In the most recent period, on the issue of body steel body and aluminum body once again been of concern to the public, after all, drawn from the body structure is the core of the protection of the occupants, a poor body material models are undoubtedly equal in a piece of tofu, when occupants accident casualty rate has skyrocketed. But relative, so far the dispute on steel and aluminum body body body constantly, which is mainly due to differences between the two body characteristics of different materials brings, what good or bad has become the focus of debate. That from a technical and practical applications for both steel and aluminum body body body in the end who better to do so?
the steel body of the vehicle body by definition is the body’s primary steel materials, but also the body into a variety of structural steel, which contains ordinary steel, high strength steel, ultra-strong steel, hot formed steel, but even in the steel structure will be used in some special parts combining aluminum alloy material; compared only steel material, aluminum alloy material proportion is much lower. So here we have to distinguish between good all-steel body structure is not any car a little bit of aluminum alloy material does not exist, empathy, aluminum structure, too, the focus is to look at the reasonableness of the required material and structural cost structure itself needed parts.
However, different steel materials also have different levels of strength (ordinary steel lt; high strength steel lt; ultrahigh strength steel lt; thermoforming steel), wherein the maximum heat-formed steel strength, the tensile strength of the high strength steel sheet is generally about 400-450MPa, hot-formed steel is formed by heating, by a series of post-treatment can increase the tensile strength to 1300-1600 MPa, is 3-4 times of ordinary steel. But based on the difficulty of manufacturing, the manufacturing cost and body structural requirements, usually hot formed steel used on the core portion of the vehicle body frame, such as the last line of defense occupants – cockpit. General car A, the cards materials B, C pillars and cockpit will be used directly below the hot formed steel, because you want to ensure the safety of occupants in case of an accident, the core is to ensure that the cockpit structure where the occupants complete deformation. And we are looking at 25 one hundred biasCrash test also points than the consequent, which is also the focus of the test materials and structural strength of the car.
In addition to the cockpit body, but the steel body will be used to heat an outer steel, other parts of the basic use of other steel material, For example a door, hood, trunk, roof, bumper. However, in the vehicle body framework, the closer to the higher strength grade steel used in the cockpit. But steel is to the car has a very fatal flaw, and that is its larger self, and therefore made out of the car in terms of heavy vehicles is relatively high. Car manufacturers in order to solve this problem, developed the aluminum body structure.
Aluminum aluminum body referred to here is an aluminum alloy, rather than pure, this ten million Do not misunderstand. With respect to the steel alloy, which is light weight of the biggest advantages; it has a very conclusive data indicate that the vehicle mass reduction percentage 10 allows fuel efficiency percentage of about 6 to 8 percentage, use of aluminum in bodywork may cause 20-30 weight percent of the vehicle is reduced to be 10 percent reduction in fuel consumption, which means saving 0.5 liters of fuel per hundred kilometers. For a life cycle of up to two hundred thousand kilometers of the car, this is a very impressive data. This advantage in today’s electric vehicles are equally applicable, the power to weight loss is equivalent to more services in mileage, to make electric cars run farther.
However, the aluminum body is not all aluminum with materials, even aluminum body is true, these claims only for the steel body frame, the proportion of aluminum alloy they used to be much higher. And on the strength, the strength of aluminum alloy can reach 5-600Mpa above, second only to the strength of high-quality steel, so apply it can also make people more at ease. But by a large force in the area with aluminum is not rational, after all, not high-strength steel its high strength, so “all-aluminum body,” in fact, will be vulnerable to the force of the site into a high-strength steel added, so as to improve vehicle safetySex.
advantage aluminum body is very obvious is that it’s lighter and able to meet the demand for lightweight vehicles, in order to reduce fuel consumption and improve the performance of vehicle performance, so the aluminum body will be used in motor racing, but if you want to achieve the ultimate in lightweight, more will be applied to the carbon fiber material. And in terms of aluminum compared to steel, there is a fairly obvious advantage of aluminum alloy, it has not translucent to ultraviolet light, water and gas impermeability, there is no smell and non-toxic, making it a no contaminated material, the cycle is also an environmentally friendly material. Energy absorbing alloy and higher performance, it can be an ideal material for manufacturing a vehicle body deformation zone, in order to increase the passive safety of the vehicle body; Briefly, when a collision occurs, the deformation of the aluminum body much lower than steel.
but the relative disadvantage of the aluminum body structure also very obvious, which it is also derived from the aluminum itself unique physical and chemical properties. First, the difficulty of stitching on the aluminum body, if the welding process to the aluminum alloy, steel is much higher than the degree of difficulty, firstly because aluminum has a strong oxidizing power, easy to form a dense compaction dioxide upon exposure to air an aluminum film having a melting point up to 2050deg; C, well above the melting point of the aluminum alloy. Followed by aluminum thermal conductivity and specific heat capacity higher than about doubled steel, in the welding process a lot of heat is rapidly conducted to the interior of the base metal, the aluminum welding than the welding steel to consume more calories. In addition, when welding aluminum face still hot cracking tendency, prone to problems like pores and no color change, compared in terms of steel, aluminum body production process more complicated, but also a higher degree of difficulty , followed by of course a lot of labor and energy costs.
opposing, manufacturers also avoid aluminum another difficulty welding using splicing be preparedAluminum body made, for example, self-piercing riveting technology, the servo motor powered by direct compression rivet Chery JLR be used in the caulking plate, sheet and riveting the rivet to be deformed plastically under the pressure of the rivet, after filling in the rivet forming die in order to develop a new sheet material connection technology.
The last question is about the cost of maintenance, which is aluminum in a practical application the largest body drawbacks, all-aluminum body of the vehicle upon collision, deformation of the metal distortion, since the particularity of processing, the maintenance costs are much higher than conventional materials. And because the repair process is very complex, 4S shop basically impossible to repair large-scale, often make all-aluminum body without repair directly scrapped.
From the point of view advantages, aluminum body occupies the advantage of low weight, which is particularly important for the motor vehicle . The so-called inferior to 10 horsepower increase vehicle weight by 10 pounds, the lighter vehicle speed faster while tilting the smaller during cornering, and at the same intensity, the safety lighter of the car, whereas the more body weight , the greater its inertia generated, the greater after the accident withstand the impact, the higher the occupants suffered injuries. It can be seen aluminum body in safety, performance and practicality does have a more outstanding performance.
However, cost of materials, manufacturing difficulty and maintenance costs, the aluminum body structure ordinary person can not really bear, so it usually only on high-end performance car brands or models, but also in the car insurance industry, premium aluminum body will be higher than normal body steel body, so when you covet this type of body structure time, or take a look at your wallet right.
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