PDLP Chapter 1021 What to do when your disguise is exposed?
Chapter 1021 What to do when your disguise is exposed?
Don't worry, we can understand what this means by putting it another way.
That's the CCT curve.
Actually, the biggest culprit for Jiangxia's laziness in getting out of bed in the morning is this thing.
Last night, Chief Engineer Wang Li and I brainstormed for most of the night. Lying in bed, the guy suddenly had a flash of inspiration: In modern steel metallurgy, there seem to be a few particularly important "magic curves" that can link microstructure and macro properties.
what do you say that is?
TTT?
CCT?
Unfortunately, this falls under highly specialized theoretical knowledge, and for a while, it's like looking through frosted glass—vague and unclear, unable to grasp its specific form.
He tossed and turned in bed several times like a pancake, finally regaining his senses and bringing up the CCT curve from the depths of his memory.
We also have to thank Baosteel, that big spender, for accepting some of the technology from Xiaobenzi and fully implementing Xiaobenzi's visualization and Kanban management style.
This CCT curve was just brazenly posted at the workshop entrance.
During the visit, Jiang Xia got a general idea of what was going on. Fortunately, rationalization allowed him to examine his memories from a third-person perspective, resulting in a magnificent CCT curve. As for TTT (Time to Trial and Trial), he had absolutely no idea!
After Jiang Xia finished drawing, the factory directors gathered around, their eyes focused on the large blackboard.
There were clearly defined coordinate grids crisscrossing the surface, forming a mysterious "map".
The left vertical axis of the graph is clearly marked with "temperature," with the scale ranging from over a thousand degrees Celsius at the top to the frigid room temperature at the bottom. The bottom horizontal axis is marked with "time," but this time is not uniformly distributed; instead, it uses a logarithmic scale, meaning that time spans from a mere second to several hours are compressed onto this axis, with the right side representing even longer periods of time.
On this stage defined by temperature and time, several winding curves outline different "realms." The high-temperature area in the upper left corner of the drawing is blank, representing the initial state of either a completely liquid or completely austenitic state.
Starting from the boundary of this blank area, two main curves meander down like the boundary of a canyon: the upper one is the "transformation start line" and the lower one is the "transformation end line".
The region between them, shaped like a long, narrow bay, is clearly marked as the "pearlite transformation zone." This means that if the cooling path of the steel passes through this "bay," its interior will begin and eventually complete the transformation into pearlite.
Below and to the right of this "bay," the drawing outlines another irregularly shaped area with different shades, labeled the "bainitic transformation zone." Its lower location implies that lower temperatures and longer time are required to enter this area.
Most striking is a sharp, beak-like curve protruding near the left vertical axis in the diagram, which is the "nose tip" formed by the sudden leftward turn and reversal of the "pearlite transition initiation line".
The area above this "nose tip," corresponding to the extremely high cooling rate, is completely blank, marked only with two words: "Martensite".
A horizontal Ms line runs across this area, marking the temperature threshold at which martensite begins to form.
All the curves eventually converge in the lower right corner, pointing towards room temperature.
The factory managers, especially the knowledgeable Lao Li and Lao Wang, stared intently at the clearly defined "nose tip" and different areas, their eyes unblinking.
They knew from experience that water quenching and oil quenching would produce different results, but they had never so intuitively "seen" how different cooling rates, like choosing a road, would select drastically different internal characteristics and futures for the steel.
Well, the above flowery passage was just something Jiang Xia made up in her head.
Just like chivalric romances always say something about how something propelled the great wheels of history.
Actually?
Chen Ming from Hongfeng Factory was the first to speak. He pointed to the iconic "nose" of the "pearlite transformation start line" and hesitated, saying, "Engineer Jiang, this diagram... is beautifully drawn, and the logic sounds clear. But the temperature and time at this 'nose'... our experienced furnace workers know from experience that 'it hardens at this point,' but they've never measured the exact temperature and seconds. Are the points on this diagram accurate?"
