The decisive factors for the selection of mold copper tube materialMold copper tube is an accessory used for cast steel continuous casting machine. The molten

 The decisive factors for the selection of mold copper tube material

Mold copper tube is an accessory used for cast steel continuous casting machine. The molten steel is directly cast in the mold copper tube, and the steel billet is continuously cooled and formed in the copper tube. In order to solve the problem that the copper tube is in contact with the cooled billet shell and separated from time to time during the working process, the mold copper tube is still bent to one side Square or rectangular copper tube, the inner cavity of the copper tube is tapered from the upper mouth to the lower mouth, and the inner cavity of the copper tube is a double-cone or tri-cone or multi-cone, or a parabolic cavity from the upper mouth to the lower mouth. Shape, the taper of the upper section or the upper part is greater than the taper of the lower section or the lower part. It is best that the taper of the straight surface is greater than the taper of the curved surface. Avoid the air gap between the blank shell and the inner wall of the copper tube during the working process, which is more in line with the contraction change law of the blank shell.

Shape characteristics of mold copper tube

The appearance and shape of the mold copper tube is generally a square tube or a copper tube that is bent to one side.

During the solidification process of the casting blank, the shape of the inner cavity of the mold copper tube and the shrinkage law of the shell during solidification remain consistent, thereby reducing the thermal resistance of the gap between them.

The mold copper tube is a very important part of the continuous casting machine, which is equivalent to the human heart, without any flaws or incompleteness. It is a heat conduction component. After the hot molten steel in the cavity is gradually cooled, the heat is introduced, and the cooling water outside the tube circulates to conduct the heat, realizing the principle of heat conduction. Therefore, under the violent heat exchange environment with such continuous high temperature, the material requirements of the mold copper tube are very strict. Neither crystal softening nor plastic deformation can occur.

Use scientific experiments to show that the mold copper tube can meet the safety requirements of continuous casting

Through software analysis, digital simulation of the temperature field, stress field and displacement field distribution on the wall surface of the 10mm copper mold cast with 0.2% C molten steel. The results are as follows:

The peak temperature of the hot surface of the mold is 525K, and the peak temperature of the cold surface is 475K; the deformation value of the outer wall of the mold is 0.789mm, which is larger than the deformation of the inner wall; the maximum equivalent stress and the maximum strain of the mold appear when the molten steel is in contact with air The rounded corners of the inner wall are 218MPa and 0.002079 respectively. Mold temperature, deformation and stress meet the safety requirements of continuous casting.

The decisive factors for the selection of the mold copper tube material

Because the inside of the copper pipe is in contact with high-temperature molten steel, the temperature difference between the inner and outer surfaces of the copper pipe is large, the thermal stress is high, and it is extremely volatile. The shape of the inner cavity of the copper tube is very important. It is necessary to protect the inner shape of the copper tube to match the shape of the crystal solidified blank shell, so that the air gap can be small and uniform. Therefore, the copper tube material is required to have strong thermal deformation resistance, that is, it is required High recrystallization temperature, low thermal expansion coefficient, good thermal conductivity, high thermal fatigue strength, etc.

The selection of copper tube materials develops in the direction of red copper→phosphorus deoxidized copper→silver copper→chromium zirconium copper. Since the recrystallizer temperature of chromium zirconium copper is the highest among the above materials, its resistance to thermal deformation is the strongest. However, due to its high cost, there are problems such as a large rebound of copper tubes in the extrusion process. At present, there are not many domestic mold copper tubes used in manufacturing.