Centre spinning method of boiler center barrel

A centrifugal casting and boiler technology, applied in the field of centrifugal casting of central cylinders for boilers, can solve the problems of rough surface, easy deformation, low hardness, etc., and achieve the effects of accurate geometric dimensions, refined metallographic structure, and high hardness

Inactive Publication Date: 2008-02-06
贾友军
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The central cylinder for boilers of sand casting has the disadvantages of loose texture, coarse metallography, difficulty in removing pores, sand holes, and slag inclusions, and the thickness of the cylinder wall is uneven, there is a certain error in geometric dimensions, and the surface is rough, so it cannot be effectively used. Extend the service life of the central tube; the rolled central tube for boilers is rolled and welded from formed plates. The disadvantages are: it is difficult to unify the welding rod and the base material, and the hardness is low, easy to deform, and not resistant to erosion and wear. Therefore, the service life of the central cylinder cannot be extended.

Method used

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  • Centre spinning method of boiler center barrel
  • Centre spinning method of boiler center barrel
  • Centre spinning method of boiler center barrel

Examples

Experimental program
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Effect test

Embodiment 1

[0030] To produce the center cylinder for long cylinder boilers, use a double roller horizontal centrifuge and a long cylinder mold. The length of the long cylinder mold is 2300mm, the outer diameter is 3500mm, and the inner diameter is 3200mm. Placed between the double rollers of the centrifuge, using FeCr / Al 2 o 3 Re-ceramic composite material, through the centrifuge to make the elongated drum mold press n = 36 √ G / R ‾ The rotation speed calculated by the formula is rotated, and the calculated rotation speed is 336 rpm. During the rotation, the prepared molding sand is added to the water glass and sprayed evenly around the inner wall of the long cylindrical drum mold as a molding release lining. When the sand layer reaches a thickness of 100mm, use a drying car to spray a warm fire at 500°C to dry the molded release lining sand layer to a thic...

Embodiment 2

[0033] To produce the central cylinder for short cylinder boilers, use a double roller horizontal centrifuge and a short cylinder mold. The length of the short cylinder mold is 2000mm, the outer diameter is 1800mm, and the inner diameter is 1500mm. Placed between the double rollers of the centrifuge, using FeCr / Al 2 o 3 Re ceramic composite material, through the centrifuge to make the short cylinder type roller mold press n = 36 √ G / R ‾ The rotation speed calculated by the formula is rotated, and the calculated rotation speed is 360 rpm. During the rotation, the prepared molding sand is added to the water glass and sprayed evenly around the inner wall of the short cylinder drum mold as a molding release lining. When the sand reaches a thickness of 70mm, use a drying car to spray it with a warm fire at 900°C to dry the formed release lining s...

Embodiment 3

[0036]To produce the center cylinder for long cone boilers, use a double roller horizontal centrifuge and a long cone cylinder mold. The length of the long cone cylinder mold is 4000mm, the outer diameter of the upper mouth is 2500mm, and the inner diameter is 2200mm. The outer diameter of the lower mouth is 2200mm, and the inner diameter is 1900mm. The long tapered cylinder mold is placed between the double rollers of the horizontal centrifuge, and the FeCr / Al 2 o 3 Re ceramic composite materials, the long cone-shaped roller mold is pressed by a centrifuge n = 36 √ G / R ‾ The rotation speed calculated by the formula is rotated, where R is the radius of the waist, and the calculated rotation speed is 317 rpm. During the rotation, the prepared molding sand is added to the water glass and sprayed evenly on the inner wall of the long cone drum mold ...

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Abstract

The invention discloses a centrifugal casting method of central cylinder for boiler, main procedures of the invention are as follows: a corresponding forming mould of roller is produced, a forming stripping bush is prepared, sprinkled, and dried, fireproof coating is sprayed and dried, cast, a formed central cylinder cast for boiler is cooled by steam, a martensite is formed on the inner surface of the alloy steel molten and so on. The central cylinder for boiler produced by the centrifugal casting method of central cylinder for boiler has accurate geometric dimensioning with the length L between +-0.1 percent and the diameter theta between +-1 percent, high rigidity which is HRC45-65, thinning metallurgical structure and the equiax crystal reaches 30 to 70 percent. The service life of the central cylinder is 3 to 5 times longer than that produced by sand casting, and can be widely used for the production of central cylinder for boiler.

Description

technical field [0001] The invention relates to a casting method of a central cylinder for a boiler, in particular to a centrifugal casting method for a central cylinder for a boiler. Background technique [0002] Boiler central tube is an important part of boiler components. Its geometric shape is divided into long tube type, short tube type, long cone tube type, semi-double layer type, single flange type and variable diameter type. Its function is Separate the flue gas in the cyclone and buffer the speed of the flue gas and air flow. During the operation of the boiler, the central cylinder is subjected to high temperature burning and the erosion friction of dust in the flue gas flow and the SO in the flue gas flow 2 Corrosion, and long-term service at a high temperature of 1100 ° C, so the service life of the central cylinder is short. Judging from the current usage conditions, the general service life of the center cylinder is 6 to 24 months, so it needs to be replaced ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D13/02
Inventor 贾友军贾从昌
Owner 贾友军
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