Ji Wusheng had been watching the blast furnace without saying a word. This time he decided to let the naturalized migrant workers follow the process themselves - he had discussed and rehearsed the specific smelting process many times with the workers in charge of the trial, and he also
He made plans for various accidents that might occur. In this trial, he wanted to see if a naturalized migrant foreman like Zhao Youcai could roughly complete the entire work process without the guidance and assistance of the elders.
Now two blast furnaces and one open-hearth furnace are equipped with naturalized foremans according to shifts, but their work does not completely reassure Ji Wusheng. Every time the iron is tapped, slag is removed or the ingredients are adjusted, he has to come over to take a look and give guidance.
For a moment. This time he wanted to see if his best furnace manager could completely break away from the guidance of the elders.
Seeing Zhao Youcai looking at him, he nodded and said loudly: "Zhao Youcai, you will be in charge now!"
Zhao Youcai's face suddenly flashed a look of nervousness and excitement, and he responded loudly: "Understood!" He turned around and began to direct the workers in front of the furnace to get into their positions, waiting for the opportunity to officially load the materials. He himself watched closely.
Catching the flames in the blast furnace,
"Start the first feeding!" Zhao Youcai suddenly shouted. The feeding workers on standby started the equipment and put a batch of materials into the blast furnace.
The materials for making ferrosilicon are mixed according to the ratio of silica sand, coke, pig iron, and quicklime in the ratio of 5:3:1:2.5. Because it is the first batch of materials, the proportion of coke is relatively high. After the fifth batch of materials is added,
The proportion of coke input can be gradually reduced.
After adding the material, Ji Wusheng quietly left the observation platform - the first iron tapping would be in 3 hours, and he planned to come back at that time to see the actual iron tapping.
Three hours later, Ji Wusheng returned to the special blast furnace. The workers were nervously preparing for the first molten iron tapping. Ji Wusheng silently checked whether there were any foreign objects in the main ditch and the lower slag ditch - this
It was the first time for the special blast furnace to tap iron. Theoretically, there should be nothing in the two ditches. However, many times the accident happened because things that "should" did not happen according to common sense.
The iron slag tank that was supposed to be free of foreign matter was mixed with garbage at some point. As soon as the hot iron slag entered the tank, it exploded like shrapnel, killing two-thirds of a blast furnace working class in an instant.
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This kind of incident where iron was tapped without preparation, causing major accidents, has happened more than once.
Ji Wusheng followed standard work procedures and personally inspected every link: whether the mud sleeve of the taphole was intact, whether the gates of the iron ditch and the lower slag ditch were lowered, whether the flow nozzle of the slag-iron ditch was intact...
"I have sent someone to send melt samples to the laboratory." Zhao Youcai was busy instructing the workers to make iron preparations. He just saw Ji Wusheng coming and hurried over to report, "The iron preparations are ready. We are waiting for the test results of the melt samples.
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Ji Wusheng nodded.
"I think there will definitely be no problem this time."
"Whether there is any problem depends on the results of the laboratory." Ji Wusheng was amused by his confident energy, "You can't tell with your eyes!"
"Yes." Zhao Youcai responded loudly. At this time, a worker hurried over, waving a piece of paper in his hand. Ji Wusheng knew that it was just sent by wired telegram from the Heavy Industry Laboratory without looking at it.
Melt sample test results.
The worker saw Ji Wusheng present and was about to hand the order to him. Ji Wusheng shook his head and motioned to hand it to Zhao Youcai directly. Zhao Youcai took it and looked at it, excitedly clenched the note into a ball, turned around and shouted loudly
, asking workers to prepare to release the first furnace of molten ferrosilicon.
The casting molds coated with coke powder are ready, and the workers, holding steel drills, are nervously waiting for the order to open the taphole.
Zhao Youcai pulled the cord of the warning bell. Suddenly the bell rang loudly.
"Take out the iron!"
He gave the order, and several workers used a crane to move a hand-operated drill to the taphole. Zhao Youcai first checked whether there was wet mud in the mud sleeve of the taphole. After confirming that the taphole was dry, he nodded.
Start drilling.
"Be sure to move steadily!" Zhao Youcai shouted, carefully holding the drilling rig close to the mud casing. The temperature at the taphole was the highest in the entire blast furnace workshop. The strong thermal radiation made it difficult for people to stand there for a long time, but Zhao Youcai
It is better to check the position of the drill bit carefully. When drilling, the drill bit must be aligned with the center of the funnel-shaped deep pocket of the taphole sleeve. Otherwise, the taphole sleeve will be drilled or the taphole will be drilled biased. Mud or slag will occur when the taphole is blocked.
The phenomenon of iron erupting out of the ditch.
"Drill!"
The workers began to shake the drilling rig, and the drill bit slowly drilled into the mud jacket. Every time it drilled a few turns, the drilling rig had to withdraw. Several workers immediately used the blow pipes drawn from the blast furnace to blow the revolving mouth and blow out the drilled mud.
Powder. In order to observe the condition of the tap hole, whether the red point is drilled, and measure the depth of the tap hole to determine how much more drilling is required to avoid burning the drill bit and drill pipe after drilling leakage.
