Siheyuan (traditional courtyard house): Starting with the Korean War, returning home to take charge

After the rocket artillery improvement plan was finalized, He Yuzhu reviewed Engineer Zhou's report again. The last page of the report read: "Insufficient lifespan of the directional tubes; ordinary steel suffers severe ablation after sixty rounds, leading to decreased accuracy." He put the report down, leaned back in his chair, and stared at the ceiling. Heat-resistant gun steel—the first thing that came to his mind was Qian Zhiyuan. Back when they were working on composite armor for tanks, Qian Zhiyuan and his team had tested hundreds of batches, and the final product was even superior to the Soviets'. But Qian was sixty-seven this year, his health had only recently recovered, and it was He Yuzhu who saved him from his last hospitalization with systemic medication. Could he handle such a heavy burden again?

He Yuzhu paced around the office twice before finally picking up the phone.

He dialed the materials research institute's number countless times until his fingers found it automatically. When the call connected, a young voice answered. "Director He? Director Qian is in the lab, please wait a moment."

Footsteps came from the other end of the phone, followed by the sound of a door opening, and then Qian Zhiyuan's voice rang out, hoarse and panting. "Xiao He, what's up?"

He Yuzhu held the microphone, not mentioning the gunpowder steel incident immediately. "Director Qian, how have you been lately?"

Qian Zhiyuan laughed, but the laugh was short. "I'm alright. My legs are a little weak, so I can't walk very fast. You must have something to tell me."

He Yuzhu was silent for a few seconds. "Director Qian, the directional tubes of the rocket launchers don't have enough lifespan; they burn out after firing only a few dozen rounds. We need heat-resistant gun steel. Can you procure that?"

There was silence on the other end of the phone. He Yuzhu could hear Qian Zhiyuan's breathing, steady and unhurried. After almost ten seconds, Qian Zhiyuan finally spoke.

"Heat-resistant gun steel? It's different from tank armor. Armor resists impact, this resists ablation. We have to start from scratch."

He Yuzhu said, "Whatever you need, I'll provide it. Equipment, materials, personnel—just name your name."

Qian Zhiyuan remained silent for a while. "Xiao He, I'm sixty-seven this year. I haven't touched this stuff in over ten years, so I can't guarantee anything."

He Yuzhu tightened his grip on the microphone. "Just do your best. If you can't get it working, I won't blame you."

A sigh came from the other end. "Alright. I'll give it a try. I'll send you samples in six months."

He Yuzhu put down the phone and stood by the window. The sky outside was overcast, looking like it was about to rain. He drew the curtains and sat at the table for a long time.

The Materials Research Institute was located in the west of the city. The courtyard was small, consisting of several rows of drab, gray bungalows. When He Yuzhu first visited, the furnace had just been lit. Qian Zhiyuan was wearing a faded blue cotton jacket with the sleeves rolled up to his elbows, and asbestos gloves on his hands. He squatted in front of the furnace, staring at the thermometer, his reading glasses slipping down to the tip of his nose.

"Xiao He, you're too early. The first batch isn't even out yet."

He Yuzhu stood to the side, watching the thermometer needle slowly climb upwards. The workshop was hot, making everyone's faces feel flushed. Qian Zhiyuan stood up, his legs went weak, and he grabbed the nearby shelf for support.

"The first batch's formula is 3% chromium, 1% molybdenum, and 0.5% tungsten. Let's try it out first."

He Yuzhu remained silent. The furnace stopped, and Qian Zhiyuan led his men to pour the molten steel into test pieces, cool them, polish them, and place them on the testing table. A flamethrower was aimed at the test piece, and blue-white flames licked the metal surface. The thermometer jumped to 1200 degrees Celsius. Qian Zhiyuan stared at the test piece, watching it change from silvery-white to dark red, and from dark red to orange-red.

Thirty seconds later, a dent appeared on the surface of the test piece.

Qian Zhiyuan turned off the flame, waited for the sample to cool, and touched the crater with his finger. "The ablation is too fast. The formula is no good. Change it."

The following month, when He Yuzhu returned, the workshop was piled high with discarded test pieces. Qian Zhiyuan was squatting on the ground, holding a notebook filled with numbers. When he saw He Yuzhu come in, he stood up, but his legs buckled again, and he stumbled to the side.

"Adding chromium to 5% and molybdenum to 2% reduced the ablation rate, but it wasn't hard enough. After quenching, it became too brittle and cracked easily."

