Precision forging method for fan-shaped support

Abstract

The invention relates to the technical field of forging, and particularly discloses a precision forging method of a fan-shaped support, which comprises the following steps: step 1, removing an oxide skin on the surface of an AISI422 steel ingot, preheating the AISI422 steel ingot to 1150 + / -10 DEG C, keeping for 3 hours, forging to obtain an AISI422 fan-shaped blank forging, annealing and heating the AISI422 fan-shaped blank forging to 680 + / -10 DEG C, keeping for 80 hours, cooling in a furnace until the temperature is less than or equal to 250 DEG C, taking out of the furnace, and cooling. According to the precision forging method for the fan-shaped support, the axial flow fans which move from far to near at the constant wind speed and surround the periphery of the rotating area of the AISI422 fan-shaped blank forge piece at equal intervals circumferentially, the cooling speed of the AISI422 steel blank forge piece is increased, uniform heat dissipation of the AISI422 steel blank forge piece is achieved, the AISI422 steel blank forge piece is prevented from being damaged due to large surface temperature difference, and the service life of the fan-shaped support is prolonged. Forging tempering cooling waiting time is shortened, and forging efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of forging technology, in particular to a fan-shaped support precision forging method. BACKGROUND

[0002] AISI422 steel is a reinforced 12% Cr type martensitic heat-resistant stainless steel, due to its alloying elements Cr, W, Mo content is slightly higher, so the strength is good; The notch sensitivity is small, and it has good damping and anti-relaxation, and the comprehensive performance is good, so it is applied to the fan-shaped plate in the hot rolling reel equipment of the steel plant;

[0003] The existing public literature technology "Manufacturing process of AISI422 steel fan-shaped plate-Yang Yunzhi, Wu Huna, Lu Changhe" proposes the manufacturing process flow of AISI422 steel fan-shaped plate blank: electric furnace smelting + LFV→ pouring ingot→ annealing→ hot sending to forging steel company→ forging→ post-forging annealing→ roughing→ flaw detection→ quenching and tempering→ flaw detection→ inspection→ check and hand over; It is indicated that the contents of Si, Mn, Ni and S need to be strictly controlled during smelting, the initial forging temperature is controlled to be 1150 DEG C during forging, the final forging temperature is controlled to be 920 DEG C, and annealing and quenching and tempering are carried out according to the correct process;

[0004] The existing public literature technology "Cracking analysis and heat treatment process improvement of AISI422 steel fan-shaped plate-Qiu Yan, Zhou Feng" indicates that AISI422 steel has high tempering resistance, and is prone to cause insufficient tempering, so a supplementary tempering can be added accordingly, a quenching and tempering process of 1050 DEG C quenching + 750 DEG C + 700 DEG C tempering is adopted, the organization is tempered sorbite + carbide particles with martensite orientation maintained, and the fan-shaped plate made by the process meets the design requirements and has good strength and plasticity indicators; However, the fan-shaped plate forgings after the first tempering at 750 DEG C and the second tempering at 700 DEG C in the quenching and tempering process are furnace cooled to ≤300 DEG C and then air cooled, and the fan-shaped plate forgings are cooled to room temperature only by air cooling when the cooling temperature is ≤300 DEG C, which wastes a lot of waiting time and affects the forging efficiency.

[0005] Therefore, there is an urgent need for a fan-shaped support precision forging method which can improve the forging efficiency while ensuring the quality of the forgings to solve the problems raised in the above background technology. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art, the present application provides a fan-shaped support precision forging method, which moves the axial flow fan rotating around the AISI422 fan-shaped blank forging rotating area at a constant wind speed from far to near, accelerates the cooling speed of the AISI422 steel blank forgings, realizes uniform heat dissipation of the AISI422 steel blank forgings, prevents the AISI422 steel blank forgings from being damaged due to large surface temperature difference, shortens the tempering cooling waiting time of the forgings, and improves the forging efficiency, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A precision forging method for a fan-shaped support, the precision forging method comprising the following steps:

[0009] Step 1: remove the oxide scale on the surface of the AISI422 steel ingot, preheat the AISI422 steel ingot to 1150±10℃ and hold it for 3 hours before forging to obtain an AISI422 sector-shaped blank forging. After annealing the AISI422 sector-shaped blank forging to 680±10℃ and holding it for 80 hours, the blank is cooled in the furnace to ≤250℃ and then taken out of the furnace for cooling;

[0010] Step 2: After roughing and flaw detection, the AISI422 sector-shaped forging is heated and quenched to 1150±10℃ and held for 3.5h. It is then taken out of the furnace and oil-cooled to ≤150℃.

