Traveling through the sword to engage in military industry.

Chapter 84: Open-hearth steelmaking, you will succeed if you spend money!
Jincheng.

Three days later, Ren Zhong received the analysis report that Professor Hu had worked on overnight. Sure enough, the main reason was the excessive impurity content in the raw materials, and the refining temperature was also a little excessive.

In terms of technology, Ren Zhong's super simple open-hearth furnace cannot make detailed adjustments to the refining process.

Professor Hu proposed suggestions for refined management of material feeding, especially the removal of sulfur and phosphorus additives, and ensuring accurate metering and uniform feeding with other raw materials. After all, it is a flat furnace, not a converter, and the distribution of raw materials has a great influence on the smelting temperature and impurity removal.

The money was in place, and Professor Hu's service was also very good. After finding the problem, he thoughtfully gave a new material weight ratio based on the raw material composition test results, and recommended regular spot checks on the raw material composition to prevent changes in the incoming material composition from affecting the scrap rate.

In terms of temperature, Professor Hu knew that there was little room for adjustment, so he suggested purchasing a set of infrared temperature measuring equipment to measure the temperature inside the furnace from the outside. Although its accuracy is much lower than that of modern steelmaking temperature control systems, it is at least more reliable than judging by color based on experience with the naked eye.

Since this cannot be adjusted finely, we can only adjust the gas valve and intensively measure the temperature changes to find a suitable gas supply.

A detailed report manual, with both theoretical and practical aspects. Ren Zhong likes such tools, and the hundreds of thousands of dollars he spent were not wasted at all.

After receiving the manual, it was converted into traditional Chinese characters and printed out as usual, and that was it. Ren Zhong then gave Professor Hu a new task, which was to configure a proportioning process for producing gray cast iron based on the material composition here.

According to the next plan, we will start producing machine tool castings, and the raw material needed to produce machine tool castings is gray cast iron!

Gray cast iron refers to cast iron with flake graphite. It is called gray cast iron because the fracture surface is dark gray when it breaks. Due to its excellent properties, including casting performance, vibration reduction, wear resistance, cutting performance, and low notch sensitivity, it has become the most widely used cast iron, and its output accounts for more than 80% of the total cast iron output!

It is the best choice for manufacturing various racks and box castings! According to the tensile strength, gray cast iron is divided into 6 different types, and the main surface numbers are HT100/HT150/HT200/HT250/HT300/HT350. The greater the load and the better the airtightness, the higher the gray cast iron number is required.

If you want to achieve more advanced applications such as engine cylinders, at least HT200 or above is required. However, for Renzhong's machine tool production that will soon be launched in the world of Liangjian, it is enough to reach the HT150 level.

Therefore, the first customized product development task given to Professor Hu Rentao was to develop HT150 gray cast iron.

In Yangcun, Xu Jiucheng was at a loss as he held a pile of ore and scrap steel, with deep dark sockets around his eyes.

The process flow design diagram and raw material ratios that Ren Zhong gave him, and even various chemical reaction formulas to help explain the entire principle of open-hearth steelmaking, made Xu Jiucheng fascinated. According to his understanding, there was no problem in refining the first batch of steel.

Everything is in line with the above production process description. Now there is a problem, which means that the composition of the expected material is different from the theoretical composition. According to Xu Jiuchen's idea, there is no other way at present, and he can only start doing experiments with different configurations to find a new ratio.

However, with so many raw and auxiliary materials, it is extremely difficult to work out a ratio that can achieve the ideal performance of steel. The metal materials include: molten iron (or pig iron blocks), scrap steel, ferroalloys, direct reduced iron ore, and auxiliary non-metallic materials: slag-making limestone, quicklime, oxidizer, coolant, etc. If this experimental plan is carried out according to the variation range of 0.5% of the content of each input, Xu Jiuchen feels that he can fill up three sheets of rice paper and still not be able to finish it!

From a mathematical point of view, this is a relationship of continuous multiplication of at least 8 parameters!
If these things are produced in large steel mills, the production workshops basically have a mature ingredient ratio, which is a formula ratio that has been experimentally verified in the laboratory.

