Lin Gao Qiming

Chapter 147 Casting Cannons ([-])

Now the artillery team has to make a choice again, whether to use the solid casting and deepening drilling process to manufacture the barrel, or continue to use the hollow casting method.

"The next step is to test the drilling method, right? But first we need to build a drilling machine." Several people in the mechanical team were very excited.

"The drilling method is a bit difficult." Lin Shenhe thought for a while, "The efficiency is also a bit low. I think you can try RodmanCasting."

"Center cooled casting?" Wang Luobin asked.

"You know?" Lin Shenhe was a little surprised, "I thought not many people in China knew about this."

"Personal hobbies are purely personal hobbies." Wang Luobin thought that if I were not as free-spirited in the big aquatic country as you are in the decadent US emperor, I would have made cannons a long time ago.

The so-called RodmanCasting casting method is the inner mold cooling method.

Its principle is simple: the cooling rate of pig iron during casting will affect its mechanical properties. Theoretically, the higher the cooling rate, the harder the texture. The ideal cannon is the hardest in the middle (bore), but in reality it is the opposite. When casting a cannon It is the slowest cooling in the middle.Because the first outer layer wraps the inner layer, the outer layer is not cold and the inner layer cannot cool down.Secondly, the surface area of ​​the outer tube is also larger than that of the inner tube.Whether it is radiation or convection conduction heat dissipation, the heat dissipation rate is equal to the surface area, so the outside will be cold first.And this makes the distribution of the barrel density unsatisfactory, and the life of the barrel is greatly reduced.

Those who cool down first shrink first.After the outer layer is cooled and hardened, if the inner layer is not cooled, the outer layer will be harder than the inner layer, and the inner tube of the inner layer may be deformed, or cracks may occur when the inner layer cools.This leads to an increase in the scrap rate when casting the cannon, shortens the life of the barrel, and sometimes affects the firing performance of the cannon.

During the American Civil War in 1860, Major Thomas D. Rodman of the U.S. Army invented this hollow casting process, casting guns around the core, and cooling the inside of the core with flowing water. This is a method to harden the inside of the gun bore first. .This is the so-called RodmanCasting casting method.This process is a logical development of earlier sleeve gun experiments.As the outer metal cools, it shrinks inward, continuing to pressurize the already hardened inner layer.In this way, the explosive force of the propellant is absorbed by the entire thick metal layer around the barrel instead of expanding outward in layers.During the American Civil War and the next 20 years, most of the US Navy's heavy cast iron guns were manufactured in this way. The greatest significance of the RodmanCasting method is to greatly reduce the scrap rate of barrels during casting, especially when casting heavy guns.

From a cost point of view, the RodmanCasting casting method has greatly reduced the scrap rate and reduced the casting cost of the artillery.Secondly, this process greatly increases the barrel life of the artillery and reduces the cost of use.

The enemies and potential enemies faced by the traversers are far greater than the traversers in terms of manpower and material resources.To defeat them, the traversers must control their various costs.

"You can try this method, but in this case, we need to make a hard inner mold that can hold water, so we can't use the clay mold just now." Ji Wusheng considered the issue of casting.

"Let's use the iron mold casting method. It seems that the Chinese are the first to use it."

"Yes, it was invented by Gong Zhenlin. He is also considered a genius."

Gong Zhenlin was the magistrate of Jiaxing County, Zhejiang Province. He had nothing to do with the arms industry, but he had a reputation for being "ingenious". During the Opium War, Yuqian, the governor of Liangjiang, was transferred to the Ningbo military camp to be in charge of casting artillery.

At that time, China's cannon casting technology was very backward, and the method was as follows:

Use water and mud to make a mold, and then Fan Jin pours it into a mold, layer by layer.The clay mold must be thoroughly dried, otherwise, although the outside is dry, the inside is wet, and when it encounters molten metal, the moisture will generate itself, and the cast cannon will have honeycombs, and the barrel will easily burst and hurt people when it is cast.It usually takes a month to dry the clay mold, and it takes two to three months if it is rainy, snowy and cold.Moreover, a clay model can only cast one cannon, and it can be discarded immediately and cannot be used again.

From these descriptions, it can be seen that the technology used by Chinese cannon-casting craftsmen in 1840 is roughly the same as the European casting technology before 1713, which was experimentally used by people across the country.However, some very simple processing methods used by European gunsmiths 150 years ago, such as the reinforcing ribs of clay molds, the firing of clay molds, and the boring of iron cannons after casting, are completely unknown.

The craftsmen have no rules for the manufacture of clay molds, and the size technique is completely kept in mind, and the proportional size of the artillery is not paid much attention to.These technologies, which are far behind the times, are the cost of living for craftsmen, and are regarded as "secret methods". There is neither any technical exchange nor improvement.In this way, under the cannon-making level that is out of touch with the times, there are actually multiple "schools" that are completely closed and kept secret from each other.The result is that the manufactured cannons are not even as good as the imitated Hongyi cannons of the Ming Dynasty.

