Back at school, Yu Hua picked up the armor steel sample without stopping and left again, still avoiding the organization's protective forces. After a lot of twists and turns, he finally delivered the armor steel sample to Rabe before three o'clock in the afternoon.
Then, Yu Hua got the phone number of Rabe's residence and agreed to call him at 8 a.m. three days later to get the final result.
After everything was done, the next thing Yu Hua had to do was wait.
In the evening, West Courtyard, House No. 28.
"Xiaohua, since you are a recommended student and have already registered at school, the school has arranged for you to start formal classes tomorrow. Have you confirmed your general elective courses?" Mrs. Wu Xiaoyuan was clearing away the dishes. Just after dinner, Hua Luogeng was sitting on the sofa.
, drinking a cup of chrysanthemum tea, and said to Yu Hua.
As a recommended student, Yu Hua has completed the registration process and has no reason to stay idle. Tomorrow, Yu Hua will begin his journey of seeking knowledge as a student of National Tsing Hua University.
"The students are going to apply for Professor Zhao Zhongyao's Nuclear Physics and Professor Zhuang Qianding's Mechanical Engineering." Yu Hua nodded and gave his goal.
Hua Luogeng asked curiously: "Are you still interested in nuclear physics and mechanical engineering?"
"Yes, students have loved physics since childhood. Professor Zhao Zhongyao's nuclear physics is very interesting, and Professor Zhuang Qianding's mechanical engineering allows me to study mechanical engineering systematically and consolidate my foundation." Yu Hua replied.
"I will not interfere with your choice, but remember to bite off more than you can chew. Professor Zhao and Professor Zhuang are very strict. I will report it to you tomorrow."
Hua Luogeng nodded and wrote down the general electives given by Yu Hua, and then said: "Usually go to class when you should, don't violate school rules, and respect teachers and elders. However, if someone bullies you, don't be afraid. Academic matters
, I am there for everything.”
"Students note."
Yu Hua understood Hua Luogeng's good intentions, took note of it carefully, and then said: "Master, the student's academic level has improved recently and he has more ideas about asymmetric cryptography theory. The student wants to engage in research in this area."
One month has passed, and his mathematical level and knowledge reserve have been greatly improved. Yu Hua has many ideas and understandings about asymmetric cryptography, and it is time to engage in academic research.
"Yes, I support you, but research must be carried out and study must not be left behind." Hua Luogeng heard this, without hesitation, decisively chose to support Yu Hua's idea, and told him again.
"Student understands." Yu Hua nodded, showing no impatience with Hua Luogeng's repeated instructions. This was the master's concern for him.
The things that should be discussed were basically finished. Yu Hua took advantage of the fact that it was still dark and proposed the idea of moving to the student dormitory to his master and his wife. It was not good to always live in Hua Luogeng's house. Before, it was because there was no place to live, but now there is a dormitory.
, naturally they have to move away.
After hearing Yu Hua's decision, Hua Luogeng nodded in support and asked Yu Hua to build a good relationship with his classmates like an elder. Although his wife Wu Xiaoyuan was a little reluctant, she still chose to support Yu Hua.
Ten minutes later.
The door of the house slowly opened.
Yu Hua dragged his leather suitcase containing personal clothes and books out of the house and stood at the door, followed by Hua Luogeng and Wu Xiaoyuan.
The whole person stood at the door, turned around, and bowed to the two of them and saluted: "Master, Master, the students have gone to the dormitory."
Hua Luogeng nodded and smiled without saying anything.
"Xiaohua, pay attention to safety and come back if you need anything. This will always be your home." Wu Xiaoyuan smiled, looking at Yu Hua with eyes full of kindness and relief, just like looking at a junior who is about to spread his wings and fly.
"Yes." After hearing what his wife said, Yu Hua was moved and nodded seriously. Without further delay, he said goodbye to the two of them and turned towards the Tsinghua student dormitory.
"This child, I am not as good as him, and his future achievements are limitless." Hua Luogeng looked at Yu Hua's retreating back, his eyes full of expectation, and said softly.
…
Rongshu Hutong, Peking, Siemens office, third floor, temporary laboratory.
Here, an unknown material testing experiment is about to be conducted.
Two technicians belonging to Siemens wearing white lab coats were busy, one middle-aged and one young. The young experimenter debugged the Brinell hardness tester placed on the experimental table, and next to it was a metal material tensile tester.
and other test equipment.
The entire laboratory was set up temporarily. Since the armor steel samples arrived yesterday, in order to keep it confidential and test it as soon as possible, Rabe directly used the authority of the person in charge and spent nearly 1,000 yuan with company funds to set up this temporary experiment in the Siemens office.
