Production method of high-strength forged shaft

Abstract

The invention discloses a production method of a high-strength forged shaft, and relates to the technical field of forged shaft production and manufacturing, the production method comprises the following steps: S1, pretreatment; step S2, closed rolling extrusion; s3, finish forging is conducted; s4, performing heat treatment again; and step S5, detecting. The production method of the high-strength forged shaft is simple and easy to implement, low in energy consumption, high in efficiency, small in dependence on equipment and suitable for continuous large-scale production; the forged shaft manufactured through the production method is high in mechanical strength, sufficient in toughness, good in performance stability and long in service life.

Description

Technical Field

[0001] The invention relates to the technical field of forged shaft production and manufacturing, and in particular to a production method of a high-strength forged shaft. Background Art

[0002] A forged shaft is a cylindrical object that passes through the middle of a forged bearing, wheel hub or gear. It is a mechanical component used to support a rotating component and rotate with it to transmit motion, torque or bending moment. The forged shaft is one of the important components of a machine. Its main function is to support the transmission components of the rotating motion (such as gears, worm gears, etc.) and transmit motion and power. An ideal forged shaft needs to have not only excellent mechanical properties, but also better performance stability.

[0003] The existing forged shafts have insufficient mechanical strength, insufficient toughness, low production efficiency, and performance stability that needs to be further improved due to inappropriate composition formula and forging process selection. In order to solve the above problems, a Chinese invention patent with authorization announcement number CN106040955B discloses a forging process for a gear shaft, comprising the following steps: 1) in the first fire, the billet steel ingot is heated to a temperature of 1200°C, the jaws are pressed, the edges are chamfered, and the water inlets are staggered; 2) in the second fire, the billet obtained in step 1 is heated again to 1150-1180°C, and a circular arc toothed convex upper and concave anvil is used for upsetting and drawing; 3) in the third fire, the billet obtained in step 2 is heated again to 1100-1120°C, and closed rolling is performed; 4) final forging: the final forging temperature is 800°C, a flame furnace is used for one-stage heating, a circular arc toothed convex upper and concave anvil is used for upsetting, and the billet is drawn to a specified size; 5) heat treatment: heating to 850±10°C and keeping warm for 1-1.5 hours, air cooling to 500°C, heating to 600±10°C, and air cooling. The products produced by this process have uniform internal deformation, are easy to form, have good internal quality and high toughness. However, their mechanical strength still needs to be further improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for producing a high-strength forged shaft. The method is simple and easy to operate, has low energy consumption, high efficiency, low dependence on equipment, and is suitable for continuous large-scale production. The forged shaft made by this production method has high mechanical strength, sufficient toughness, good performance stability, and long service life.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for producing a high-strength forged shaft, comprising the following steps:

[0006] Step S1, pretreatment: after the steel ingot is subjected to the first heat treatment, the jaws are pressed, the edges are chamfered, and the bottom of the ingot is removed; then the second heat treatment is carried out, upsetting and stretching are carried out to obtain a blank;

[0007] Step S2, closed rolling extrusion: heating the blank made in step S1 to a certain temperature and then performing closed rolling extrusion;

[0008] Step S3, final forging: final forging adopts one-stage heating in a flame furnace, upsetting again, and stretching to a specified size;

[0009] Step S4, re-heat treatment: cooling the forging and then performing a re-heat treatment process;

[0010] Step S5, inspection: ultrasonic flaw detection is performed on the entire shaft. After the detection is non-destructive, fine processing and spraying are performed according to the drawings. Finally, the production is completed after passing the inspection.

[0011] Preferably, the steel ingot in step S1 comprises the following components in weight percentage: C: 0.2%-0.4%, Si: 0.2%-0.5%, V: 0.1%-0.2%, Cr: 0.2%-0.5%, Co: 0.3%-0.5%, Al: 0.03%-0.06%, Cu: 0.15-0.35%, Ir: 0.01%-0.03%, rare earth elements: 0.01%-0.03%, Hf: 0.01%-0.03%, B: 0.001%-0.003%, and the balance is Fe and unavoidable impurities.

[0012] Preferably, the rare earth elements are Sc, La, and Pr mixed in a mass ratio of 1:(1-3):(0.8-1.2).

[0013] Preferably, the temperature of the first heat treatment in step S1 is 1150-1240° C., and the holding time is 3-5 hours.

[0014] Preferably, the temperature of the second heat treatment in step S1 is 1250-1280° C., and the holding time is 6-8 hours.

[0015] Preferably, the certain temperature in step S2 is 1130-1230°C.

[0016] Preferably, the final forging temperature in step S3 is 810-850°C.

[0017] Preferably, the reheat treatment in step S4 is an aging heat treatment, which includes two stages. The treatment temperature in the first stage is 630-860°C and the insulation time is 5-8h; the treatment temperature in the second stage is 480-600°C and the insulation time is 4-6h. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention will be described in detail below.

[0019] A method for producing a high-strength forged shaft comprises the following steps:

[0020] Step S1, pretreatment: after the steel ingot is subjected to the first heat treatment, the jaws are pressed, the edges are chamfered, and the bottom of the ingot is removed; then the second heat treatment is carried out, upsetting and stretching are carried out to obtain a blank;

[0021] Step S2, closed rolling extrusion: heating the blank made in step S1 to a certain temperature and then performing closed rolling extrusion;

[0022] Step S3, final forging: final forging adopts one-stage heating in a flame furnace, upsetting again, and stretching to a specified size;

[0023] Step S4, re-heat treatment: cooling the forging and then performing a re-heat treatment process;

[0024] Step S5, inspection: ultrasonic flaw detection is performed on the entire shaft. After the detection is non-destructive, fine processing and spraying are performed according to the drawings. Finally, the production is completed after passing the inspection.

[0025] Preferably, the steel ingot in step S1 comprises the following components in weight percentage: C: 0.2%-0.4%, Si: 0.2%-0.5%, V: 0.1%-0.2%, Cr: 0.2%-0.5%, Co: 0.3%-0.5%, Al: 0.03%-0.06%, Cu: 0.15-0.35%, Ir: 0.01%-0.03%, rare earth elements: 0.01%-0.03%, Hf: 0.01%-0.03%, B: 0.001%-0.003%, and the balance is Fe and unavoidable impurities.

[0026] Preferably, the rare earth elements are Sc, La, and Pr mixed in a mass ratio of 1:(1-3):(0.8-1.2).

[0027] Preferably, the temperature of the first heat treatment in step S1 is 1150-1240° C., and the holding time is 3-5 hours.

[0028] Preferably, the temperature of the second heat treatment in step S1 is 1250-1280° C., and the holding time is 6-8 hours.

[0029] Preferably, the certain temperature in step S2 is 1130-1230°C.

[0030] Preferably, the final forging temperature in step S3 is 810-850°C.

[0031] Preferably, the reheat treatment in step S4 is an aging heat treatment, which includes two stages. The treatment temperature in the first stage is 630-860°C and the insulation time is 5-8h; the treatment temperature in the second stage is 480-600°C and the insulation time is 4-6h.

[0032] Due to the application of the above technical scheme, the patent of the present invention has the following advantages compared with the prior art: the present invention makes the high-strength forged shaft have high mechanical strength, sufficient toughness, good performance stability and long service life through the reasonable selection of the steel ingot composition formula and production process parameters; the production method is simple and easy, with low energy consumption, high efficiency, low dependence on equipment, and is suitable for continuous large-scale production.

[0033] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0034] Example 1

[0035] A method for producing a high-strength forged shaft comprises the following steps:

[0036] Step S1, pretreatment: after the steel ingot is subjected to the first heat treatment, the jaws are pressed, the edges are chamfered, and the bottom of the ingot is removed; then the second heat treatment is carried out, upsetting and stretching are carried out to obtain a blank;

[0037] Step S2, closed rolling extrusion: heating the blank made in step S1 to a certain temperature and then performing closed rolling extrusion;

[0038] Step S3, final forging: final forging adopts one-stage heating in a flame furnace, upsetting again, and stretching to a specified size;

[0039] Step S4, re-heat treatment: cooling the forging and then performing a re-heat treatment process;

[0040] Step S5, inspection: ultrasonic flaw detection is performed on the entire shaft. After the detection is non-destructive, fine processing and spraying are performed according to the drawings. Finally, the production is completed after passing the inspection.

[0041] The steel ingot in step S1 includes the following components in weight percentage: C: 0.2%, Si: 0.2%, V: 0.1%, Cr: 0.2%, Co: 0.3%, Al: 0.03%, Cu: 0.15%, Ir: 0.01%, rare earth elements: 0.01%, Hf: 0.01%, B: 0.001%, and the balance is Fe and unavoidable impurities; the rare earth elements are Sc, La, and Pr mixed in a mass ratio of 1:1:0.8; the temperature of the first heat treatment in step S1 is 1150°C, and the holding time is 3h; the temperature of the second heat treatment in step S1 is 1250°C, and the holding time is 6h.

[0042] The certain temperature in step S2 is 1130°C; the final forging temperature in step S3 is 810°C; the reheat treatment in step S4 is an aging heat treatment, which includes two stages, the treatment temperature in the first stage is 630°C, and the holding time is 5h; the treatment temperature in the second stage is 480°C, and the holding time is 4h.

[0043] Example 2

[0044] A method for producing a high-strength forged shaft, which is basically the same as Example 1, except that the steel ingot in step S1 includes the following components by weight percentage: C: 0.25%, Si: 0.3%, V: 0.12%, Cr: 0.3%, Co: 0.35%, Al: 0.04%, Cu: 0.2%, Ir: 0.015%, rare earth elements: 0.015%, Hf: 0.015%, B: 0.0015%, and the balance is Fe and unavoidable impurities; the rare earth elements are Sc, La, and Pr by weight The ratio of 1:1.5:0.9 is mixed; the temperature of the first heat treatment in step S1 is 1170°C, and the holding time is 3.5h; the temperature of the second heat treatment in step S1 is 1260°C, and the holding time is 6.5h; the certain temperature in step S2 is 1150°C; the final forging temperature in step S3 is 820°C; the second heat treatment in step S4 is aging heat treatment, including two stages, the first stage treatment temperature is 650°C, the holding time is 6h; the second stage treatment temperature is 500°C, and the holding time is 4.5h.

[0045] Example 3

[0046] A method for producing a high-strength forged shaft is basically the same as that of Example 1, except that the steel ingot in step S1 comprises the following components by weight percentage: C: 0.3%, Si: 0.35%, V: 0.15%, Cr: 0.35%, Co: 0.4%, Al: 0.045%, Cu: 0.25%, Ir: 0.02%, rare earth elements: 0.02%, Hf: 0.02%, B: 0.002%, and the balance is Fe and unavoidable impurities; the rare earth elements are Sc, La, Pr The mixture is mixed in a mass ratio of 1:2:1; the temperature of the first heat treatment in step S1 is 1210°C, and the holding time is 4h; the temperature of the second heat treatment in step S1 is 1265°C, and the holding time is 7h; the certain temperature in step S2 is 1200°C; the final forging temperature in step S3 is 835°C; the second heat treatment in step S4 is an aging heat treatment, which includes two stages, the first stage treatment temperature is 800°C, and the holding time is 6.5h; the second stage treatment temperature is 530°C, and the holding time is 5h.

[0047] Example 4

[0048] A method for producing a high-strength forged shaft, which is basically the same as Example 1, except that the steel ingot in step S1 includes the following components in weight percentage: C: 0.35%, Si: 0.45%, V: 0.18%, Cr: 0.45%, Co: 0.45%, Al: 0.055%, Cu: 0.32%, Ir: 0.025%, rare earth elements: 0.025%, Hf: 0.025%, B: 0.0025%, and the balance is Fe and unavoidable impurities; the rare earth elements are Sc, La, and Pr in weight percentage. The mixture is mixed in a weight ratio of 1:2.5:1.1; the temperature of the first heat treatment in step S1 is 1230°C, and the holding time is 4.5h; the temperature of the second heat treatment in step S1 is 1275°C, and the holding time is 7.5h; the certain temperature in step S2 is 1220°C; the final forging temperature in step S3 is 840°C; the second heat treatment in step S4 is an aging heat treatment, which includes two stages, the first stage treatment temperature is 850°C, and the holding time is 7.5h; the second stage treatment temperature is 580°C, and the holding time is 5.5h.

[0049] Example 5

[0050] A method for producing a high-strength forged shaft, which is basically the same as Example 1, except that the steel ingot in step S1 includes the following components in weight percentage: C: 0.4%, Si: 0.5%, V: 0.2%, Cr: 0.5%, Co: 0.5%, Al: 0.06%, Cu: 0.35%, Ir: 0.03%, rare earth elements: 0.03%, Hf: 0.03%, B: 0.003%, and the balance is Fe and unavoidable impurities; the rare earth elements are Sc, La, Pr, etc. The temperature of the first heat treatment in step S1 is 1240°C, and the holding time is 5h; the temperature of the second heat treatment in step S1 is 1280°C, and the holding time is 8h; the certain temperature in step S2 is 1230°C; the final forging temperature in step S3 is 850°C; the second heat treatment in step S4 is aging heat treatment, including two stages, the first stage treatment temperature is 860°C, and the holding time is 8h; the second stage treatment temperature is 600°C, and the holding time is 6h.

[0051] Comparative Example 1

[0052] A method for producing a high-strength forged shaft is basically the same as Example 1, except that Ir and Co are not added.

[0053] Comparative Example 2

[0054] A method for producing a high-strength forged shaft is basically the same as Example 1, except that no rare earth element or Hf is added.

[0055] In order to further illustrate the beneficial technical effects of each product, relevant performance tests were carried out on the high-strength forged shafts produced by the production methods of the high-strength forged shafts involved in each example. The test methods refer to the current national standards of my country or conventional methods in this field. The test results are shown in Table 1.

[0056] Table 1

[0057] project tensile strength Yield Strength Elongation unit MPa MPa ％ Example 1 1750 1500 22.5 Example 2 1758 1512 22.8 Example 3 1770 1520 23.0 Example 4 1775 1526 23.5 Example 5 1783 1530 23.7 Comparative Example 1 1684 1378 16.9 Comparative Example 2 1700 1423 16.3

[0058] It can be seen from Table 1 that the high-strength forged shaft produced by the production method of the high-strength forged shaft in the embodiment of the present invention has higher yield strength and tensile strength and better toughness. The combined use of Ir, Co, rare earth elements and Hf is beneficial to improving the above properties.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing a high-strength forged shaft, characterized in that: The steps include: Step S1, pretreatment: after the steel ingot is subjected to the first heat treatment, the jaws are pressed, the edges are chamfered, and the bottom of the ingot is removed; then the second heat treatment is carried out, upsetting and stretching are carried out to obtain a blank; Step S2, closed rolling extrusion: heating the blank made in step S1 to a certain temperature and then performing closed rolling extrusion; Step S3, final forging: final forging adopts one-stage heating in a flame furnace, upsetting again, and stretching to a specified size; Step S4, re-heat treatment: cooling the forging and then performing a re-heat treatment process; Step S5, inspection: ultrasonic flaw detection is performed on the entire shaft. After the detection is non-destructive, fine processing and spraying are performed according to the drawings. Finally, the production is completed after passing the inspection.

2. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The steel ingot in step S1 includes the following components in weight percentage: C: 0.2%-0.4%, Si: 0.2%-0.5%, V: 0.1%-0.2%, Cr: 0.2%-0.5%, Co: 0.3%-0.5%, Al: 0.03%-0.06%, Cu: 0.15-0.35%, Ir: 0.01%-0.03%, rare earth elements: 0.01%-0.03%, Hf: 0.01%-0.03%, B: 0.001%-0.003%, and the balance is Fe and unavoidable impurities.

3. The method for producing a high-strength forged shaft according to claim 2, characterized in that: The rare earth elements are Sc, La and Pr mixed in a mass ratio of 1:(1-3):(0.8-1.2).

4. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The temperature of the first heat treatment in step S1 is 1150-1240° C., and the insulation time is 3-5 hours.

5. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The temperature of the second heat treatment in step S1 is 1250-1280° C., and the insulation time is 6-8 hours.

6. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The certain temperature in step S2 is 1130-1230°C.

7. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The final forging temperature in step S3 is 810-850°C.

8. The method for producing a high-strength forged shaft according to claim 1, characterized in that: The second heat treatment in step S4 is an aging heat treatment, which includes two stages. The treatment temperature of the first stage is 630-860°C and the insulation time is 5-8h; the treatment temperature of the second stage is 480-600°C and the insulation time is 4-6h.