“Yes,” Zhou Anmin from Jin’an Factory frowned. He specialized in special materials and was more sensitive to testing equipment, so his doubts were direct:
"Could it be that the 'divine illustrations' in the books don't match up in our smoky, fiery workshop? Where did this illustration come from?"
Where did it come from? Of course, it was copied.
Of course, that's not the way to put it. Jiang Xia nodded: "A precise CCT curve needs to be determined experimentally. It mainly relies on a device called a 'dilatometer', which precisely measures the tiny length changes of steel during controlled cooling (the volume changes during phase transformation) to infer the temperature and process of the phase transformation. Only by combining this with extensive metallographic observations can a relatively accurate curve be drawn."
"I derived this by chance!"
dilatometer? Derivation?
Several factory managers looked at Jiang Xia and thought this kid was like a toad yawning—what a boastful tone!
At this moment, Liu Dayong, who had been staring at the blackboard without saying a word, suddenly exclaimed, "Huh? This temperature at the bend... this point that starts to change when it gets cold... why does it look so familiar?"
Then he quickly turned around and headed straight for his bicycle parked outside the door.
Before long, Liu Dayong returned with a black leather notebook whose edges were worn white, and he was flipping through it as he walked.
"Found it! This is the quenching record of a medium carbon manganese steel we tested two years ago. We failed many times, only a few batches were successful, and the performance was unstable. I wrote down the heating temperature, the approximate cooling situation, and the final measured hardness and impact toughness for each batch... Come and take a look, guys!"
He pointed to a few lines of messy but barely legible data on his notebook: "This furnace, water-quenched, has a very high hardness, but it cracks easily when hit, it's brittle! This furnace, quenched in hot oil, has a slightly lower hardness, but better toughness. This furnace, I tried water-quenching it first and then immediately putting it in oil, but... the performance is still not right."
He looked up, then at the CCT curve on the blackboard, his eyes growing brighter and brighter: "Hey! Young man, come and see, let's assume my steel 'nose' is around this temperature..."
Liu Dayong's rough fingers poked near the curved "nose": "Water quenching is too fast, it must have rushed past the 'nose' and gone to the 'martensite' region on the left, so it's hard and brittle! Hot oil quenching is slower, it might just brush past the tip of the 'nose', or brush down to the right, resulting in a different structure..."
It might be a mixture, or perhaps poor-quality bainite? That's why the performance isn't ideal! I tried water first, then oil, to control the cooling rate, but I didn't time it well…”
Liu Dayong became more and more excited as he spoke. Although his word choice was not very precise, his direction was surprisingly correct!
He used the most basic production records to vaguely confirm the pattern revealed by the CCT curve—different cooling rates result in drastically different final performance.
Chen Ming also leaned over to look at Liu Dayong's notes, then at the diagram, and said thoughtfully, "Now that you mention it, Director Liu... I think I vaguely remember it. Our factory also had a similar phenomenon when processing a certain alloy steel; the performance differed greatly between air cooling and heat cooling after it came out of the furnace. We used to attribute it to 'uneven cooling,' but now it seems that the cooling rate might have fallen into different areas on the diagram..."
Although Zheng Guoxing didn't speak, his tightly pursed lips loosened slightly, and his gaze toward the curve of the blackboard became less scrutinizing and more focused.
Zhou Anmin stroked his chin and murmured, "It seems this map... isn't just a figment of imagination. But the precise measurements..."
Jiang Xia listened to their discussion without feeling offended or embarrassed. On the contrary, he felt that entrusting the task of testing the new type of steel to these people from the factories under the Fifth Ministry of Machinery Industry was the right choice!
Because their attitude was really upright!
As Jiang Xia observed these factory directors, another gaze was also watching him.
“When you were explaining just now, you kept blurting out ‘a principle based on…’ and ‘a prediction based on…’... This tone and way of speaking sound so familiar to me.”
Zhao Weiguo from Yanbei Machinery Factory looked the overly young guide up and down, then suddenly slapped his forehead:
"You wouldn't happen to be... the 'capable person' everyone's talking about at the Red Star Comprehensive Machinery Factory, would you?"
"what?"
"what!"
Oops, Xiao Jiang's disguise has been exposed!