Office, technical personnel are company employees.
Although the cost is expensive, it is nothing compared to Y-shaped armor steel.
The current mainstream method for testing the hardness of metal materials is the Brinell hardness test. The principle is to apply pressure to a cemented carbide ball of a certain diameter under specified conditions, press it into the sample material, remove the pressure after the specified holding time, and measure the test.
The diameter of the indentation on the surface of the sample material is calculated, and the hardness value is finally calculated.
The unit of Brinell hardness is HBW, generally written as HB.
The metal material tensile tester, commonly known as a universal material detector, can be used to detect mechanical properties such as yield strength and tensile strength of materials.
The material testing experiment was about to begin. Rabe stood outside the laboratory, staring through the window glass at the two experimenters who were making final preparations. He was fully focused, his right hand was slightly clenched, and two emotions of anxiety and anticipation coexisted in his heart.
The final results of this test experiment are crucial.
In the laboratory, two experimenters, Hans and Marcus, completed the final equipment debugging. Immediately afterwards, Marcus, the leader, said to Hans: "Hans, start the experiment."
Hans nodded, opened the box where the experimental samples were stored, took out a steel plate sample with a silver-gray metallic luster, and placed it on the base stage of the Brinell hardness tester, facing the 10 mm diameter carbide circle perpendicular to the top.
The ball is fixed.
After doing this, Hans began to turn the control handwheel of the tester, and the stage carrying the Y-shaped armor steel sample rose up to contact the 10 mm alloy ball, and then manually applied the load.
The pressure load of the alloy ball continued to increase, and the unit value reached 19,600 Newtons. However, the armor steel sample seemed to be fine. The contact surface between the ball and the steel plate was only dented a small area, which could not meet the measurement standard.
This steel plate is so strong!
Seeing this situation, Marcus and Hans looked at each other and noticed the surprise in each other's eyes. The steel plate did not change under such a pressure load.
The unit load of 19,600 Newtons is a full 2,000 kilograms of force, which is a painful upper limit for most carbon steels and alloy steels.
What is the condition of this steel plate? Why can it withstand such high pressure without deforming and causing indentations?
"The pressure load was increased to 2500 kilograms of force." Marcus looked at the armor steel sample on the stage, and said to Hans with strong interest in his heart.
Hans nodded and continued to increase the load pressure, reaching 2500 kilograms of force, reaching a pressure value of 24,500 Newtons. As the load pressure increased to a higher level, the Y-shaped armor steel on the stage finally could not withstand such terrifying pressure, and the contact surface
The 10 mm metal ball is sunken and pressed into the interior of the armor steel.
"Keep it 15S." Marcus looked a little excited when he saw this. Although he was not a technical expert in the metallurgical industry, he also understood that the steel plate in front of him was nothing special.
Maintaining it for a certain period of time and then removing the applied force is a standard procedure for strength testing.
Fifteen seconds later, Hans, who was responsible for the actual operation, cut off the load output and controlled the stage to lower. The Y-shaped armor steel sample broke out of contact with the metal ball indenter, and a spherical metal indentation as big as a grain of rice came into view.
Hans immediately used a micrometer to measure the diameter of the spherical indentation. After getting the accurate reading, he was stunned.
"What's the diameter reading?" Marcus asked quickly, with a hint of urgency in his words.
"3.98 mm, boss." Hans' tone was trembling.
When Marcus heard this answer, he was startled for a moment, and felt a little confused: "What, 3.98 mm?! God, that means the actual hardness of this steel plate is about 490HB. Measure it again, and measure 2 points in a row.
,In addition, the pressure load was increased to 3,000 kilograms of force, and three points were still tested."
The diameter of the spherical indentation is 3.98 mm, which means that the entire spherical indentation surface area reaches about 50 mm. The Brinell hardness value is 24,500 N pressure divided by the spherical indentation surface area, and the final value is 490HB.
What is the concept of 490HB?
Marcus was lucky enough to visit the arms giant Krupp next door in 1927 and witnessed the KC armor steel produced by Krupp for the army. The hardness value of this armor steel barely exceeded the 300HB mark.
Hardness value cannot become the core index of steel, but it is an important parameter to measure the performance of steel.
This steel plate sample, which doesn't look brittle at all, has a Brinell hardness as high as 490HB, which Marcus really can't imagine.
"Yes!" Hans, a young technician who clearly understood the numerical significance of 490BH, nodded repeatedly, put the armor steel sample back on the measuring machine again, and measured it again.
The standard measurement process for metal material hardness is to obtain three spherical indentations and obtain the average of the three, which is the most scientific.
