Now the artillery team members have to make a decision again, whether to use solid casting and deepening drilling process to make the barrel, or to continue to use hollow casting method.
"Next step, let's test the drilling method? But we have to build a drilling machine first." Several people in the mechanical team were very interested.
"The drilling method is a bit difficult." Lin Shenhe thought for a while, "The efficiency is also a bit low. I think we can try rodmancasting."
"Central cooling 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 If I hadn't been able to do whatever I wanted in a big aquatic country like you in the corrupt American empire, I would have made cannons long ago.
The so-called rodmancasting casting method is the internal mold water cooling method.
Its principle is very 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
However, the intermediate cooling is the slowest. Because the first outer layer wraps the inner layer, the outer layer will not cool down if the inner layer is not cold. Secondly, the surface area of the outer tube is larger than that of the inner tube. Whether it is radiation or convection conduction heat dissipation, the heat dissipation speed is consistent with the surface area.
are equal, so the outside will be cold first. This makes the distribution of barrel density unsatisfactory and greatly reduces the life of the barrel.
The one that cools first shrinks first. After the outer layer cools and hardens, if the inner layer has not yet cooled, the outer layer will be harder than the inner layer, and the inner tube of the inner layer may deform, or cracks may occur when the inner layer cools.
This leads to an increase in the scrap rate during gun casting, shortens the life of the barrel, and sometimes affects the firing performance of the gun.
During the American Civil War in 1860, U.S. Army Major Thomas Rodman invented this hollow casting process. The cannon was cast around the core, and the inside of the core was cooled by running water. This was a method to harden the inside of the gun bore.
This is called rodmancasting. This process is a logical development of the earlier experiments with sleeve guns. The outer layer of metal shrinks inward as it cools, continuing to pressurize the already hardened inner layer. In this way, the explosion of the propellant
The force is absorbed by the entire thick metal layer around the barrel, rather than expanding outward layer by layer. During the American Civil War and the following 20 years, most of the U.S. Navy's heavy cast iron cannons were manufactured using this method. rodmancasting casting method
The greatest significance is to significantly reduce the barrel rejection rate during casting, especially when casting heavy artillery.
From a cost perspective, the rodmancasting casting method greatly reduces the scrap rate and the casting cost of the artillery. Secondly, this process greatly increases the life of the barrel of the artillery and reduces the cost of use.
The enemies and potential enemies faced by time-travelers are far greater than the time-travelers in terms of manpower and material resources. To defeat them, time-travelers must control their various costs.
"We can try this method, but in this case we have 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.
"Use the iron mold casting method. It seems that the Chinese were the first to use it."
"Yes, it was invented by Gong Zhenlin. He is also a genius."
Gong Zhenlin was the county magistrate of Jiaxing County, Zhejiang. He had nothing to do with the arms industry, but he had a reputation for being "ingenious". During the Opium War, he was transferred to the Ningbo Military Camp by Yuqian, the governor of Liangjiang during the Opium War, to be responsible for casting cannons.
At that time, China's cannon casting technology was very backward. The method was:
Water and mud are used to make a mold, and then the mold is cast with gold and the layers are combined. The mud mold must be dried thoroughly, otherwise although it is dry on the outside, it is moist on the inside. When it encounters molten metal, moisture will be generated by itself, and the cannon will be cast.
There are honeycombs, and the barrel can easily burst and injure people when used. It often takes a month to dry the clay mold, and if it rains, snows, and is cold, it takes two or three months. Moreover, only one cannon can be cast from a clay mold.
, discard it immediately and cannot be used again.
Judging from these descriptions, the technology used by Chinese gunsmiths in 1840 was roughly the same as the European casting technology experimentally used by traverseers before 1713. However, some of the techniques used by European gunsmiths 150 years ago
Very simple processing methods, such as reinforcing ribs of clay molds, roasting clay molds and boring after casting of iron cannons are completely unknown.
The craftsmen have no standards for the manufacture of clay molds, and the dimensional techniques are all kept in mind, and the proportions and sizes of the artillery are not paid much attention to. These technologies that are far behind the times are the craftsmen's bread and butter, and are regarded as "secret techniques."
, there is neither any technical exchange nor improvement. Under such a level of cannon casting that is out of touch with the times, there are actually multiple "schools" that are completely closed and secretive to each other. The result is that the cannons produced are not even as good as the imitations of the Ming Dynasty.
red barbarian cannon,
Due to the emergency of the war, the front-line artillery losses were high and the demand for Gong Zhenlin was huge. If a batch of artillery were to be produced in one month, the forts in Humen, which had been stripped of all their cannons by the British, would not be able to replenish them for many years. After several experiments, he finally invented the iron gun.
