WO2021120391A1

WO2021120391A1 - Method for deformation correction after heat treatment of thin-wall gear ring part

Info

Publication number: WO2021120391A1
Application number: PCT/CN2020/076953
Authority: WO
Inventors: 黄大伟; 杨孟云; 章宇顺; 孙茂青
Original assignee: 南京金鑫传动设备有限公司
Priority date: 2019-12-16
Filing date: 2020-02-27
Publication date: 2021-06-24
Also published as: CN110983018A

Abstract

A method for deformation correction after heat treatment of thin-wall gear ring part. A caliper is used to locate deformation points twice, and finally high-accuracy measurement is realized by means of a displacement sensor, thereby improving the correction accuracy. Different heat treatment processes are used with regard to the temperature of a flame gun and different circumferential sections of a part so as to avoid the problem of secondary deformation, thereby prolonging the service life of the part, and preventing the phenomena of deformation and scrapping of a thin-wall gear ring after heat treatment on the basis of controlling the processing cost such that same is not increased.

Description

Method for correcting deformation of thin-walled ring gear parts after heat treatment

Technical field

The invention belongs to the heat treatment technology of a circular gear ring, and in particular relates to a deformation correction method for thin-wall gear ring parts after heat treatment.

Background technique

Thin-walled ring gears have the advantages of saving material costs, reducing equipment weight, optimizing assembly space, and facilitating update and interchange. They are widely used in cement, steel, wind power, ships, docks and other fields, while thin-walled ring gears (especially hardened High-alloy materials with good permeability) after the heat treatment of quenching + high temperature tempering, uncontrollable elliptical or irregular circular deformations often occur. Generally, enterprises due to outdated heat treatment equipment, single heat treatment tooling, lack of heat treatment expertise, and no funds Many reasons such as the investment of trial parts caused the gear ring to fail to meet the accuracy requirements of the drawing after heat treatment and deformation, and the number of scraps throughout the year was not a small number, and the benefit was seriously damaged. This paper proposes a new method of deformation correction after heat treatment to prevent the phenomenon of deformation and scrapping of thin-walled ring gear after heat treatment on the basis of controlling the processing cost without increasing.

Summary of the invention

Purpose of the invention: In order to improve the machining accuracy of thin-walled ring gear parts, the present invention aims to provide a method for correcting deformation of thin-walled ring gear parts after heat treatment.

Technical solution: A method for correcting deformation of thin-walled ring gear parts after heat treatment, as follows:

(1) Place the part on the mirror platform, detect the position of the symmetry point of the part through a caliper, and mark the lowest point and highest point of the part;

(2) Taking the lowest point and highest point as the dividing points, divide the entire part into equal parts, and mark the dividing points on the part's circumference;

(3) Use a caliper to detect the dividing points of step (2), and calculate the deviation value from the design size of the part;

(4) Different heating temperature is controlled in the area where the different deviation values are located. The heating mode changes from low to high corresponding to the high to low heating temperature, and the heating is performed at intervals by drawing a circle;

(5) Displacement sensors are set at the marked dividing points in step (2), and the parts are fixed on the rotating shaft for rotational movement to obtain the data of each displacement sensor;

(6) According to the standard value of each displacement sensor and the design size of the part, adjust the deviation position;

(7) Perform low-temperature tempering to remove the tissue stress of the heat-treated parts and keep them warm.

Further, step (1) includes determining the position of the circle center of the ring type part, the caliper detects the size of the diameter through the center of the circle, the thickness of the part is measured at both ends, and the highest point and the lowest point are marked.

Step (2) The lowest point position and the highest point position are divided points, and the equally divided circle segment corresponds to a center angle of less than 90°.

Step (3) includes sorting the position of the part division points according to the calculated deviation value, and comparing with the design size, marking and sorting in two groups according to expansion or contraction.

In step (4), the measured size is smaller than the design value as the cold shrinkage state, the measured size greater than the design value is the thermal expansion state, the pre-cooling shrinking state area corresponds to high temperature heating, and the thermal expansion state corresponds to low temperature heating.

