China entered the Iron Age during the Spring and Autumn Period and the Warring States Period, and the iron sword production of Wu Yue during the Warring States Period has reached a considerable extent, and iron, which is stronger than bronze, has become a tool and has also promoted the development of the times.

From iron to steel, it stands to reason that there is almost no boundary, and the carbon in the iron is constantly consumed, and when it reaches a certain amount, it is steel, but in the records of history, many of the names of steel are mostly iron, and very few are really called steel.

The main problem is that in the feudal era, there was no obvious understanding of the relationship between iron and steel, only knowing that steel was refined into steel, knowing that steel was better than iron, and where it was better, but not knowing.

Zhao Xin gave standardization, as well as an understanding of steel, which directly determined that even if it was manual, it could be more efficient to make steel.

The steel of the Northern Song Dynasty is mainly handmade, which is made by iron, and it is made into steel, so the price is extremely high, because the yield is not high.

Generally, a good blacksmith, 10 times of refining, can finally succeed once or twice, which is already very amazing, a little bit, maybe hundreds of times to succeed.

This kind of consumption is just a labor cost, it is a very high number, not to mention that it may not necessarily come out after thousands of tempering, if the probability is a little higher, the scrap rate is a little lower, this fine iron will not be so expensive.

Since Zhao Xin dares to open this common sense, he has absolute confidence in this, and the pure handmade system in later generations can already guarantee the finished product.

It's not that the masters of later generations are stronger than the masters of the feudal era, in fact, they are far inferior, but the understanding of steel in later generations has been deepened to a certain extent, even ordinary people understand the difference between steel and iron.

To put it bluntly, steel is an alloy with a carbon content of between 0.2 and 2.06%, and the hand-made method of later generations is creased with the help of wrought iron and pig iron, but unlike the casual construction of the feudal era, the proportion will be controlled here.

Wrought iron contains almost no carbon, pig iron is more than 2%, generally below 5%, later generations of forgers, according to experience, to an average amount, while calculating the amount of pig iron and wrought iron, so that the carbon content is kept between 0.8-1.2%.

More than 0.6%, that is, high-carbon steel, compared with pig iron, there is a margin of about 0.6%, even if there is an error, it can also be guaranteed in more than eighty percent, which can ensure efficiency.

9 times out of 10, in this way, the price of steel can be reduced to the same extent as iron, or a little higher, which greatly reduces the cost.

This ratio is high-carbon steel, the hardest steel, and the flexibility is a little worse, but it is an excellent choice for making armor and weapons, and many famous swords in history are used in such materials.

Compared with the whole process of not participating in the cement experiment, Zhao Xin participated in the whole process of the experiment of steel construction, because some of the key points, steps and proportions, etc., must also be grasped by him, and even one time may not be successful, and many experiments must be carried out.

Although ancient China has created a brilliant scientific and technological civilization, it has also created four major inventions that have attracted worldwide attention, which has played a huge role in promoting science and technology in China and the world.

However, without a complete and orderly system, without a book for cultivating and learning skills, some skills are often lost after war.

Of course, this also has a lot to do with the fact that China does not attach great importance to Confucianism, and even the more obscure and difficult to understand medicine has a complete system and training methods because of its involvement with Confucianism.

In addition to the military science and law that have been incorporated into Confucianism and the court, there is a certain development, other industries among the hundred schools of thought have been suppressed, especially since the Northern Song Dynasty, the development of Confucianism has risen to a peak, and craftsmen have been suppressed even more, and some inventions are of little significance.

When Xue Yu arrived, Zhao Xin's experiment happened to be carried out to a more critical level.

According to different proportions, Zhao Xin calculated, and then scanned the failed products, and roughly analyzed a part of the data through the card system, and then calculated according to the success and failure, and finally calculated the carbon content of different colors and performance pig iron.

This carbon content is far from being accurate to a few decimal places, but there is a general range, and the error within 0.5% can actually be carried out.

This basic data will become more and more accurate through continuous experiments, continuous recording and calculation, but unfortunately this work cannot be handed over to others.

Even if it is the simplest calculation of a ratio, if there are accurate numbers, four calculations, which is a little difficult for the Northern Song Dynasty, and some people who study it may not be able to calculate it.