Mold casting method.
The iron mold casting method is to use iron to make a hard mold. When casting the cannon, first brush the inside of each valve of the iron mold with two layers of slurry. The first layer of slurry is made of fine rice husk ash and fine sand mud;
The second layer of slurry is made by mixing water with fine fine kiln coal. Then, the two petals are joined together, tightened with iron hoops, and heated step by step. Finally, the molten metal is poured. After enough molten liquid has been poured, cool it down.
After forming, immediately peel off the iron mold in the order of the mold flaps, like peeling off the shell of a bamboo shoot, to gradually expose the gun barrel, and then remove the mud embryo in the barrel, leaving the inside of the barrel naturally smooth.
Compared with traditional clay-moulded cannons, the advantages of iron-moulded cannons are: the cast cannon body is of good quality and has smooth inner and outer surfaces, unlike clay molds that will cause bubbles to form in the cannon body. Furthermore, there is no need to laboriously paint the cannon body.
The clay molds are dried, so the manufacturing speed is fast and are not affected by the climate. Because the molds 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 produces batches
The appearance and performance of the products are almost exactly the same, which is crucial for artillery.
Colleagues praised it and said: "The method is the simplest and the most convenient to use. One job can save hundreds of workers, and one shot can save dozens of times the capital. Moreover, the spin casting does not delay the time, is flawless and natural.
Smooth, get twice the result with half the effort, infinite utilization, open up the guideline of public opinion, and open up eternal methods, how can it be said that it is beneficial to the country's military preparation?"
The mold-casting method invented by Gong Zhenlin was 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 positive mold from wood first, and then Ji Wusheng and Zhan Wuya worked together to cast sand into an iron female mold, which could be used to cast the cannon core.
It is also made of iron and is hollow inside, with pipes at both ends for water inlet 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 close to the inner mold is the first to cool and condense into steel under the action of water, while the outer layer
The molten metal cools slowly. Because of the principle of thermal expansion and contraction, after the entire casting is cooled, the later-cooled part of the outer layer will tightly hug the first-cooled part of the inner layer, so that the entire casting will produce an inward
The tightening force is the force that enables the barrel to withstand greater chamber pressure. This method of internal mold controlled cooling can have the effect of "self-tightening of the barrel."
The barrel's service life is greatly extended through the barrel's self-tightening process. It can also significantly reduce the thickness of the barrel, reduce its weight, and increase the maneuverability of the artillery.
The process of rodmancasting is very simple. After getting the mold, the artillery team quickly produced the first finished product. This gun is much better than the clay mold, especially the gun body no longer needs to be polished, and the smoothness of the gun barrel is also improved.
Greatly improved, although the boring process is still needed, the consumption of tools is much smaller.
In order to test whether the cast cannon complies with various technical parameters, the artillery team decided to conduct a test firing in Bopu. The cannonballs are solid bullets made of pig iron. During casting, the clearance accuracy was controlled as much as possible to prevent the difference from being too large.
The mechanical team made two-wheeled gun mounts for the two guns, and also brought an ammunition front carriage. It looked very similar. Wang Luobin went to the farm and lent four horses from the farm. But the horses
When we arrived at the scene, we discovered a problem: there were no harnesses suitable for multi-horse traction - the two-wheeled carts running on the road were all pulled by a single horse, and the harnesses were bought directly from the original time and space. Although the harnesses are not that advanced,
knowledge, but no one knew how to make it. In the end, I had to continue to use the database and found the answer from a photo.
Before the harness could be made, the impatient Navy heard that the cannons had been cast and immediately sent a rowing boat to transport the cannons. The two 6-pound cannons and their mounts were tied to floating rafts of empty oil drums.
, towed by rowing boat to Bobu Port.
The cannons were placed in the open space next to the shipyard in Bopu. There was an endless stream of people watching the fun, especially the navy personnel. Almost everyone couldn't put it down for these two black iron cannons. They are so cute no matter how you look at them, Navy
One of them, Li Haiping, simply suggested that we just load the cannon onto the ship.
"Ready to load it on the ship? You see clearly, this is a towed 6-pound cannon, a real army artillery." When Zhang Bolin saw that his beloved cannon was about to be taken away by the navy, he immediately jumped out to stop it.
"Pull it down, it's a towed one, why don't you give me a self-propelled one?" Li Haiping looked disapproving, "The navy doesn't like this little piece of artillery."
"What did you say?!" Zhang Bolin suddenly became furious and wanted to rush up and punch him to show him the power of the army.
"What are you arguing about?" Wang Luobin hurried over to smooth things over, "It's still unknown whether this cannon can be fired. What are you arguing about!"