[0011] Step 3: Clean the oil stains on the surface of AISI422 sector blank forging, temper the AISI422 sector blank forging once, heat the AISI422 sector blank forging to 750℃ and hold for 9h, then cool the furnace to ≤300℃ and take it out of the furnace;

[0012] Step 4: vertically clamp the AISI422 sector-shaped blank forging on a vertical bracket, and drive the vertical bracket to rotate the AISI422 sector-shaped blank forging at a constant speed. At the same time, the maximum temperature difference on the surface of the AISI422 sector-shaped blank forging is monitored in real time to be ≤25°C. Axial flow fans are moved from far to near in a circular manner and equidistantly around the rotating area of ​​the AISI422 sector-shaped blank forging according to the maximum temperature difference on the surface of the AISI422 sector-shaped blank forging. The AISI422 sector-shaped blank forging is cooled by the axial flow fans until the AISI422 sector-shaped blank forging is cooled to room temperature.

[0013] Step 5: Secondary tempering of AISI422 sector-shaped forgings: After tempering, heat the AISI422 sector-shaped forgings to 700°C and hold for 9 hours, then cool to ≤300°C and take them out of the furnace;

[0014] Step 6: After repeating step 5, the AISI422 steel blank forging is completed after flaw detection and inspection.

[0015] As a further solution of the present invention: in step 4, the rotation area of ​​the AISI422 sector-shaped blank forging is the three-dimensional space volume swept by the upright AISI422 sector-shaped blank forging when it rotates with the intersection of its two right-angled sides as the center point.

[0016] As a further scheme of the present application: the number of axial flow fans is 3, the center point is the intersection point of two right angle edges of the AISI422 sector blank forging, the horizontal plane azimuth angle of the three axial flow fans is 0°, 120° and 240° respectively, and the horizontal plane air outlet direction angle is 180°, 300° and 60° respectively.

[0017] As a further scheme of the present application: the farthest distance of the axial flow fan from the center point is 4.5D, D is the impeller length of the axial flow fan, with the center point being the intersection point of two right angle edges of the AISI422 sector blank forging.

[0018] As a further scheme of the present application: the transverse airflow diffusion angle of the initial position of the axial flow fan covers the circumference of the rotating area of the AISI422 sector blank forging ≤120°, and the transverse airflow diffusion angle of the terminal position covers the circumference of the rotating area of the AISI422 sector blank forging 45°.

[0019] As a further scheme of the present application: the central jet area of the longitudinal airflow diffusion angle of the axial flow fan covers the arc thick edge of the AISI422 sector blank forging, and the airflow diffusion area covers the right angle thin edge of the AISI422 sector blank forging.

[0020] As a further scheme of the present application: the wind speed of the axial flow fan when moving from the initial position to the terminal position is constant, and the wind speed gradually increases after the axial flow fan reaches the terminal position.

[0021] Compared with the prior art, the advantages of the present application are that: the sector support precision forging method proposed in the present application adopts the precision forging method for forging the sector support, rotates the AISI422 sector blank forging at a constant speed, moves the axial flow fan around the rotating area of the AISI422 sector blank forging from far to near at a constant wind speed, shortens the distance between the axial flow fan and the AISI422 sector blank forging, increases the impact force of the airflow of the axial flow fan, gradually increases the airflow wind speed of the axial flow fan after the axial flow fan reaches the terminal position, speeds up the cooling speed of the AISI422 steel blank forging, realizes uniform heat dissipation of the AISI422 steel blank forging, prevents the AISI422 steel blank forging from cracking due to large surface temperature difference, shortens the tempering cooling waiting time of the forging, and improves the forging efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a precision forging process schematic diagram of the sector support according to an embodiment of the present application;

[0023] Figure 2 It is an air cooling schematic diagram of the AISI422 sector blank forging according to an embodiment of the present application;

[0024] Figure 3A schematic diagram of the post-forging annealing structure of the AISI422 sector blank forging according to an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the quenching and tempering process of the AISI422 sector blank forging according to an embodiment of the present application;

[0026] Figure 5 A schematic diagram of the structure of the AISI422 sector blank forging after secondary tempering according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] Embodiment 1

[0028] In combination Figure 1-Figure 5 As shown in the drawings, in this embodiment, a method for precision forging of a sector support, the steps for forging the sector support using the precision forging method are as follows:

[0029] Step one, remove the surface oxide scale of the AISI422 ingot, preheat the AISI422 ingot to 1150±10℃ and maintain for 3h before forging, obtain the AISI422 sector blank forging, and anneal the AISI422 sector blank forging at 680±10℃ and maintain for 80h, then furnace cool to ≤250℃ and discharge for cooling.

