Now the people in the artillery team 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. [No pop-up novel website].
"Shall we test the drilling method next? 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 rodmag."
"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 done whatever I wanted in a big aquatic country than you do in the decadent American empire, I would have made cannons long ago.
The so-called rodmag 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 in the middle (the bore is the hardest, but in reality it is the opposite. When casting a cannon, 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 is equal to the surface area. , so the outside will be cold first. This makes the distribution of barrel density unsatisfactory and greatly reduces the life of the barrel.
What cools first shrinks first. After the outer layer is cooled and hardened, 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 gun's firing performance.
During the American Civil War in 1860, Thomas Rodman, a major in the U.S. 6th Army, understood this hollow casting process and cast the cannon around the core. The inside of the core was cooled by running water. This was a method of hardening the inside of the gun bore. . This is the so-called rodmag casting method. This process was a logical development from earlier experiments with sleeve guns. The outer layer of metal shrinks inward as it cools, continuing to pressurize the hardened inner layer. In this way, the explosive force of the propellant 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 next 20 years, most of the U.S. Navy's heavy cast iron guns were manufactured using this method. The greatest significance of the rodmag casting method is to significantly reduce the barrel rejection rate during casting, especially when casting heavy guns.
From a cost perspective, the rodmag casting method greatly reduces the scrap rate and reduces the casting cost of the artillery. Secondly, this process greatly increases the life of the artillery barrel and reduces the cost of use.
The enemies and potential enemies faced by the time-travelers are far greater than those of the time-travelers, both in terms of manpower and material resources. If time travelers want to defeat them, they 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."
"That's right, it's Gong Zhenlin Ming's. He can be considered a wizard."
Gong Zhenlin was the county 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, 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 and the layers are combined. The clay mold must be dried thoroughly. Otherwise, although it is dry on the outside, it is moist on the inside. When it comes into contact with molten metal, moisture will be generated by itself. The cast artillery will have honeycombs, and the barrel will easily burst and injure people when it is fired. It usually takes a month to dry the clay mold. If there is rain, snow, cold weather, it will take two to three months. Moreover, a clay mold can only cast one cannon, and it is discarded immediately and cannot be used again.
Judging from these descriptions, the process used by Chinese gunsmiths in 184o was roughly the same as the European casting process experimentally used by traversers before 1713. However, some very simple processing methods used by European gunsmiths 150 years ago, such as reinforcing ribs of clay molds, roasting clay molds, and boring iron cannons after casting, were completely unknown.
The craftsmen have no standards for making clay molds. They only keep the dimensions in mind, and they don't pay much attention to the proportions and dimensions of the artillery. These technologies that are far behind the times are the bread and butter of craftsmen. They are regarded as "secret methods" and there is neither any technical exchange nor improvement. Under such a level of cannon-making 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 was that the cannons produced were not even as good as the imitation Hongyi cannons of the Ming Dynasty.
Gong Zhenlin: Due to the emergency situation of the war, the front-line artillery losses were high and the demand was huge. If a batch of artillery was to be produced in one month, the Humen forts, which had been demolished by the British, would not be able to replenish them for many years. After several experiments, he finally understood the method of casting cannons in iron molds.
The iron mold cannon casting method is to use iron to make a hard mold. When casting a cannon, first brush the inside of each flap 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 of fine fine kiln coal mixed with water. Then, the two petals are brought together, tightened with iron hoops, heated, and then molten metal is poured. After enough melt has been poured and cooled to form, the iron mold is immediately peeled off in order of the mold halves, like peeling off the shell of a bamboo shoot, to gradually expose the cannon body. Then the mud embryo in the core is removed, and the inside of the barrel is naturally smooth.
Compared with traditional clay-moulded cannons, the advantages of iron-moulded cannons are that the cast cannon body is of good quality and has smooth inner and outer surfaces, unlike clay molds that can produce bubbles in the cannon body. Furthermore, because there is no need to laboriously apply clay molds and dry them, the production is quick and 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 produces products in batches with almost identical appearance and performance, 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 cost. And the spin casting and spinning out will not delay the time, flawless and natural." It is smooth, can get twice the result with half the effort, can be used endlessly, blazes the trail of public opinion, and opens up eternal methods. How can it be said that it is beneficial to the country's military preparations?"
Gong Zhenlin's mold-casting method 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 it into an iron female mold, so that it could be used to cast cannons. The core 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 generate an inward tightening force, that is, there is Only with this force can the barrel be able to withstand greater chamber pressure. This method of internal mold controlled cooling can have a "self-tightening" effect.
The barrel that has undergone the barrel's self-tightening process has a greatly extended service life. It can also significantly reduce the thickness of the barrel, reduce its weight, and increase the mobility of the artillery.
The rodmag casting method 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. In particular, 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 required, the consumption of tools is much smaller.
In order to test whether the cast cannon met various technical parameters, the artillery team decided to conduct a test firing at Bo Pu. Cannonballs are solid bullets made of pig iron. During casting, the clearance accuracy was controlled as much as possible so that the difference would not be too large. The mechanical team made two-wheeled gun mounts for the two guns and also brought an ammunition forward truck. It looks a lot like that. Wang Luobin went to the farm and lent out four horses from the farm. But when the horses arrived at the scene, they discovered a problem: there were no harnesses suitable for multi-horse traction - the chariots running on the road were all pulled by a single horse, and the harnesses were purchased directly from the original time and space. Although horse gear is not a profound knowledge, no one knows 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 cannon had been cast and immediately sent a rowing boat to transport the cannon. The two 6-pound guns and their mounts were tied to floating rafts of empty oil drums and towed by rowing boats to Bopu Port.
The cannons were placed in the open space next to the shipyard in Bopu, and there was an endless stream of people watching the excitement, especially the navy personnel. Almost everyone couldn't put it down for these two black iron cannons. No matter how cute it looks, a man named Li Haiping from the Navy simply suggested that we just put the cannon on the ship.
"Ready to load it on the ship? You see clearly, this is a towed 6-pound cannon, an authentic artillery piece of the Army." 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. Can 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 was 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 unclear whether this cannon can be fired. What are you arguing about!"
