Liu Yahui took the initiative to propose that he wanted to be transferred to Yan Baosheng's senior engineer group.

Since Liu Yahui is leaving, Zhao Qingshan will not forcibly stay.

Liu Yahui took refuge in Yan Gaogong, and there were three people left in Zhao Qingshan's special team.

With the in-depth promotion of the 945 steel project, the research group has successively added some newcomers.

Zhao Qingshan's group maintained three people, and he said that our group was not fighting in one group, and three people were enough.

945 steel batch after batch of off the production line, the supply state is hot rolling, in the process of smelting, hot rolling, 945 steel still has some problems that need to be improved.

"Pull one radish at a time, let's lower the sulfur content first. Zhao Qingshan said.

Sulfur exists in the form of sulfide inclusions in steel, which has adverse effects on the plasticity, toughness, welding properties, thickness direction properties, fatigue properties and corrosion resistance of steel.

The sulfur content in high-grade high-quality steel is generally less than 0.02%~0.03%, and the desulfurization standard of 945 steel is more stringent, with the recommended sulfur ≤content of 0.01% in the supply state of 8~16mm, and the recommended sulfur content in the supply state of other specifications ≤ 0.015%.

The sulfur content of 945 steel that has been rolled off the production line is 0.02~0.05%, and it is found that there is a certain gap from the supply standard after various performance tests.

In order to solve the problem of desulfurization, the research group held a technical seminar, which was attended by Ye Guoguo, Chief Engineer Tian and the leaders of each group.

"Desulfurization is not only for 945 steel, for other steel grades, the lower the sulfur content, the better. Through RH refining, we can make high-grade high-quality steel with a sulfur content of 0.02%, and put it on the market, which has been well received by customers. The significance of 945 steel is significant, it is a political task that must be completed, the military representative does not clearly stipulate the sulfur content in the performance standards, but we work backwards according to the performance requirements, hoping that the sulfur content of 945 steel is less than or equal to 0.01~0.015%. High standards and strict requirements, we take the sulfur content of 8~16mm supply state ≤ 0.01% as the challenge goal, and see what new desulfurization method is used to achieve the goal. Ye Guoli has a great sense of urgency, the deadline for the military representative to demand the supply of 945 steel is February 28, 1989, although there is still one year and eight months, but there are many technical problems that need to be solved.

Chief Engineer Tian took a look, all the men who came to the meeting, he lit a cigarette, took two puffs and said: "We are now using RH to add solvent to desulfurization, and the sulfur content of 0.02% is already the limit." To achieve less than 0.01%, we must adopt new process methods. ”

"What is Lao Tian's opinion?" Ye Guoguo's addiction to smoking came up, and he groped for a while, but found that he didn't bring cigarettes.

Tian handed a cigarette to Ye Guoguo, he said: "Pittsburgh is the steel capital of the United States, I went to a steel mill in Pittsburgh in 1985 to exchange experience, the steel mill's output is not large, 85 years of annual output of less than 2 million tons, but they are refining high-quality steel, part of which is exported to China. In fact, I only stayed in the workshop of the steel mill in Pittsburgh for half an hour, and Lao Mei did not allow us Chinese to take pictures, so we could only look at the flowers. During that visit, I found that the desulfurization method of Laomei was different from ours, they sprayed a desulfurizer at the same time as RH oxygen blowing decarburization, which reduced the sulfur content to 0.01~0.015%. ”

"Oh?" Ye Guoguo's eyes lit up, and he asked, "And then?"

Chief Engineer Tian said: "Director Ye, you also know that these steel mills in capitalist countries have a very high degree of secrecy about their core technology, and Lao Mei only allowed me to look in the workshop for half an hour, and what kind of door can I see? Lao Mei is greedy for money, if you don't give them money, they won't give you the real thing. ”

"After returning from Pittsburgh, I have been studying the desulfurization methods of Laomei, but there is very little valuable research data. At present, it is speculated that Laomei uses calcium oxide desulfurizer in RH refining, which should be the most advanced and efficient desulfurization method in the world. However, the specific technical details of the desulfurizer of Laomei cannot be obtained, and they cannot be bought with money, so they have no idea of making a transaction at all. ”

"Lao Mei has already had an atomic bomb, and they will never provide us with even half a page of the technical details of the atomic bomb, so why don't we make an atomic bomb? That mushroom cloud in Lop Nur is inspiring, if we don't give us technology, we will develop it ourselves!" Ye Guoguo suddenly became excited as he spoke, and he said again: "In terms of deep desulfurization, Chief Engineer Tian pointed out a new path that can be tried, do you have any opinions?"

Zhao Qingshan took the lead in speaking: "Director Ye, Chief Engineer Tian, colleagues, I have already begun to study the problems of deep desulfurization, before the start of the 945 steel project, I have studied a small experience, with the in-depth promotion of the 945 steel project, my idea of deep desulfurization tends to mature. Chief Engineer Tian pointed out that the direction is very correct, and the desulfurizer of calcium oxide is ...... To be precise, I think it is a desulfurizer based on calcium oxide + calcium difluoride, which has a high potential to achieve deep desulfurization with a content of less than 0.01% in Jianggang. ”

"Xiao Zhao, you can always surprise us, then you can be specific. ”

Zhao Qingshan walked to the blackboard in the conference room, he picked up the chalk, and said while writing: "The desulfurization reaction of molten steel is:

3（CaO）+2[Al]+3[s]=（Al2O3）+3（CaS）

The desulfurization efficiency of molten steel mainly depends on the aluminum content in the steel and the slag index (S· P）：

（S· P）=a^1/3 Al2O3/(%S)sat·aCaO

When (S· When P) is equal to 0.1, the sulfur distribution ratio between slag and steel is the largest.

Therefore, the optimal composition of desulfurization slag is:

60%（CaO）+25%（Al2O3）+10%（SiO2）。

RH powder spraying uses CaO + CaF2 desulfurization agent, and the desulfurization ratio of this kind of powder is calculated by me as:

La=（%S）/[%S]=1260-25（% Al2O3）-75（%SiO2）±250

The desulfurization rate of molten steel is: d[%S]/dt=-A/VKs{[%S]-[%S]e}

……”