Chapter 1315 - Silicon Steel Sheets
The Ma'ao Steel Complex's rolling mill was quite large—very modern by this timeline's standards, because its main equipment had almost entirely been unloaded from the ship and installed. But by old-timeline standards, this rolling mill was a classic example of outdated capacity that should be eliminated. According to some knowledgeable transmigrators from the industrial sector, walking in felt like returning to a 1990s township steel plant. Even the supporting power equipment was steam-powered—before the national grid structure was established in the 1980s and 90s, localities had all relied on their own city power plants for electricity, unable to fully guarantee even residential power. So quite a few township small steel plants at the time had used steam engines for power. The Shagang Group, China's most successful private steel enterprise, had originally used steam engines to drive its rolling mills.
Continuous casting and rolling was something the metallurgical transmigrators wouldn't dare dream of, so this rolling mill used steel ingots for processing and also forged wrought iron. Several huge wrought-iron truss-frame factory buildings housed the rolling mill's main equipment: 2 initial forging machines, 2 hot-rolling mills, 2 hot piercing machines, 2 cold-rolling steel machines, 2 cold-drawn steel tube machines, 2 cold-drawn bar machines, and 2 cold-rolled tube machines. Roughly capable of cold-rolling and hot-rolling various common sizes of steel plate, strip steel, wire rod, and various sections.
Although well-equipped, most equipment wasn't frequently used. First, there were very few workers who could operate this equipment, and even among transmigrators, not many could use it—making training skilled workers a lengthy process. Second, the rolling mill required very complex supporting equipment; a whole series of ancillary processes including annealing and pickling all seriously hampered equipment from running at full capacity. Finally, whether hot-rolling or cold-rolling, lubricating oils and coolants were needed. Though Lingao's industry could supply substitutes in a makeshift way, aside from cooling water which could be supplied freely, other oil and grease lubricants were all subject to supply quotas. Consequently, much equipment was in a start-stop-start state.
Cold-rolling had higher technical requirements than hot-rolling, with demanding post-processing that required high skill levels. The rolling mill's cold-rolled finished product rate had always been low. This was also why Ji Wusheng had decided to only manufacture hot-rolled silicon steel sheets.
The hot-rolling silicon steel sheet process was also very complex, with production cycles of 12-15 days—and for transformer-grade silicon steel sheets, possibly up to 20 days. Therefore dedicated annealing furnaces had to be specifically allocated to avoid long-term tie-ups. Manufacturing and commissioning this supporting equipment had taken the steel complex a long time.
During hot-rolling, a single-heating rolling method was used. Silicon steel ingots were loaded into a heating furnace for preheating. The heating furnace temperature had to be maintained at 950-1020°C, roughly allowing the finishing temperature to be controlled above 700°C.
The heating furnace used was a chain type—not very thermally efficient, but its advantage was uniform heating, suitable for Lingao's industrial level. And silicon steel sheet rolling demanded very uniform heating. Sacrificing some thermal efficiency was an unavoidable choice.
First the silicon steel ingots were rolled through a mill into certain-sized rolling stock, then processed through a tandem mill into thin slab stock, then hot-rolled—this way, slab tolerances could be controlled to ±0.3mm levels, roughly meeting tolerance control requirements.
After the slab was rolled into shape, a certain number were stacked according to specifications, then the rolling stock was heated to rated temperature in a heating furnace for formal hot-rolling.
After hot-rolling was complete, natural stack cooling was normally done first—but this process was unfavorable for decarburization. Therefore the transmigrator technicians in the metallurgical sector chose the rapid water cooling technique once used by Shanghai Silicon Steel Plant. The hot-rolled silicon steel sheets were plunged into water within 10 seconds for rapid cooling. This process not only reduced natural cooling time but also substantially improved decarburization levels.
However, since immersion in water was essentially a quenching operation, it would greatly increase the sheet's hardness. This had little effect on motor silicon steel but would affect the mechanical workability of higher-silicon transformer silicon steel, so it was only used in motor silicon steel production.
After cooling, the silicon steel sheets were manually separated and underwent first composition testing to determine whether elemental content was suitable. Then another hot-rolling leveling pass was done before finally entering the annealing furnace for annealing.
Annealing was a crucial step in silicon steel sheet decarburization. The sheet's carbon content had to be reduced to 0.02% during annealing to be considered qualified. The transmigrators agreed that under Lingao's conditions this standard could be relaxed somewhat—after all, even so it was better than low-carbon steel. During annealing, the stacking method was still used. Ma'ao's rolling mill annealing furnace used coal gas as fuel for heating—ideally, pure hydrogen heating for annealing gave the best decarburization results. Ji Wusheng could only settle for coal gas.
During annealing, temperature was gradually raised at 15-30°C per hour up to 690-750°C, held for 11 hours, then reduced at 10-15°C per hour down to complete cooling.
Annealing furnace temperature control required tremendous effort. Lingao's industry had no automatic temperature control equipment. Everything relied on human labor checking thermometers and increasing or decreasing the heating nozzle gas flow to control temperature—fine-grained temperature control was very difficult to achieve precisely.
