Dongfeng Tianlong A couple's balance
The Dongfeng Commercial Vehicle Foundry No. 2 Plant has a very private corner and is separated from the residential area by a single wall. This is the material laboratory for the foundry No. 2 plant where all new material tests are conducted. The material experimenter Zheng Xiaoqin is a pale and weak girl. When the reporter entered the lab, she was completely unaware of it. She was only absorbed in the test equipment and computer screen, and kept recording data on the book.
At this time, when a "bang" was heard and the reporter shouted, Zheng Xiaoqin looked up and smiled. He said, "Scared you? It was a bit scary to prepare. I did so at the beginning. I was used to it. Now, the tensile strength in the test is getting bigger and bigger, and the sound of casting fractures is even louder.†Zheng Xiaoqin dedicates the test block on the device and replaces it with a new one.
The chief of the second casting factory brought the reporter to the tension testing machine and told reporters: “This is our tensile testing machine. It is used to test the strength and elongation of castings. The number of ductile iron castings consists of two sets of figures. The preceding number represents the tensile strength of the casting, and the following figure is the elongation rate of the casting.For example, we often say QT550-6, that is, the tensile strength is more than 550 MPa, and the length of the elongated specimen is more than 6%. High toughness means that both numbers must be high. Only in this way can we reduce the wall thickness and ensure the weight reduction while ensuring the carrying capacity. We are trying to obtain high-strength, high-toughness castings through continuous tests."
The strength and elongation of castings are actually a pair of life and death. It's like glass and rubber bands. Glass is hard but broken when touched. Rubber bands are tough but overwhelmed. Truck castings, however, must be pulled and tamped again, and they have strength and resilience.
Zhou Tianfei, chief of the Technology Section of the Foundry No.2 Factory, who always loves to frown, said: “People often say that fish and bear's paws are not shared, but we just have to have both. Not so, the cast rice bowl can't hold it!†Embarrassed the eyebrows.
In fact, it is the king's order that is really bad, because he is the head of the technical section material group and is the cutter for material improvement. He said: "The most difficult thing to do with material experiments is the groping stage. It's like in a dark cell you will hit a wall everywhere. Once you find a direction, you will find that success is like breaking a layer of window paper." Reporter, in the experiment, they added conventional elements such as carbon-silicon-manganese, and now they use a variety of precious metal elements and their operation methods have also changed. Therefore, it is very difficult to control the melting of molten iron. It is necessary to consider both material and cost. “It used to be like riding on a prairie. Now it's like dancing on steel wire. Hot processing is not like cold processing. The process is difficult to observe. Sometimes we really don’t know which part has a problem.â€
The order of the king said that he had done axle housing tests last year and had done many times. Each time there were three bridge shells, there was always a failure. How couldn't I find what was the problem? Later, after all-round testing, it was discovered that the key quality control standards need to be improved on the basis of the original. After continuous groping, Wang ordered them to overcome many difficulties and finally succeeded in developing lightweight castings. High-strength and high-tenacity endured the verification of millions of fatigue tests.
Using technology to shake the market
Who moved our cheese? The Casting Factory of the past few years has been rethinking this issue.
Shen Baowei, the manager of the second casting factory marketing department, introduced that in the past, castings made at the No. 2 Casting Plant were lighter than aluminum. However, the strength and toughness ratio was less than that of steel. However, the cost competition was not high for private companies. However, castings also have the unique advantages of low cost, good shock absorption and one-shot molding. Foundry No. 2 has more than 40 years of experience in casting. How to regain market share with technical advantages has become a problem for the management team of the foundry No. 2 Plant. After discussion and thinking, they believe that the production of high-end lightweight castings with iron-based steel is not only a problem for the factory. The only way that is necessary also meets the strategic requirements for Dongfeng commercial vehicle lightweighting.
To achieve lightweight castings, we need to start from two aspects, one is the optimization of product structure, the other is the development of high strength and high toughness materials. In May 2016, the Dongfeng Commercial Vehicle Technology Center took the lead in the improvement of iron-based steel. The goal was to achieve vehicle cost reduction. This is a win-win improvement project for Dongfeng Commercial Vehicle Company and Foundry No. 2 Plant. In more than a year, a total of more than 60 parts have been completed in trial production. Mass production of the first beam and large castings has reduced weight by nearly 10% and cost by 30%. The high-strength and high-toughness TF980 balance shaft support jointly developed by Casting No. 2 Plant and Dongfeng Equipment Manufacturing Co., Ltd. has reduced weight by 20%.
Attempts to reduce the weight of the second foundry plant also involved more aspects. For example, the iron saddle steel used in automobile saddles increased its tensile strength from 420 MPa to 550 megapascals to reduce the cross-section and improve the structure through material lift. Optimize to combine multiple parts into one part to achieve a 15% weight reduction. For another example, instead of a gray iron brake drum with a vermicular iron brake drum, compensation for the Three Guarantees can be reduced from 45% to 10%.
At present, the foundry No.2 Plant has been able to produce QT800-5 as-cast high-strength, high-toughness materials. QTD1050-6 with a large number of isothermally quenched ductile irons has been able to meet the requirements of automotive castings. Technical advantages also bring cost advantages. By replacing steel with iron, the cost is reduced by about 10%-30%. In order to shake the market with technology, 24,000 tons of new market demand for foundry No. 2 was added, and the structure of the factory's products was optimized.
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