Aluminized steel and preparation method thereof

Abstract

The invention discloses aluminized steel comprising a steel workpiece, wherein a eutectic aluminized alloy layer and an aluminum layer are sequentially arranged on the surface layer of the steel workpiece from inside to outside, and the thickness of the aluminized alloy layer is 14-29 microns. A preparation method of the aluminized steel comprises the following steps: co-firing the steel workpiece to remove oil; pickling to remove rust; washing; carrying out surface activating; carrying out auxiliary infiltrating; drying; carrying out rapid induction aluminizing; immediately immersing the dried steel workpiece in molten aluminum heated to 680-700 DEG C in an induction manner, wherein the infiltration time is 2-3 minutes; and the aluminized steel is obtained by the steps. The aluminized steel disclosed by the invention has superior corrosion resistance, heat resistance, wear resistance and photo-thermal reflectivity, and meanwhile, the bending property of the aluminized steel can be improved, the surface brittleness of diffusion aluminized layers is eliminated and the thermal shock resistance and thermal fatigue resistance can be improved. The preparation method disclosed by the invention can be used for effectively controlling the thickness of the aluminized layer, shortening the technique preparation period, improving the efficiency and increasing the yield.

Description

technical field [0001] The invention relates to the field of infiltrated steel in metal heat treatment, in particular to aluminized steel, and further includes a preparation method of aluminized steel. Background technique [0002] Aluminizing is one of the effective measures for steel protection, which can significantly improve the corrosion resistance, heat resistance and overall wear resistance of steel in strong corrosive media and oxidizing media. If the aluminum content in the steel is greater than 8%, dense Al can be formed on the surface of the steel. 2 O 3 The oxide film makes it have excellent corrosion resistance and oxidation resistance. But such high amounts of aluminum would make the steel brittle, difficult to hot and cold work and weld, and unable to withstand shock and vibration loads. The method of coating aluminum on the surface can not only increase the aluminum content of the surface layer of the steel workpiece, but also maintain the good plasticity ...

AI Technical Summary

Problems solved by technology

[0004] As far as hot dip aluminizing equipment is concerned, resistance heating impregnating aluminum equipment commonly used in China mainly relies on radiation heat transfer, which has the following disadvantages: slow heating speed (generally less than 10°C / s), low power utilization rate (at 40% Below), the furnace temperature is not easy to control (the upper and lower sides of the furnace are easy to temperature), the life of the hot-dipped aluminum-melting iron crucible is short (usually within a few months), and the dissolved iron is easy to contaminate the aluminum liquid, etc., and these factors greatly restrict aluminizing The development of technology and its large-scale popularization and application in various industries

However, there are still disadvantages in this process: resistance furnace equipment is still used for heating and melting aluminum, iron pots lined with non-metallic materials are used for aluminum melting crucibles, and the rapid aluminizing process relies on external power generation devices

The heating efficiency of the resistance furnace is still relatively low, and the thermal conductivity of the iron pot as the lining material is low, which leads to the fact that the temperature of the molten aluminum cannot be compensated for in time during mass production. Therefore, the maximum annual output of the production line is only about 10,000-12,000 tons

In addition, the thickness of the iron-aluminum alloy layer of aluminized steel workpieces cannot be effectively controlled (generally exceeding 30 microns, and the thickest reaches 75 microns), which will damage the final bending properties, toughness, and stamping performance of the material

[0007] At present, the steel workpiece pretreatment pickling process in the aluminizing industry is mostly a horizontal pickling tank, the acid concentration is high, the gas volatilization is very polluting to the environment, and the pickling time of the workpiece is long, the efficiency is low, and the pickling workpiece is easy Hydrogen embrittlement causes cracks in the final aluminized layer

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