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Clean step quenching method achieved by taking hot water as cooling medium

A technology of graded quenching and cooling medium, applied in the direction of quenching agent, quenching device, heat treatment equipment, etc., can solve problems such as deformation and cracking, achieve the effects of eliminating pollution, easy large-scale industrial promotion, and expanding the scope of application

Active Publication Date: 2017-07-07
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] The purpose of the present invention is to overcome the above defects in the prior art and provide a clean graded quenching method that can effectively solve the deformation and cracking problems of the workpiece after quenching, has no environmental pollution, is safe and environmentally friendly, and uses hot water as the cooling medium

Method used

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  • Clean step quenching method achieved by taking hot water as cooling medium
  • Clean step quenching method achieved by taking hot water as cooling medium
  • Clean step quenching method achieved by taking hot water as cooling medium

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Embodiment 1

[0034] In this embodiment, the chuck for the machine tool is made of 45 steel, and the hardness after quenching and tempering is required to be 43-47 HRC.

[0035] The original process is: heating at 820-840°C and quenching step by step in a nitrate bath, staying at 170°C for 12 minutes, air cooling to room temperature, and tempering at 180°C for 2 hours after shaping.

[0036] Adopt the inventive method, machine tool uses chuck hot water graded quenching process curve such as figure 1 As shown, wherein, the composition of the first hot water tank is 20% NaCl aqueous solution, the temperature is 100-110°C, and the composition of the second hot water tank is 100% H 2 O, the temperature is 95-100°C, the chuck is heated in a protective atmosphere at 830-850°C, then quenched into the first hot water tank for 8 minutes, then transferred to the second hot water tank for 8 minutes, taken out, and air-cooled to room temperature. Tempering at 200°C after shaping, hardness 43-47HRC pla...

Embodiment 2

[0038] In this embodiment, the outer diameter of the bearing ring: Φ 外 =284mm. Inner diameter: Φ 内 =226mm, height 60mm, material is GCr15, requires 63-65HRC.

[0039] The original hot oil graded quenching process: heating at 835°C to 845°C, quenching into 80°C hot oil for graded quenching, staying for 15 minutes, air cooling to room temperature, and tempering at 160°C for 4 hours.

[0040] By adopting the method of the present invention, the hot water graded quenching process curve of the bearing ring is as follows: figure 2 As shown, among them, the water temperature of the first hot water tank is 80°C, the composition is 15% NaCl aqueous solution, the water temperature of the second hot water tank is 95-100°C, and the composition is 100% H 2 O, the workpiece is heated at 835°C to 845°C and then quenched into the first hot water tank for 10s, then immediately transferred to the second hot water tank for grading and staying for 15 minutes, air-cooled to room temperature, t...

Embodiment 3

[0042]In this embodiment, the 9Mn2V cold rolling roll has a body section of Φ160×400 and requires 58-62HRC.

[0043] The original process is: heating at 790-800°C, rapid quenching oil quenching and cooling to room temperature, and tempering at 180°C for 6 hours.

[0044] Using the hot water graded quenching method of the present invention, two hot water tanks are equipped, the water temperature of the first hot water tank is 60°C, and the composition is 100% H 2 O (0% NaCl) stirring speed 0.5 ~ 0.75m / s, the water temperature of the second hot water tank is 100°C and the composition is 100% H 2 O.

[0045] 9Mn2V cold roll hot water graded quenching process curve is as follows image 3 As shown, the workpiece is austenitized by heating at 790-800°C, quenched into the first hot water tank for intermittent quenching, and the rhythm is hot water 3s air cooling 2s hot water 3s air cooling 2s... 20 times alternately, the total time is 100s , transfer to the second hot water tank a...

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Abstract

The invention relates to a clean step quenching method achieved by taking hot water as a cooling medium. The method comprises the steps that a workpiece obtained after heating and austenitizing is quenched into a first hot water tank to be cooled, when the surface temperature of the workpiece is lowered to 100-160 DEG C, the workpiece is transferred into a second hot water tank for isothermal holding, after the inner temperature of the workpiece is basically uniform, the workpiece is taken out, and then step quenching of the workpiece is completed. Compared with the prior art, the method has the advantages that the whole process is simple in step, by adjusting parameters such as the temperature, the concentration, the intermittent standing time and the stirring speed of the hot water tanks, the cooling speed of the workpiece can be accurately controlled, the application range of hot water isothermal quenching can be widened, the limitation that an existing method that intermittent quenching is conducted through cold water is difficult to be applied to small and medium parts is overcome, operation is safer and more convenient, the economic reform cost is low, energy is saved, large-scale industrial promotion is easy, and a very good application prospect is achieved.

Description

technical field [0001] The invention belongs to the technical field of heat treatment technology, and relates to a clean graded quenching method using hot water as a cooling medium. Background technique [0002] Quenching is a key process in the heat treatment of steel, which is characterized by heating the workpiece (mechanical parts, tools, molds, etc.) above the critical point, and then cooling it at a sufficiently fast speed. If the cooling rate is lower than the quenching critical cooling rate of the steel used, the proper structure and properties after quenching will not be obtained. Conversely, if the cooling rate is too fast, it will cause increased quenching distortion and even cracking. Therefore, the appropriate cooling medium must be selected according to the composition of the steel and the thickness of the workpiece. [0003] Water-based quenching medium (including clear water, inorganic salt solution, alkaline solution and organic solution) is a commonly use...

Claims

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Application Information

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IPC IPC(8): C21D1/20C21D1/60C21D1/63C21D11/00
CPCC21D1/20C21D1/60C21D1/63C21D11/005
Inventor 顾剑锋潘健生王博
Owner SHANGHAI JIAO TONG UNIV
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