Publish Time: 2023-03-28 Origin: Site
Because the tensile strength of ordinary hard aluminum alloy is between 380-450Mpa, which is almost twice that of ordinary cast aluminum alloy, and the strength of super hard aluminum alloy can reach 600Mpa. Although the unit price of wrought aluminum alloy is higher than that of cast aluminum alloy, and its forming cost is also higher than that of casting process, due to the significant reduction in product structure size, plus the possibility of further heat treatment strengthening, welding and surface anodizing, the latter The price/performance ratio of aluminum alloy is obviously higher than the former, so more and more occasions hope to use or switch to deformed aluminum alloy to produce parts. For the use of sports parts, such as airplanes, ships, automobiles and motorcycles, sports bicycles, etc., wrought aluminum alloys have irreplaceable advantages in terms of energy saving and speed benefits brought about by weight reduction.
Jiahangaero said that due to the significant progress in continuous casting and forging technology, deformed aluminum alloy blanks with the same complex structure as die-casting parts can also be produced very easily and smoothly at a similar workshop cost. Therefore, deformed aluminum alloys are used instead The traditional production of cast aluminum alloy blanks not only has economic advantages, but also has become a trend.
Basic situation and performance comparison of cast aluminum alloy and deformed aluminum alloy
Industrial aluminum are divided into two categories: cast aluminum alloys and wrought aluminum alloys. Generally speaking, cast aluminum alloys are suitable for the production of aluminum castings by casting methods, while deformed aluminum alloys are suitable for the production of aluminum products by pressure processing (extrusion and forging).
Deformed aluminum alloys include: anti-rust aluminum (LF), duralumin (LY), super duralumin (LC), wrought aluminum (LD) and special aluminum (LT). Since the average comprehensive mechanical properties of deformed aluminum alloys are always higher than those of cast aluminum alloys (the forged properties of cast aluminum alloys are also several percent higher than their as-cast properties on average), many brands of deformed aluminum alloys can also pass quenching and aging. And other heat treatment methods to improve the mechanical properties, so the industrial design hopes to apply more deformed aluminum alloys to meet the requirements of use.
Jiahangaero understands that two factors limit the application range of wrought aluminum alloy or weaken its industrial economy:
First, the castability of wrought aluminum alloys is very poor, and its liquid fluidity is generally only one-third of that of cast aluminum alloys. It is difficult to produce blanks with complex structures by traditional casting methods.
Second, even if the deformed aluminum alloy blank is produced by casting, if the common defects of shrinkage cavity and porosity and pinholes in the casting process cannot be solved, then the subsequent heat treatment and surface anodizing processes cannot be continued.
The most fundamental reason is that even if the internal defects of the deformed aluminum alloy blank in the as-cast state are eliminated, the performance after heat treatment is greatly reduced due to the coarse metallographic grains and dendrites, or is only similar to that of ordinary cast aluminum alloys. , the use of this relatively expensive material variety has lost its due economic significance. However, the emergence of continuous casting and forging technology has effectively changed this situation.
Jiahangaero refers to the continuous casting and forging technology. It refers to using the same set of molds on the same equipment to continuously complete the blank filling and forging production. Its essence is a technology that relies on the functions of the equipment. Therefore, different continuous casting and forging equipment have different continuous casting and forging subdivision processes.
Continuous casting and forging equipment can be divided into horizontal type and vertical type according to the arrangement of the equipment, and can be divided into cold chamber type and hot chamber type according to the way of casting soup. The continuous casting and forging process, according to the number of forging power cylinders installed in the equipment, can be divided into two categories: unidirectional continuous casting and forging and multi-directional continuous casting and forging.
Two typical continuous casting and forging processes and equipment: one is the "liquid metal die forging" (or "melting soup forging") invented by the Soviets and completed by hydraulic presses, while the other is the use of Chinese inventions "Die casting die forging" realized by patented technology (or "squeeze die casting die forging" - referred to as "die casting die forging").
"Liquid metal die forging" process and equipment technology
For the "liquid metal die forging" process, although we can't clearly see its obvious "casting" - "forging" separation process, but the process completed by hydraulic press, its essence can still be classified as continuous casting and forging A kind of craft. It is also a kind of unidirectional continuous casting and forging process.
The "liquid metal die forging" process completed by a hydraulic press can produce some blanks with less complex structures and low requirements on the axial dimension accuracy of the blanks.
Since the hydraulic press is a general-purpose universal device, even if it uses a double movable beam hydraulic press, it still has only three power heads, so it is difficult to complete the continuous movement that requires multiple power heads and continuous compound movements. Casting and forging process. In addition, it has no filling mechanism, and complex blanks cannot be produced at all.
In production practice, the production efficiency of the process completed with this equipment is very low, and the industrial economy is not good. Due to the lack of technological means, workers have to manually operate at close range and contact high-temperature molds and blanks, which is not only labor-intensive, but also extremely inconsistent with the safety and civilized production requirements of modern industry. The lack of technical means also causes this production process to rely too much on the skills of the operator, which makes the repeatability and reliability of the process low, and it can no longer adapt to the progressive requirements of industrial production.
Jiahangaero have advanced "pressure casting die forging" technology and equipment technology
"Die casting die forging" process and equipment technology is referred to as "die casting die forging" technology. The "die-casting" here is not the "high-pressure die-casting" that we understand in a narrow sense, but it is a broad concept that includes all casting filling process concepts such as high-pressure die-casting, low-pressure casting, gravity casting, and vacuum suction casting. .
So "die-casting and die-forging" technology is a continuous casting and forging process that takes "die-forging" as the ultimate feature no matter what kind of casting filling method is used. The continuous casting and forging process is therefore also called a "principle process".
The most commonly used equipment at present is the horizontal cold chamber (hot chamber) die-casting die forging machine. Its shape is similar to that of traditional die-casting machines, and it can be used with traditional ironing, spray cooling and pick-up manipulators. It has been able to produce "die-casting die forging" equipment with a maximum forging pressure of more than 30,000KN, and can produce blanks including forged wheels of large trucks and forged cylinders of automobile engines. It can also produce continuous casting and forging blanks of magnesium alloys and ferrous metals. Since its production cycle is basically the same as that of ordinary die-casting machines, the process cost of workshop production is almost the same as that of die-casting processes.
Jiahangaero says that the continuous casting and forging production of wrought aluminum alloys is a new thing, which meets the development requirements of modern industrial products in the direction of light weight and high strength, and has a good application prospect. The continuous casting and forging production of deformed aluminum alloys is not very different from the continuous casting and forging production of ordinary cast aluminum alloys, and the technical difficulty is in the operable control. Familiarity with the common cast aluminum alloy continuous casting and forging process is the basis for producing continuous casting and forging parts with complex structural deformed aluminum alloy blanks. The "squeeze die-casting die forging machine" is the most industrially economical process and equipment for continuous casting and forging of deformed aluminum alloys.