[0030] Step two, after roughing and flaw detection of the AISI422 sector blank forging, heat up and quench, quench to 1150±10℃ and maintain for 3.5h, then discharge and oil cool to ≤150℃.

[0031] Step three, clean the oil stains on the surface of the AISI422 sector blank forging, once-temper the AISI422 sector blank forging, heat the AISI422 sector blank forging to 750℃ and maintain for 9h, then furnace cool to ≤300℃ and discharge.

[0032] Step four, vertically clamp the AISI422 sector blank forging on the vertical support, drive the vertical support to rotate the AISI422 sector blank forging at a constant speed, at the same time, monitor the maximum temperature difference on the surface of the AISI422 sector blank forging in real time, when the maximum temperature difference on the surface of the AISI422 sector blank forging is ≤25℃, move the axial flow fan from far to near around the rotating area of the AISI422 sector blank forging at a constant wind speed, shorten the distance between the axial flow fan and the AISI422 sector blank forging, increase the impact force of the airflow of the axial flow fan, after the axial flow fan reaches the termination position, gradually increase the airflow speed of the axial flow fan, speed up the cooling speed of the AISI422 steel blank forging, until the AISI422 sector blank forging cools to room temperature.

[0033] Step five, the secondary tempering AISI422 sector blank forging, the AISI422 sector blank forging is heated to 700℃ for 9h, and then cooled to ≤300℃ in the furnace.

[0034] Step six, the secondary tempering AISI422 sector blank forging is cooled to room temperature by the cooling method in step four. After the AISI422 steel blank forging is qualified by flaw detection and inspection, the forging is completed.

[0035] In this embodiment, the central jet flow area of the longitudinal airflow diffusion angle of the axial flow fan covers the arc thick edge of the AISI422 sector blank forging, and the airflow diffusion area covers the right-angle thin edge of the AISI422 sector blank forging. The arc thick edge and the right-angle thin edge of the AISI422 sector blank forging are cooled by the central jet flow area and the airflow diffusion area of the axial flow fan respectively, the cooling intensity of the arc thick edge and the right-angle thin edge of the AISI422 sector blank forging is controlled, the AISI422 steel blank forging is uniformly cooled, and the AISI422 steel blank forging is prevented from cracking due to a large surface temperature difference.

[0036] In this embodiment, the intersection of the two right-angle edges of the AISI422 sector blank forging is taken as a center point, the farthest distance of the axial flow fan from the center point is 4.5D, D is the length of the impeller of the axial flow fan, the horizontal airflow diffusion angle of the initial position of the axial flow fan covers ≤120° of the circumferential angle of the rotating area of the AISI422 sector blank forging, and the horizontal airflow diffusion angle of the terminal position covers 45° of the circumferential angle of the rotating area of the AISI422 sector blank forging. By controlling the initial distance of the axial flow fan, the horizontal airflow diffusion angle of the axial flow fan covers 120° of the circumferential angle of the rotating area of the AISI422 sector blank forging, the airflow of adjacent axial flow fans is prevented from interfering with each other to generate turbulence, the air cooling effect of the forging is ensured, at the same time, by controlling the terminal position of the axial flow fan, the distance between the axial flow fan and the AISI422 sector blank forging is shortened, the impact force of the airflow of the axial flow fan is increased, the cooling speed of the AISI422 steel blank forging is accelerated, and the waiting time for tempering cooling of the forging is shortened.

