A few days later, the hot air chamber was put into operation.

Usually two of the three hot air chambers are heated, and one is used to complete the heated fire extinguishing, which is connected to a blower to supply hot air to the ironmaking furnace and the steelmaking furnace.

After the temperature of the hot air chamber is lowered, the next hot air chamber is used to supply hot air, and the cooled hot air chamber is ignited and heated.

Three hot air chambers circulate heat to keep the hot air continuous.

The temperature of the crucible furnace was immediately raised, and now even mild steel could be melted to a liquid state.

The temperature of the furnace on the blast furnace side of the iron smelting furnace has also risen a lot.

Su Chengyu made a long and narrow groove, through which the molten iron burned by the blast furnace flowed through the groove, and the craftsmen sprinkled limestone, lime, rust, and iron ore powder into the groove continuously.

Due to the high temperature of molten iron, the molten iron is not easy to thicken, and most of the sulfur and phosphorus impurities are precipitated through chemical reactions when flowing through these desulfurization and dephosphorization agents.

There are many benefits of desulfurization and phosphorus removal in hot metal pretreatment. For example, sulfur will partially dissolve in molten metal in the presence of slag. In addition, molten iron contains a large number of reducing elements such as silicon and manganese, which can greatly improve the activity coefficient of sulfur and phosphorus, so that these impurities can react more fully with desulfurization and dephosphorization agents. This is also the reason why pretreatment desulfurization and dephosphorization are commonly carried out in the modern steelmaking industry.

After this treatment, the most harmful impurities in the molten iron, sulfur and phosphorus, have been greatly reduced, and the quality of the steel smelted as raw materials is also better.

Especially when the molten iron is still in liquid or paste, it can also be stirred and decarburized, although it does not reach the level of direct wrought iron, but the carbon content has been greatly reduced.

Even nowadays, the steel smelted by the soil method in many places is not as good as the iron from the blast furnace of Suji Iron Field.

One of the important purposes of Su Chengyu's great effort is to preheat the integrated production mode of iron and steel in advance.

When you want to go to the open-hearth furnace to make steel, you only need to upgrade the steelmaking furnace.

Before leaving the iron field, Su Chengyu handed Lu Ning the blueprint of a short sword, and instructed him to cast a small protrusion at the front end of the barrel of all flintlock guns.

The short sword on the drawing is one and a half feet long, with a narrow blade, and the position of the hilt is replaced by a circular sleeve with a hollow groove in the shape of a "B" on the sleeve.

Lu Ning picked up a gun, picked up a small piece of scrap iron and tried to roll it on the gun, and finally understood what Su Chengyu meant by what he said about sticking the short sword on the gun.

It turns out that the protrusion on the tube is a tenon, and after the sleeve is put on, it rotates back and forth, and the tenon can be stuck into the hollow groove.

This is exactly the sleeve bayonet that was commonly equipped in all countries in the eighteenth century. But it's an unprecedented invention today.

After Su Chengyu arranged the affairs of the iron field, he rushed to the Ganzhou Ordnance Bureau non-stop.

Even with a hydraulic forging machine and a foot boring machine, if you want to make 300 sets of busts and 3,000 flintlock guns in two months, it is definitely not something that less than 40 blacksmiths and more than a dozen firearms craftsmen such as Lu Ning can do in the Su Ji Iron Yard.

Moreover, these people had to make new forging machines and boring machines, and although the craftsmanship of the eight hundred cavalry swords was not complicated, it also required a lot of manpower.

He estimated that at least one hundred and fifty or sixty skilled craftsmen would be needed to ensure that the weapons and equipment of the Dragon Guard could be in place in time.

And it is almost impossible to recruit so many skilled workers in Longnan or even in Ganzhou in a short period of time.

So he thought of the Ganzhou Ordnance Bureau.

It's not that the Ordnance Bureau will make weapons and equipment for him, a flintlock gun, plate armor and other new things are more complicated in process and need to rely on equipment, and it is unlikely that the Ordnance Bureau will be able to produce them within two months.

