Chapter 104: Silicon Steel Sheets

The rolling mill at the Ma Niao Steel Complex was vast and, by the standards of this world, exceptionally modern. Its main equipment had been almost entirely offloaded from the ship and installed. By the standards of the old world, however, the mill was a textbook example of obsolete production capacity, fit only for elimination. According to several well-traveled Elders from the industrial sector, stepping inside was like time-traveling to a township steel mill from the 1990s. Even its power equipment was steam-driven. Before the establishment of the national power grid in the 1980s and 90s, many regions relied on their own small urban power plants, which struggled to even meet civilian demand. Consequently, many small township steel mills of that era used steam engines as their primary power source. Shagang Group, China’s most successful private steel enterprise, had started with a steam engine driving its rolling mill.

Continuous casting and rolling was a technology the metallurgy Elders dared not even dream of. This mill processed steel ingots and also forged wrought iron. Within several enormous, wrought-iron, truss-style workshops lay the mill’s primary rolling equipment: two blooming mills, two hot rolling mills, two hot piercing mills, two cold rolling mills, two cold-drawing steel pipe machines, two cold-drawing bar machines, and two cold-rolling steel pipe machines. Together, they could produce various common specifications of steel plates, strips, wires, and section steel through both hot and cold rolling.

Though fully equipped, most of the machinery was used infrequently. Firstly, there were very few workers, or even Elders, who knew how to operate this equipment, which meant training a skilled workforce would take considerable time. Secondly, the rolling mill required a complex array of supporting equipment; a series of auxiliary projects like annealing and pickling severely hampered the mill’s ability to operate at full capacity. Lastly, both hot and cold rolling required lubricating oil and coolant. While the Lingao industry could produce substitutes, only cooling water could be supplied freely. Oil-based lubricants were subject to strict quotas. As a result, much of the equipment was in a state of constant starts and stops. The technical demands of cold rolling were higher than hot rolling, and the post-processing required a high level of skill. The yield of cold-rolled products had always been low, which was why Ji Wusheng had decided to produce only hot-rolled silicon steel sheets for now.

The process of hot-rolling silicon steel sheets was complex, with a production cycle of 12-15 days. For transformer-grade sheets, the cycle could stretch to 20 days. This necessitated a dedicated annealing furnace to avoid long-term occupation of the equipment. The manufacturing and commissioning of these supporting facilities had taken the steel complex a great deal of time.

They used a single-heating rolling method. Silicon steel ingots were loaded into a heating furnace for preheating, with the temperature maintained between 950°C and 1020°C, which could roughly ensure a final rolling temperature above 700°C.

The heating furnace was a chain-type furnace. Its thermal efficiency was low, but it provided uniform heating, which was better suited to Lingao’s industrial level and essential for rolling silicon steel sheets. The loss of some thermal efficiency was an unavoidable trade-off.

First, the silicon steel ingots were rolled into slabs of a specific size. They were cross-rolled into thin slabs and then hot-rolled, which allowed them to control the slab tolerance to within ±0.3mm, roughly meeting the requirements.

Once the slabs were formed, they were stacked and heated to the rated temperature in the heating furnace for the formal hot rolling.

After hot rolling, the first step was natural stack cooling. However, this process was not conducive to decarburization. The metallurgy Elders opted for the rapid water-cooling technology once used by the Shanghai Silicon Steel Plant. The hot-rolled sheets were rapidly cooled in water within 10 seconds. This not only reduced the natural cooling time but also significantly improved the level of decarburization.

However, since immersion in water was equivalent to quenching, it significantly increased the hardness of the steel sheets. This had little impact on motor-grade silicon steel, but it would affect the machinability of transformer-grade silicon steel, which had a higher silicon content. Thus, it was only used for producing motor-grade steel.

The cooled silicon steel sheets were then manually turned over for their first composition inspection to ensure the elemental content was correct. They were then hot-rolled and leveled again before finally entering the annealing furnace.

Annealing was a key step in the decarburization process. The carbon content had to be reduced to 0.02% to be considered qualified. The industrial Elders agreed that Lingao’s conditions allowed for more lenient standards—in any case, it was better than low-carbon steel. They used the stacking method for annealing, with a furnace heated by coal gas. Ideally, pure hydrogen would be used for heating and annealing for the best decarburization effect, but Ji Wusheng had to be content with coal gas.

During annealing, the temperature was gradually increased at a rate of 15°C-30°C per hour to between 690°C and 750°C, held for 11 hours, and then lowered at a rate of 10°C-15°C per hour until completely cooled.

