I! Pretending to Be Reborn, Director of Doomsday Hoax

"The delivery of these steels has to go through dozens of processes such as smelting, continuous casting, rough rolling, finishing rolling, and heat treatment. We have carried out standardized treatments on them, trying to get the most standard finished products." Buzzing.

The sound of the wind rang endlessly.

Xu Qiu looked up, and saw that the mechanical arm was hanging a piece of rough steel, which was carrying out fully automatic steel transfer and rolling.

Those are all subspecies of bainitic rails.

In fact, with the development of railways in various countries in the direction of high speed and heavy load, higher requirements are put forward for the performance of steel rails.

The pearlitic steel rail, the star of the steel rail in those days, has been unable to improve its mechanical properties and wear resistance through alloying, heat treatment, etc., let alone add another cold resistance.

For bainitic steel, it has high strength, good toughness and plasticity, and the limit of thinning the interlamellar spacing is lower, so that more extreme performance can be excavated.

"Which specific subspecies are there?" Xu Qiu asked 3.5.

He Yude said: "There are species."

"Mainly low carbon, about 0.26%. High lead, about 1.94%. High Meng, etc."

"Our first stage is to increase the tensile strength of the bainite rails to enhance their load capacity."

"At present, there are two methods. The first is composite alloying, which mainly uses 0.5% Mo.B as the basic component, and then adds alloying elements such as C" and Ni to improve toughness and obtain bainite under air cooling. dominant organization."

"The second method is heat treatment. After hot rolling and tempering, the impact toughness of bainite can be greater than 60j per square centimeter, which is twice the requirement for extremely cold steel rails!"

At this time, Wo Chengwen walked over with his workers and pushing a forklift.

There are still a few pieces of steel on the forklift.

"Director Xu, these types of bainite steels have certain defects. We have tried various methods, but we can't solve them!"

Four one-square-meter-sized steel blocks were placed on the ground.

Xu Qiu squatted down and carefully checked the questions above.

The molded wall of the first steel plate was displaced and deformation defects appeared.

"The overall vacuum degree of the sand mold, the sand grain size and the suction volume of the sand box and the system are very important to the molding. If the sand grain size is coarse and the composition is single, and the vacuum degree and suction volume of the sand box are low or uneven, it is easy to appear. Sand filling density and Reduced hardness."

"In addition, during the filling process of molten steel, the filling pressure of molten steel may easily lead to bulging in parts with low sand vacuum and low air extraction, or the push of runners may cause the mold wall of the corresponding part to sag, or a certain part of the upper mold may The vacuum degree and air extraction volume are low and the sand mold collapses."

"Generally, the hardness of the upper type is lower than that of the lower type, and the swelling of the upper type is easy to cause false and wrong shapes."

"It's very simple to improve this problem, to ensure the vacuum degree, the sand size and the suction volume of the sand box and the system!"

What Xu Qiu blurted out stunned Zou Baitao, Li Bingqing, Wo Chengwen and others.

This... is really not something that only steel smelting experts can say?

"Director Xu, you...are also involved in smelting steel?!" Zou Botao said in shock.

It doesn't matter if you are a master of physics, but also provided blueprints for dungeons, nuclear power trains, and nuclear power difference machines...

Now he can actually talk about the smelting and casting of steel!

"Old Li, pay attention to the processing technology of this No. [-] defective subspecies, and pay attention to the overall vacuum degree of the sand mold, the grain size of the sand, and the suction volume of the sand box and the system!"

Wo Chengwen had an excited look on his face.

He once prepared special steel for the structure of the bird's nest, and he is also a genius in steel casting and improvement. As soon as Xu Qiu said it, he had a faint feeling in his heart that improving according to the other party's words could make up for this defect!

"So, Director Xu, what about the second defective subspecies?"

These are the questions that bother them.

Xu Qiu glanced at it.

Defect subspecies No. [-] is mainly caused by earthworm crawling defects.

A large number of earthworm-like cracks are distributed on the surface and side walls of the steel, presenting an irregular chain-like distribution, and there are chain-like pores in many places.

Wo Chengwen said with a headache:

"This kind of defect has never been encountered before. We have produced hundreds of types of steel, and none of them has such a large number of air bubbles in it. Several methods have been improved, such as capping, molten steel filling, etc., to no avail! "

Xu Qiu looked at the smelting furnace.

The fiery red steel is continuously cast, cooled, and finally shaped.

where is the problem..…

Xu Qiu turned his gaze to the rolling and drying area.

He thought of something, his eyes lit up, and said: "The film at the parting surface of the casting is easy to not absorb properly and produce paint accumulation, which is difficult to dry. When the molten steel is filling the mold, the film at this part is difficult to crack and gasify quickly. This is earthworm. base of the crack!"

"In addition, once the film is curled, it will entrain paint and sand, which will cause earthworm crawling defects and inclusions in this part of the casting."

"Of course, metal oxides and other impurities mixed in molten steel move to the side wall of the casting under the strong vacuum suction of the side wall of the sand mold. If the pouring rate is not uniform and stable, the casting side wall Earthworm crawling defects similar to the parting surface are generated on the surface!"

"The solution is also very simple. The parting surface of the casting is thickened, and the entire casting process ensures that the steel plate remains vertical and prevents curling and wrapping debris!"

