Chongzhen Emperor Zhu Youzhen Khan, but he still patiently explained, "I make iron for further steelmaking, don't you see how many big boilers there are?" Steelmaking is mainly made of pig iron made from blast furnaces, sponge iron and scrap steel made by direct reduction ironmaking method as raw materials, and steelmaking is made into steel by different methods. There are three main types of steelmaking methods: converter steelmaking, open-hearth steelmaking, and electric arc furnace steelmaking (see steel, converter, open-hearth, and electric arc furnace). The above three steelmaking processes can meet the requirements of general users for steel quality. In order to meet the needs of higher quality and more varieties of high-grade steel, a variety of methods of furnace treatment (also known as furnace refining) of molten steel have emerged. For example, argon blowing treatment, vacuum degassing, desulfurization outside the furnace, etc., after additional treatment of molten steel made by converters, open-hearth furnaces, and electric arc furnaces, high-grade steel grades can be produced. For some special purposes, the steel that requires extra high quality is still not met by the furnace treatment, and the special steelmaking method is used. For example, electroslag remelting is a refining process in which steel smelted in converters, open-hearth furnaces, electric arc furnaces, etc., is cast or forged into electrodes, and the slag is resistively heated for secondary remelting; Vacuum metallurgy, i.e., the metallurgical process carried out at pressures below 1 atmosphere up to ultra-high vacuum, including the smelting, purification, refining, forming and processing of metals and alloys. ”

Xu Guangqi didn't understand what he heard, in fact, Chongzhen Emperor Zhu Youzhen was not very familiar with it, he took the time to understand, but he had never worked in the smelter! These materials and drawings are all tested by him from modern times, and the biggest sorrow of Chongzhen Emperor Zhu Youzhen is that he does not have enough time! He has to do a lot of things at the same time, and he has to rely on a Ming scientist like Xu Guangqi!

After the molten steel is smelted in the furnace, it must be injected into the casting mold through a steel drum (ladle). Only ingots or billets that have solidified into a certain shape can be reprocessed. Ingot casting can be divided into upper casting method and lower casting method. The internal structure of the upper cast steel ingot is generally better. Fewer inclusions. Low operating costs; The surface quality of the lower cast steel ingot is good, but due to the injection pipe and soup channel, the inclusions in the steel increase. In terms of ingots, new technologies such as continuous steel casting, pressure casting and vacuum casting have emerged.

Although the smelting technology of Chongzhen Emperor Zhu Youzhen is the most advanced, because of his own lack of experience, the steel has been smelted, and the waste is also very large, but fortunately, he himself hinted that everything is a bit wasteful. Fortunately, these are the resources of the country, and with the advancement of technology in the future, these iron embryos can be reprocessed!

Chongzhen Emperor Zhu Youzhen's smelting technology and welding technology made it possible to cast large-scale machinery! The technology he mastered was not solid, and he did not have the ability to produce such high-precision equipment as submachine guns, and the conditions were not enough, but in two years, he produced a ship with a length of 64 meters, a width of 9.75 meters, a draft of 4.57 meters, a displacement of 1,350 tons, and a power of two reciprocating steam engines. 6 round coal-fired boilers with twin shaft propulsion. The power is 2,600 horsepower, the speed is 15-16 knots, the endurance is 5,000 nautical miles/8 knots, the normal coal tank carries 250 tons of coal, and the maximum coal load is 300 tons. The hull is made of wooden outer steel, deck armor 0.27 inches, turret armor 1 inch, conning tower armor 0.5 inches, and the bow waterline is equipped with ramming angles 11 feet, and the whole ship has a total strength of 137-140 people.

Main weapons: 2 10-inch main guns (each gun weighs 25 tons, 26 times the caliber), 4 40-pounder secondary guns, 2 9-pounder guns, 4 11mm 10-barreled machine guns, 4 37mm single-barreled guns, and 1 ship-based pole mineboat.

To achieve this standard, Chongzhen Emperor Zhu Youzhen is still confident, he set himself the goal within half a year, but he also knows that this task is a bit tight, and he doesn't know whether the situation of testing the water is ideal or not, after all, he is not an experienced engineer and technician!

Experience is the greatest asset of an engineering construction project!

"Ironclads can be used for a variety of purposes, including combat ships on the high seas, coastal defense ships, and long-range cruisers. Ironclads were transformed from wooden ships that still had to be hoisted to fill the steam engine's inadequacy to combat ships and cruisers made of steel with gun emplacements. This transformation continued to evolve thanks to the development of heavy naval guns, the increasingly sophisticated steam engine, and the rapid development of metallurgical technology, which made steel shipbuilding feasible. Looking at the endless sea, Chongzhen Emperor Zhu Youzhen said in high spirits.

Xu Guangqi was dizzy when he heard it, he was a pragmatist, and when things were not shown in front of him, it was impossible for him to be so excited with the emperor, "Heavy naval artillery? What size of a cannon is a heavy naval gun? ”

Chongzhen Emperor Zhu Youzhen smugly stroked, "So thick!" 50,000 pounds! ”

Xu Guangqi was shocked, "If there is such a heavy cannon, how can the warship carry it?" And the old minister still has questions, can this steel cast ship float in the water? ”

Emperor Chongzhen Zhu Youzhen put the model of the torpedo destroyer he brought from modern times in the water, and explained with a smile, "Archimedes' principle is that the buoyancy of an object is equal to the gravity of the object to discharge the liquid (gas can also be), although the density of iron is greater than that of water, but the middle of the ship is empty, the total weight of the ship is equal to the total weight of iron, but the volume of the ship is not the volume of iron, that is to say, the buoyancy of the ship is not equal to the buoyancy of iron, but greater than the buoyancy of iron, since the buoyancy is greater than gravity, the ship cannot sink." ”

Xu Guangqi looked at the iron-hulled boat floating in the water, and was very surprised, although he could understand these truths, but he had tried the weight of this boat just now, and he never imagined that it could really float in the water, he still couldn't believe it, "Your Majesty, this is a small boat, such a big ship, are you sure that you can use the welding torch you said to weld it seamlessly?" ”

Chongzhen Emperor Zhu Youzhen nodded, "Of course, when everything is complete, I will teach the craftsmen to weld, and there must be talents who specialize in welding, these craftsmen of the Ming Ordnance Manufacturing Bureau are not allowed to leave the Daming Ordnance Manufacturing Bureau for life, you must pay attention to secrecy, no one is allowed to go out except yourself!" You give me someone to take overall responsibility, I remember, your nephew Xu Zhengming is not bad, he gave me a lecture last time! I think he's good, is he married? ”

Xu Guangqi nodded, "I got married, but once I entered the Ming Ordnance Manufacturing Bureau, I couldn't come out for life?" And can't the children and grandchildren come out? (To be continued......)