A method for manufacturing large-scale ingots through electromagnetic regulation and self-inoculation treatment

A self-inoculation and ingot casting technology, which is applied in the direction of manufacturing tools, casting equipment, casting melt containers, etc., can solve the problem of reducing interface heat transfer, cracks, chiller distribution uniformity, cold core and ingot interface structure uniformity and Stress problems are difficult to control and other problems, and the effects of uniform temperature field distribution, increased nucleation particles, and simple device structure are achieved.

Active Publication Date: 2018-11-06
UNIV OF SCI & TECH LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for steel castings with large cross-sectional dimensions, it is difficult to achieve rapid solidification through interface heat transfer. The ingot is cooled by increasing the external cooling intensity, and the temperature gradient of the ingot cross-section cannot be too large, otherwise crack defects will occur
Step cooling is beneficial for forming a positive temperature gradient from outside to inside, ensuring sequential solidification, and forming shrinkage cavities in the riser, but the cooling gradient and its dynamic control are not very operable
Electromagnetic stirring water-cooled mold casting steel ingot under the action of electromagnetic field strengthens the temperature uniformity in the steel ingot mold, and enhances heat transfer through the water-cooled mold, but it still only transfers heat through the mold wall interface, and the cooling intensity is difficult to achieve rapid cooling
[0005] Some technicians have explored the method of combining accelerated cooling with nucleation promotion, promoting the supercooling of molten steel in the mold by adding chilled iron, and reducing the heat transfer at the interface. Segregation large-scale steel ingot manufacturing method", the Chinese patent No. CN101406937 discloses "a kind of internal cooling method for suppressing macro-segregation of large steel ingots", and the Chinese patent No. CN104259441A discloses "built-in cold core and top electromagnetic field casting large steel ingot method” etc.; by adding chilling body and cold core casting, solidification can be achieved in both directions, increasing the cooling intensity and improving the central structure, but the uniformity of the distribution of the chilling body in the melt and the uniformity of the interface structure between the cold core and the ingot and stress problems are difficult to control

Method used

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  • A method for manufacturing large-scale ingots through electromagnetic regulation and self-inoculation treatment
  • A method for manufacturing large-scale ingots through electromagnetic regulation and self-inoculation treatment
  • A method for manufacturing large-scale ingots through electromagnetic regulation and self-inoculation treatment

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Effect test

Embodiment 1

[0041] Such as figure 1 As shown, the ingot mold in this embodiment is a nodular cast iron ingot mold, and the ingot mold is preheated at 300°C before casting and kept for 12 hours; the two-phase feeding nozzle is preheated to 1550°C.

[0042] The casting steel type is Q345B steel, the design ingot weight is 50kg, the melting temperature is 1620°C, the casting temperature is 1580°C, the estimated casting time is 2min, the casting process is protected by argon, and the molten slag is sprinkled on the liquid surface after pouring.

[0043] In order to ensure the action time and effect of the electromagnetic field and the inoculant, two electromagnetic fields are used, that is, the electromagnetic device I5 applied to the straight section of the two-phase feeding nozzle and the electromagnetic device II6 applied to the riser of the ingot mold.

[0044] The structural parameters of the inoculant are provided by numerical simulation and thermodynamic calculation results. The inocul...

Embodiment 2

[0048] Such as figure 1 As shown, the ingot mold in this embodiment is graphite ingot mold, and the ingot mold is preheated at 200°C before casting, and kept for 12 hours; the two-phase feeding nozzle is preheated to 685°C.

[0049] The casting metal is aluminum-silicon alloy, the design ingot weight is 20kg, the melting temperature is 800°C, the casting temperature is 750°C, and the casting process is protected by argon.

[0050] The inoculant is made of aluminum-silicon alloy small pieces. In order to prevent foreign impurities from being brought in, the inoculant is cleaned first and then dried in a vacuum oven at 100°C for 24 hours for later use.

[0051] When casting, the aluminum-silicon alloy liquid in the ladle is poured into the ingot mold through the two-phase feeding nozzle. When the aluminum-silicon alloy liquid is poured to 1 / 2 of the inner cavity height of the ingot mold, the feeding control valve is opened and stored in the incubator. The aluminum-silicon alloy...

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Abstract

The invention relates to a method for manufacturing large-scale ingots through electromagnetic regulation and self-inoculation treatment, comprising: 1) a Y-shaped two-phase feeding nozzle is adopted for molten metal casting, and an electromagnetic device I is arranged outside the straight section of the two-phase feeding nozzle; an ingot mold Electromagnetic device II is installed on the outside of the riser; 2) Preheating of the ingot mold and the two-phase feeding nozzle before casting; 3) Argon protection during the casting process, and the liquid metal level rises to 1 / 2 to 2 / 3 of the height of the inner cavity of the ingot mold Add the inoculant from time to time, turn on the electromagnetic device I at the same time, and turn on the electromagnetic device II when the metal liquid level rises to the height of the riser line of the ingot mold; both the electromagnetic device I and the electromagnetic device II operate at low frequency; 4) After the casting is completed, turn off the electromagnetic device Ⅰ. Adjust the electromagnetic device II from low-frequency operation to medium-frequency operation, and use the Joule heating effect of the medium-frequency magnetic field to keep the riser of the ingot mold warm until the ingot is solidified. The invention can refine the solidification structure of the steel ingot, reduce the center segregation, reduce the center porosity, thereby improving the internal and external quality of the ingot.

Description

technical field [0001] The invention relates to the technical field of metal casting, in particular to the technical field of large ingot solidification structure and segregation control. Background technique [0002] Large castings and forgings are the basis for the development of the equipment manufacturing industry, and are widely used in important fields such as metallurgy, shipbuilding, national defense, electric power, nuclear energy, high-rise buildings, petrochemicals, etc. It has irreplaceable advantages in the production. Large-scale castings and forgings are mostly used in extreme and special environments. Therefore, steel not only requires high strength and plasticity, but also has extremely strict requirements on microstructure, composition uniformity, and defects such as segregation and cracks. [0003] Liquid metal solidification forming is one of the most important links in the ingot production process. The solidification structure is hereditary to the subse...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D27/02B22D1/00B22D41/62B22D7/12
CPCB22D1/00B22D7/12B22D27/02B22D41/62
Inventor 沙明红郑婷李胜利郭庆涛李久慧贾春堂
Owner UNIV OF SCI & TECH LIAONING
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