How to prevent the tundish nozzle from clogging

Tundish nozzle plays a very important role in ladle steel making.It is very important to learn the measures to prevent the clogging of the nozzle of the tundish. There are some measures to stop clamping at tundish nozzle.

Measures to stop clamping at tundish nozzles

(1) Ensure that there is no deformation in the sliding mechanism of the continuous casting sizing nozzle, there is no foreign matter on the sliding stroke of the sizing nozzle, and the gap between the sizing nozzles is less than or equal to 0.3mm.

(2) The size of the zirconium sizing nozzle is reasonably designed, there is no damage and cracks before use, and the board surface is flat without unevenness.

(3) The production rhythm is stable, the quality of molten steel is qualified, and there is no phenomenon of high and low temperature and molten steel interception.

(4) The personnel for replacing the sizing nozzle are skilled, and there should be no accidental burning or diameter expansion caused by human factors.

The disorder of casting process because of nozzle clogging is a long-standing issue ever since the continuous casting process has been introduced. Nozzle clogging is the build-up of solid or semi-solid material on a refractory surface which can become problematic during steel pouring, as it can affect the stream dynamics, reduce the pouring rate, and cause large agglomerated particles to be intermittently released into the liquid steel stream in severe cases. Because of the nozzle clogging, the casting speed is frequently decreased, and even an entire cast is to be abandoned.  Further, nozzle clogging can give rise to both quality and productivity problems.

During the continuous casting of liquid steel, steel flows from the tundish to the mould through a submerged entry nozzle, (SEN) as shown. This protects the liquid steel from reoxidizing in contact with the atmosphere. The flow rate is controlled with a gate or stopper rod to maintain optimum casting conditions. If the nozzle clogs and the flow control cannot make up for the reduced flux, the nozzle has to be replaced which means the production is interrupted. The clog build-up can also result in decreased steel quality as oxide particles can loosen from it, giving rise to rather large inclusions.

Tundish Nozzle

Tundish nozzle clogging problems take several different forms, and can occur anywhere inside the nozzle, including the upper well, bore, and ports. They are classified into four different types according to their formation mechanism namely

 (i) the transport of oxides which are present in the steel to the nozzle wall,

 (ii) air aspiration into the nozzle,

 (iii) chemical reaction between the nozzle refractory, and the steel, and (iv) steel solidified in the nozzle. In practice, a given nozzle clog is frequently a combination of two or more of these types, and its exact cause(s) can be difficult to identify.

Problems caused by clogged tundish nozzles:

Clogging of the tundish nozzle is a major castability problem in continuous casting of steel for several reasons. Firstly, clogging increases the frequency of operation disruptions to change nozzles or tundishes or even to stop casting. These extra transitions increase operating cost, decrease productivity, and lower quality. Secondly, clogging can lead directly to a variety of quality problems. Clogs change the nozzle flow pattern and jet characteristics exiting the ports, which can disrupt flow in the mold, leading to surface defects in the steel product and even breakouts. Dislodged clogs also disturb the flow and either become trapped in the steel or change the flux composition, leading to defects in either case. Quality problems also arise from the mold level transients which occur as the flow control device compensates for the clogging.

FAQ:

What is a tundish nozzle?

Tundish Nozzles are an integral part of Continuous Steel Casting process. These products are instrumental in controlling the flow of Molten Steel from Tundish to Continuous Casting.

What is the HS code for tundish nozzle?

69032090

What is the function of a nozzle?

The primary function of a nozzle is to control flow rate and convert the spray liquid into droplets (via atomisation) that are of a suitable size for depositing on the intended target.

What are the uses of tundish?

What does a tundish do? A tundish is installed to prevent cross-contamination between an overflow pipe and a drain pipe. Unsanitary water from the drain pipe could theoretically enter the system if a tundish is not installed to block this.

The number of melting sequences is important in choosing a Tundish nozzle. Different nozzles for single use Melting or multiple melts are produced and used. It seems necessary to use more resistant material to achieve higher sequences. Welcome contact us to choose the right nozzle at the lowest cost.

Tundish Refractory Products