Why do cracks appear after the continuous casting tundish is baked?

March 18, 2019

In recent years, there have been many cracks or even collapses in the impact zone of tundish after continuous casting and baking in a factory, which have seriously affected the production and operation of the site. Combining with the guidance of technicians from refractory manufacturers, some measures have been formulated to improve the operation of the workshop. Here is a detailed description.

Problematic tundish

Problematic tundish:

Mainly at the corner of the connection between slag retaining wall and impact zone. It is found to be partially peeled off during the continuous casting and baking process or before the pouring.

Analysis of reasons:

a. It may be caused by a bump in the process of pulling out the tire to cause internal cracks in the dry material.

b. Because of the poor lubrication effect of the package tire, the process of pulling out the package tire drives the dry material to cause looseness.

c. The dry slag material is loosened during the disassembly process of the slag wall formwork.

d. During the process of lifting the tundish, or bumping during the cover of the crane cover.

e. Other reasons

The slag adhering to the dry material is obviously lower than the dry material, and the bump is caused during the lifting process of the crane.

Improvement measures:

(1) Add a layer of spread material to the corner between the retaining wall and the impact zone, with a thickness of about 10mm, from the retaining wall to the small surface of the impact zone 1/2, to play a firm role in avoiding the dry material falling off in the impact zone.

(2) The retaining wall template is coated with a layer of graphite powder before use to play a lubricating role to avoid dry material cracks in the lower template process after the tundish is baked.

(3) Add a layer of graphite powder before the use of the intermediate package, that is, apply it twice. Increase the lubrication effect and avoid cracking of dry material during the process of pulling out the tire;

(4) Sending guardianship during the process of pulling out the packaged tires to avoid cracking or collapse of the dry material caused by pulling out the tires.

(5) Observe whether there is any bumping dry material on the cover after continuous casting.

(6) Before tying the permanent layer, it must be ensured that the venting holes of the cladding are transparent.