Ruan Fugen asked Sun Guohua for verification again, confirming that Du Xiaodi was one of the two Songjiang welders who Sun Guohua said was "skilled", and Du Xiaodi also showed Ruan Fugen the certificate of his training in Japan, which made Ruan Fugen feel a little more at ease. Pen, fun, pavilion www. biquge。 info

Because of the tight time of the mission, Ruan Fugen did not dare to delay, and immediately returned to Hoi An with Du Xiaodi. Bi Jianxin heard that Ruan Fugen had hired a new welder, and he also came to the workshop with his arm in plaster. When he saw Du Xiaodi's appearance, Bi Jianxin's thoughts were the same as Ruan Fugen's, and they all felt that Du Xiaodi was playing with everyone. Everyone knows the phrase "welders should be small", but it doesn't mean that a 20-year-old girl can be on her own. This is a type II pressure vessel for welding, not a solder joint iron sheet, steel pipe, etc., the welding quality is not up to standard, these containers will crack under high pressure, that is not a joke.

"Master Bi, don't worry, I understand this truth. Du Xiaodi changed into a welding overalls, stood heroically in front of Bi Jianxin and Ruan Fugen, and said lightly. Just such a little pressure vessel common sense, Lao Bi has been making noise in front of her for a long time, are you sure that Tongyuan Boiler Factory is smaller than your Hoi An Chemical Machinery Factory?

"Otherwise, you solder something else first, and let me ...... Uh, and Director Ruan?" Bi Jianxin said.

Du Xiaodi said: "There's no need for this, right? Didn't Director Ruan say that the time is very tight? In this way, I'll go and weld a seam first, and Master Bi will see if it's qualified." If I don't qualify, I'll leave immediately, and I'll pay for the travel and accommodation in Hoi An by myself. ”

"This ......" Bi Jianxin was speechless, people are here to help, it is said that they have not even mentioned the remuneration, is it too unsympathetic to pick and choose like this? However, this little girl's skills are not clear at all, can she be allowed to weld directly on the equipment? In case it is not welded well, it is not only time that is lost, but also the semi-finished products that have been made, after all, if the things that have been welded are damaged, it will be much more troublesome to repair the welding. At that time, will it be enough for her to pay for the road and accommodation by herself? Who will bear the loss of the factory?

"Forget it, Master Xiao Du is right, time is precious, let's start welding first. Nguyen Phuc Gen made a quick decision. He thought that the person recommended by Sun Guohua should not be so unreliable. According to what Bi Jianxin said, it is undoubtedly safer to let Du Xiaodi try his hand at welding a few pieces of waste materials first, and then let her drill into the container to weld. However, in this way, doesn't it seem that he doesn't trust this Xiao Du? If someone really has some ability, and he leaves in a fit of anger because of his distrust, he will be blind.

Thinking of this, he also let it go, isn't it just a heat exchanger, it's a big deal, if the welding is broken, let's make a new one, that is, hundreds of thousands of things.

Du Xiaodi also intends to raise the bar with Bi Jianxin. People said that they wanted to test her skills, which is actually a reasonable request. But Du Xiaodi has her own ideas, she feels that she has already shown Ruan Fugen a training certificate in Japan, which is enough to prove her level, and it is completely unnecessary to do this kind of examination. Besides, Bi Jianxin's skills are not as good as hers, what qualifications does he have to be able to test himself?

Hearing Ruan Fugen's agreement, Du Xiaodi smiled slightly, and got into the narrow heat exchanger with the welding tongs. Pressure vessels are all tanks or large cylinders one by one, and a lot of welding work is done inside these vessels. Du Xiaodi is petite, and he has an advantage over male workers in drilling this kind of jar.

"Attention, here we go!"

As Du Xiaodi gave an order in the container, everyone became nervous. Through the observation port of the container, Ruan Fugen and Bi Jianxin could see the arc light inside the container flashing, and bursts of sizzling sounds came from the welding point.

"Yes, it's very skilled. Bi Jianxin listened to the sound of the arc and nodded with satisfaction. This is the skill of the expert, he does not need to look with his eyes, just listen to the sound, he can imagine the welding situation. The arc sound is continuous, the tone is even, there are no fluctuations, and the movement of the solder joint is very smooth, which fully demonstrates the operator's precise control ability.

"Hey, what's going on, how did the solder joints move to it?"

As he listened, Bi Jianxin's brows furrowed, and he asked in disbelief.

"What? Moved to the top, isn't this a back weld?" Ruan Fugen also heard it, and the place where the sound came out had clearly moved from the bottom to the side to the top, and now it should be in a state of back welding.

Most chemical vessels are spherical or cylindrical, and this heat exchanger is a large cylinder, which is processed flat on the ground. A weld that surrounds the cylinder naturally includes half of the back weld. Back welding is a very complex skill, with Bi Jianxin's ability, I dare not say that I have mastered it very well.

