Modification agent and modification method for iron-rich phase in secondary aluminum

Abstract

The invention relates to an alterant of an iron-rich phase in secondary aluminum and an alteration method. The alterant is composed of a [Mn] agent and a [B] agent. The alteration method includes the steps that part of secondary aluminum is heated to form a melt, then the [Mn] agent is added, the remaining secondary aluminum is added after the [Mn] agent melts, the [B] agent is added, refining is carried out after the [B] agent melts, pouring is carried out after standing is carried out for a period of time, and the secondary aluminum obtained after alteration treatment is obtained. According to the alterant and the alteration method, the Fe element in the iron-rich phase can be replaced through the [Mn] agent, the advantage growth orientation of the iron-rich phase is changed, and therefore a needle-like beta-Fe phase is eliminated; meanwhile, the forming temperature of the iron-rich phase can be reduced through B in the [B] agent, the growth time of a primary iron-rich phase is shortened, the growth space of the primary iron-rich phase is reduced, the B can also serve as a surface-active element, and is absorbed to the surface of the iron-rich phase in the initial phase of formation of the iron-rich phase, and growth of the iron-rich phase is restrained, so that through the combined action of the [Mn] agent and the [B] agent, existence of the needle-like iron-rich phase and the primary iron-rich phase can be completely eliminated, the uniform Chinese character type iron-rich phase is obtained; and in addition, the adding amount of the Mn can be greatly reduced, and the mechanical performance and the machining performance of the secondary aluminum can be greatly improved.

Description

technical field [0001] The invention relates to a modification agent and a modification method for iron elements in aluminum alloys, in particular to a modification agent and a modification method for iron-rich phases in recycled aluminum. Background technique [0002] Fe element is the most common impurity element in recycled aluminum. It has high solubility in aluminum melt. The maximum solubility can be as high as 2.5% and 5.0% at 700 °C and 800 °C, but its solid solubility at room temperature is very low. Only 0.05wt.%, the rest of the iron phase exists in the form of the second phase, usually called iron-rich phase. According to the morphology of the iron-rich phase, it can be roughly divided into two types, namely α-Fe phase and β-Fe phase. Among them, the β-Fe phase is mainly distributed in the grain boundary in the form of narrow and long needles. When the force is applied, the matrix is ​​severely split, and the plasticity drops sharply. At the same time, the quali...

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Problems solved by technology

[0006] The above-mentioned CN101899634A relates to the method of combining the addition of alloying elements and ultrasonic vibration technology to eliminate the needle-like iron phase, but the method needs to first pour the alloyed aluminum melt into a prefabricated pulping container, and implement it in the pulping container Ultrasonic vibration, the pulping container needs to be equipped with heating and heat preservation devices, the process is relatively complicated, and the energy consumption and melting loss are relatively large

CN104278166A achieves the quenching effect and improves the morphology of the iron-rich phase by adding solid alloys to the superheated melt, supplemented by stirring, but the existing research results show that measures such as stirring and quenching with superheating agents can only refine the iron-rich phase. Phase particles, can not achieve the purpose of eliminating needle-like iron phase, performance improvement is relatively limited, and this method is suitable for small batches and laboratory tests, not suitable for large-scale industrial production

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