Of course, neither Marcus nor Hans are serious materials scientists or metallurgical experts. Marcus is a senior electrical engineer at Siemens in China, and Hans is an assistant electrical engineer. Both of them have certain scientific and engineering skills.
The level and metallurgical foundation are not up to the level of a technical expert in materials science.
However, it is still no problem to conduct a material performance test.
Soon, Hans measured two spherical indentations under a load of 2500 kg, with diameters of 3.99 mm and 3.98 mm respectively. Combining the first spherical indentation value, the average of the three was 3.983 mm, and finally obtained the Brinell
The hardness value is 490HB.
Then, Hans successively conducted hardness tests under a load of 3,000 kilograms. The diameters of the three spherical indentations were expanded to 4.77 mm, 4.78 mm, and 4.77 mm respectively. The surface area of the spherical indentations was 60 mm. The Brinell hardness value remained at 490 HB.
Two pressure loads, a total of six test points, and all test data are recorded.
"God, what is going on with this steel plate..."
As an electrical engineer, Marcus went crazy looking at the experimental data. His eyes turned to the ordinary-looking steel plate on the stage. He was completely shocked by this steel plate.
Who made this steel plate?
Why can it have such high hardness?
No one answered the question in Marcus' mind.
Hans asked: "Boss, should we conduct the next round of testing now, or should we give the data to Mr. Rabe first?"
"Test it first. Use the metal material tensile tester to test its yield strength and tensile strength. I have a feeling in my heart that this steel plate contains a great secret..." Marcus heard the sound and came to his senses.
He took a deep breath to stay calm and spoke in a serious voice.
The material performance test continued. The Y-shaped armor steel sample with six spherical indentations on the surface was transferred to the tensile tester. The young Hans was familiar with the road, as if he had returned to the scene when he was studying at the Zurich Institute of Technology. He was rigorous and careful.
Skilled in operating the tensile tester.
This is an English-made mechanical tensile tester. The maximum load force can reach 150 kN. It is the most testing equipment on the market. After fixing and locking both ends of the steel plate, everything is ready. Marcus gave the order to start the test.
Yield strength is the yield limit of a metal material when yielding occurs. For metal materials without obvious yielding, the stress value that produces 0.2% residual deformation is stipulated as the yield limit.
External forces greater than the yield limit will cause the metal material to permanently fail and deform, making it impossible to recover.
If the yield limit of carbon steel is 200MPa, if it exceeds this limit, it will break and be permanently deformed.
After receiving the instruction, Hans began to operate and continued to increase the load.
The Y-shaped armored steel in the instrument was immediately pulled by two forces from different directions. The martensite in the internal metallographic structure easily withstood the two outward pulling forces. The grain structure was extremely stable, and it appeared to the outside as...
Not moving at all.
10 thousand cattle.
20 thousand cattle.
50 thousand cattle.
The pressure load continued to increase. Marcus looked at the terrifying values on the tensile tester, his eyelids jumped wildly, and his heart became more and more shocked. This steel plate not only has extremely high hardness, but also has a very high yield strength.
How is this possible?
The pressure load has been increased to 100 kN. However, the steel plate in the tester still has not changed. If it were not for the tensile tester making a working sound that symbolizes mechanical strength, it would seem as if no test was conducted at all.
There was an invisible solemn atmosphere in the air. It was obvious that the Y-shaped armor steel sample standing in the tester had brought unprecedented pressure to Marcus and Hans.
The tester values steadily increased. After a while, when the pressure load increased to an unprecedented and terrifying height, the grains inside the Y-shaped armor steel sample finally broke, the internal stress reached the limit, and the material deformed significantly.
Seeing this scene, Marcus immediately stopped Hans. His face was more serious than ever before, and he recorded the tensile parameters as quickly as possible. Based on detailed calculations, he obtained the yield strength value and the tensile strength value respectively.
Yield strength value: 580Mpa,
Tensile strength value: 862Mpa.
Looking at the two results, Marcus almost suffocated. His right hand was shaking slightly and his heart was beating wildly. He had no idea that this steel plate that Mr. Rabe got from unknown sources would have such terrifying performance parameters.
Too exaggerated.
It's too scary.
"How was this steel plate smelted? If it was developed by the British and used as a protective material for tanks or warships, it would be a nightmare for our country..." Marcus stabilized his body and stared at the yield strength.
value and tensile strength value, we immediately realized the huge application value of this steel plate in the military field.
The same is true for young Hans. He graduated from the Institute of Technology in Zurich and clearly understands what this set of material performance data means.
There was a suffocating and desperate atmosphere in the makeshift laboratory.
"Hans, send this test report to Mr. Rabe, and then, in my name, ask him to get the formula for this steel plate for the motherland." Marcus said seriously.