Furthermore, the heating temperature range is 500° C.-1000° C., and the low-temperature heating and high-temperature heating are the magnitude comparison values after adjusting the heating temperature of the flame gun according to the number of interval hot spots.

The low-temperature tempering temperature in step (7) is 200°C-250°C, and the holding time is greater than or equal to 24 hours.

Furthermore, in the method, the hot spot is the side wall of the non-tooth part. For the outer gear ring, the inner wall corresponding to the deformation point is selected as the hot spot, and for the inner gear ring, the outer wall corresponding to the deformation point is selected as the hot spot. The distance between the hot spots is 100mm-150mm.

Beneficial effects: Compared with the prior art, the correction method provided by the present invention makes the processing accuracy of ring gear parts higher. The method uses the positioning of the two deformation points of the caliper, and finally realizes high-precision detection through the displacement sensor. The correction accuracy is further improved by the centrifugal force changes of the different mass points of the ring gear parts under rotation; and the present invention has different heat treatment processes for the temperature of the flame gun and the different circumferential sections of the parts, avoiding the problem of secondary deformation and lengthening The service life of the parts.

Description of the drawings

Figure 1 is a schematic diagram of the caliper detection of the present invention;

Fig. 2 is a schematic diagram of the way of dividing one-sixth of a circle in an embodiment;

Figure 3 is a schematic diagram of the selection of hot spots on one-sixth of the circumference of the outer ring gear components;

Detailed ways

In order to describe the technical solution disclosed in the present invention in detail, the following further elaboration is made with reference to the drawings and specific embodiments of the specification.

The invention discloses a deformation correction method for thin-walled ring gear parts after heat treatment. The basic implementation process includes determining the high and low points of the ring gear that become elliptical after being heated, and then heating the low point area of the ellipse with a flame gun, and using the heat The principle of expansion and contraction is corrected, and then the ovality is measured while heating until the ellipticity meets the requirements of the part drawing. Finally, the corrected ring gear is normalized to eliminate the tissue stress.

Take the parts of the ring gear other than this embodiment as an example, as shown in Fig. 1-Fig. 3, the processing method for deformation correction of thin-walled ring gear parts after heat treatment is described in detail as follows:

(1) Place the part on the mirror platform, use a caliper to measure the ring gear in advance to find the highest and lowest four points. As shown in Figure 1, point A represents the highest position point, point B represents the lowest position point, and A- A is the low point of the ellipse, and B-B is the high point of the ellipse, which corresponds to the deformation of the ring gear during thermal expansion and contraction during the heat treatment process. The highest point and the lowest point are measured and marked symmetrically. For the thermal processing of the gear ring, the inner and outer gear rings are generally deformed in an elliptical shape after heat treatment. This is the preliminary inspection using a caliper.

(2) Using the lowest point and the highest point as the dividing points, divide the entire part into equal circular sections, and mark the dividing points on the circular section of the part; as shown in Figure 2. Select the lowest point of the A-A ellipse for flame gun heating. The specific position is the cross section of the tooth width center and the quintile point in the 1/6 circumference area.

(3) After completing the preliminary caliper detection and positioning of the highest point and the lowest point in steps (1) and (2), use the caliper to detect the division points of step (2), and calculate the deviation value from the design size of the part; Distinguish whether it is heated expansion state or cold contraction state, and better control the temperature of the heated flame gun and divide different temperature application circumferential sections.

(4) The area where different deviation values are located controls different heating temperatures. The heating method changes from low to high corresponding to the high to low heating temperature, and the heating is performed at intervals by drawing a circle. Take 4 to 5 of the low points of the outer ring gear and heat them with a flame gun at a distance of 100mm. For the further divided circumferential sections in step (3), a lower temperature is selected for heating due to expansion, and a higher temperature is used for heating at the lowest point to restore a certain expansion to the design requirements.

Further, as shown in Fig. 3, a flame gun is used to heat each of the five points on the left and right in a circular manner. The flame temperature is 800℃～900℃, and each point lasts for about 5 minutes on average. After the ten points are heated, the temperature of the heated area drops to about 40℃. Use a caliper to test the ovality of the ring gear. If the ovality still does not meet the requirements of the drawing, continue to heat the ring gear according to the above method until the ovality meets the part drawing. demand.

