Crystallizer, forced water cooling bottomless steel ingot mold, is a very important part of continuous casting machine. It is called as the heart of continuous casting equipment.

The definition of crystallizer:

It is a kind of tank-shaped vessel, equipped with a jacket on wall or a coiler inside to heat or cool the molten liquid in the tank. The crystallizer tank can be used as evaporation crystallizer or cooling crystallizer. The stirrer can be added in order to improve the intensity of crystal. The crystallizer tank can be operated continuously or intermittently. The crystal is larger through intermittent operation, but it is easy to connect into clusters and entrain liquid, which influences the purity of products. It is suitable for the production of small-batch products (such as chemical reagents and biochemical reagents), with simple structure and low production intensity.

At this time, the inner wall of crystallizer is subjected to the combined action of mechanical stress and thermal stress produced by the static pressure of high temperature molten steel and friction force with the relative movement of the billet shell. So the working condition is extremely bad. In order to obtain qualified billet, the crystallizer should meet the following basic conditions:

1) Good thermal conductivity to condense molten steel rapidly

2) Good wear resistance to lengthen the life of crystallizer, reduce maintenance workload and time of replacing crystallizer and improve the operating rate of continuous casting machine

3) Sufficient rigidity, especially in the situation of sudden cooling and heating and big temperature gradient

4) Simple and compact structure, easy to manufacture, convenient to disassemble and adjust. The cooling water channel can be connected automatically, which is convenient for rapid replacement. The light dead weight reduces the inertia force when the crystallizer vibrates and the driving power of vibration device and makes the crystallizer vibrate smoothly.

The function of crystallizer: 

a. To solidify liquid steel into the required specification and shape of billet shell.

b. To separate the billet shell from the crystallizer wall without breaking and leaking through the vibration of crystallizer
c. To avoid billet from off-square, bulging, cracks, etc. through adjusting the crystallizer parameters
d. To ensure the billet to form uniformly and stably

The type of crystallizer:

(1) It can be classified into straight and arc type according to the shape of its inner wall.

   1) Straight crystallizer. The inner wall of straight crystallizer moves along the billet shell vertically, so the heat-conducting property is good and the billet shell cools uniformly. This crystallizer is simple in structure, easy to produce, install and debug, uniform in inclusion distribution and beneficial to improve the quality and casting speed of billet shell, to cause bend and crack the casting billet and to increase the height and investment of continuous casting machine. The straight crystallizer is applied to the vertical, vertical-bending and straight arc continuous casting machine.

   2) Arc crystallizer. The inner wall of arc crystallizer moves along the billet shell in the shape of round and arc, so the casting billet cannot be bent or cracked easily. But the heat-conducting property is worse than that of straight crystallizer, and the inclusion distributes unevenly, partial to the inner arc side of shell. The arc crystallizer is used in the full-arc and oval continuous casting machine.

(2) It can be classified into evaporation crystallizer and cooling crystallizer based on the way of molten liquid reaching hyper-saturated state, mother liquid circulation crystallizer and magna (mix of mother liquid and crystal) circulation crystallizer based on the flow mode, and continuous crystallizer and intermittent crystallizer based on the operating mode.

Common description of continuous casting crystallizer:

It is a kind of molten steel refrigerating and molding equipment, basically consisting of frame, water tank and copper plate (back plate and copper plate), adjustment system (adjustment device, speed reducer, etc.), lubrication system (oil pipeline), cooling system and spraying equipment.

The continuous casting crystallizer needs to be used together with continuous casting crystallizer protective material (slag).

Application of protective material:
a. To ensure the smooth going of continuous casting process
b. To improve the surface quality of casting billet