Starter head for semi-continuous casting the hard aluminum alloy billet

Abstract

The invention provides a dummy bar head used for semi-continuous casting of duralumin round ingot; the material of the dummy bar head is steel and the mainbody thereof is a dummy bar body; the upper part of the dummy bar body is provided with a chamber; the circumferential surface of the chamber is a negative conical surface with the taper ranging from -2 DEG to -10 DEG; the bottom surface of the chamber is provided with a central convex platform and a ring-shaped convex platform; the circumferential surface of the central convex platform and the ring-shaped convex platform is a conical surface with the taper ranging from 1 DEG to 30 DEG; the bottom of the dummy bar body is provided with a connecting thread; the dummy bar body is fixed on a supporting platform by the connecting thread; the negative conical surface of the circumference of the upper chamber of the dummy bar body is used for improving the adhesion force of ingot casting and dummy bar head in the initial stage of the casting and is beneficial to demoulding after the semi-continuous casting is finished; the ring-shaped convex platform and the central convex platform in the chamber increase the homogenization of bottom cooling of the ingot casting in the initial stage of the semi-continuous casting, prevent the bottom crack of the ingot casting, support and stabilize the ingot casting; the dummy bar head has simple structure, convenient installation and usage, long service life and is applicable to the semi-continuous casting of duralumin round ingot.

Description

technical field [0001] The invention relates to a dummy head for semi-continuous casting of hard aluminum alloy round ingots, belonging to the technical field of semi-continuous casting of aluminum alloys. Background technique [0002] When the traditional direct cooling semi-continuous casting process is used to prepare aluminum alloy round ingots, the initial stage of casting is the most unstable and also the most critical stage in the entire casting process, and casting problems such as bottom cracking and aluminum leakage are prone to occur; especially for 2× For hard aluminum alloy round ingots represented by ×× and 7××× series, due to the high content of alloy elements in the ingot, the number of eutectic phases with low melting point at the grain boundary is large, and the plastic zone of the ingot is small during the solidification process , the brittle zone is large, the ability of the ingot to resist cracks is low, coupled with the uneven cooling of the bottom of t...

AI Technical Summary

Problems solved by technology

[0002] When the traditional direct cooling semi-continuous casting process is used to prepare aluminum alloy round ingots, the initial stage of casting is the most unstable and also the most critical stage in the entire casting process, and casting problems such as bottom cracking and aluminum leakage are prone to occur; especially for 2× For hard aluminum alloy round ingots represented by ×× and 7××× series, due to the high content of alloy elements in the ingot, the number of eutectic phases with low melting point at the grain boundary is large, and the plastic zone of the ingot is small during the solidification process , the brittle zone is larger, the ability of the ingot to resist cracks is low, coupled with the uneven cooling of the bottom of the ingot, the internal stress of the ingot is very large, which greatly increases the tendency of the bottom crack of the ingot

[0003] At the beginning of casting, the cooling conditions from the center to the edge of the ingot are quite different, the temperature difference between the inner and outer layers is large, the cooling rate of the inner layer of the ingot is lower than that of the outer layer, and the shrinkage of the inner layer is hindered by the already condensed outer layer, making the ingot The center is subjected to tensile stress along the circumferential direction. This tensile stress continues to increase from the moment of crystallization to the complete cooling of the ingot. When the deformation value allowed by the metal is exceeded, cracks are generated. For large-scale hard aluminum alloy round ingots, cracks Tendency is greater, it is difficult to cast success

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