Studying at Western University starts with a knife-forging competition

Chapter 85

Matt didn't press the matter about the recipe. He held the blank up to the high window, letting natural light shine on its surface. The blue layer was less noticeable in the sunlight than under the lamplight, but it was still discernible upon close inspection. He flipped the blank over to examine the other side, then placed it back on the worktable and took his phone out of his pocket.

"I need to take a couple of pictures," he said, adjusting the angle. "These are for my dad. He has a few friends in Boston who also play with knives. Doug posted a picture of your short sword on social media the other day, and someone forwarded it to him. He's looked at it several times, incredibly envious, but he still doesn't know who made it." Matt squatted down in front of the workbench and pressed the shutter a few times, then took two more pictures from a different angle. "I'll use this sword to make him jealous today, to let him know that I'm roommates with the champion of the knife-making competition. When the video is posted, I'll have him brag about it to everyone in the Boston community."

Lin Yuan leaned against the materials shelf, arms crossed, watching him take pictures, without saying a word.

Daniel walked in through the door, a faint scent of tobacco clinging to him. He walked to the workbench, glanced at the defective material, his gaze lingering on the cool white base, and raised an eyebrow slightly. "This color is nice. Yesterday it was dark gray, how did it turn white today? And with a hint of blue." He leaned closer, examining the grain more carefully. "The cloud-like patterns are finer than yesterday, how many folds?"

"Nine wheels, over 3,500 layers of composite steel," Lin Yuan said.

Daniel shook his head and said in a tone that was somewhere between admiration and amazement, "I worked on Magna's parts line for over ten years, dealing with steel plates every day, and I never imagined that steel could produce such an effect." He reached out to touch the surface of the billet, but his fingers stopped less than an inch from the steel surface, and he turned to look at Lin Yuan.

"It's completely cooled down, you can touch it now," Lin Yuan said.

Daniel gently touched the surface of the blank with his fingers, feeling the texture of the grain, then withdrew his hand and walked to the material rack to continue working on the sanding belt. As he worked, he would occasionally glance back at the cold white blank on the worktable, muttering something under his breath. His voice was too soft to hear clearly, but judging from his tone, he was probably sighing.

Lin Yuan put on his heat-resistant gloves again, clamped the billet into the furnace, and began normalizing. This is a pretreatment step in heat treatment—refining the grains and eliminating forging stress in preparation for quenching. The furnace temperature is controlled in a range slightly lower than the quenching temperature. The billet is heated evenly in the furnace, and the color of the oxide scale on the surface gradually changes from dark gray to light gray.

After normalizing, he removed the billet and placed it on refractory bricks to cool naturally. Once it reached room temperature, he began the final checks before quenching. He measured the thickness of the blade at various points with calipers, and all measurements were within tolerance. He confirmed the symmetry of the rhomboid cross-section with a protractor, finding the deviations on the left and right sides negligible. He ran his finger along the blade line, finding no burrs or microcracks.

Quenching began. Lin Yuan reheated the billet to the quenching temperature. The flames in the furnace changed from bright orange to bright yellow. He confirmed through the observation hole that the temperature had reached the critical point, then used tongs to remove the billet and quickly walked towards the quenching tank. The tank was filled with rapid quenching oil.

Pre-cooling. The sword blank was held in the air for a few seconds to allow the surface temperature to drop slightly from its peak, preventing excessive thermal shock when immersed in the oil. Then, he immersed the sword blank into the oil at a precise angle, with the blade contacting the oil surface first, and then the entire sword smoothly sliding in. The oil hissed sharply and crisply, and oil fumes surged up from the groove and were drawn away by the exhaust pipe.

He silently counted the required time, then took out the sword blank. The blade was straight, without any warping. He scanned the interior with his internal vision; the martensitic transformation had progressed evenly, without any cracks.

The tempering process then began. Lin Yuan placed the broken sword into the tempering furnace, set it to 200 degrees Celsius, and kept it at that temperature for two hours. He closed the furnace door, took off his gloves, walked to the worktable, sat down, and took a few sips of water from his thermos.

Matt came over and sat down on the stool next to him. "We've shot enough footage today to make a clip."

"Once the equipment arrives and is assembled, we'll take pictures of the finished product display." Lin Yuan placed the thermos on the table. "We'll go to school tomorrow to print the equipment; Xiao Li has already sent over the modeling files."

Matt nodded, took out his phone and sent a message to Zhang Yue, saying that they had filmed some more footage and would edit it all together once the final product was released.

Two hours later, the tempering was complete. Lin Yuan took the sword blank out of the furnace and let it cool naturally in the air. The surface of the sword was covered with a uniform layer of dark gray oxide, but after wiping it off, the underlying color revealed was the cool white that it had just appeared today.

He placed the unfinished sword upright against the corner of the office area, next to the test version from yesterday.

As Daniel left, he glanced at the two unfinished swords one last time, uttering a mumbled exclamation of admiration, as if he thought the two swords were too beautiful.

The printing equipment is scheduled for Friday morning.

Lin Yuan imported the modeling files sent by Xiao Li into the school's 3D printer a day in advance. This time, he used aluminum alloy powder instead of the brass he used when making the short cross-blade for Doug.

The blade of the sword with the divine leather stitch is already long enough. Adding the fittings would significantly increase the weight of the entire sword. Aluminum alloy has a density of only about one-third that of brass, but it is strong enough and has high printing accuracy, making it the most suitable choice.

The printing took nearly four hours. He went to Professor Robert's office in between and borrowed a sandblasting machine from the adjacent materials processing lab. After the fixture parts were taken out of the printer, they were immediately surface-treated. The sandblasted aluminum alloy parts changed from the matte gray of the printed state to a uniform silver-gray, with a delicate surface texture that did not leave obvious fingerprints when touched.

The parts were lined up on the workbench. The blade, the guard, the segmented decorative rings of the handle, the counterweight—each piece was individually packaged in a plastic bag, each labeled with its name and assembly order. He picked them up one by one and inspected them, measuring the dimensions of the mating surfaces with calipers to ensure that every opening and boss matched its corresponding position on the sword blank. Xiao Li's modeling precision was truly remarkable; the gap between the central through-hole in the blade and the rhomboid cross-section of the sword blank was less than half a millimeter, resulting in a perfect fit after assembly.

He performed a complete process for the surface treatment of the equipment. First, he used fine sandpaper to run the sandblasted surface again to completely smooth out the printed texture. Then, he used a wool wheel dipped in polishing compound to give the aluminum alloy a warm luster between matte and mirror finish. It wasn't the retro gold of brass, nor the cold, bright silver of stainless steel, but a more understated silver-gray with a subtle grainy texture.