[0037] Embodiment 2

[0038] Based on embodiment 1, the initial position of the axial flow fan is 4.5D away from the center point of the rotating area of the AISI422 sector blank forging, the terminal position (the circumferential angle covered by the horizontal airflow diffusion angle of the axial flow fan is reduced from 120° to 45°) is 1.5D away from the center point of the rotating area of the AISI422 sector blank forging, and the method for moving the axial flow fan from the initial position to the terminal position is as follows according to the maximum surface temperature difference of the AISI422 sector blank forging ≤25℃:

[0039] Step one, real-time monitoring of the maximum temperature difference of the AISI422 sector blank forging surface, confirming that the maximum temperature difference of the AISI422 sector blank forging surface is ≤15℃, when the maximum temperature difference of the AISI422 sector blank forging surface is ≤15℃, the axial flow fan moves to the center point at a speed of 0.1D / min;

[0040] Step two, when the maximum temperature difference of the AISI422 sector blank forging surface is >15℃, ≤20℃, the axial flow fan stops moving, and continues to move after the temperature difference falls to ≤15℃;

[0041] Step three, when the maximum temperature difference of the AISI422 sector blank forging surface is >20℃, ≤25℃, the axial flow fan moves to the initial position at a speed of 0.1D / min, and stops moving after the temperature difference falls to >15℃, ≤20℃;

[0042] Step four, repeat the above steps until the axial flow fan stops moving to the termination position.

[0043] The above method is used to move the axial flow fan from far to near to cool the AISI422 sector blank forging, prevent the maximum temperature difference of the AISI422 sector blank forging surface from being >25℃, avoid the AISI422 steel blank forging from cracking due to large surface temperature difference, and ensure the quality of the AISI422 steel blank forging.

[0044] Example 3

[0045] Based on Example 2, an axial flow fan with a impeller length of 500mm is used to cool the AISI422 sector blank forging, the initial position of the axial flow fan is 2250mm(4.5D) away from the center point of the AISI422 sector blank forging rotating area, the termination position(the horizontal airflow diffusion angle of the axial flow fan covers a circumferential angle of 45°) is 750mm(1.5D) away from the center point of the AISI422 sector blank forging rotating area, and the initial constant wind speed of the axial flow fan is set to 15m / s, the method for moving the axial flow fan from far to near to cool the AISI422 sector blank forging is:

[0046] Step one, real-time monitoring of the maximum temperature difference of the AISI422 sector blank forging surface, confirming that the maximum temperature difference of the AISI422 sector blank forging surface is ≤15℃, when the maximum temperature difference of the AISI422 sector blank forging surface is ≤15℃, the axial flow fan moves to the center point at a speed of 50mm / min;

[0047] Step two, when the maximum temperature difference of the AISI422 sector blank forging surface is >15℃, ≤20℃, the axial flow fan stops moving, and continues to move after the temperature difference falls to ≤15℃;

[0048] Step three, when the maximum temperature difference of the AISI422 sector blank forging is greater than 20 DEG C and less than or equal to 25 DEG C, the axial flow fan moves to the initial position at a speed of 50 mm / min, and when the temperature difference falls back to greater than 15 DEG C and less than or equal to 20 DEG C, the movement is paused;

[0049] Step four, the above steps are repeated until the axial flow fan stops moving after moving to the termination position (750 mm);

[0050] Step five, after the axial flow fan reaches the termination position, the wind speed gradually increases from 15 m / s to an upper limit of 25 m / s at a rate of 0.2 m / s / min, and is maintained until the AISI422 sector blank forging is cooled to room temperature.

[0051] The following table is the comparison data of the traditional process natural air cooling and the cooling process of the application after the AISI422 sector blank forging is cooled to 300 DEG C and discharged from the tempering furnace:

[0052]

[0053]

[0054] Therefore, after the AISI422 sector blank forging is cooled to 300 DEG C and discharged from the tempering furnace, under the premise that the maximum temperature difference is less than or equal to 25 DEG C, the axial flow fan rotating around the AISI422 sector blank forging rotating area at a constant wind speed is moved from far to near, the distance between the axial flow fan and the AISI422 sector blank forging is shortened, the impact force of the axial flow fan airflow is increased, after the axial flow fan reaches the termination position, the wind speed of the axial flow fan airflow is gradually increased, the time of the traditional process natural air cooling is shortened from 8 h to 4.5 h, the cooling speed of the AISI422 steel blank forging is accelerated, the tempering cooling waiting time of the forging is shortened, and the forging efficiency is improved.

