In the 90s, you could acquire max-level skills every 14 days.

Chapter 115 The Vast Universe on the Blueprints

The first laboratory of the Department of Mechanical Engineering is located on the basement floor of the Engineering Building.

Walking down the cement steps and pushing open the iron gate, you're greeted by a strong smell of engine oil.

The laboratory is not large, about 80 square meters.

Four rows of fluorescent tubes overhead illuminated the room in a snowy white light.

Along the north wall are three pieces of equipment: a C6132 horizontal lathe, a vertical drilling machine, and at the very back is an electrical discharge machining (EDM) machine.

Fang Qiming was standing next to the EDM machine, explaining the lathe to a student.

Four young men were standing next to him.

Three men and one woman, each with measuring tool drawings and scattered test pieces piled on their worktables.

When Zhang Yong pushed the door open and came in, the eyes of the four people swept over him almost simultaneously.

The first to speak was a round-faced boy closest to the door, Qian Zhiyuan, a second-year graduate student and Fang Qiming's most valued student.

"Teacher Fang, who is this—"

"Zhang Yong." He beckoned to Zhang Yong. "Come here quickly."

Qian Zhiyuan's gaze slid from the bruises on Zhang Yong's face to the brown paper bag in his hand.

Continuing education students.

He knew this person.

A few days ago, Teacher Fang mentioned in a group meeting that a new student in the continuing education program was coming to take charge of a boiler renovation project.

At the time, none of the graduate students took it seriously.

What kind of boiler modification can adult education students do? Besides, their research topics are all high-tech and cutting-edge. Who would want to work on a boiler?

Fang Qiming had already deftly pushed the things on the control panel to the side, making a large space.

"Come on, you've been waiting for a while, hurry up and open the blueprints."

"it is good."

Zhang Yong opened the kraft paper bag, took out three large folded sheets of white paper, and laid them flat on the table one by one.

There were faint traces of soot on the paper, and the lines drawn with blue ink from the fountain pen were straight and even.

The front sectional view, side view, and top view are all included, along with numerous numbers.

Fang Qiming bent down and leaned closer, adjusting his glasses on the bridge of his nose.

He looked at the three pictures over and over for a while, then traced a line with his finger along the reserved position of the secondary air nozzle.

"Who did you say you drew this with last time?"

"Wei Shuyun from Tsinghua University next door drew the lines and marked the scales, I reported the data, and a classmate from the teachers' college assisted with the measurement."

Fang Qiming nodded and didn't ask any more questions.

Qian Zhiyuan had already approached.

He first glanced at the front sectional view, his brow furrowing slightly. Then he flipped to the side view, picked up the set square next to him, and compared the angle of the nozzle pre-drilled hole.

He put down the set square and spoke.

"Teacher Fang, I'm going to say something that might not be very pleasant to hear."

Fang Qiming looked up at him.

Qian Zhiyuan used the tip of his pen to mark the nozzle hole positions on the drawing.

"The inclination angle of these three pre-drilled holes is marked as 35°, and the spacing is 120 mm."

"But this is the result of a single manual measurement, without theodolite calibration or verification of the actual curvature of the furnace wall surface."

""

He paused for a moment.

"The inner diameter tolerance of the furnace wall of Soviet-style boilers is inherently large, with fluctuations of plus or minus five millimeters when they leave the factory."

"In addition, with over 20 years of thermal deformation, the actual deviation from the original design may be even greater."

He placed the set square on the drawing.

"Under these conditions, if you try to directly machine the nozzle based solely on the angle and spacing determined by touch and visual inspection, it will most likely not be able to be installed."

Even if your measurement is perfectly accurate, you still need to consider tolerances.

After he finished speaking, he glanced at Zhang Yong.

The tone was sincere and polite, but the meaning was very clear: the drawing was not precise enough and could not be used.

The other three graduate students next to him remained silent, but they all had similar thoughts.

The laboratory was quiet for a short while.

The buzzing sound of the EDM machine was exceptionally clear.

Fang Qiming also looked up at Zhang Yong, wanting to see how he would refute him.

Zhang Yong extended his index finger and pointed to the location of a pre-drilled hole on the drawing.

