Working Condition of Pipe Mould

In the production process of water-cooled centrifugal pipe mould, thhe qualified hot metal is directly casted on the inner wall of the pipe mould through the running channel, and the hot metal is uniformly distributed in the cavity of the inner wall under the action of high-speed rotating centrifugal force, the outer wall of the mould is filled with flowing cooling water at 40-75℃, which makes the hot metal in the inner wall gradually solidified and shaped under the double effects of centrifugal force and high cooling strength.

The hot metal in the sector pouring ladle with the temperature 13000—1400℃ cast into the inner wall of the pipe mould through the running channel with 1200--1260℃. The temperature of the inner wall of the pipe mould rises rapidly from 100--250℃(before pouring) to 650-700℃ after the hot metal adhered to the inner wall of the pipe mould. During the solidification process, the heat of hot metal is quickly carried away by the cooling water outside the mould body, while the temperature of the inner wall of the mould decreases. Since the effect of the cooling water, the increase of outer wall temperature is not obvious by about 100℃. After the cast iron pipe is pulled out, the temperature of the inner wall of the mould is reduced to 100--250℃. In a production cycle of 40-100 seconds, the inner wall temperature of the mould changes periodically with highest temperature 700℃ and the lowest temperature 100℃. In the continuous production, the cast pipe mould is always in the heat conduction process of alternating heat and cold. The thermal stress of the pipe mould body is changed circularly under the frequent alternation of temperature, and the inner surface of the pipe mould, in particular, the transition zone of the socket is prone to produce thermal fatigur cracks(aracking). As a result, the mould must be removed and replaced after a certain period of time or pulling out number of pipes, and the stress can be eliminated by finishing or repairing the cracks, thereby, the service life of the pipe mould can be extended.