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Vacuum isothermal heat treatment process of large die-casting mould

A technology for isothermal heat treatment and die-casting molds, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve problems such as mold life not meeting requirements, mold performance degradation, mold deformation, etc., and achieve significant technological progress and structural performance Small, guaranteed service life effect

Inactive Publication Date: 2010-11-10
FAW GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of traditional rapid cooling can easily lead to deformation or even cracking of the mold; many heat treatment counterparts at home and abroad mostly adopt furnace temperature control heating, and adopt the heat treatment process of step quenching with cooling pressure less than 6Bar. Although the deformation has been effectively improved, it has led to The decline of mold performance makes the mold life not meet the requirements

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Embodiment 1 Vacuum isothermal heat treatment of large clutch housing die-casting mold

[0017] The outer dimensions of the die-casting mold for the large clutch housing are 940×920×310, the vacuum heat treatment weight is 1256 kg, the finishing allowance is 2 mm on one side of the mold, and the hardness is required to be HRC44-46 after heat treatment.

[0018] The mold is made in an imported vacuum heat treatment furnace. The effective size of the furnace is: 1000mm×1000mm×1500mm, and the rated heat treatment weight is 1500 kg. When loading the furnace, drill a Φ2.2×16 hole on the back of the mold for inserting a thermocouple. The temperature at this point is the surface temperature of the mold, which is recorded as Ts. Insert the thermocouple into the center of the water pipe of the mould, and block both ends with asbestos to ensure that the end of the thermocouple is in contact with the inner wall of the water pipe of the mould. The temperature at this point is the c...

Embodiment 2

[0034] Embodiment 2 Vacuum isothermal heat treatment of large-scale gearbox housing die-casting mold

[0035] The external dimension of the die-casting mold for the large gearbox housing is 840×820×410, the vacuum heat treatment weight is 1456 kg, the finishing allowance is 2 mm on one side of the mold, and the hardness is required to be HRC42-46 after heat treatment.

[0036] The mold is made in an imported vacuum heat treatment furnace. The effective size of the furnace is: 1000mm×1000mm×1500mm, and the rated heat treatment weight is 1500 kg. When loading the furnace, drill a Φ2.2×16 hole on the back of the mold for inserting a thermocouple. The temperature at this point is the surface temperature of the mold, which is recorded as Ts. Insert the thermocouple into the center of the water pipe of the mould, and block both ends with asbestos to ensure that the end of the thermocouple is in contact with the inner wall of the water pipe of the mould. The temperature at this point...

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Abstract

The invention relates to a vacuum isothermal heat treatment process of a large die-casting mould, which is characterized by comprising the steps of: inserting thermocouples into the core and the surface layer of a mould, raising the temperature of a furnace to 550-625 DEG C at the speed of 150-200 DEG C per hour firstly, then raising the temperature of the furnace to 825-875 DEG C at the speed of 100-150 DEG C per hour, raising the temperature of the furnace (Tf) to reach an austenization sate within 20 minutes and preserving the temperature for 30 minutes; quickly cooling under cooling pressure not lower than 9Bar, decreasing the cooling pressure to 2Bar when the temperature of the surface of the mould (Ts) is decreased to 427 DEG C, stopping the rotation of a cooling fan and turning on a convection fan; and filling nitrogen pressure to be above 6Bar after isothermy, turning off the convection fan and restarting the cooling fan to rotate so as to realize quick cooling. Therefore, the invention can achieve the most ideal structure property and the minimum deformation, can guarantee the service life of the large die-casting mould, and has scientific and reasonable process, obvious technological advance and considerable economic values and market prospect.

Description

Technical field: [0001] The invention relates to a vacuum isothermal heat treatment process for a large die-casting mold, in particular to a vacuum heat treatment process for a large, complex and long-life die-casting die. Background technique: [0002] Die-casting molds such as automobile engine cylinder blocks, gearbox housings, and clutch housings are often large in size (over 900 mm in size and over 1,000 kg in weight), complex in cavity (many core-pulling mechanisms, uneven thickness), and wall thickness exceeding 300mm. The use of traditional rapid cooling can easily lead to deformation or even cracking of the mold; many heat treatment counterparts at home and abroad mostly adopt furnace temperature control heating, and adopt the heat treatment process of step quenching with cooling pressure less than 6Bar. Although the deformation has been effectively improved, it has led to The decline in mold performance makes the life of the mold fail to meet the requirements. Th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/00C21D1/20C21D1/773B22D17/22
Inventor 方建儒孙伟
Owner FAW GROUP
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