Low-stress machining method for aluminum alloy annular forge piece

Abstract

The invention discloses a low-stress processing method of an aluminum alloy annular forge piece, which comprises the following steps of: heating an aluminum alloy bar, preserving heat, upsetting, punching, pre-rolling, finally rolling into a ring piece, carrying out solution treatment on the ring piece, adopting an aqueous medium at the temperature of more than or equal to 85 DEG C during solution cooling, carrying out cold bulging after solution treatment, controlling the bulging quantity to be 1.8-2.2%, carrying out aging treatment after bulging, and finally carrying out low-stress processing on the ring piece. And thus, the low-stress aluminum alloy ring piece is obtained. According to the method, the residual stress of the aluminum alloy ring piece can be effectively removed, and the forge piece performance is improved. The method is used for machining the aluminum alloy annular forgings.

Description

Technical Field

[0001] The present invention relates to a processing method, and particularly to a low-stress processing method for aluminum alloy ring forgings. Background Art

[0002] Aluminum alloy ring parts are mainly applied to important components such as the casing of an aero-engine. In actual applications, problems such as deformation during machining and extremely poor dimensional stability often occur. An important factor causing part machining deformation is the excessive residual stress inside the blank. Reducing the internal residual stress of the blank ring can effectively alleviate the deformation caused by the release of residual stress during the machining of parts. Currently, residual stress is usually removed or adjusted by the following methods: ① Removing stress through thermal action, that is, adjusting the structure by heating to relax or remove the residual stress; ② Removing and adjusting residual stress by mechanical action, that is, using plastic deformation generated inside the material to reduce or adjust the residual stress. The first method cannot completely remove the residual stress, and generally can only remove 30% - 60% of the residual stress; the second method often damages the integrity of the forging. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method of "solution treatment + cold expansion + aging" to remove the residual stress of aluminum alloy ring forgings, which can remove more than 90% of the residual stress of the ring forgings and improve the performance of the ring forgings.

[0004] To solve the above technical problem, the low-stress processing method for the aluminum alloy ring forging of the present invention includes the following steps in its technical solution:

[0005] Cut the aluminum alloy into bars according to a certain specification; light the electric furnace and heat it to 450 ± 10 °C. After reaching the temperature, put the aluminum alloy bars into the electric furnace for heating and heat preservation. The heat preservation time is calculated according to 1.8 min / mm; take out the bars from the electric furnace and transfer them to a press for upsetting and punching to make an intermediate blank, and the transfer time ≤ 50 s; heat the intermediate blank back to the furnace while it is hot and heat it to 450 ± 10 °C for heat preservation, and the heat preservation time is calculated according to 1.8 min / mm;

[0006] Take out the intermediate billet for rolling. First pre-rolling: The core roll is rolled at a feed rate of 2.42 mm / s. After reaching the expected size, the feed rate of the core roll is reduced to 0.58 mm / s for rolling; Second pre-rolling: The core roll is rolled at a feed rate of 1.28 mm / s. After reaching the expected size, the feed rate of the core roll is reduced to 0.33 mm / s for rolling; Third pre-rolling: The core roll is rolled at a feed rate of 0.75 mm / s. After reaching the expected size, the feed rate of the core roll is reduced to 0.42 mm / s for rolling; Roll forming: The core roll is rolled at a feed rate of 0.37 mm / s. After reaching the expected size, the feed rate of the core roll is reduced to 0.09 mm / s for rolling, and then take out to obtain an aluminum alloy ring part;

[0007] Put the aluminum alloy ring part into an electric furnace at a temperature of 530 ± 5 °C for heating and heat preservation. The heat preservation time is 170 min to 180 min; Then take out the ring part and put it into a water tank for cooling. The transfer time ≤ 10 s and the water temperature ≥ 85 °C;

[0008] After taking out the ring part from the water tank, cool it to room temperature and put it into a bulging machine for cold bulging. The bulging amount is 1.8% - 2.2%;

[0009] Put the bulged ring part into an electric furnace at a temperature of 190 ± 5 °C for heating and heat preservation. The heat preservation time is 11 hours to 12 hours, and disperse air cooling; Finally, obtain an aluminum alloy ring part with low stress.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The low-stress processing method of the aluminum alloy ring forgings described in the present invention, the method of "solution + cold bulging + aging", effectively removes the residual stress of the ring parts. The size of the ring parts is relatively stable after rough machining and heat treatment, and effectively improves the deformation after machining of the parts. The solution cooling uses a water medium above 85 °C, which improves the water temperature requirement compared with the traditional solution, increases the fluidity of water (reduces viscosity), is beneficial to the temperature uniformity during the solution cooling of the forgings, and is beneficial to reducing the residual stress level; Cold bulging is carried out after solution. The bulging deformation amount is controlled at 1.8% - 2.2%, adjusts the residual stress inside the forgings, reduces the residual stress level and improves the stress distribution. Specific Embodiments

