High strength steel plate (high strength plate) refers to the grade Q460 steel, high strength, especially in the normalizing or normalizing and tempering state has high comprehensive mechanical properties. Mainly used in large ships, Bridges, power plant equipment, medium and high pressure boilers, high pressure vessels, rolling stock, lifting machinery, mining machinery and other large welded structural parts.
Model Number
Q460 is a high strength low alloy steel. Q460's grade expression method: its steel number is crowned with "Q", which represents the yield point of the steel, that is, the yield strength. The following number indicates that the yield point value of 460 represents 460 mpa, mpa is 10 to the sixth power, and pa is the unit of pressure PASCAL. Q460 is the steel force strength of 460 mpa will occur plastic deformation, that is, when the external force is released, the steel can only maintain the shape of the force and can not return to the original shape, this strength is greater than the general steel. The general quality grade symbols are A, B, C, D and EQ460. On the basis of ensuring low carbon equivalent, the content of microalloying elements is appropriately increased. Good welding performance requires low carbon equivalent of steel, and the addition of microalloying elements will increase the carbon equivalent of steel while increasing the strength of steel. However, the increase in carbon equivalent is very small, so it will not affect the welding performance of the steel.
Progress
The rapid development of the automobile industry has played an important role in the national economy and social development. However, due to the impact of energy shortage, environmental pollution and other problems, the contradiction of the development of the industry has become increasingly prominent. Looking to the future, the development of the industry can only be sustainable if it is established in the context of nature, ecology, energy saving and safety.
In this context, the application of automotive lightweight and high-strength steel has become an important development direction. However, with the increase of the strength of the high strength steel sheet, the traditional cold stamping process is easy to crack during the forming process, which can not meet the processing requirements of the high strength steel sheet. In this case, the international gradually study of ultra-high strength steel sheet hot stamping forming technology - a new process of forming, heat transfer and organizational phase change, mainly using the high temperature austenite state, the plastic increase of sheet metal, yield strength reduction characteristics, through the mold forming process. However, hot forming requires in-depth research on process conditions, metal phase transformation, CAE analysis technology, but the technology is monopolized by foreign manufacturers, and the domestic development is slow.
According to survey statistics, the application of high-strength steel in some automobile brands continues to expand, and the application of high-strength steel in the body frame of some models has reached 90%. According to the Energy Department of the American Iron and Steel Institute, even if the value of high-strength steel is reduced, it is still much more difficult to stretch than traditional cold plate. The elongation of high strength steel is only half that of ordinary steel.
When the material is stamped, it will harden, and different steels will harden to different degrees. Generally, high-strength low-alloy steel is only slightly increased by 20MPa, less than 10%. Note: The yield strength of duplex steel has increased by 140MPa, an increase of more than 40%! During the forming process, the metal will become completely different, unlike before the stamping process began. The yield strength of these steels increases greatly when they are stressed. The higher yield stress of the material combined with work hardening equals a large increase in the flow stress. Therefore, cracking, rebound, wrinkling, workpiece size, mold wear, micro-welding wear and so on have become the focus of problems in the process of high strength steel forming.
Based on the characteristics and characteristics of high-strength steel, if the metal flow cannot be changed and friction can be reduced, then the cracking and texture of high-strength steel (HSS) can cause the component scrap rate to increase. The material's high kilopound force per square inch (KSI), increased resilience, tendency to work harden, and ability to operate at elevated molding temperatures are all challenges for molds.
Significance
It is an indisputable fact that lubrication affects formability. As a result, high-performance lubricants provide a higher performance film to protect the metal from breaking, fracturing or being welded to the mold. A good lubricant also reduces friction heat, keeps the metal flowing continuously and controls wrinkling or breaking.
In response to this problem, the United States IRMCO company, as a world-renowned professional company engaged in lubrication research and manufacturing, has successfully developed a new water-based lubrication technology to solve the molding problem of high-strength steel since 30 years ago. The following, combined with years of research and use from the perspective of lubrication and combined with the characteristics of the lubrication technology to talk about views and opinions. As follows:
First, lubrication guarantee under harsh conditions.
1, because the yield force of high-strength steel is large, to yield it requires more energy than the general plate, this energy in addition to deformation, to a large extent is the plate and the mold between the push (friction). Therefore, as the deformation temperature of the metal in the stamping die will continue to rise, the oil-based lubricant will become thinner, and in some cases it will reach the flash point or burn (smoke), and the lubrication will fail. The IRMCO polymer extreme temperature lubricant contains extreme pressure resistance and has "heat seeking" and will stick to the metal, forming a tough protective barrier on the surface of the mold and plate as the temperature rises, thereby reducing friction and temperature to help the workpiece to better extend, in order to control friction and metal flow; At the same time, it protects the metal from overheating, blackening and cracking and bonding.
At the same time, according to the problems in the actual test, we replicate the results of the field test in the laboratory. Different formulations of oil-based and conventional (soap) -based synthetic lubricants do not work properly on high strength steel. Scrap rate and mold wear (abrasion) out of control.
Luye Technology Laboratory of the United States on IRMCO products and automotive industry certified tensile oil and synthetic lubricants on the United States DP780 ultra-high strength steel comparative experiments. The Interlaken stretch forming test method of Ohio State University was used. This method proved to be very accurate for testing actual results. The IRMCO achieved a value of 145, which is more than 25% higher than the 115 for the automotive industry's certified stretch oils and 110 for synthetic lubricants. The larger the value, the better the molding capacity
2, due to the temperature generated during the stamping process, and because the heat capacity of the oil is relatively large, the thermal diffusion is relatively poor. IRMCO water-based lubricant is generated by temperature to form water vapor to carry away heat, which not only effectively reduces the temperature and protects the mold, but also effectively controls the micro-welding wear caused by temperature. At the same time can also improve the stroke.
Second, the performance of the tool coating is closely related to the quality of the lubricant.
Traditional physical vapor deposition (PVD) and chemical vapor deposition (CVD) coatings require external lubrication for maximum performance. IRMCO notes: "The thermal diffusion process can reduce friction and wear problems. The vanadium carbide produced by thermal diffusion can form a durable, hard surface, which greatly improves the service life of tools during harsh forming and stamping dies. If the lubricant used cannot withstand the high temperatures, wear and work hardening of advanced high-strength steels, the value will be significantly reduced. Therefore, the use of lubricants that meet the needs of high-strength steel is the key to maximizing the service life of the coating."
According to the first implementation of IRMCO technology and many years of application experience, high-strength steel stamping dies can meet the production needs without spending high coating costs, and can extend the life of the die. It can be seen that IRMCO lubrication technology has a protective effect on the mold. After stamping three thousand workpieces, the surface quality of the workpiece and the surface of the mold have been significantly improved (surface scratches are significantly reduced).
Third, high-performance lubrication can make the quality of the workpiece more stable.
Die clearance and die geometry design are important contents to realize the dimensional accuracy of the workpiece. Therefore, this is directly related to the technical requirements for metal materials and lubricants. If the gap is smaller and the friction is tighter, the requirements for lubricants are higher, but the molding accuracy of the workpiece is also relatively higher. Because IRMCO can better control friction and metal flow, it can ensure that the workpiece quality is more stable.