Second, the quality difference between the products of the Ministry of Industry of the Ming Dynasty is famous all over the world, and the Ordnance Bureau under the Ministry of Industry is the hardest hit area. The wages of the craftsmen are low, and they have no enthusiasm for labor. Officials at all levels of the Ministry of Industry are corrupt and the materials they procure are of inferior quality. In this way, it is not possible for what is made not to rot.

Su Chengyu's trip was to borrow some people from the Ganzhou Ordnance Bureau.

Most of the craftsmen in the Ministry of Industry are skilled craftsmen, and as long as they are given generous treatment and strict quality control, they can produce high-quality products.

After borrowing these craftsmen and adding the advanced equipment of Su Ji Iron Yard, it is possible to meet Su Chengyu's requirements for efficiency.

The Ganzhou Ordnance Bureau is the weapons and equipment manufacturing department attached to the original Ganzhou Weixia, and the Qing army has carried out several expansions after attacking the Yangtze River, and is responsible for the supply of weapons to the entire Jiangxi Ming Army.

Su Chengyu's car parked in the southwestern suburbs of Ganzhou Prefecture, where the Ordnance Bureau was located.

Due to the continuous temporary expansion, the Ganzhou Ordnance Bureau covers a wide area, but all kinds of workshops are scattered everywhere in a disorderly manner, without any rules. At a glance, there are fifty or sixty sheds of various sizes.

There are many craftsmen and vehicles shuttling back and forth between the buildings. Almost all of the sheds were covered with black smoke and the sound of clanging bells.

It took Qiao Qian a long time to catch a person in charge and ask him to find the ambassador of the Ordnance Bureau. The man searched for a long time in the Ordnance Bureau, and finally led a thin man in his thirties to meet him.

When the thin man learned that the plainly dressed young man in front of him was actually a county king, he hurriedly knelt down to pay respects, "I didn't know that His Highness was coming, and he never greeted him from afar." Xu Erlu, secretary of the Ministry of Lower Government and Industry, is currently the deputy envoy of the Ganzhou Ordnance Bureau. ”

Su Chengyu lifted him up, and saw that his face was covered with black ash, and the word "Sichuan" was washed out by the sweat on his forehead, obviously a hard-working official.

He followed Xu Er Lu into a dilapidated house with wooden planks put together at random, and various drawings and official letters were pushed on the table, which seemed to be the office of Secretary Xu.

It took a long time for a gray-covered little official to bring tea.

"I'm training in Longnan," Su Chengyu picked up the teacup and glanced at it, and immediately put it down, "But the new army is training for the first time, and the equipment is lacking......"

Xu Erlu immediately said: "Your Highness, the lower official is only responsible for managing the manufacturing of goods, and the allocation of weapons in the warehouse must have a warrant from Yang Butang." ”

Su Chengyu shook his head with a smile, "I'm not here to ask for weapons. I want to borrow some. ”

"People? Who is Your Highness going to borrow? ”

"I need one hundred and sixty military craftsmen, and I have my own place to forge weapons in Longnan." Su Chengyu knew that there was no convenience for nothing, and added, "The purchase of idle silver from these military craftsmen is naturally from me." In addition, for each craftsman, I will supply the Ordnance Bureau with five taels of silver to replenish the manpower. ”

The craftsmen of the Ordnance Bureau are usually both craftsmen and military members, so they are called military craftsmen.

Xu Er looked embarrassed on the road, "If Your Highness had come a few months earlier, it would be okay for the six hundred craftsmen of the Ordnance Bureau to borrow some from you." He sighed and continued, "But the war in Ganzhong has been tense recently. The rebel general Bai Zhiyi and Liu Yipeng have captured Yuanzhou Mansion, and only Wan'an County is still struggling to support Ji'an Mansion. Yang Butang is recruiting a large number of soldiers, and it is difficult for the Ordnance Bureau to draw more manpower now. ”