Method of bainite hardening steel in use for plastic die

A technology of plastic mold steel and bainite, applied in the field of bainite quenching, can solve the problems of complex heat treatment process, high price, industrial pollution, etc., and achieve the effect of saving heat treatment cost, prolonging service life and simple treatment.

Inactive Publication Date: 2005-01-12
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These elements are generally harmful elements, which are likely to cause industrial pollution in metallurgical production engineering. This is one of the obstacles to the promotion of free-cutting steel. This type of steel is more expensive, and the heat treatment process is more complicated and the cost is also higher.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 3Cr2MnMo plastic mold plate, the overall size is 2450mm×1300mm×430mm (thickness), heated in a trolley-type gas heating furnace, preheated at 600°C for 1 hour, and then heated to 920°C for austenitization for 7 hours. After the heat preservation is over, the trolley is driven out, and the mold plate is lifted by the crane and cooled to room temperature in the air, and a uniform hardness of 40±1HRC can be obtained. Tempering is carried out at 600°C for 2.5-3 hours, so that the overall template reaches 34-36HRC Hardness, used to make large-scale plastic molds.

Embodiment 2

[0020] The processed plastic mold has an external dimension of 400mm×550mm×250mm (thickness), and the material is 3Cr2NiMnMo. Heating in a vacuum furnace capable of gas quenching, the preheating temperature is 600°C for 1.5 hours, then raised to 930°C for austenitizing heating, and kept for 4 hours. After the heat preservation is over, feed 1bar nitrogen for slow cooling (equivalent to cooling in air) to obtain a uniform hardness of 40±1HRC, take it out after cooling to room temperature, and then temper in a vacuum tempering furnace at 230°C for 4 hours, after cooling Putting it into injection molding processing, the service life can be increased by more than 3 times.

Embodiment 3

[0022] The plastic mold plate produced by steel has an external dimension of 795mm×3700mm×203mm (thickness), and the material is 3Cr2NiMnMo. It is heated in a large trolley-type gas furnace. The preheating temperature is 650°C, and the final austenitization temperature is 900°C. Keep warm for 3.5 hours. After the trolley is driven out, the formwork is hoisted by a crane and cooled to room temperature in still air, and then enters the tempering furnace at a tempering temperature of 650°C for 4 hours, so that the hardness of the entire formwork can be within the range of 30±1HRC.

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PUM

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Abstract

A bainite quenching method for a plastic mold steel is to cool down mid-carbon, Cr, Ni Mn and Mo hard plastic mold steel in air or N atmosphere equal to the air cooling speed after austenite, the surface of the piece and core are converted to get the bainite group at 400deg.C and get the hardness at 40 minus or plus IHRC.

Description

technical field [0001] The invention relates to a bainite quenching method, in particular to a bainite quenching method for plastic mold steel. Used in the technical field of metal heat treatment. Background technique [0002] Pre-hardened plastic mold steel is a steel type developed in the past 10 to 20 years, mainly including 3Cr2MnMo and 3Cr2NiMnMo. Due to the high requirements for the use of plastic mold steel, deformation of the cavity is not allowed. At present, the main process method is to obtain martensite structure after austenitization and oil quenching of the steel, and tempering at a higher temperature to make it The hardness is kept in the range of 30 ~ 45HRC, and then the cavity is machined, and it is directly applied after machining. Although this approach solves the problem of deformation of the machining cavity, because the hardness of the workpiece is low, the service life of the corresponding mold is not high. If the hardness of the mold is to be increa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C33/38C21D1/20
Inventor 潘健生胡明娟顾剑锋朱祖昌宋冬利
Owner SHANGHAI JIAO TONG UNIV
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