However, what Zhao Xin wants is a probability, a mixture, and a fuzzy, and according to some data, he finally gives a relatively accurate and small error, which can only use the methods of advanced mathematics or number theory.

This thing, even in the later generations, it is unlikely that an outstanding high school graduate will make it, let alone in this era, in the entire Great Song Dynasty, only Zhao Xin understands this calculation.

After getting the exact news from Xue Yu, Zhao Xin couldn't leave immediately, because this steelmaking had reached a critical level.

After the run-in of many blacksmiths, coupled with Zhao Xin's data, the proportion of steel has increased from 1% at the beginning to 50%, which has made the blacksmiths overjoyed.

These blacksmiths are all nearby, or from the forbidden army, the latter in the entire Northern Song Dynasty, can already be called the more elite kind, but compared with the Ministry of Industry Bureau, it is far behind.

A master craftsman, or a leader or something, when making fine iron, can have 3 percent, which is already the pinnacle, but they can reach 50 percent, not one or two, but most people reach 50 percent, they are excited, just by virtue of this, their level can be raised by one liter, even if they return to the barracks, the monthly salary can also be raised by one liter.

Only 5 into what is this, the use of number theory, practice at least 500 times of materials, although each time is not much, the consumption of labor and raw materials is also a lot, only 5 into this, this is too low, fortunately, after a large amount of accumulation, number theory and probability of this kind of thing, the more accumulated data, the more accurate the final result, steel, different from the special profiles of later generations, must be accurate to several decimal places, but about 2%, and even almost 1.4 error range, this can only be 5 percent.

Zhao Xin continued, he was in charge of the data calculation, and let the blacksmiths also get together, recall some experience, and try to solve the problem.

Finally, through comparison and calculation, the carbon content of various pig iron was roughly calculated, and a series of data were calculated by using wrought iron and pig iron folds, and a certain margin was given with a fuzzy method, giving a relatively complete method.

It includes most of the proportioning and mixing methods of the body and wrought iron, and also refines the steps of building, reduces the meaningless steps, and requires a certain effect to be achieved every time to save labor costs.

In this way, the efficiency has been significantly improved, in the past, it may take three to five days to build a weapon, and some more valuable treasures even take ten days.

Take the Falling Moon Bow as an example, his body alone is not formed at one time, in the natural meteoric iron, after several rounds, the impurities are removed, and gradually beaten to form, now, even if it is fine iron, it takes up to 4 hours, which is greatly reduced compared to before.

The reduced time is the cost, which the Northern Song Dynasty has not yet realized, but later generations have expressed in countless papers that manpower is also a cost, and the faster the production, in fact, it is to reduce this cost, and the cost is reduced in disguise.

Just when many blacksmiths were elated, they could steadily reach a ninety percent chance of steelmaking, and they got it, which was somewhat unexpected, and most of the steel's properties were very good, almost comparable to natural refined iron.

However, Zhao Xin's teaching is still not over, these steelmaking processes are not wrong, and he is missing one of the most critical steps, quenching.

China's metal smelting process has occupied a leading position in the world for a long time, but there is one thing that has always been a weakness, that is, quenching.

Quenching is also known as dipping, mainly the high-temperature material, quickly reduce the temperature, to form an alloy at room temperature, from the Bronze Age, has been used to this day, most of the Chinese smelting, is to quench with water, and even has continued to the entire feudal era.

Water is a more common quenching material, which can quickly reduce the temperature and ensure the efficiency of quenching.

Most of the time, there is no stable alloy formed, the stress is released unevenly, and more than half of the loss of steelmaking is caused by quenching, and the steel that fails to quench is even inferior to iron, which is also the fundamental reason for the high steel price of Liangpin.

Zhao Xin knew that the simplest way to quench was the nomadic people and later generations who still preserved the cold weapon craft, water and oil quenched in sections.

This is a matter of timing, experienced masters, can grasp this opportunity, so that the alloy formation is better, water and oil different release environment and cooling, will make the internal stress get a huge release, the final performance is better, even if you do not master this timing, such a quenching method is better than simply using water, putting the red-hot weapon in the water.

This is the simplest and easiest to master, water and oil are common in real life, and this timing can also be done through non-stop experimentation.