A centrifugal casting furnace tube and its preparation process

A preparation process and centrifugal casting technology, applied in the direction of improving process efficiency, etc., can solve problems such as grain boundary embrittlement, shortened service life of furnace tubes, and reduced creep resistance of furnace tube materials, so as to achieve fine grains and impurities The effect of reducing the content and improving the comprehensive mechanical properties

Active Publication Date: 2018-03-27
ZUORAN JINGJIANG EQUIP MFG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the smelting process of adding old furnace tubes, the low melting point impurities remaining on the old furnace tube walls may be brought into the newly manufactured furnace tubes. During the long-term high-temperature service of the furnace tubes, the impurity elements will segregate at the grain boundaries of the furnace tubes , grain boundary embrittlement, which reduces the creep resistance of the furnace tube material, resulting in a greatly shortened service life of the furnace tube

Method used

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  • A centrifugal casting furnace tube and its preparation process
  • A centrifugal casting furnace tube and its preparation process
  • A centrifugal casting furnace tube and its preparation process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Centrifugal casting of pipes with a size of Φ550 / 350×2000mm, the casting method is

[0034] (1), determine the composition of the furnace tube material and weigh the ingredients according to mass percentage (wt%):

[0035]

[0036]

[0037] (2) Heat scrap steel in an electric furnace to about 1500°C and melt it. After the molten steel is melted, add ferromanganese and ferrosilicon to melt it in turn, and use aluminum wire to deoxidize, then add pure nickel, ferromolybdenum, and ferrochrome in turn. , deoxidize again with aluminum wire and remove slag on the molten steel surface, then add rare earth nickel-gadolinium and nickel-cerium intermediate alloy in turn, deoxidize again with aluminum wire, remove slag on the molten steel surface and let it stand to obtain molten steel;

[0038] (3) According to the formula N=20×(G / r) 1 / 2 , Calculate the centrifugal speed of the pipe cavity of centrifugal casting. Among them, N is the centrifugal speed of the cavity, r is ...

Embodiment 2

[0041] Embodiment 2: The centrifugal casting size is the pipe material of Φ460 / 350×2000mm, and its casting method is

[0042] (1) Determine the composition of the furnace tube material and weigh the ingredients by mass percentage (wt%):

[0043]

[0044] (2) Heat scrap steel in an electric furnace to about 1500°C and melt it. After the molten steel is melted, add ferromanganese and ferrosilicon to melt it in turn, and use aluminum wire to deoxidize, then add pure nickel, ferromolybdenum, and ferrochrome in turn. , deoxidize again with aluminum wire and remove slag on the molten steel surface, then add rare earth nickel-gadolinium and nickel-cerium intermediate alloy in turn, deoxidize again with aluminum wire, remove slag on the molten steel surface and let it stand to obtain molten steel;

[0045] (3) According to the formula N=20×(G / r) 1 / 2, Calculate the centrifugal speed of the pipe cavity of centrifugal casting. Among them, N is the centrifugal speed of the cavity, r ...

Embodiment 3

[0048] Embodiment 3: The centrifugal casting size is the pipe material of Φ420 / 240 * 2000mm, and its casting method is

[0049] ((1) Determine the composition of the furnace tube material and weigh the ingredients by mass percentage (wt%):

[0050]

[0051] (2) Heat scrap steel in an electric furnace to about 1500°C and melt it. After the molten steel is melted, add ferromanganese and ferrosilicon to melt it in turn, and use aluminum wire to deoxidize, then add pure nickel, ferromolybdenum, and ferrochrome in turn. , deoxidize again with aluminum wire and remove slag on the molten steel surface, then add rare earth nickel-gadolinium and nickel-cerium intermediate alloy in turn, deoxidize again with aluminum wire, remove slag on the molten steel surface and let it stand to obtain molten steel;

[0052] (3) According to the formula N=20×(G / r) 1 / 2 , Calculate the centrifugal speed of the pipe cavity of centrifugal casting. Among them, N is the centrifugal speed of the cavity...

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Abstract

The invention discloses a centrifugal casting furnace tube and a preparation technology thereof. The preparation technology comprises the following steps: taking steel scrap, ferromanganese and ferrosilicon, ferrochromium, pure nickel, ferromolybdenum and rare earth nickel gadolinium, and nickel cerium intermediate alloy as the raw materials, adopting an aluminium wire for deoxygenation, and deslagging on the liquid level of molten steel to obtain molten-state molten steel; according to the formula N=20*(G / r)<1 / 2>, calculating the centrifugal rotational speed of a steel tube cavity manufactured through centrifugal casting; when the rotating speed of the steel tube cavity reaches the calculated centrifugal rotational speed, pouring molten steel to the cavity from a steel ladle, and adopting argon during the pouring process to ensure that molten steel is not oxidized, wherein the pouring temperature is 1523-1573 DEG C and the pouring time is about 5-10 minutes; demoulding, cooling a centrifugal steel tube to the room temperature, and removing impurities on the inner surface layer of the steel tube through the inner boring machining method to obtain the centrifugal casting furnace tube. According to the invention, the prepared centrifugal casting furnace tube has excellent mechanical property under high temperature, and grain boundary embrittlement caused by segregation of impurity elements on the grain boundary of the furnace tube during the preparing process is also avoided.

Description

technical field [0001] The invention belongs to the technical field of centrifugal casting alloy furnace tubes, and in particular relates to a centrifugal casting furnace tube and a preparation process thereof. Background technique [0002] In my country, the centrifugal casting furnace tube was gradually localized in the 1970s, and it took nearly two decades to form a certain production scale. In the field of petrochemical industry, high-alloy centrifugal casting furnace tubes have been widely used as furnace tubes for reforming furnaces and cracking furnaces, such as hydrogen production reforming furnaces in Nanjing Oil Refinery, Zhenhai Petrochemical General Plant, and cracking furnaces in Yanshan Petrochemical Company. [0003] In recent years, the centrifugal casting alloy furnace tube has gradually developed towards high parameters and large-scale, and the service conditions have become more complex and harsh. Therefore, the performance requirements of the domestic cen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/58C22C38/42C22C38/44C22C33/06B22D13/02C21C7/06
CPCB22D13/02C21C7/06C22C33/06C22C38/005C22C38/02C22C38/04C22C38/42C22C38/44C22C38/58Y02P10/20
Inventor 巨佳王章忠巴志新马利峰李栋展益彬张保森毛向阳章晓波
Owner ZUORAN JINGJIANG EQUIP MFG
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