Production and application of isostatically pressed refractory materials

introduction of Isostatical refractory

Definition of the three isostatical refractory

the monolithic stopper rod, the ladle shroud, and the submerged entry nozzle—are essential refractory materials used in continuous steel casting. They primarily serve to protect the casting process (ladle shroud and submerged entry nozzle) and control the flow of molten steel (stopper rod).

Here is the table that explain the function of ladle shroud,tundish stopper,sub entry shroud,and ladle shroud manipulator

Classification of stoppers:

1. Based on additional functions, they can be classified as:

a: Standard stopper

b: Ventilated stopper

2. Classification by connection method:

a: Threaded type

b: Pin-type

Classification of submerged tundish nozzles

• Submerged tundish nozzles for square and round billets
• Submerged tundish nozzles for medium-thick slabs
• Submerged tundish nozzles for thin slabs

Types of ladle shroud:

• Standard ladle shroud
• Argon-shielded ladle shroud

the design and production of isostatical refractory

Stopper Rod Body Design:

The rod body design takes into account safety and installation factors. The overall wall thickness of the rod must be greater than 40mm, and at the slag line, it must be no less than 50mm. If a carbon fiber plug is used, the wall thickness at the plug location must be no less than 30mm.

The design of sections A and B of the rod tail: The rod tail consists of two sections. Section A is a straight section, which ensures high strength near the plug. Section B is a tapered section, which ensures the required slag line thickness.

Additionally, the inner core diameter must be controlled. Increasing the inner core diameter can reduce rod bending and core deformation, but it also reduces the rod wall thickness.

Stopper Head Design:

Common types of stopper head include:

1. Semi-circular tip;

2. Three-segment arc tip;

3. Two-segment arc tip;

4. Two-arc with diagonal line tip.

The taper of these four types of plug tips gradually decreases from left to right. A larger taper results in longer lifespan and stronger wear resistance, but poorer flow control accuracy. This type of head is suitable for slab casting with high flow rates and severe wear. Conversely, a smaller taper results in shorter lifespan and weaker wear resistance, but better flow control accuracy. This type of plug is suitable for billet casting with lower flow rates and less slag carryover. Currently, the most commonly used plug tip is the three-segment arc type. This type offers good wear resistance and high flow control accuracy, and its taper can be adjusted by varying the radius of the three arcs to suit most continuous casting applications.

Relationship between the stopper rod and the tundish nozzle

The effective stroke of the stopper rod is related to the shape and dimensions of the stopper rod and the tundish nozzle as follows:

Where:

Y…Effective stroke of the stopper rod;

Rn…Radius of the tundish nozzle;

x…Contact angle between the stoper rod and the tundish nozzle;

y…Radius of the contact circumference between the stopper rod and the tundish nozzle.

Sub Entry Nozzle  Design

Figure A shows a conical design, while Figure B shows a combination of a cylindrical and conical shape.

In the figures:

φA – Outer diameter of the top surface of the conical or cylindrical sprue;

φB – Opening diameter of the sprue bowl;

φC – Diameter at the point where the arc of the sprue bowl is tangent to the flow channel of the molten metal; this line is called the throat line;

φD – Outer diameter of the bottom end of the conical sprue;

R – Radius of the arc of the sprue bowl;

h – Height of the conical section;

h1 – Depth of the throat line;

h2 – Height of the cylindrical section of the sprue bowl;

h – Total height of the cylindrical and conical sections of the sprue.

SEN Rear design: