CN114427019A - A kind of alloy steel flange groove heat treatment process - Google Patents

Abstract

The invention relates to a heat treatment process for an alloy steel flange groove. The alloy steel flange groove is sequentially subjected to quenching and tempering, stress relief annealing and laser quenching, and the process is completed. Compared with the prior art, the process of the present invention can improve the vertical surface hardness and wear resistance of the flange groove, while ensuring the dimensional accuracy and surface quality before and after heat treatment.

Description

A kind of alloy steel flange groove heat treatment process

technical field

The invention belongs to the technical field of mechanical manufacturing, and relates to a heat treatment process for an alloy steel flange groove.

Background technique

Alloy steel flanges are commonly used connectors in mechanical mechanisms and are widely used. Some special-purpose flanges will have grooves. In order to increase the dimensional accuracy in the assembly process and the wear resistance in the actual use process, the vertical surface of the groove needs to be hardened and heat treated. Generally, oxyacetylene flame heating or high frequency induction hardening is used. Oxyacetylene flame has a large heat input and high requirements on the operator's proficiency, which is easy to cause local micro-melting, large and irregular distortion. High-frequency induction hardening has a fast heating speed and a small amount of distortion, but needs to customize a special-shaped induction coil, which is expensive and has poor processing flexibility. The non-hardened area is hardened because it is not protected. The liquid will contaminate the flange surface, which will adversely affect the subsequent processing.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an alloy steel flange groove heat treatment process, which can improve the vertical surface hardness and wear resistance of the flange groove, and at the same time ensure the dimensional accuracy and surface quality before and after heat treatment.

The object of the present invention can be realized through the following technical solutions:

A heat treatment process for an alloy steel flange groove is completed by sequentially quenching and tempering, stress relief annealing and laser quenching of the alloy steel flange groove.

Further, the quenching and tempering process includes two processes: quenching and high temperature tempering, wherein, the quenching process is to heat the alloy steel flange groove, then heat preservation, and then oil quench and cool; the high temperature tempering process is to heat the alloy steel after quenching. The blue tank continues to be heated and kept warm, and the furnace is air-cooled.

Further, the specific process conditions in the quenching process are: heating to 860° C., and then maintaining the temperature for 2 hours. The oil temperature during oil quenching is 20 to 50 °C.

Further, the specific process conditions in the high temperature tempering process are: heating to 580-600° C., and keeping the temperature for 4 hours.

Further, the stress-relieving annealing process is as follows: heating the workpiece for heat preservation, and then air-cooling the workpiece.

Further, the specific process conditions of stress relief annealing are: heating to 560° C. and holding for 2 hours.

Further, the laser quenching process is as follows: spray laser paint on the hardened area of the alloy steel flange groove (generally its facade), and cover the remaining non-hardened areas with copper foil, and then use a laser to perform laser scanning.

Further, in the laser quenching process, the laser coating used is a commercially available CT-150 semiconductor laser special quenching coating, and its coating thickness is 0.03-0.06 mm.

Further, in the laser quenching process, the thickness of the copper foil is 1-2 mm.

Further, the laser is a semiconductor-coupled fiber output laser system (it can also be other conventional commercially available lasers in the field that meet the corresponding use requirements), and its output power is 2.7-3.3KW, and the scanning speed is 3-5mm/s, A rectangular spot is used, and the spot size is (3-5) × (3-10) mm.

In the present invention, laser quenching utilizes a focused laser beam with high energy density (10 ⁴ -10 ⁵ W/cm ² ), high coherence and high directivity to rapidly scan the surface of the workpiece, so that the workpiece surface can be rapidly scanned (10 ⁵ - 10 5 - 10 5 W/cm 2 ). 10 ⁶ ℃/s) for self-cooling and quenching to form a hardened layer. Laser quenching can significantly improve the surface properties of the workpiece, and has excellent characteristics such as small distortion, good processing flexibility, high surface quality, high degree of automation, and wide application. After laser quenching, a very fine martensite structure can be obtained in the hardened zone, with fine grains and high dislocation, and the hardness is about 15%-20% higher than that of conventional quenching, and as long as the process is proper, the surface after quenching is almost free of oxidation and decarburization. phenomenon, the surface roughness is almost unchanged, and can be used as the final process of workpiece processing.

Compared with the prior art, in the present invention, the flange has good mechanical properties and metallographic structure through quenching and tempering treatment, and the residual machining stress of the flange groove is eliminated by stress relief annealing, and finally, laser quenching is used to make the groove stand upright. The surface is hardened, the CT-150 coating increases the laser absorption efficiency of the workpiece surface, and the copper foil protects the non-hardened area. This process makes the flange groove facade get a uniform and stable hardened layer, the hardness of the non-hardened area is almost unchanged, and the distortion of the entire flange is extremely small and the dimensional stability is excellent. In addition, the process has many advantages such as high degree of automation, high processing efficiency, good processing flexibility, high quality stability, and environmental protection.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

In the following examples, if there is no special description of the raw materials, equipment or processing technology, it means that they are all conventional commercially available raw materials, or equipment or conventional processing technology in the field.

Example 1

Coupling flange, the material is 35CrMo, the outer diameter is Φ350mm, the hardness after quenching and tempering is 22-27HRC, the disk surface is evenly distributed with 16 grooves, the groove depth is 5mm, and the groove elevation hardness is 50-55HRC.

Its heat treatment process includes the following steps:

The first step: conditioning treatment. Heating and quenching, heating the flange to 860°C and heat preservation for 2h, oil quenching after being released, the oil temperature is 36°C.

Tempered at high temperature, heated to 580°C and kept for 4h, then air-cooled. The hardness after quenching and tempering is 24.5HRC.

The second step: stress relief annealing. The flange was heated to 560°C and kept for 2h, and then air-cooled.

The third step: laser quenching. The 0.05mm thick CT-150 paint is evenly sprayed on the facade of the flange groove, using LASERLINE original LDF4000-400 semiconductor-coupled fiber output laser (maximum power 4KW), the output power is 2.7KW, the scanning speed is 4mm/s, and the rectangular spot size is 3×5mm. The non-hardened area is covered with 1mm thick copper foil.

After the process is completed, the hardness of the flange groove elevation is 51-53HRC, the hardness of the non-hardened area is 26.2HRC, and the maximum deformation of the disk surface is 0.05mm.

Comparative Example 1

Using the same batch of coupling flanges as in the embodiment, the first two steps also use quenching and tempering treatment and stress relief annealing with the same parameters. The oil is cooled, heated to 180°C and tempered at low temperature for 2h). After the process is completed, the hardness of the flange groove elevation is 48-51HRC, the hardness of the non-hardened area is 45HRC, and the maximum deformation of the flange surface is 0.65mm. The amount of distortion is too large to allow subsequent processing.

Comparative Example 2

Using the same batch of coupling flanges as in the embodiment, quenching and tempering treatment and laser quenching with the same parameters, the stress relief annealing process of the second step is omitted. After the process is completed, the hardness of the flange groove elevation is 48-51HRC, the hardness of the non-hardened area is 45HRC, and the maximum deformation of the flange surface is 0.17mm. The amount of distortion is so large that subsequent processing cannot be performed.

Embodiment 2

Coupling flange, the material is 42CrMo, the outer diameter is Φ310mm, the hardness after quenching and tempering is 28-32HRC, the disk surface is evenly distributed with 16 grooves, the groove depth is 7mm, and the groove elevation hardness is 53-58HRC.

Its heat treatment process includes the following steps:

The first step: conditioning treatment. Heating and quenching, the flange is heated to 860 ° C and kept for 2 hours, and oil quenched after being released, the oil temperature is 28 ° C.

Tempering at high temperature, heating to 600°C and holding for 4h, then air-cooled. After quenching and tempering, the hardness is 30HRC.

