(1) Al-Ti-B wire quality. The role of Al-Ti-B wire is so fine and uniform particles of metal crystal, resulting in good mechanical properties and processability. Its quality directly affects the size of the grains. Currently the quality of domestic Al-Ti-B wire is very unstable product of acceptable quality must be selected

(2) Al-Ti-B wire wire feeder failures. Al-Tl-B wire feed motor and control cabinet installation next to the holding furnace, high temperature, dust, drain easily lead to motor electrical components fever, fatigue, damage, can not guarantee the normal amount of added Al-Ti-B wire, and artificial Add A1-Ti-B wire speed uneven slab quality can not be guaranteed.

(3) The melt temperature is caused by an important reason for coarse grains. When the vertical plate when the temperature needs to be higher than normal production temperature of 2030C, in winter even a male high 40 ℃ to vertical plate success. Pre-production stage of the vertical plate more often, it is bound to cause the melt to form a large grain burnt, as technology continues to improve, due to the high temperature caused by defects in the vertical plate of coarse grains gradually reduced.

(4) can also cause low cooling intensity of coarse grains. Normal production requires cooling water 0.35 a 0.4MPa, the cooling water temperature less than 25 ℃. In the hot summer, due to the various aspects of water consumption increases, the supply pressure casting machine temperature often below standard. In July and August, the water pressure only 0.250.3MPa.

Roll in use for a long time, within the circulating water scale is too thick or partial blockage will affect the strength of the roll cooling. To prevent coarse grain casting board, be sure to use quality and stability of Al-Ti-B wire steam production, wire confidential to maintain the normal operation, and constantly improve the level of vertical plates, regular cleaning inside the roller circulating water to maintain adequate cooling water pressure, water temperature.