[0055] The precision forging method of the sector support provided by the application obtains the AISI422 steel blank forging with the structure of the tempered sorbite + carbide particles keeping the martensite orientation through secondary tempering, so that the AISI422 steel blank forging has good strength and plasticity indexes, the forging quality is improved, meanwhile, when the AISI422 steel blank forging is tempered, the AISI422 sector blank forging is rotated at a constant speed, the axial flow fan rotating around the AISI422 sector blank forging rotating area at a constant wind speed is moved from far to near, the distance between the axial flow fan and the AISI422 sector blank forging is shortened, the impact force of the axial flow fan airflow is increased, after the axial flow fan reaches the termination position, the wind speed of the axial flow fan airflow is gradually increased, the cooling speed of the AISI422 steel blank forging is accelerated, the AISI422 steel blank forging is uniformly cooled, the AISI422 steel blank forging is prevented from cracking due to a large surface temperature difference, the tempering cooling waiting time of the forging is shortened, and the forging efficiency is improved.

[0056] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent substitutions or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A precision forging method for a fan-shaped support, characterized in that: The precision forging method comprises the following steps: Step 1: remove the oxide scale on the surface of the AISI422 steel ingot, preheat the AISI422 steel ingot to 1150±10℃ and hold it for 3 hours before forging to obtain an AISI422 sector-shaped blank forging. After annealing the AISI422 sector-shaped blank forging to 680±10℃ and holding it for 80 hours, the blank is cooled in the furnace to ≤250℃ and then taken out of the furnace for cooling; Step 2: After roughing and flaw detection, the AISI422 sector-shaped forging is heated and quenched to 1150±10℃ and held for 3.5h. It is then taken out of the furnace and oil-cooled to ≤150℃. Step 3: Clean the oil stains on the surface of AISI422 sector blank forging, temper the AISI422 sector blank forging once, heat the AISI422 sector blank forging to 750℃ and hold for 9h, then cool the furnace to ≤300℃ and take it out of the furnace; Step 4: vertically clamp the AISI422 sector-shaped blank forging on a vertical bracket, and drive the vertical bracket to rotate the AISI422 sector-shaped blank forging at a constant speed. At the same time, the maximum temperature difference on the surface of the AISI422 sector-shaped blank forging is monitored in real time to be ≤25°C. Axial flow fans are moved from far to near in a circular manner and equidistantly around the rotating area of ​​the AISI422 sector-shaped blank forging according to the maximum temperature difference on the surface of the AISI422 sector-shaped blank forging. The AISI422 sector-shaped blank forging is cooled by the axial flow fans until the AISI422 sector-shaped blank forging is cooled to room temperature. Step 5: Secondary tempering of AISI422 sector-shaped forgings: After tempering, heat the AISI422 sector-shaped forgings to 700°C and hold for 9 hours, then cool to ≤300°C and take them out of the furnace; Step 6: After repeating step 5, the AISI422 steel blank forging is completed after flaw detection and inspection.

2. A precision forging method for a fan-shaped support according to claim 1, characterized in that: In step 4, the rotation area of ​​the AISI422 sector-shaped blank forging is a three-dimensional space volume swept by the vertical AISI422 sector-shaped blank forging when it rotates with the intersection of its two right-angled sides as the center point.

3. A precision forging method for a fan-shaped support according to claim 1, characterized in that: There are three axial flow fans, with the intersection of two right-angled sides of the AISI422 fan-shaped blank forging as the center point. The horizontal azimuth angles of the three axial flow fans are 0°, 120° and 240°, and the horizontal air outlet direction angles are 180°, 300° and 60°, respectively.

4. A precision forging method for a fan-shaped support according to claim 1, characterized in that: Taking the intersection of two right-angled sides of the AISI422 sector-shaped blank forging as the center point, the maximum distance between the axial flow fan and the center point is 4.5D, where D is the length of the axial flow fan impeller.

5. The precision forging method of a fan-shaped support according to claim 1, characterized in that: The lateral airflow diffusion angle at the initial position of the axial flow fan covers the circumference of the AISI422 sector-shaped blank forging rotation area of ​​≤120°, and the lateral airflow diffusion angle at the terminal position covers the circumference of the AISI422 sector-shaped blank forging rotation area of ​​45°.

6. A precision forging method for a fan-shaped support according to claim 1, characterized in that: The central jet area of ​​the longitudinal airflow diffusion angle of the axial flow fan covers the arc-shaped thick edge of the AISI422 sector-shaped blank forging, and the airflow diffusion area covers the right-angled thin edge of the AISI422 sector-shaped blank forging.

7. A precision forging method for a fan-shaped support according to claim 1, characterized in that: The wind speed of the axial flow fan when it moves from the initial position to the end position is a constant wind speed, and the wind speed gradually increases after the axial flow fan reaches the end position.

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