In the past, they welded this kind of ring weld with a step-by-step approach. After welding, the welder comes out of the container, and the other workers help rotate the container 180 degrees so that the part that needs to be welded on the back turns to the bottom, and then the welder goes in to continue welding.

This is, of course, a safer approach that avoids the use of more technically demanding upside welding methods and thus reduces the risk of errors. At the same time, however, the man-hours required for manufacturing have increased dramatically, and it takes time for welders to get in and out, and to rotate the container. If there are several ring welds, such work has to be repeated several times, and the cumulative time is very considerable.

Some people may say, why can't you weld all the welds on one side and then turn them around to weld the other side. This brings us to the issue of process design. Just like screwing during assembly, you can't tighten one side and then the other side, because this will cause uneven force on both sides and the assembled workpiece will be skewed.

Just now I heard that Du Xiaodi had finished welding the weld below, and the workers standing outside were already ready, planning to wait for Du Xiaodi to come out and then use a crane to turn the heat exchanger around. Who would have thought that Du Xiaodi didn't use this trick at all, she directly used the back welding technique. This hand, in the eyes of Ruan Fugen and Bi Jianxin, was extremely shocking, and it was commonplace for Du Xiaodi.

Tongyuan Boiler Factory is a national key enterprise specializing in the manufacture of pressure vessels. As Du Xiaodi said, the second-class pressure vessel is a product that does not require the help of senior welders like Du Xiaodi for Tongyuan Boiler Factory, and she and her master, brother and others are only responsible for the welding of the third-class container. Due to the large number of production tasks, it is impossible for them to rely on rotating products to circumvent the back-up welding like Nguyen's factory, otherwise they will not want to complete the task. Back welding is a basic skill for Du Xiaodi, and when she drilled into this heat exchanger, she thought about coming out halfway to rotate the container and then welding, isn't this an extra move?

"This is the standard upward welding technique!" Bi Jianxin almost put his ear on the heat exchanger, he only hated that the heat exchanger space was too small, he couldn't get into it to see Du Xiaodi's demeanor, he could only imagine the operation inside by listening to the sound.

To put it simply, electric welding is to use an arc to melt the metal on the contact surface of two workpieces, and after solidification, they will become one. When the metal melts, it forms a liquid area called a melt pool. The difficulty of back-up welding lies in the fact that the molten pool is suspended in the air, and the liquid metal will fall due to gravity. The trick of back welding is to quickly intermittently start and extinguish the arc, melting only one thin layer of metal at a time, so that it is already in a semi-solidified state before it has time to fall.

During this period, the rhythm control of arc initiation and arc extinguishing is very important, and it is difficult to do without thousands of practices, coupled with good understanding and stable mentality. Bi Jianxin listened to the fast and uniform arc sound of a chicken pecking rice from the heat exchanger, and he could guess that Du Xiaodi skillfully made the conversion between arc initiation and arc extinguishing, what an amazing technique!

"Okay, Director Ruan, please ask the flaw detector master to check it out. ”

Before everyone could recover from the surprise, Du Xiaodi had already completed the operation of a weld and drilled out the heat exchanger. She put down the welding tongs and mask, took off her gloves, and said to Ruan Phuc Gen with a smile. Looking at her relaxed expression, it seems that she has not just completed a difficult welding, but has drunk a cup of tea somewhere.

The flaw detector was about to drill into the heat exchanger with the flaw detector, only to see a figure flashing, and Bi Jianxin rushed in front of him. He was tall and had a plaster cast on one hand, but his movements were so quick that he startled everyone.

"Great, great!"

After a while, Bi Jianxin's excited praise came from the heat exchanger, and then, he got out of the heat exchanger, and he didn't care about wiping the iron filings and dust all over his face, but said loudly: "Don't look at it, it must be the first level, I have never seen such a beautiful weld!

Hearing Bi Jianxin say this, Du Xiaodi, who was still self-conscious just now, was embarrassed all of a sudden. She is actually a very low-key person, who has shown strength in front of Bi Jianxin before, but she is not angry with Bi Jianxin's contempt for her. Now that Bi Jianxin is so praised by people of her age, she can't afford it.

"Master Bi, you have won the award, but this is nothing. Du Xiaodi said.

The flaw detector still dutifully drilled into the heat exchanger to do the flaw detection, which was a necessary procedure, and Ruan Fugen would not have omitted this step because he trusted Du Xiaodi or Bi Jianxin. Bi Jianxin glanced left and right, found a water cup, picked up the kettle and poured most of the cup of water, then came to Du Xiaodi with both hands, raised the water cup respectfully, and said:

"Master Du, I don't know Mount Tai with my eyes, and I was offended just now. If Master Du doesn't care, can you accept me as an apprentice and teach me this technique of back welding. ”