After twenty continuous days of this struggle, the first batch of motor-grade silicon steel sheets was manufactured. Ji Wusheng immediately dispatched someone to send them to Ge Xinxin for spectrographic composition analysis.
The composition analysis results were barely satisfactory. By old-timeline standards, the silicon steel sheets that the metallurgical sector had fought for months to produce, expending large amounts of manpower and resources, were simply scrap. Magnetic property testing was then performed. The results were even more appalling—even the portions with the best magnetic properties had disappointing test results. The transmigrators in the Power sector who had been eagerly awaiting silicon steel sheets all felt like cold water had been poured over them, ice against their chests: most of the silicon steel sheets produced with such great effort didn't even qualify for a national standard grade designation. Roughly 10% barely scraped into the low-grade silicon steel category. Most disheartening was that approximately 20% of the finished products had mechanical property problems and were completely unworkable scrap.
Such a failed trial production was unprecedented in Lingao's industrial history. But the transmigrators in the metallurgical sector knew there was no forcing this. Any further quality improvement would have to wait until the overall industrial level rose another tier before slowly experimenting and improving.
"Well, this makes the motor industry a joke," Qian Liushi said, looking at the test report with a long face.
Faraday wasn't as pessimistic. "I think it's fine. No matter what, having something is better than having nothing—that's first. Second, the worst of it is still better than low-carbon steel, isn't it?"
"True enough, but with performance like this, is there still any possibility of copying existing motor designs?" Qian Liushi said. "I think it's doubtful."
"Although this silicon steel sheet isn't the silicon steel sheet we hoped for, at least it's not low-carbon steel." Faraday said. "Granted, it's only marginally better. But it's still a hope. You can only have adults after you have babies, right? From low-carbon steel to silicon steel—that's a qualitative leap. We just have to work hard to adapt to current conditions."
"I suppose that's all we can do. It's just that the motors will probably have to be redesigned." Qian Liushi said. "Silicon steel sheets are in this sorry state. Let's not harbor any overly complex hopes. How do you plan to solve the permanent magnet problem for permanent magnet motors?"
"I checked the materials. The Shilu iron ore is 42% purity magnetite—quite good raw material for sintering ferroferric oxide. We can use this for the permanent magnets first. Efficiency will be somewhat lower, of course, but since we're prepared to move ahead with our grade-less silicon steel sheets, this is even less of a concern."
"Shilu Iron Mine hasn't been developed yet. And I hear external transport is difficult, so the Planning Commission didn't include it in the First Five-Year Plan."
Although since the stable supply of Southeast Asian slaves began, more than one transmigrator had suggested moving Shilu development forward into the First Five-Year Plan, and transmigrators had raised the matter again after Operation Engine, the Planning Commission had consistently rejected this.
The main difficulty with Shilu Iron Mine development wasn't mining itself—it was ore transport. Shilu Iron Mine was located in the mountains. Unlike Tiandu, which was near the coast, it was surrounded by rugged highlands. A railway had to be built for large-scale export. Back then, the Japanese had filled the route with corpses before completing the Basuo Line.
If merely expending human lives could complete the railway from Shilu to Basuo or Shilu to Tiandu, the Planning Commission would have pressed ahead without hesitation. But the enormous material consumption of railway construction made Wu De balk, not to mention some engineering challenges—such as how to construct tunnels. Moreover, Basuo wasn't a natural harbor and would require artificial improvements before ore ships could use it.
For now, the Planning Commission could only settle for first building a simple road from Changhua to Shilu to establish basic transportation between the two places and ensure the Council's influence in that region.
"That's true," Qian Liushi thought for a moment. "But magnetite isn't exactly rare. With some serious searching it wouldn't be hard to get. If it really comes to it, we'll take a company with us, carry it on men's backs and pack animals, and take the overland route through Changhua to Shilu. Bring out ten-odd tons first and use that. Surely that won't require much investment or project approval."
The silicon steel project report also reached the Manufacturing Director's office at the first opportunity. The machinery sector wasn't as picky as the Power sector. From Zhan Wuya's perspective, the immediate priority was solving whether something existed at all before discussing whether it was good. He urgently needed to expand power supply to support non-ferrous metals smelting—besides providing electrolytic copper, he also hoped to obtain nickel, cobalt, and other non-ferrous metals from it to smelt stainless steel.
The Chemical sector had been requesting stainless steel for a long time. Chemical equipment required large quantities of corrosion-resistant pipes and vessels that needed stainless steel to manufacture. If they remained stuck at the level of manufacturing ceramic or glass equipment, Lingao's chemical industry would essentially just be scaled-up laboratory production, fundamentally unable to achieve self-replication of the chemical industry, let alone upgrading.
Therefore, the moment silicon steel sheet trial production succeeded, Zhan Wuya immediately reported to the Planning Commission requesting formal launch of the electrolytic copper workshop project.
(End of Chapter)