Wo Chengwen's eyes brightened, and he shouted, "Old Li, did you hear that, the No. [-] defective subspecies has also been recast according to Director Xu's words!" Xu Qiu didn't stop, looking at the third and fourth steel plates.

The third problem is the veined crack and spur defect

This kind of defect occurs because the coating of bainite steel needs to be dried during the casting process. Once the baking is not done properly, it is easy to cause dry cracking of the coating on the upper surface.After adding sand, the fine sand powder fills the cracks in the coating, relying on the entrustment of the film without breaking and leaking.

Of course, it is also possible that the vacuum degree of the sand box and the suction volume are low, resulting in low cross-type strength of the sand mold, and the sand mold sinks and the coating cracks during the process of lifting or dropping the core.

Therefore, it is not found in the middle of forging and cannot be corrected in time. Once pouring is performed, the film cracks and gasifies or burns out, and molten steel fills the cracks.

At this time, the fine sand powder or paint will all enter the steel, forming veined cracks and spurs on the surface of the casting!

The problem with the fourth piece of steel is the sticky sand defect

If the paint spraying is not standardized, the coating is too thin or loose, or the refractoriness of the paint aggregate is insufficient, it is easy to produce sticky sand defects on the outer wall!

What is even more frightening is the inner wall of the casting. Since the sand core is in a vacuum state, the sand core with a slightly thicker core sand is prone to infiltration of molten steel due to vacuum and vacuum, forming sticky sand defects that are difficult to clean! These two problems will also directly affect The performance of bainite steel!

After Xu Qiu finished reading these four steel plates, he had a rough estimate of the steelmaking process of the Capital Iron and Steel Group.

"I have a plan that can solve all these problems at once..."

After thinking for a while, Xu Qiu said quietly.

boom!

The whole steel plant is quiet!

Wo Chengwen, He Yude and dozens of top steel designers and engineers looked at Xu Qiu with incredulous eyes,

These problems that have troubled them for a long time, Xu Qiu can completely solve them with one plan? !

This...how is it possible! ! .

Chapter 76 The meteorite fell, and the end of the world is coming!

After that blizzard, the whole world began to be shrouded in the shadow of the doomsday statement that "the sun goes out".

As the blizzard stops, the northern hemisphere gets hot again.

In the southern hemisphere, it is winter itself. After the blizzard stops, the temperature rises, but a large amount of snow is still preserved. It is expected that the average temperature of this winter will drop a lot.now.

Longguo, Tiandu, within the Capital Iron and Steel Group.

In the hot steel workshop, the steel workers were sweating profusely, and everyone's face was reddened by the scorching heat. However, they all had unconcealable smiles on their faces.

Longguo wants to research new extremely cold steel rails, and they are the pavers for this batch of steel rails!

When the dungeon was being built, they were asked to produce steel here.

When the whole people started to grow vegetables, many of them wanted to return to their hometowns to work in agriculture and support the country, but they were also required to work overtime here to make steel.

Later, the demolition began, and they still made steel here!

The lives of all people are undergoing earth-shaking changes, only they, as before the disaster, still can only deal with blowers, gears, and mechanical arms.

Now.…

Finally it's their turn!

"A...solution to all of the above problems?"

Wo Chengwen, He Yude and others looked at Xu Qiu in astonishment.

They are tortured by the inevitable defects of the bainitic steel subspecies.

Now Xu Qiu told them that there is a plan that can solve all these problems?

how can that be!

Those present included the academician who designed the Longguo standard EMU, the third-generation Fuxing.

There is the designer of Longguo's new CRH1A, and the proposer of the magnetic levitation + true low-altitude mode.

There are even several space station engineers who specialize in the production of special steel for the Ministry of Military Affairs, as well as the National Aeronautics and Space Administration's production line! !

These people who represent the highest academic level in the steel industry are powerless, Xu Qiu...can you?

"Please... Director Xu enlighten me!"

He Yude came forward leaning on a cane, and said respectfully.

Everyone's eyes were also full of disbelief, and...a glimmer of expectation!

Xu Qiu's calm eyes swept across the crowd, and wisdom shone in his eyes.

This is the wisdom that belongs exclusively to the master of mechanics and surpasses the contemporary wisdom!

He exhaled lightly and began his narration.

"Bainitic steel is already one of the most outstanding types of steel in the 21st century. It is difficult to strengthen the performance of bainitic steel on this basis, and even add extreme cold resistance and strong load capacity. Female Q ascends to the sky!"

"Therefore, it is normal for various defects to occur during the casting process."

"The casting method you use should be EPC, also known as lost foam casting. This is one of the most advanced casting processes in the world and is known as a 'revolution' in the history of casting."

"But the disappearing casting method has a big problem!"

"When producing thick and large castings, such as the extremely cold steel rails we want to develop, foam slag inclusions are not easy to remove, which can easily lead to interruptions, cracks, etc. Production of low-carbon alloy steel castings is also easy to increase carbon, which brings troubles to smelting and heat treatment !"

"Internationally, there are established solutions to these problems, such as adopting the process of firing first and then pouring, standardizing the design of pouring risers, and adopting vibratory casting to refine the grains and other measures..."

"These methods can indeed solve the appearance and internal quality problems of castings to a certain extent, but they only treat the symptoms but not the root cause!"