Temperature control of the annealing furnace was extremely energy-intensive. The Lingao industry had no automatic temperature control equipment. The temperature was managed entirely by manually checking thermometers and adjusting the gas flow to the heating nozzles. Achieving precise temperature control within a narrow range was difficult.

After twenty days of continuous work, the first batch of motor-grade silicon steel sheets was produced. Ji Wusheng immediately sent samples to Ge Xinxin for spectrographic analysis.

The results were barely satisfactory. By the standards of the old world, the silicon steel sheets produced after months of hard work and a massive expenditure of manpower and resources were scrap. The subsequent magnetic test was even more disastrous. The best-performing samples yielded unsatisfactory results. The Elders in the power sector, who had been eagerly awaiting the new material, felt as if they had been doused with cold water. Most of the hard-won silicon steel sheets could not even be graded according to national standards. About 10% barely qualified as low-grade silicon steel. Most tragically, about 20% of the finished products had mechanical performance issues and were unusable scrap.

It was the first such failed trial production in Lingao’s industrial history. But the metallurgy Elders knew they couldn’t force it. Further improvements in quality would have to wait for the overall industrial level to advance.

“What’s the point of a motor industry with this?” Qian Liushi said, his face a mask of woe as he reviewed the test report.

Faraday was more optimistic. “I don’t think it’s so bad. Having something is better than having nothing, that’s the first point. Second, even the worst of it is still better than low-carbon steel, isn’t it?”

“That’s true, but with this level of performance, can you still copy existing motor designs?” Qian Liushi asked. “I have my doubts.”

“These may not be the silicon steel sheets we hoped for, but they aren’t low-carbon steel either,” Faraday said. “Of course, they are only marginally better. But it’s a start. You have to have a baby before you can have an adult, right? From low-carbon steel to silicon steel is a qualitative leap. We can only try to adapt to the conditions we have.”

“That’s the only way,” Qian Liushi said. “The motor will probably have to be redesigned. The silicon steel sheets are what they are. We can’t have unrealistic hopes. How do you plan to solve the problem of permanent magnets for the motors?”

“I’ve checked the data. The Shilu iron ore is 42% pure magnetite, a very good raw material for sintering. We can use it to make permanent magnets. The efficiency will be poor, certainly, but since we’re already using these ungraded silicon steel sheets, that’s a minor issue.”

“The Shilu iron mine hasn’t been developed yet. And I hear transportation is a nightmare, so the Planning Department didn’t include it in the first five-year plan.”

Though more than one Elder had suggested advancing the development of Shilu since the stable supply of Southeast Asian slaves began, and some had raised it again after Operation Engine, the Planning Department had consistently vetoed the idea.

The primary difficulty in developing the Shilu mine was not extraction, but transportation. The mine was located deep in the mountains, far from the sea, surrounded by rugged terrain. Large-scale transport would require a railway, like the Basuo line the Japanese had built at great human cost.

If sacrificing lives were the only obstacle, the Planning Department would not have hesitated. But the massive material consumption of building a railway, not to mention engineering challenges like tunnel construction, made Wu De flinch. Furthermore, Basuo was not a natural deep-water harbor; it would require significant artificial improvements before ore carriers could use it.

For now, the Planning Department was content to build a simple road from Changhua to Shilu, establishing basic transportation and ensuring the Yuanlao’s influence in the area.

“That’s true,” Qian Liushi mused. “But magnetite isn’t rare. It’s not hard to find if you look. If all else fails, we can take a company, have men and horses carry it out, and transport a dozen tons from Shilu via the land route from Changhua. That shouldn’t require a major investment or a formal project, right?”

The report on the silicon steel project also reached the office of the manufacturing director. The machinery sector was not as picky as the power sector. In Zhan Wuya’s view, the priority was solving the problem of “have or have not,” not “good or bad.” He urgently needed to expand the power supply for the non-ferrous metal smelting industry. In addition to providing electrolytic copper, he hoped to obtain nickel and cobalt to smelt stainless steel. The chemical sector had been demanding stainless steel for a long time. A vast number of corrosion-resistant pipes and containers in their equipment needed to be made of it. If they remained at the level of manufacturing ceramic or glass equipment, Lingao’s chemical industry would be little more than a scaled-up laboratory, unable to self-replicate, let alone upgrade.

Therefore, as soon as the trial production of silicon steel sheets was successful, he immediately reported to the Planning Department, requesting the formal launch of the electrolytic copper workshop project.