"Slow down, don't be anxious!" Zhao Youcai stared closely at the drilling rig and the taphole. Starting the drilling rig is a technical job, and the movements must be very stable to prevent the drill pipe from swinging too much or the drill bit getting stuck. The drilling rig workers were all passing on the simulated mud jacket.
Hundreds of training sessions.
"The iron is being tapped!" Following Zhao Youcai's loud shout, the alarm bell rang again. As the hot furnace flames spurted out, red molten iron surged out of the tap hole and sloped down along the main iron ditch.
The taphole was suddenly shrouded in smoke. Molten iron flowed out of the iron ditch and poured into the mold coated with coke powder. Choking smoke and flames rose from time to time.
With the end of the first hot metal tapping, Ji Wusheng quietly left the blast furnace workshop. The following is the normal production process. Iron will be tapped approximately every three hours. What he needs to be concerned about is the specific details of each batch of ferrosilicon.
elemental content.
There was a composition report of the melted sample sent to the office: the silicon content was 16.21%, which was roughly the same as the proportion they estimated. Before starting the refining, he estimated that the silicon content of the first five batches would be between 14 and 20%, and then the silicon content would be between 14 and 20%.
As the feed ratio changes, the silicon content will rise to 17-30%.
"It's a good start." Ji Wusheng breathed a sigh of relief and looked at the overall composition report. This batch of ferrosilicon met the needs of silicon steel making.
Smelting silicon steel is more difficult than ferrosilicon. The smelting method prepared by the metallurgical port is to use a converter to smelt silicon steel.
There are 4 small converters brought from the old time and space at the Metallurgical Port. To be cautious, Ji Wusheng decided to only use the smallest 1-ton converter.
In the old days, ferrosilicon smelting by the empty converter method required oxygen blowing and argon gas protection, as well as rh vacuum treatment, etc. Ji Wusheng did not have this condition, so he had to resort to the air blowing method as the next best option.
Before starting smelting, ferrosilicon first undergoes pretreatment in the iron furnace, firstly further desulfurization, so that the sulfur content of the molten iron entering the furnace is less than 0.005%. As for the residual manganese and phosphorus elements in the pig iron, they are no longer processed. Although
Manganese element has certain side effects on the magnetism of silicon steel, but manganese sulfide synthesized from manganese element and sulfur element can improve the processability of hot rolling and avoid cracking during hot rolling. As for the phosphorus element itself, it can improve iron loss, and
It has the effect of strengthening the adhesion of the oxide scale on the surface of the hot-rolled plate, and it is not easy to produce an oxidized adhesive white film after annealing. However, too high a phosphorus element will also make the plate brittle, so it must be controlled under a certain content.
As for other elements, they must be controlled at extremely low levels, especially nitrogen - the nitrogen element has a negative impact on silicon steel. In the silicon steel converter blowing process in the old time and space, one used pure oxygen, but injected it during steelmaking.
Argon is used as a protective gas. However, there are no two conditions in Lingao, so it can only be lacking.
The day after ferrosilicon was smelted, Ji Wusheng personally went into battle and cooperated with a group of industry veterans to test the silicon steel. Thanks to the spectroscopy method that can conduct semi-quantitative analysis of elements, Ji Wusheng was the first to prepare materials.
Now we have a rough grasp of the specific element composition and content of the raw materials to be put into the converter, and we can accurately prepare suitable raw materials. This is of great benefit to the work of refining special steel.
After struggling day and night, trying many times, and adjusting ingredients and processes, they finally got good news from the melt sample analysis in the heavy industry laboratory. They refined silicon steel with a silicon content of 3% and a carbon content of less than 0.04%. This
Seed steel is the raw material used to roll silicon steel sheets used in motors.
The ideal silicon content of motor steel is 2.4 to 2.8%, but this kind of steel can be considered a qualified material. However, it is not enough to just make suitable molten steel. The steel industry in Lingao does not have a continuous casting and rolling process. The molten steel must be cast first.
Steel ingots can be used by hot rolling mills.
Casting steel ingots use a protective slag process, generally using graphite powder. Graphite powder has a better effect, but it has obvious carburizing properties, sometimes increasing to 0.01 to 0.02%, which is very difficult for silicon steel that has strict requirements on carbon content.
It was said that there was great damage. After reading the information, several people finally decided to use the process of carbonized chaff shell containing 40% carbon which was used by domestic steel plants in the 1970s. The ignition point of this material is much lower than that of graphite powder. When casting
When the mold is used, the carbon in the mold powder is burned off first, and the carburization phenomenon is significantly reduced. Moreover, this kind of mold powder can also greatly absorb al2o3 in the molten steel, which is of great benefit in reducing impurities in the molten steel.
In order to produce this kind of carbonized bran shell, Ji Wusheng took people to Xiao Bailang's activated carbon production workshop to inspect the kiln. After dozens of experiments, he finally made a carbonized bran shell with a carbon content of 40%.
After a lot of hard work, the Ma Niao Iron and Steel Consortium finally cast qualified silicon steel ingots. Then, they continued their efforts and tested silicon steel with a silicon content of 4.1% for transformers. However, it was not completed until the silicon steel with the appropriate content was produced.
Half of the workload - the specific quality of silicon steel depends to a large extent on the subsequent cold rolling or hot rolling process. (To be continued...)