Because of the urgent situation of the battle, Gong Zhenlin had a lot of wear and tear on the front-line cannons, and the demand was huge. If a batch of cannons were to be produced in such a month, the forts in Humen, which had been stripped of cannons by the British, would not be able to replenish them for many years.After several experiments, he finally invented the iron mold casting method.

The iron mold casting method is to make a hard mold with iron.When casting cannons, first brush the inside of each petal of the iron mold with two layers of slurry.The first layer of slurry is made of fine rice husk ash and fine sand; the second layer of slurry is made of fine kiln coal mixed with water.Then, the two petals are joined together, tightened with iron hoops, heated, step by step, and finally the molten metal is cast.After pouring enough molten liquid and cooling to shape, immediately peel off the iron mold according to the order of the mold parts, like peeling off the shell of a bamboo shoot, gradually revealing the gun body, and then remove the mud embryo in the gun core, and the inside of the bore is naturally smooth.

Compared with traditional clay cast cannons, iron mold cast cannons have the advantage that the cast cannon body is of good quality, and the inner and outer surfaces are smooth, unlike clay molds that will cause air bubbles in the cannon body.Furthermore, because there is no need for hard coating of clay molds and other drying, the production speed is fast and it is not affected by the weather.Because the mold can be reused, the production speed is fast, the output is large, and the cost can be kept very low.The greater significance lies in standardized manufacturing.Standardized manufacturing mass-produces products with almost exactly the same appearance and performance, which is crucial for artillery.

Colleagues praised: "The method is the simplest, and it is the most convenient to use. One job earns hundreds of benefits, and one shot saves dozens of times of capital. And the spin-casting and spinning out, without delay, flawless, natural It is smooth, can get twice the result with half the effort, can be used infinitely, open the way of public opinion, and open the door of the eternal method, which is beneficial to the country's military preparations, how superficial it is!"

Gong Zhenlin invented the method of casting molds and cannons, 30 years earlier than the West. This is a rare scientific and technological achievement in modern China that leads the world.

The artillery team continued to harass the wood processing factory, asking them to make a male mold out of wood first, and then Ji Wusheng and Zhan Wuya carried out sand casting together to cast an iron female mold, which could be used to cast cannons.The core is also made of iron, the inside is hollow, and there are pipes at both ends for water intake and drainage.

When the molten metal is poured into the mold, the molten metal begins to cool slowly. At this time, the water in the inner mold comes in handy. The molten metal near the inner mold is first cooled and condensed into steel under the action of water, while the outer layer The molten metal cools more slowly.Because of the principle of thermal expansion and contraction, after the entire casting is cooled, the part that is cooled after the outer layer will tightly hug the part that is cooled first in the inner layer, so that the entire casting will generate an inward tightening force, that is, there is This force enables the barrel to withstand greater chamber pressure.This method of controlling cooling by the internal model can have the effect of "self-tightening of the barrel".

After the barrel self-tightening process, the service life is greatly extended, and the thickness of the barrel can be greatly reduced, the weight can be reduced, and the mobility of the artillery can be increased.

The process of RodmanCasting casting method is very simple. After having the mold, the artillery team quickly produced the first finished product. This gun is much better than the clay model, especially the gun body does not need any polishing, and the smoothness of the gun bore is also improved. Greatly improved, although the boring process is still required, but the consumption of tools is much smaller.

In order to test whether the cast cannon meets various technical parameters, the artillery team decided to conduct a test firing at Bopu.The shells are solid shells cast from pig iron.When casting, try to control the accuracy of the clearance so that the difference will not be too large.The mechanical group made two-wheeled gun mounts for the two guns, and also brought an ammunition front cart.It looks like that.Wang Luobin went to the farm once and only lent 4 horses from the farm.But when the horses arrived at the scene, they found a problem: there was no harness suitable for multiple horses—the two-wheeled carts running on the road were all drawn by a single horse, and the harness was bought directly from the original time and space.Although saddlery is not a profound knowledge, no one knows how to make it.In the end, I had to continue to play the role of the database, and found the answer from a photo.

Before the harness was made, the impatient navy heard that the cannon had been cast, and immediately sent a rowboat to transport the cannon.Two 6-pound guns and gun mounts were tied to the floating raft of empty oil barrels, and were towed by rowboats to Bopu Port.

The cannons were placed in the open space next to Bopu's shipyard, and there was an endless stream of people watching the excitement, especially the navy, almost everyone loved the two black iron cannons.No matter how cute it looks, Li Haiping, a member of the Navy, simply suggested that the cannon be loaded on board.

"Load it on the ship? You can see clearly, this is a towed 6-pound cannon, an out-and-out army artillery." Seeing that his beloved cannon was about to be taken away by the navy, Zhang Bolin immediately jumped out to stop it.

"Pull it down, it's still a traction type, you can give me a self-propelled type?" Li Haiping looked disapproving, "This little broken cannon, the navy still doesn't like it."

"What did you say?!" Zhang Bolin was furious, wanting to rush up and punch him, to show him the strength of the army.

"What are you arguing about?" Wang Luobin hurried over to smooth things over, "Whether this cannon can be fired is still unknown, what are you arguing about!"

(End of this chapter)