[0012] To implement the low-stress processing method of the aluminum alloy ring forgings described in the present invention, equipment such as a forging heating furnace, a press, a manipulator, a ring rolling mill, a heat treatment furnace, a bulging machine, and a water tank are required. Taking the 2A70 aluminum alloy ring forging as an example, its specific implementation method:

[0013] The main chemical element contents (by weight percentage) of the 2A70 aluminum alloy are as follows: the Mn content is ≤0.2%, the Si content is ≤0.35%, the Ni content is 0.9% - 1.5%, the Ti content is 0.02% - 0.1%, the Cu content is 1.9% - 2.5%, the Fe content is 0.9% - 1.5%, the Mg content is 1.4% - 1.8%, the Zn content is ≤0.3%, and the balance is Al.

[0014] The steps of this method are as follows:

[0015] Cut the 2A70 aluminum alloy into bars according to certain specifications; light the electric furnace and heat it to 450 ± 10°C. After reaching the temperature, put the 2A70 aluminum alloy bars into the electric furnace for heating and heat preservation. The heat preservation time is calculated as 1.8 min / mm; take out the bars from the electric furnace and transfer them to under the press for upsetting and punching to make an intermediate blank, and the transfer time is ≤50 s; heat the intermediate blank back to the furnace while it is hot and heat it to 450 ± 10°C for heat preservation, and the heat preservation time is calculated as 1.8 min / mm;

[0016] Take out the intermediate blank for rolling. The first pre-rolling: the core roll rolls at a feed speed of 2.42 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.58 mm / s for sizing; the second pre-rolling: the core roll rolls at a feed speed of 1.28 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.33 mm / s for sizing; the third pre-rolling: the core roll rolls at a feed speed of 0.75 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.42 mm / s for sizing; roll forming: the core roll rolls at a feed speed of 0.37 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.09 mm / s for sizing, and then take it out to obtain a 2A70 aluminum alloy ring;

[0017] Put the 2A70 aluminum alloy ring into an electric furnace at a temperature of 530 ± 5°C for heating and heat preservation, and the heat preservation time is 170 min - 180 min; then take out the ring and put it into a water tank for cooling, and the transfer time is ≤10 s, and the water temperature is ≥85°C;

[0018] After taking out the ring from the water tank, cool it to room temperature and put it into a bulging machine for cold bulging, and the bulging amount is 1.8% - 2.2%;

[0019] Put the bulged ring into an electric furnace at a temperature of 190 ± 5°C for heating and heat preservation, and the heat preservation time is 11 hours - 12 hours, and cool it by scattered air cooling; finally obtain a 2A70 aluminum alloy ring with low stress.

Claims

1. A low-stress processing method for an aluminum alloy ring forging, characterized in that, It includes the following steps: Cut the aluminum alloy into bars according to certain specifications; light the electric furnace and heat it to 450±10°C. After reaching the temperature, put the aluminum alloy bars into the electric furnace for heating and heat preservation. The heat preservation time is calculated as 1.8 min / mm; take out the bars from the electric furnace and transfer them to under the press for upsetting and punching to make an intermediate blank, and the transfer time ≤ 50 s; put the intermediate blank back into the furnace while it is hot and heat it to 450±10°C for heat preservation, and the heat preservation time is calculated as 1.8 min / mm; Take out the intermediate blank for rolling. The first pre-rolling: the core roll is rolled at a feed speed of 2.42 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.58 mm / s for sizing; the second pre-rolling: the core roll is rolled at a feed speed of 1.28 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.33 mm / s for sizing; the third pre-rolling: the core roll is rolled at a feed speed of 0.75 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.42 mm / s for sizing; roll forming: the core roll is rolled at a feed speed of 0.37 mm / s. After reaching the expected size, reduce the feed speed of the core roll to 0.09 mm / s for sizing, and then take it out to obtain an aluminum alloy ring; Put the aluminum alloy ring into an electric furnace at a temperature of 530±5°C for heating and heat preservation, and the heat preservation time is 170 min to 180 min; then take out the ring and put it into a water tank for cooling, and the transfer time ≤ 10 s, and the water temperature ≥ 85°C; After taking out the ring from the water tank, cool it to room temperature and put it into a bulging machine for cold bulging, and the bulging amount is 1.8% to 2.2%; Put the bulged ring into an electric furnace at a temperature of 190±5°C for heating and heat preservation, and the heat preservation time is 11 hours to 12 hours, and disperse air cooling; finally obtain an aluminum alloy ring with low stress.