The automobile Hot Dip Galvalume Steel Coil unit focuses on the production of outer plates. The thickness of the product specifications is mostly between 0.6 and 1.2mm, the width of the plate is mostly 800 to 1850mm, and the widest can reach 2000mm. The product level is quite complex, from CQ, DQ, DDQ, EDDQ (IF) to BH, DP, TRIP, and other automotive high-strength steel plates. Using a variety of advanced technologies, the coating morphology and thickness accuracy can be accurately controlled, such as the coating thickness error is less than 2~3g/m2. Furthermore, the zinc-free steel plate can be produced by using lead-free galvanizing. This kind of coating is not easy to produce intergranular corrosion and has a long service life. Therefore, it is suitable for the automobile and electrical appliances industries. Almost every hot-dip galvanizing unit in Japan is equipped with a zinc-iron alloying furnace. The standard galvanized layer thickness of the zinc-iron alloyed plate (Galavneal) is 160~180g/m2 on both sides, and the alloy coating contains Fe8%~12% [2].
Foreign countries developed micro-alloy steel and phosphorous alloy steel in the 1970s, bidirectional DP steel and bake hardening steel in the mid-1980s, and phase transformation and induced plasticity TRIP steel in the 1990s [3]. At present, the international cooperation project "Ultra-Lightweight Steel Carbody (ULSAB) Development" is proceeding smoothly. Its goal is to achieve a driving fuel consumption of 34KM/3L (US) and a car bodyweight reduction of 25%. The primary starting point is to adopt many high-strength and ultra-high-strength steel plates in the car body structure. The most prominent feature of the ultra-light steel car body through the large ULSAB is that it does not sacrifice performance to reduce the car's weight [4]. The design basis of ultra-light steel vehicles is that the proportion of high-strength steel used in the body structure exceeds 90%. During the ten years from 1985 to 1995, high-strength steel in the body increased from 10% to 30%. With the surface treatment performance, The improvement of automobile life span extends from 6.7 years to 9.3 years. After deducting the energy increase in the manufacture of high-performance steel plates, 357*104L of heavy oil can save a year, which is almost equivalent to saving a percentage of the energy consumption of the domestic steel industry. A few. In 2000, the use of high-strength steel plates in Japanese automobile manufacturing reached 36.3%.
