Liquid die-forging and rolling combined forming method for 7075 aluminum alloy irregular-section large-size annular piece

Abstract

The invention discloses a liquid die-forging and rolling combined forming method for a 7075 aluminum alloy irregular-section large-size annular piece. The liquid die-forging and rolling combined forming method comprises the following steps of: 1) melting; 2) carrying out liquid die-forging: fixing a die-forging die on an indirect extrusion caster, casting an alloy solution in the die-forging die, and keeping pressure for 35-45 seconds at specific pressure of 160-200 MPa so as to obtain a near-net section annular blank, wherein a casting temperature is 680-700 DEG C, a pressurizing speed is 35-40 mm / s; mold-filling time is 1-6 seconds, and the specific pressure is 160-200 MPa; 3) homogenizing: carrying out heat preservation for 6-24 hours after cooling the near-net section annular blank to 440-470 DEG C; 4) carrying out waste heat constant-temperature rolling: rolling at a constant temperature on a radial shaft combined ring rolling machine when the temperature of the homogenized near-net section annular blank is reduced to 440-460 DEG C; 5) carrying out heat treatment: carrying out heat preservation on the annular blank for 1-2 hours at the temperature of 460-477 DEG C, quenching with cold water, and heating the annular blank to 170-180 DEG C and carrying out heat preservation for 6-8 hours after carrying out heat preservation for 6-8 hours at the temperature of 100-110 DEG C; and 6) finishing.

Description

technical field [0001] The invention relates to a short-process processing and forming method for large-diameter metal rings with complex cross-sections, in particular to a liquid die forging and rolling composite forming method for large-scale rings with different cross-sections of 7075 aluminum alloy. Background technique [0002] With the rapid development of my country's aerospace industry, high-thrust launch vehicles are in urgent need of large-scale complex-section aluminum alloy rings with a diameter of more than 5 meters. The so-called complex cross-section ring refers to a metal ring with a large difference in the cross-sectional area of ​​the ring in the axial direction, a large change in the shape and size of the cross-section of the ring, and a relatively complex shape of the inner surface and the outer surface. An important part of the success of a rocket project is the key connector of the launch vehicle. The special use environment puts forward almost strict ...

AI Technical Summary

Problems solved by technology

[0004]1) The process is lengthy, with many procedures and low production efficiency;

[0005]2) The rolled and expanded ring blank needs to be prepared by punching, and the final cross-sectional shape needs to be guaranteed by cutting excess dressing, so the material utilization rate is low;

[0006]3) The machining process cuts off the metal flow line, resulting in a decrease in the comprehensive mechanical properties of the ring;

[0007]4) The preparation process requires repeated heating, resulting in coarse grains, severe surface oxidation, and large energy consumption

[0008]The Chinese patent with the publication number CN 101817134A discloses a method for short-flow casting-rolling composite forming of metal rings. Although the method satisfies the beneficial effect of short production process and saving energy, materials and manpower to a certain extent, the method adopts centrifugal casting ring billet, which cannot meet the processing requirements of complex cross-section rings, and the comprehensive mechanical properties of the metal rings obtained are The performance is still not up to the use requirements of launch vehicles