After finishing the ushering in the officialdom, Li Zhi began to study crucible steelmaking. Pen ~ fun ~ pavilion www.biquge.info

Although the quality of Suzhou steel is good, reaching the standard of ordinary steel in later generations, it still contains considerable sulfur and phosphorus, and it is a little reluctant to make tool steel. Moreover, the price of Suzhou steel is expensive, and a pound of Suzhou steel costs two or five dollars of silver, which is used to make bayonets, resulting in a high cost of bayonets. Li Zhi now has 8,000 rifles in service and 2,000 rifles in stock, and the cost of these 10,000 rifle bayonets will reach 25,000 taels of silver. If Li Zhi wants to expand his troops, he will have to spend more silver to buy Sugang.

In addition, Li Zhi also needed high-quality steel to make the main springs and buckle reeds of the flintlock gun machine. The quality of the steel is the key to the effect of these two springs, which directly determines the firing rate of the rifle. At present, the firing rate of rifles made of Sugang is more than eighty percent, and if the firing rate is further increased, the hit rate of shooting can also be improved to a certain extent.

Finally, good steel can bring huge profits to Li Zhi. If Li Zhi sells better steel at a slightly lower price, he can snatch a lot of Sugang market and make huge profits.

You must know that in this era, steel is extremely scarce and can even be used as an equivalent. Some wealthy families would stock up on some steel in case they needed it. If Li Zhi smelts good steel, there will definitely be a market.

Li Zhi was in desperate need of better and cheaper high-quality steel, and the crucible steelmaking that appeared in the mid-18th century was undoubtedly the only option available to Li Zhi. This steelmaking method uses wrought iron as raw material, graphite as crucible carburizing material and reducing agent, and limestone as slag making agent, and the steel quality is very good. This steelmaking method was used for a century in history until it was replaced by the invention of electric arc furnace steelmaking at the end of the 19th century.

As an eighteenth-century technique, the crucible steelmaking method was relatively simple. Li Zhi had studied some earth-based crucible steelmaking methods before the crossing, and now he is using them.

The difficulty of crucible steelmaking is that it requires a temperature of 1,600 degrees, and Li Zhi found Cai Huaishui and asked him to be responsible for purchasing a crucible that can withstand such a high temperature.

Cai Huaishui is now making four taels a month, and he has married Cui'er as his daughter-in-law, and he just gave birth to a big fat son last month. Four taels of silver is enough for a family of five to live a well-off life, not to mention Cai Huaishui's cooking kiln head in the glass workshop and taking care of three meals a day. Although he was kicked out of the house by his father, he did not starve to death outside, but lived a good life. He is now very satisfied with his life in Fanjiazhuang, and he is also quite loyal to Li Zhi who brought him this life.

"Cai Huaishui, I need a crucible with a temperature higher than that of burning glass, do you know where it is?"

Cai Huaishui thought for a while and said: "My lord, it is also possible to make a crucible with such a high temperature, then you have to use black talc to make a crucible, this black talc mineral is not much, make a big mouth of rice bowl, a four-inch deep crucible costs two taels of silver, someone in Texas uses such a crucible to burn porcelain, and you can buy it there." ”

Li Zhi thought about it, guessed that the black talc that Cai Huaishui said was probably graphite, and said: "Is it cheaper to use half black talc and half clay to make a crucible." ”

"That crucible will cost you a penny, two, two, or three pennies."

Li Zhi did the math and felt that the crucible that Cai Huaishui said could hold at least a dozen catties of steel, so the cost of crucible steelmaking was much cheaper than buying Sugang. Li Zhi nodded and said, "It's okay, then you can contact and buy such a crucible, buy a hundred first." If I make steel from the crucible you bought, I will reward you with twenty taels of silver. ”

Cai Huaishui was overjoyed when he heard this, and said: "The owner borrowed four horses and two carriages from my three families, and I took someone to Texas to buy a black talc crucible." ”

Cai Huaishui set off for Texas on the same day, and returned six days later with a hundred crucibles in a horse-drawn cart.

Li Zhi took a closer look at the crucible and found that it was indeed made of graphite and clay.

With the crucible, Li Zhi began to build a furnace for crucible steelmaking. This kind of furnace is made of refractory bricks, and the bottom is empty, and there is a blast outlet next to the cavity, which is constantly blown by manpower. In the middle of the stove there is a bridge made of iron bars. The bridge is filled with coke, a graphite crucible is placed in the middle of the coke, and a hole is left in the lid above the stove. This hole is used to observe the molten iron and stir the molten iron.

In this stove, you can put five crucibles.

Coke was used in steelmaking at the end of the Ming Dynasty. Li Zhi sent people to search around Tianjin, found a coking workshop near the government-run steel mill in Zunhua, and bought coke.

It took three days to make the furnace, and Li Zhi began to experiment with steelmaking.

Li Zhi filled the stove with coke, placed wood under the coke, set the wood on fire, and gradually burned the charcoal. At this time, the crucible is not put into the furnace, and the empty crucible is put in when the furnace has been boiling for half an hour. Then blow the air hard, and after the crucible is burned hot, the preheated wrought iron is put into the crucible.

At the same time, put some lime powder in the wrought iron to make slag.

Turn off the furnace and burn for a few hours, wait for the crucible material in the furnace to seep into the molten iron, turn the molten iron into molten steel, open the furnace scoop out the slag floating on the molten steel, and then pour out the molten steel. After the molten steel is turned into ingots in the mold, the required steel is obtained.

Li Zhi didn't know how many hours it would take to burn it to complete the carburization, so he tried to burn it many times. The crucible was used repeatedly when making steel, and one crucible cracked the fifth time it was used. The leaked molten iron wasted an entire furnace, but fortunately it did not leak outside the furnace and hurt Li Zhi.

It seems that this graphite crucible can only be reused three or four times, and Li Zhi has since thrown away all the crucibles that have been used three times and no longer uses them.

Finally, after burning more than a dozen crucibles of molten iron, Li Zhi found that it was more appropriate to burn for two and a half hours of carburizing, and what was burned was steel.

But after the first furnace of molten steel is boiled, the effect is not good. Li Zhi asked the blacksmith to make a spring out of the steel he had made. As a result, the elasticity of the spring weakened after being pressed more than a dozen times, and it was obvious that the steel smelted this time was not qualified.

Li Zhi guessed that there was too much phosphorus and sulfur in steel, especially too much phosphorus. Phosphorus and iron form an extremely brittle compound triferrophosphate, which causes a sharp decrease in the plasticity and toughness of steel at room temperature.

Li Zhi experimented again, this time waiting for the molten iron to be burned, adding more limestone, fluorite, river sand and soda ash to the crucible to make slag, and then stirring the molten iron with iron rods during the refining process, hoping to remove more sulfur and phosphorus.

The quality of the steel made from this crucible has been significantly improved, and the springs made are comparable to those of Suzhou steel products. But Li Zhi is still not satisfied, the products made by crucible steelmaking should be stronger than that of Suzhou Steel, and obviously the production process can be improved. (To be continued.) )