. MIG welding is susceptible to the influence of wind, and sometimes it is caused by wind and pores, so wind speed should be taken in the above places.

Stainless steel flux-cored wire welding points and precautions.

1.The flat characteristics of the welding power supply are adopted, and the reverse polarity is used in DC welding. You can use a regular CO2 welder to weld, but the pressure of the feed wheel should be slightly loosened.

2.The shielding gas is generally carbon dioxide gas, and the gas flow rate is 20"25L min is more suitable.

3.The distance between the welding nozzle and the workpiece is 15"25mm is appropriate.

4.The general welding current is about 15 mm when the dry elongation is less than 250 A, and about 20 mm when the welding current is above 250 A"25mm is more suitable.

Manual welding: 1. Chromium stainless steel has certain corrosion resistance (oxidizing acid, organic acid, cavitation), heat resistance and wear resistance. It is usually used in power stations, chemical industry, and petroleum.

and other equipment materials. The weldability of chromium stainless steel is poor, and attention should be paid to the welding process, heat treatment conditions and the selection of suitable welding electrodes.

2. Chromium 13 stainless steel has large hardening after welding, and is prone to cracks. If the same type of chromium stainless steel electrode (G202, G207) is used for welding, it must be preheated at more than 300 degrees and about 700 meters after welding.

(1) When storing or transporting, stainless steel should not be mixed with general steel, so as not to be polluted by impurities such as rust.

2) The stainless steel surface should avoid abrasion or collision. Especially when marking the line, it is strictly forbidden to use the scribing needle or punch the eye, otherwise it will directly affect its corrosion resistance.

3) When beveling stainless steel weldments, carbon arc gouging should not be used, so as to avoid carburization, which is not conducive to the anti-intergranular corrosion of weldments, and should be machined or plasma arc cutting and cutting.

4) When correcting stainless steel, it should not be directly hammered with a hammer, so as not to cause dents on the surface of the workpiece and affect its corrosion resistance.

5) The head and other parts of the container should be cold-pressed forming, not hot-pressed forming. If hot press forming is necessary, changes in corrosion resistance should be checked and heat treated accordingly.

6) When the stainless steel is subjected to post-weld heat treatment, the surface of the steel should not be left with grease and other dirt before heating, and it must be cleaned to avoid carburizing during heating. The heating should be uniform, and when the stress relief treatment above 800 900 is carried out, the temperature rise should be slow below 850. However, temperatures above 850 should be moderately rapid to avoid the tendency to increase grain growth.

7) The surface treatment of stainless steel for grinding, polishing, pickling and passivation shall not be reckless, and the treatment process must comply with the operating procedures to the uniform silver-white surface of the steel.

We are specialized in welding stainless steel plates, if you encounter more than 3 steel plates or channel steel angles and other thicker materials, we use electric welding, but also use stainless steel electrodes, so that the fire is more thorough.