The second step: stress relief annealing. The flange was heated to 560°C and kept for 2h, and then air-cooled.

The third step: laser quenching. Evenly spray 0.05mm thick CT-150 paint on the facade of the flange groove, use LASERLINE original LDF4000-400 semiconductor-coupled fiber output laser (maximum power 4KW), the output power is 3.0KW, the scanning speed is 4mm/s, and the rectangular spot size is 3×7mm. The non-hardened area is covered with 1mm thick copper foil.

After the process is completed, the hardness of the flange groove elevation is 56-57HRC, the hardness of the non-hardened area is 31.8HRC, and the maximum deformation of the disk surface is 0.03mm.

Comparative example three

Using the same batch of coupling flanges as in the second embodiment, the first two steps also use quenching and tempering treatment and stress relief annealing with the same parameters, and only the third step adopts high-frequency induction quenching (current frequency: 200KHz, quenching temperature 900℃, using Quenching oil for cooling, heating to 180 ℃ low temperature tempering 2h). After the process is completed, the hardness of the flange groove elevation is 53-56HRC, the hardness of the non-hardened area is 49HRC, and the maximum deformation of the flange surface is 0.40mm. The amount of distortion is too large to allow subsequent processing.

Comparative Example 4

Using the same batch of coupling flanges as in the second embodiment, quenching and tempering treatment and laser quenching with the same parameters, the stress relief annealing process of the second step is omitted. After the process is completed, the hardness of the flange groove elevation is 55-57HRC, the hardness of the non-hardened area is 45HRC, and the maximum deformation of the flange surface is 0.16mm. The amount of distortion is so large that subsequent processing cannot be performed.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (10)

1. an alloy steel flange groove heat treatment process is characterized in that, get the alloy steel flange groove successively through quenching and tempering, stress relief annealing, laser quenching, namely complete. 2. a kind of alloy steel flange groove heat treatment process according to claim 1 is characterized in that, described quenching and tempering process comprises two processes of quenching and high temperature tempering, wherein, the quenching process is to heat the alloy steel flange groove After heat preservation, oil quenching and cooling; the high temperature tempering process is to continue heating and heat preservation of the quenched alloy steel flange groove, and air cooling it out of the furnace. 3 . The heat treatment process for an alloy steel flange groove according to claim 2 , wherein the specific process conditions in the quenching process are: heating to 860° C., and then maintaining the temperature for 2 hours. 4 . 4 . The alloy steel flange groove heat treatment process according to claim 2 , wherein the specific process conditions in the high-temperature tempering process are: heating to 580-600° C., and keeping the temperature for 4 hours. 5 . 5 . The alloy steel flange groove heat treatment process according to claim 1 , wherein the stress relief annealing process is: heating and maintaining the workpiece, and then air-cooling the workpiece. 6 . 6 . The alloy steel flange groove heat treatment process according to claim 5 , wherein the specific process conditions of stress relief annealing are: heating to 560° C. and keeping the temperature for 2 hours. 7 . 7. a kind of alloy steel flange groove heat treatment process according to claim 1, is characterized in that, described laser quenching process is: spray laser paint in the hardened area of alloy steel flange groove, other non-hardened areas are covered The copper foil is then scanned with a laser. 8. A kind of alloy steel flange groove heat treatment process according to claim 7, characterized in that, in the laser quenching process, the laser coating used is CT-150 semiconductor laser special quenching coating, and its coating thickness is 0.03～ 0.06mm. 9 . The alloy steel flange groove heat treatment process according to claim 7 , wherein, in the laser quenching process, the thickness of the copper foil is 1-2 mm. 10 . 10. The alloy steel flange groove heat treatment process according to claim 7, wherein the laser is a semiconductor-coupled fiber output laser system, the output power is 2.7-3.3KW, and the scanning speed is 3-5mm/ s, using a rectangular light spot, the spot size is (3-5) × (3-10) mm.