WO2001094056A1

WO2001094056A1 - A slide gate plate system reinforced with steel fibre

Info

Publication number: WO2001094056A1
Application number: PCT/IN2000/000062
Authority: WO
Inventors: Shri Gopal Rajgarhia
Original assignee: Orient Abrasives Limited
Priority date: 2000-06-09
Filing date: 2000-06-09
Publication date: 2001-12-13
Also published as: AU1411101A

Abstract

The Slide Gate Plate System is used to cast molten steel into tundish or ingots in a controlled manner. The Slide Gate Plates are placed outside the ladle and consist of two refractory plates - one fixed and another moving. The fixed plate is also called top plate (3) and sliding plate is also called bottom plate (1). The slide gate plate of the present invention is provided with steel fibre of requisite quality as reinforcing material in the area (A) of said plate other than those areas, which come in contact with molten metal (B). By doing this, cracking and crack propagation in slide gate plates has been arrested drastically leading to much longer life and many more cycles of re-use.

Description

TITLE : A SLIDE GATE PLATE SYSTEM

REINFORCED WITH STEEL FIBRE Field of invention:-

This invention relates to a Slide Gate Plate refractory. This invention particularly relates to a Slide Gate Plate refractory hereinafter referred to as Slide-Gate Plate refractory reinforced with stainless steel fibre.

Prioy art:

The Slide Gate Plate is conventionally used in a moulding process to cast molten steel into tundish or ingot in a controlled manner. Heitherto known Slide Gate system consists of two refractory plates—one of them being fixed and called top plate, and other being moving or sliding and called bottom plate. The fixed plate is attached to the bottom of the ladle and the sliding or the moving plate is further attached to a collector nozzle for discharge of steel into tundish_. or ingot mould.

The Slide Gate Plates are exposed to very high theπnal and mechanical shock. Due to the fact that a large temperature differences occurs between the peripheral portion of the flow out nozzle side of the Slide Gate Plate and the outer portion away from the nozzle hole. This high thermal differential leads to spalling causing thereby considerable damage/cracking to such Slide Gate Plates. Before and after each use, the mechanical handling of plates also causes cracks to foπn/widen. The Slide Gate Refractors presently use different raw materials, like Alumina- Magnesia, Zirconia, Mullite or Zircona Mullete, etc. But the cracking due to thermal spalling/ mechanical damage is there in all the Slide Gate Plates, irrespective of the compositions. The degree of cracks may vary.

In order to obviate the above drawbacks irrespective of the refractory compositions an improved slide gate plate has been developed wherein cracking and crack propagation in the slide gate plate has been drastically reduced.

This is an object of the present invention to provide a Slide Gate Plate system, which obviates the drawbacks of the existing Slide Gate Plate by adding Steel Fibre in the Slide Gate Plates at selective areas.

Another object of the present invention is to provide a Slide Gate Plate in having a high resistant against thermal shocks.

Yet another object of the present invention to provide Slide Gate Plate which has longer life and many more cycles of reuse.

Yet another object of the present invention is to provide Slide Gate Plate which eliminates cracking and crack propagation in the said plate. Detailed description of the invention :-

Accordingly the present invention provides Slide Gate Plates which comprises of a top plate attached to the bottom of the ladle, a bottom or moving plate and a collector nozzle for discharging of steel into tundish or ingot mould wherein said bottom or moving plate is slidlingly attached to the said collector nozzle, characterised in that steel fibre of requisite quality has been added in the areas of the Slide Gate Plate other than those areas which come in contact with molten metal.

Another aspect of the present invention is to provide a method of making the Slide Gate Plate by zoning of material where some area are without and remaining are reinforced with Steel Fibre.

Brief description of the invention with reference to drawings:-

Fig-1 shows a sectional view of the conventional bottom plate alongwith nozzle and a cross section of a top plate Fig-2 shows a sectional view of a bottom plate and a cross section of the top plate of present invention.

Figure-2 comprises of bottom plate (1), collector nozzle (2), top plate (3), insert plate (4), carrier plate (5), with reinforced material with fibre in area (A) and area without fibre (B). Details of the process followed for manufacture of Slide Gate Plates :-

1. TOP PLATE :- Material in about 15-40 mm on all side around bore is put without fibre and in balance area, fibre is placed. This is done by using a format. Before pressing, the format is removed and simultaneous pressing of both mixes is done. Composition of two i.e. material with fibre and without fibre, could be same or different.

2. BOTTOM PLATE - These Plates are manufactured in two different routes :-

(i) Where an insert plate is used, which may be casted or fixed in a fired bottom plate, (ϋ) A single piece, fired plate.

Case-I

Insert plate, casted or fired fixed in fired plate.

Insert plate is made by zoning of material. Area covered by complete length of the insert and upto 15-40 mm each side of the bore is made without fibre. Area covered by complete length of the insert and beyond 15 -40mm from each side of the bore is made with fibre addition. A format is used for zoning while mould filling. After filing, the format is removed and insert is pressed. It is fired and processed. In case the bottom plate is made of casting the insert plate by the castable, the castable used is of requisite quality and with fibre addition, from 0.5% to 4.0%.

The insert plate is clamped with or without collector nozzle, fixed in steel cassette or format and is casted with the above refferred acastable with or without vibrations.

When the inset is fixed in a fired plate called a "carrier plate", the whole carrier plate is made with fibre addition of 0.5 to 4.0 %. This plate is made in the same route as insert plate but with cheaper raw materials.

After this carrier plate is fired and processed, the insert plate is fixed with this plate, with or without collector nozzle and is jointed with a suitable jointing martar. This it is dried, and processed further.

Case-II

Single piece bottom plate

If the bottom plate is in single piece, and fired, plate is made by zoning as described below.

An area, which covers upto 25 to 155 mm from outer edge of the plate bore on each sliding side of the plate in length and upto 15-40mm on each side of the outer edge of the plate bore in width, and on non sliding side in length, is made without fibre addition and rest of the plate is made with steel fibre addition. A format is placed during mould filling for zonning of the materials with and without fibre. After mould filling the format is lifted, the plate is pressed, dried, fired and processed.

The invention described above with reference to accompanying drawing is merely illustrative in nature to understand the aspects of the invention. However, this is not intended to limit the scope of the invention to the embodiments as described above. The combinations and permutation within the scope of the invention are possible without departing from the soul of the invention.

Claims

We claim: -

1) A slide gate plate system which comprises of a top plate fixedly attached to the bottom of the ladle, a bottom or moving plate and a collector nozzle for discharging of steel into tundish or ingot mould wherein said bottom or moving plate is slidlingly attached to the said collector nozzle, characterised in steel fibre of requisite quality has been added in the selected areas of the slide gate plate;

2) A method of making the slide gate plate which comprises the steps of forming of plates by zoning of material, material without fibre is used in and around the bore area and remaining is reinforced with steel fibre;

3) A method of making a slide gate plate substantially as herein described;

4) A slide gate plate system substantially as herein described particularly with reference to accompanying drawings;