(6) Compare each displacement sensor with the standard value of the design size of the part, and adjust the deviation position; then compare the data with the centrifugal force and displacement speed of the ring gear that meets the design requirements, and use the data of the displacement sensor to realize each Re-detection and re-calibration process of position points.

(7) Carry out low temperature tempering treatment to remove the tissue stress of the parts after the heat treatment, and heat preservation. After the correction of the ring gear is completed, the ten heating points will produce tissue stress from high to low temperature. In order to eliminate this stress, the ring gear is tempered at a temperature of 200°C and kept for 24 hours. In this embodiment, the outer ring gear is heated to about 800°C, and then through the principle of thermal expansion and contraction, the low point expands and the high point contracts to achieve the purpose of correction. For the inner ring gear, the correction process is just the opposite of that of the outer gear. The two high points on the outer side each take 4 to 5 points with a distance of about 100mm for heating calibration.

The method of the present invention needs to pay attention to the carburizing treatment of the tooth part when calibrating the heat treatment of the carburized and quenched parts, and the remaining part is anti-seepage, and the tooth part is a high carbon area. If the tooth is heated directly at high temperature, it will cause partial annealing and the hardness of the tooth will drop sharply. Therefore, the present invention also realizes different heating temperatures and selects hot spots by avoiding heating the tooth and sub-regions, avoiding the problem caused by calibration. Secondary deformation or impact on the service life of parts.

Claims

A method for correcting deformation of thin-walled ring gear parts after heat treatment, which is characterized by the following steps:

(1) Place the part on the mirror platform, detect the position of the symmetry point of the part through a caliper, and mark the lowest point and highest point of the part;

(2) Taking the lowest point and highest point as the dividing points, divide the entire part into equal parts, and mark the dividing points on the part's circumference;

(3) Use a caliper to detect the dividing points of step (2), and calculate the deviation value from the design size of the part;

(4) Different heating temperature is controlled in the area where the different deviation values are located. The heating mode changes from low to high corresponding to the high to low heating temperature, and the heating is performed at intervals by drawing a circle;

(5) Displacement sensors are set at the marked dividing points in step (2), and the parts are fixed on the rotating shaft for rotational movement to obtain the data of each displacement sensor;

(6) According to the standard value of each displacement sensor and the design size of the part, adjust the deviation position;

(7) Perform low-temperature tempering to remove the tissue stress of the heat-treated parts and keep them warm.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 1, wherein step (1) comprises determining the center position of the ring parts, the caliper detects the diameter through the center of the circle, and the two ends and measuring the part Thickness, mark the highest point and lowest point position.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 1, characterized in that, in step (2) the lowest point position and the highest point position are divided points, and the equally divided circle segment corresponds to a center angle of less than 90° .
The method for correcting the deformation of thin-walled ring gear parts after heat treatment according to claim 1, wherein step (3) includes sorting the positions of the part division points according to the calculated deviation value, and comparing with the design size according to the expansion Or narrow down into two groups for marking and sorting.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 1, characterized in that, in step (4), the measured size is determined to be less than the design value as a cold shrinkage state, and the measured size is greater than the design value as The expansion state when exposed to heat corresponds to high-temperature heating for the pre-cooling contraction state area, and the corresponding low-temperature heating for the expansion state when exposed to heat.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 5, wherein the heating temperature range is 500°C-1000°C, and the low-temperature heating and high-temperature heating are performed by heating the flame gun according to the number of hot spots at intervals. The heating temperature is adjusted for the size comparison value.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 1, wherein the low-temperature tempering temperature in step (7) is 200°C-250°C, and the holding time is greater than or equal to 24 hours.
The method for correcting the deformation of thin-walled ring gear parts after heat treatment according to claim 1, wherein the hot spot in the method is the side wall of the non-tooth part, and for the outer ring gear, the inner wall corresponding to the deformation point is selected to receive Hot spot, for the inner gear ring, select the hot spot on the outer wall corresponding to the deformation point.
The method for correcting deformation of thin-walled ring gear parts after heat treatment according to claim 8, wherein the distance between the hot spots is 100mm-150mm.