Riser tube and manufacturing method thereof

Abstract

The invention discloses a riser tube for a low-pressure cast aluminum alloy gearbox and a manufacturing method of the riser tube. The riser tube comprises an iron riser tube body and further comprises a ceramic protection sleeve and refractory cotton transition layers. The iron riser tube body is wrapped with the refractory cotton transition layers. The refractory cotton transition layers are wrapped with the ceramic protection sleeve. The method comprises the steps that the iron riser tube body is made of an ordinary #45 steel material; the refractory cotton transition layers are made of an ordinary fiber refractory cotton material; fixing protruding bosses are manufactured in selected positions of the inner tube wall and the outer tube wall of the iron riser tube body in the axial height direction; the refractory cotton transition layers which are 2 mm+ / -0.5 mm thick are fixed to the inner tube wall and the outer tube wall of the iron riser tube body correspondingly, SiC particles with the purity being 99%+ / -0.2% are fixed to the refractory cotton transition layers, the thickness of the SiC particles is 5 mm+ / -0.5 mm, and the iron riser tube body is placed in a dry and ventilated position to be air-dried; and the air-dried riser tube body is placed into a sintering furnace and subjected to overall sintering, the sintering temperature is about 1390-1410 DEG C, and the riser tube is obtained after roasting. According to the riser tube and the manufacturing method thereof, in the using process, the situation that corrosion occurs and consequently increased iron is generated can be avoided, and manufacturing is easy.

Description

technical field [0001] The invention relates to an aluminum alloy low-pressure casting gating system device, in particular to a structure and a manufacturing method of a riser pipe for a low-pressure casting aluminum alloy gear box. Background technique [0002] With the rapid development of the domestic high-speed rail market, the high-speed rail gearbox is one of the core components of the transmission system of the EMU. The requirements for the chemical elements of the gearbox castings are almost harsh. The low-pressure casting gearbox castings usually use iron risers. Specific The casting process determines that the riser pipe must be soaked in molten aluminum for a long time. During the manufacturing process, Fe (iron) elements and Al (aluminum) elements are easily reacted, and the iron riser pipe is easily corroded and pollutes aluminum. Sometimes the chemical element Fe of the gearbox castings exceeds the standard. In addition, during use, if the iron riser pipe is pa...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of the domestic high-speed rail market, the high-speed rail gearbox is one of the core components of the transmission system of the EMU. The requirements for the chemical elements of the gearbox castings are almost harsh. The low-pressure casting gearbox castings usually use iron risers. Specific The casting process determines that the riser pipe must be soaked in molten aluminum for a long time. During the manufacturing process, Fe (iron) elements and Al (aluminum) elements are easily reacted, and the iron riser pipe is easily corroded and pollutes aluminum. Sometimes the chemical element Fe of the gearbox castings exceeds the standard. In addition, during use, if the iron riser pipe is partially corroded and causes air leakage, it is difficult to find it on site, and it is easy to cause batch quality problems during pouring.

[0003] Fe element is an impurity element in aluminum alloy. This impurity phase mainly exists in the alloy matrix as a lath-like or needle-like AlFeSi phase, which severely splits the matrix and affects the fatigue performance and impact toughness of gearbox castings. Performance indicators such as elongation and elongation have a great impact. The Fe content of gearbox castings is required to be ≤0.12%. However, Fe increase is inevitable in the actual production process. Due to the cost of raw materials, the Fe content of raw materials is generally 0.08-0.11%. , the Fe-increasing space itself is extremely narrow, and once the control is not done properly, it is easy to cause the Fe element to exceed the standard

In the traditional gear box casting process, a kind of paint is applied to the wall of the riser pipe, but the effect of preventing the increase of Fe by the paint method is not ideal, because in the low-pressure casting production process, every blank needs to be periodically pressurized It is difficult to maintain the coating with pressure relief once and periodic flushing. Therefore, only the traditional coating protection method cannot prevent the addition of Fe to the aluminum liquid, and cannot meet the high requirements of the gearbox for Fe content.

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