He picked up a sample from the side, broke it in two with both hands, and the broken surface was shiny. He Yuzhu took it and looked at it; the fracture was clean, as if it had been cut with a knife.

"How much less resilient?"

Qian Zhiyuan opened his notebook. "It's 30% short. We need to add nickel; nickel improves toughness. But nickel is scarce, and domestic production is low, so it's difficult to adjust."

He Yuzhu put the broken piece of paper down. "I'll figure out a way to deal with the nickel. You should finalize the formula first."

In the third month, He Yuzhu arranged for a batch of nickel to be sourced from foreign trade channels through Lao Sun. When Qian Zhiyuan received the nickel, he ran his fingers over the silvery-white metal blocks, examining them for a long time. In the fourth month, when He Yuzhu visited, Qian Zhiyuan was squatting in front of the testing table. The sample had been burned for a minute, and only a thin layer of oxide scale remained on its surface, without any burn marks. He tapped it with his finger; the sound was crisp.

"The hardness is sufficient. The ablation rate is 70% lower than that of ordinary steel. The toughness has also improved." He handed over the notebook, and He Yuzhu glanced at it.

"Any more questions?"

Qian Zhiyuan thought for a moment. "We still need to test it. We need to test it several times, and only use it when the data is stable."

He Yuzhu handed the notebook back to him. "You decide what to do."

Six months later, He Yuzhu was reviewing documents in his office when the phone rang. He answered it, and Qian Zhiyuan was on the other end, his voice trembling.

"Xiao He, it's done. Come here."

When He Yuzhu arrived at the materials institute, Qian Zhiyuan was standing in front of the testing table, holding a silver-white steel rod in his hand. His fingers slowly traced the steel rod, as if touching some precious treasure. Seeing He Yuzhu enter, he handed the steel rod to him.

"Xiao He, this one can shoot even farther."

He Yuzhu took the steel rod; it was heavy, with a smooth surface that gleamed coldly under the light. He walked to the front of the testing table and looked at the sample that had been burned by the flame. The surface had only a thin layer of oxide scale, without any burn pits or cracks.

"data?"

Qian Zhiyuan opened his notebook. "The ablation rate is 70% lower than ordinary steel, the hardness is increased by 50%, and the toughness meets the standard. The lifespan of the directional tube is increased by at least three times."

He Yuzhu closed the notebook. "Okay. Send it to the factory for trial production."

Qian Zhiyuan didn't reply. He took the steel bar back from He Yuzhu and placed it on the table. He touched the steel bar, turned around, and looked out the window.

"Xiao He, this thing can be used on more than just rocket launchers."

He Yuzhu was stunned for a moment.

Qian Zhiyuan turned around, his eyes behind his reading glasses a little red. "It can also be used on tank armor. It's heat-resistant, impact-resistant, and has high hardness, much better than the composite armor we use now. If we adjust the formula and increase the thickness, it can withstand T-64 shells when used on the front of a tank."

He Yuzhu stared at the steel bar, remaining silent for a long time. "Can it withstand it?"

Qian Zhiyuan said, "Theoretically, yes. But we have to try."

He Yuzhu didn't speak. He walked to the window and looked at the sky outside. The sun peeked out from behind the clouds, shining into the courtyard of the materials institute, gilding the rusty pipes and tanks with a golden hue. He stood there for a long time, then turned around.

"Let's work on the rocket launchers first. We'll deal with the tanks later."

Qian Zhiyuan nodded.

He Yuzhu walked out of the materials institute and stood at the entrance. Yang Xiaobing was waiting in the car, the engine still running.

"Commander, is it done?"

He Yuzhu sat down. "It's done. With the new steel, the rocket launchers can fire farther. Old Qian said it can also be used on tanks."

Yang Xiaobing started the car and drove out of the materials institute. "Can it withstand a T-64?"

He Yuzhu leaned back in his chair. "Theoretically, yes. But we'll have to try."

Back in his office, He Yuzhu sat down at his desk and took the list out of his drawer. Turning to the "Materials" page, after the words "Heat-resistant Gun Steel," he wrote a few lines: "Qian Zhiyuan successfully tackled the problem in six months, reducing the ablation rate by 70%, increasing hardness by 50%, and tripling the lifespan of the directional tube. It can be used in tank armor and theoretically can withstand a T-64."