汽車車身外殼絕大部分是金屬材料，主要用鋼板。汽車的鋼板車身防銹蝕年限為什么能達(dá)10年以上？

Most of the car body shell is metal material, mainly with steel plate. Why can the steel plate body of the car reach more than 10 years?

鍍鋅薄鋼板廣泛應(yīng)用在汽車上，這是因為它有良好的抗腐蝕能力。早年人們在試驗中發(fā)現(xiàn)，將鐵和鋅放人鹽水中，二者無任何導(dǎo)線聯(lián)結(jié)時，鐵和鋅都會生銹，鐵生紅銹，鋅生“白銹”；若在二者間用導(dǎo)線聯(lián)結(jié)起來，則鐵不會生銹而鋅生“白銹”，這樣鋅就保護(hù)了鐵，這種現(xiàn)象叫犧牲陽極保護(hù)。工程師正是將這種現(xiàn)象運(yùn)用到實際生產(chǎn)中，生產(chǎn)了鍍鋅鋼板。經(jīng)研究，在鍍鋅量350克／平方米（單面）時，鍍鋅鋼板在屋外的壽命（生紅銹），田園地帶約為15-18年，工業(yè)地帶約為3-5年，這比普通鋼板長幾倍甚至十幾倍。

Galvanized sheet steel is widely used in cars because of its good corrosion resistance. In the early years, people found that when iron and zinc were put in salt water, there was no wire connection, iron and zinc would rust, iron red rust and zinc "white rust"; if the two wires, iron will not rust and zinc "white rust", so that zinc protects the iron, this phenomenon is called sacrifice anode protection. Engineers have applied this phenomenon to the actual production, producing galvanized steel plate. After research, when the galvanized amount is 350 grams / square meter (single side), the life of galvanized steel plate outside the house (red rust), the rural area is about 15-18 years, the industrial area is about 3-5 years, which is several times or even ten times longer than the ordinary steel plate.

從20世紀(jì)70年代開始轎車車身鋼板采用鍍鋅薄鋼板，裝配時鍍鋅面置于汽車內(nèi)側(cè)，提高車身耐蝕性能，非鍍鋅面置于汽車外側(cè)，噴涂油漆。隨著汽車對耐腐蝕性能的要求不斷提高，鍍鋅鋼板不斷增加鍍鋅層重量，還出現(xiàn)了雙層鍍鋅鋼板。但由于增加鍍鋅重量也會使電鍍鋅的電能消耗大幅增加，導(dǎo)致材料成本的上升，因此20世紀(jì)70年代末又出現(xiàn)一種采用熱浸鍍鋅工藝生產(chǎn)的鍍鋅鋼板，稱為熱鍍鋅鋼板。這種鍍鋅鋼板用連續(xù)熱鍍鋅工藝：冷軋板（注*）→加熱→冷卻至鍍鋅溫度→鍍鋅→冷卻→矯直。為了滿足汽車對鍍鋅鋼板的各種要求，一些生產(chǎn)廠家在鍍鋅生產(chǎn)線上對鍍鋅鋼板進(jìn)行擴(kuò)散退火等特殊處理，以使鋼板表面形成一種“鋅－鐵”合金鍍層，其特點(diǎn)是涂漆后的焊接性和耐腐蝕性比純鋅鍍層板要好。以后還出現(xiàn)了諸如“鋅－鋁－硅”、“鋅－鋁－錸”等合金化熱鍍鋅鋼板，使得熱鍍鋅鋼板的耐腐蝕性成倍提高，與油漆間的結(jié)合性能長期穩(wěn)定。目前轎車已經(jīng)廣泛使用鍍鋅鋼板，采用的鍍鋅鋼板厚度從0.5至3.0毫米，其中車身復(fù)蓋件多用0.6至0.8毫米的鍍鋅鋼板。

Since the 1970s, the steel plate of the car body is galvanized thin steel sheet. During the assembly, the galvanized surface is placed on the inside of the car to improve the corrosion resistance of the car body, and the non-galvanized surface is placed on the outside of the car to spray paint. With the continuous improvement of automobile requirements for corrosion resistance, galvanized steel plate keeps increasing the weight of galvanized layer, and double galvanized steel plate also appears. However, because the increase of galvanized weight will also greatly increase the energy consumption of electrogalvanized, resulting in the rise of material cost, so in the late 1970s, a galvanized steel plate produced by hot dip galvanized process, called hot dip galvanized steel plate. This galvanized steel plate with continuous hot galvanizing process: cold rolled plate (note *) heating cooling to galvanized temperature galvanized cooling straightening. In order to meet the various requirements of galvanized steel plate, some manufacturers treat the galvanized steel plate on the galvanized production line, so as to form a "zinc-iron" alloy coating on the surface of the steel plate, which is characterized by the weldability and corrosion resistance after painting than the pure zinc plating plate. Later, there are such as "zinc-aluminum-silicon", "zinc-aluminum-rhenium" and other hot-dip galvanized steel plates, which makes the corrosion resistance of hot-dip galvanized steel plate improved exponentially, and the combination performance with the paint is stable for a long time. At present, galvanized steel plate has been widely used in cars, the thickness of galvanized steel plate from 0.5 to 3.0 mm, in which the body cover parts of 0.6 to 0.8 of galvanized steel plate mm.

例如德國奧迪轎車的車身部件絕大部分采用鍍鋅鋼板（部分用鋁合金板），美國別克轎車采用的鋼板80%以上是雙面熱鍍鋅鋼板，上海帕薩特車身的外復(fù)蓋件采用電鍍鋅工藝，內(nèi)復(fù)蓋件內(nèi)部采用熱鍍鋅工藝，可以使車身防銹蝕保質(zhì)期可長達(dá)11年。

Such as German audi car body parts mostly use galvanized steel plate (part with aluminum alloy plate), buick car steel more than 80% is double hot galvanized steel plate, Shanghai passat body outside galvanplating process, inside cover inside hot galvanized process, can make the body rust shelf life can be up to 11 years.