"You're right. The factory tolerance for this boiler is ±5 millimeters. I saw the original drawings on site, and the original master craftsman marked it."

Qian Zhiyuan nodded and looked in the direction he was pointing.

Zhang Yong moved his finger to the side and then pointed to the marked wall thickness data.

"But you can't just look at the blueprints; you also have to consider the actual situation."

"The scale on the inner wall of this old furnace is an average of 3 mm, and the oxide layer on the outer wall is 0.5 to 0.8 mm. After the scale and oxide layer are combined, the actual load-bearing wall thickness is almost 4 mm thinner than the factory specifications."

He looked up and glanced at Qian Zhiyuan.

"When the wall thickness changes, the stiffness changes."

"When the stiffness changes, the deformation due to thermal expansion can no longer be determined solely by the coefficients in the textbook."

Qian Zhiyuan's brows furrowed even more.

The system panel silently appeared in Zhang Yong's mind.

[Automotive Repair Lv.5 Effective: Compilation of Steel Structure Stress Deformation and Assembly Fit Tolerance Data]

[Effected at Driving Lv.6: Data processing of fluid flow trajectory and dynamic changes in operating conditions]

"When I measured the wall temperature on site, the outer wall of the furnace was 85°C, and the flame temperature on the inner wall was estimated to be over 700°C."

"With an internal and external temperature difference exceeding 600°, the coefficient of thermal expansion of Q235 carbon steel under this temperature difference is 12 × 10⁻⁶ per degree."

He picked up the pen that was lying to the side and circled a number.

"With an inner diameter of 1200 mm and a temperature difference of 600°C, the radial thermal expansion should be around 8.6 mm."

"The 35° tilt angle I marked is the cold-state angle."

"After the furnace is lit, the furnace wall expands outward, and this angle will be corrected to 33°, which is exactly the optimal angle for secondary air injection."

He put down his pen.

"Don't worry, I've taken the error into account, and thermal expansion compensation has also been included."

The laboratory fell completely silent.

Qian Zhiyuan stood there, then suddenly turned around as if he had just realized something, grabbed the peeling book on the control panel, and flipped through it to the page on the coefficient of thermal expansion.

My finger swiped down the data bar.

Q235 steel, linear expansion coefficient: 12.0×10—6/C.

He flipped to the page with the radial expansion formula, picked up the calculator, and started typing away.

The result showed: 8.64 mm.

The difference between the figure calculated by Zhang Yong and the actual figure is less than one percent.

Qian Zhiyuan's fingers stopped on the calculator keyboard, his eyes widening in surprise.

The graduate student next to him also came over to take a look at the calculator screen, and all four of them stared wide-eyed.

Fang Qiming leaned against the lathe, arms crossed, and finally spoke.

"Did you understand everything?"

None of the four graduate students said a word.

"We all have this problem when we do research: we're used to measuring standard specimens with precision instruments in a constant-temperature laboratory. The conditions are good, the data looks good, the papers look better, and it's also convenient to repeatedly verify the operations."

His gaze swept across the faces of the four people one by one.

"But industrial sites are not laboratories. Temperature, humidity, and component lifespan are all different. You might set up a theodolite for half an hour, and by the time you finish taking the readings, the working conditions have already changed."

97

He pointed to the blueprints.

"These three figures were measured at the actual construction site. The temperature was constant and the machine was under high load, which is a reasonable measurement environment."

"On-site, measurement tools are often incomplete, so we need to mobilize all our knowledge and use experience and variables together for measurement and statistical control."

"That's what it means to work on a construction site. That's what it means to work with your brain."

Qian Zhiyuan's face turned slightly red.

He closed the manual and nodded slightly to Zhang Yong.

Seeing this, Fang Qiming clapped his hands and asked the students to look at the blueprints together, check for omissions and fill in the gaps, and think about how to repair the cracks in the old pipe wall.

Then he turned and walked to the tool room next door, took out a silver-gray bar and placed it on the lathe guide rail, then turned back to look at Zhang Yong.

"Being able to draw it is one thing, being able to make it is another. Today, you will try to make the parts yourself."

He patted the bed of the C6132 lathe.

"Use this manual one. This material is really hard, so don't break my blade."

All four graduate students turned to look at Zhang Yong.