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A method for near-solid pressure forming of large ring-shaped billets

A near-solid, annular technology, applied in the field of near-solid pressure forming of large annular billets, can solve the problems of low casting yield, poor structure uniformity, high forming pressure, etc., and achieve improved mechanical properties, reduced deformation work, and easy forming. Effect

Inactive Publication Date: 2016-08-17
TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the technical problems of low casting yield, poor structure uniformity, serious component segregation, high forming pressure and complicated process existing in the existing ring billet forming method, and to provide a material and energy saving, simple process, microstructure and other technical problems. Near-solid-state pressure forming method for large annular billets with excellent properties

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A kind of near-solid pressure forming method of large annular billet in the present embodiment, it is made up of following steps:

[0018] (1) The 25Mn molten steel is melted in an intermediate frequency induction furnace, and the melting temperature is 1650-1670°C;

[0019] (2) Using a ladle refining furnace for refining outside the furnace, the refining temperature is 1620-1640°C, and argon blowing and stirring are carried out;

[0020] (3) When the temperature of the molten steel drops to 1530-1550°C, inject the molten steel directly into the open metal mold cavity preheated to 300-350°C, and keep it warm;

[0021] (4) Calculate the mass fraction of the solid phase by monitoring the temperature change of the molten steel. When the mass fraction of the solid phase reaches 60% to 70%, the mold is closed and pressurized. The pressurization speed is 20mm / s and the specific pressure is 50MPa. The holding time is 3min;

[0022] (5) After the solidification is completed, ...

Embodiment 2

[0026] A kind of near-solid pressure forming method of large annular billet in the present embodiment, it is made up of following steps:

[0027] (1) The Q235B liquid steel is smelted in an intermediate frequency induction furnace, and the smelting temperature is 1650-1670°C;

[0028] (2) Using a ladle refining furnace for refining outside the furnace, the refining temperature is 1620-1640°C, and argon blowing and stirring are carried out;

[0029] (3) When the temperature of the molten steel drops to 1530-1550°C, inject the molten steel directly into the open metal mold cavity preheated to 300-350°C, and keep it warm;

[0030] (4) Calculate the mass fraction of the solid phase by monitoring the temperature change of the molten steel. When the mass fraction of the solid phase reaches 60% to 70%, the mold is closed and pressurized. The pressurization speed is 30mm / s and the specific pressure is 60MPa. The holding time is 2min;

[0031] (5) After the solidification is complete...

Embodiment 3

[0035] A kind of near-solid pressure forming method of large annular billet in the present embodiment, it is made up of following steps:

[0036] (1) The molten steel is smelted in an intermediate frequency induction furnace, and the smelting temperature is 1650-1670°C;

[0037] (2) Using a ladle refining furnace for refining outside the furnace, the refining temperature is 1620-1640°C, and argon blowing and stirring are carried out;

[0038] (3) When the temperature of the molten steel drops to 1530-1550°C, inject the molten steel directly into the open metal mold cavity preheated to 300-350°C, and keep it warm;

[0039] (4) Calculate the mass fraction of the solid phase by monitoring the temperature change of the molten steel. When the mass fraction of the solid phase reaches 60% to 70%, close the mold and pressurize. The pressurization speed is 20 ~ 30mm / s, and the specific pressure is 50~60MPa, the holding time is 2~3min;

[0040] (5) After the solidification is complete...

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PUM

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Abstract

The invention relates a nearly solid pressure forming method for a large circular steel billet. The nearly solid pressure forming method for the large circular steel billet mainly solves the technical problems of the prior circular steel billet forming method that the product yield is low, the homogeneity of structure is poor, the composition segregation is serious, the forming pressure is large and the technology is complex. According to the technical scheme, the forming method includes the following steps: (1) adopting a medium-frequency induction furnace for smelting the molten steel; (2) adopting a ladle refining furnace for external refining and argon stirring; (3) when the temperature is reduced to 1530-1550 degrees centigrade, directly injecting the molten steel into the pre-heated metal mold cavity with opening and keeping the temperature; (4) monitoring the temperature change of the molten steel, calculating the mass fraction of the solid phase, when the mass fraction of the solid phase is 60-70%, closing the die, pressing, the pressing speed is 20-30mm / s, the intensity of pressure is 50-60MPa, the pressure keeping time is 2-3min; (5) after solidifying, decompressing and fast cooling; (6) demoulding to obtain the circular steel billet with high density, small grain, even structure and excellent mechanical property.

Description

technical field [0001] The invention relates to a near-solid pressure forming method for a large ring billet, which belongs to the technical field of processing and forming large-scale rings formed by near-solid pressure forming with a metal mold. Background technique [0002] The quality of the ring billet plays a vital role in the entire ring casting-rolling composite forming process, which directly affects the implementation of the subsequent rolling process and the performance of the final ring. The existing production techniques of ring billets are mainly sand casting and centrifugal casting. Due to the insoluble defects in the sand casting process itself, a series of problems have appeared in the production process of steel castings, which are mainly manifested in the following two aspects: (1) When using ordinary sand casting methods to produce steel castings, in order to eliminate For shrinkage cavity and shrinkage defects, it is usually necessary to set up a large ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D18/02
CPCB22D18/02
Inventor 胡勇闫红红李永堂张国强
Owner TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY