Quick spheroidizing annealing process of bearing steel tubes

A bearing steel pipe and spheroidizing annealing technology, which is applied in the field of bearing steel heat treatment, can solve the problems of long time consumption and inability to achieve rapid spheroidization, and achieve the increase of carbon unevenness, shortening the time of spheroidizing annealing, and good structural properties Effect

Inactive Publication Date: 2018-07-20
JIANGSU FANLI STEEL TUBE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Obviously, the research on the spheroidizing return process of bearing steel is extremely important. In related research, there are two most commonly used spheroidizing annealing processes for bearing steel: ordinary spheroidizing annealing and isothermal spheroidizing annealing, but the time spent for the two spheroidizing annealing If the time is long, the goal of fast ballization cannot be achieved

Method used

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  • Quick spheroidizing annealing process of bearing steel tubes
  • Quick spheroidizing annealing process of bearing steel tubes
  • Quick spheroidizing annealing process of bearing steel tubes

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0028] Such as figure 1 As shown, the components used in this embodiment include by weight percentage: C: 0.95-1.05%, Cr: 1.40-1.65%, Mn: 0.2-0.45%, Si: 0.15-0.3%, Ni≤0.3, P≤0.025, S ≤0.025, Mo≤0.025, Cu≤0.025GCr15 bearing steel pipe as an example, the spheroidizing annealing process includes the following steps:

[0029] Step 1): Heat the bearing steel pipe to 765°C and keep it warm for 20 minutes;

[0030] Step 2): Cool the bearing steel pipe after the first heat preservation to 690°C and keep it warm for 10 minutes;

[0031] Step 3): repeat step 1) and step 2) once, and carry out multiple cycles of heat treatment on the bearing steel pipe after the second heat preservation;

[0032] Step 4): Cool the bearing steel pipe that has undergone multiple heat treatments to 660°C with the furnace, and keep it warm for 10 minutes;

[0033] Step 5): cooling the heat-insulated bearing steel pipe in step 4) to 610°C with the furnace;

[0034] Step 6): air-cool the furnace-cooled bea...

Embodiment 2

[0037] Such as figure 2 As shown, the components used in this embodiment include by weight percentage: C: 0.95-1.05%, Cr: 1.40-1.65%, Mn: 0.2-0.45%, Si: 0.15-0.3%, Ni≤0.3, P≤0.025, S ≤0.025, Mo≤0.025, Cu≤0.025GCr15 bearing steel pipe as an example, the spheroidizing annealing process includes the following steps:

[0038] Step 1): Heat the bearing steel pipe to 775°C and keep it warm for 20 minutes;

[0039] Step 2): Cool the bearing steel pipe after the first heat preservation to 670°C and keep it warm for 20 minutes;

[0040] Step 3): Repeat step 1) and step 2) twice, and perform multiple cycle heat treatment on the bearing steel pipe after the second heat preservation;

[0041] Step 4): Cool the bearing steel pipe that has undergone multiple heat treatments to 660°C with the furnace, and keep it warm for 20 minutes;

[0042] Step 5): cooling the heat-insulated bearing steel pipe in step 4) to 640°C with the furnace;

[0043] Step 6): air-cool the furnace-cooled bearing...

Embodiment 3

[0046] Such as image 3 As shown, the components used in this embodiment include by weight percentage: C: 0.95-1.05%, Cr: 1.40-1.65%, Mn: 0.2-0.45%, Si: 0.15-0.3%, Ni≤0.3, P≤0.025, S ≤0.025, Mo≤0.025, Cu≤0.025GCr15 bearing steel pipe as an example, the spheroidizing annealing process includes the following steps:

[0047] Step 1): Heat the bearing steel pipe to 770°C and keep it warm for 25 minutes;

[0048] Step 2): Cool the bearing steel pipe after the first heat preservation to 680°C and keep it warm for 15 minutes;

[0049] Step 3): Repeat step 1) and step 2) three times, and perform multiple cycle heat treatment on the bearing steel pipe after the second heat preservation;

[0050] Step 4): Cool the bearing steel pipe that has undergone multiple heat treatments to 660°C with the furnace, and keep it warm for 15 minutes;

[0051] Step 5): cooling the heat-insulated bearing steel pipe in step 4) to 630°C with the furnace;

[0052] Step 6): air-cool the furnace-cooled be...

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Abstract

The invention provides a quick spheroidizing annealing process of bearing steel tubes. The quick spheroidizing annealing process comprises the following steps: 1), heating the bearing steel tubes until Ac1 reaches 20 DEG C to 30 DEG C or above, and keeping a temperature for 20 minutes to 30 minutes; 2), cooling the bearing steel tubes subjected to heat insulation at a first time until Ar1 reaches10 DEG C to 30 DEG C or below, and keeping the temperature for 10 minutes to 20 minutes; 3), repeatedly carrying out the step 1) and the step 2), and performing circulating heat treatment for many times on the bearing steel tubes subjected to heat insulation at a second time; 4), cooling the bearing steel tubes subjected to heat treatment for many times along with a furnace to 680 DEG C, and keeping the temperature for 10 minutes to 20 minutes; 5), cooling the bearing steel tubes subjected to heat insulation in the step 4) along with the furnace to 610 DEG C to 650 DEG C; and 6), performing air cooling on the bearing steel tubes subjected to furnace cooling to a room temperature. Isothermic spheroidizing treatment, that is, circulation austenitizing and isothermic spheroidizing processes,on the bearing steel tubes in a double-phase area is carried out repeatedly, thinner sheet carbide formed in cooling of austenite is re-dissolved, precipitated and separated on undissolved carbide particles, and thicker sheet carbide is crushed to realize quick spheroidizing, and the spheroidizing annealing time is shortened at the same time.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of bearing steel, and in particular relates to a rapid spheroidizing annealing process of bearing steel tubes. Background technique [0002] At present, bearings are widely used as a kind of mechanical parts. Therefore, higher requirements are placed on the performance of bearings, especially for bearing steel, the raw material for making bearings. The research on its material properties is extremely important. Bearing steel After rolling, the performance is poor, the material strength is low, and it is easy to be brittle. It must be spheroidized and returned to make the carbides in the microstructure of the bearing steel spheroidized and evenly distributed on the ferrite matrix in the form of fine spheres. The bearing steel obtained in this way has good machinability, low overheating sensitivity, and is ready for later quenching and tempering. The residual carbides after quenching and temp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/32C21D9/14C21D6/00
CPCC21D1/32C21D6/002C21D6/004C21D6/005C21D6/008C21D9/14C21D2211/001C21D2211/003C21D2211/004C21D2211/009
Inventor 赵健
Owner JIANGSU FANLI STEEL TUBE
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