The number of people who know this formula is usually no more than two hands! It is basically one of the most core trade secrets of the steel plant.

Even though Xu Jiucheng was promoted to deputy chief engineer, he could only know some of the parameters of the process. Now, facing a situation where he had to start from scratch, Xu Jiucheng was at a loss.

Knowing clearly that there was a problem, but having no way to solve it, Xu Jiucheng fell into deep doubt.

"Mr. Xu, Mr. Xu!" Ren Zhong, holding the new formula and infrared thermometer, saw Xu Jiucheng sitting in front of the open furnace in a daze, and Ren Zhong could not help but shouting a few times.

Xu Jiucheng raised his head and looked at Ren Zhong with confused eyes.

"Did Mr. Xu not get enough rest these days? Are you not used to Yangcun?" Ren Zhong was shocked when he saw Xu Jiucheng's big black panda eyes. He hadn't seen Xu Jiucheng much in these two days. How come he looked as miserable as the internet addict who had been working hard for three days and three nights? It was really shocking.

"Boss Ren, it's not that," Xu Jiucheng responded weakly. "I feel guilty towards Minister Zhang and the people in the base area. I knew the problem of steelmaking, but I couldn't think of a solution."

"Oh, is that so, Mr. Xu, don't worry too much, we will start another furnace and try our new formula," Ren Zhong said calmly.

"Boss Ren has a new formula?" Xu Jiucheng didn't pay attention at first. When he reacted, Ren Zhong had already walked past him and began to direct the workers to prepare a new batch of raw materials. This time, the three large, medium and small scales next to them were used, especially the auxiliary materials with smaller quantities. The weighing accuracy was one-tenth of an ounce, that is, 3 grams as a small scale. In strict accordance with the ratio given by Professor Hu Rentao, a new batch of materials was added.

After about six or seven hours of fire, heating, and gas supply, different color spots began to appear on the infrared thermometer purchased for tens of thousands of yuan, and the temperature was displayed at the same time. When the thermometer showed that the temperature in the furnace reached 1800 degrees, Ren Zhong began to turn the gas control valve to reduce the gas input. As the amount of gas input decreased, Ren Zhong stopped only after he saw the rising temperature begin to stabilize back to 1800 degrees.

When the temperature of scrap steel, scrap iron and iron ore reaches 1800 degrees, the powerful heat energy melts them. Some molten pig iron begins to produce ferrous oxide, and the manganese in iron ore and scrap iron is oxidized by ferrous oxide to form slag. This is not the end. Then the auxiliary material limestone in the furnace begins to react chemically with impurities such as phosphorus and sulfur to form calcium phosphate and calcium sulfide, which also precipitate as slag. The excess carbon atoms in the molten iron begin to be oxidized by the oxygen to form carbon monoxide, which emerges from the molten iron as if boiling. After such a complex chemical reaction in the furnace, the molten iron gradually turns into molten steel and flows out through the steel outlet.

Xu Jiucheng, who was nervously following Ren Zhong, saw the molten steel flowing out. He couldn't wait to scoop out a spoonful from the crucible and pour it into the steel bar mold next to him which was used to preliminarily test the physical properties of the steel. Then he watched the red molten steel cool down and spread into a thin steel sheet before he began to pour cold water on the steel sheet.

When the steam disappeared, Xu Jiucheng took out the still warm steel sheet from the mold. It was about 50 centimeters long, no wider than a finger, and only two or three millimeters thick. Xu Jiucheng pulled it hard and the steel sheet immediately bent like a bow, but there was no sign of breakage!

Become!

Ren Zhong looked at Xu Jiuchen's experiment, and a smile bloomed like a spring flower!

It is indeed worthy of being a paid-for product. With this quality, it is probably as weak as the yield point of carbon spring steel.

Ren Zhong didn't know that the formula given by Hu Rentao was not simple at all. It was optimized by Hu Rentao after billions of simulated smelting operations using their laboratory's super minicomputer.

Second update, continue to ask for monthly votes!

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(End of this chapter)