CN107675112A - A kind of jacket deformation method of ultra-high-strength aluminum alloy - Google Patents

Abstract

A cladding deformation method of an ultra-high-strength aluminum alloy, and the invention relates to the field of deformation methods. The invention aims to solve the technical problems of cracking and streamline disorder existing in the component deformation process. Methods: 1. Densification treatment of the spray-deposited billet; 2. Composite with sheathing material; 3. Furnace loading to thicken the pier; 4. Car removal of the outer sheathing; The invention effectively suppresses the initiation of cracks caused by the secondary tensile stress in the deformation process of the alloy, and improves the deformation ability of the alloy; the restrictive effect of the sheath material greatly increases the dislocation density in the alloy, promotes the formation of substructures, and effectively refines the alloy Deformed structure: After being deformed by the sheath, the component structure is uniform and fine, with complete and ideal metal streamline characteristics, and the T6 state has excellent bidirectional mechanical properties. The invention is used for sheath deformation of ultra-high-strength aluminum alloy.

Description

A kind of cladding deformation method of ultra-high-strength aluminum alloy

technical field

The invention relates to the field of deformation methods.

Background technique

Al-Zn-Mg-Cu series (7XXX series) alloys are the most advantageous structural materials in the aviation industry. With the development of rapid solidification technology such as spray deposition, the Zn element content in this series of alloys exceeds 10wt%, and the strength of the alloy It can reach 800MPa or even higher, but it is accompanied by poor plasticity and forming ability. These ultra-high-strength alloys with high alloying content often produce cracks under the action of secondary tensile stress during subsequent hot processing such as rolling and forging. Although hot extrusion can make the alloy achieve better density and avoid cracks However, the strong crystallographic texture and streamline structure of the extruded alloy make it difficult for the alloy to be hot-worked again, especially for some key plate-shaped stress-bearing components, the required metal streamlines are generally along the component’s Radial distribution, the use of extruded rods with axial streamline characteristics as preforms will lead to defects such as streamline breaks, eddy currents, and turbulence.

Contents of the invention

The invention aims to solve the technical problems of cracking and streamline disorder existing in the component deformation process, and provides a method for sheathing deformation of an ultra-high-strength aluminum alloy.

A method for sheathing deformation of an ultra-high-strength aluminum alloy, specifically carried out according to the following steps:

1. Perform hot isostatic pressing pre-densification treatment on the spray-deposited billet whose composition is Al-(9～12.5)Zn-(2.0～3.0)Mg-(1.5～2.0)Cu-(0.1～0.3)Zr. The density of the post-spray deposition ingot is >99.7%, and then it is blanked by wire cutting. After blanking, the lathe is finished into a cylindrical blank with a size of Ф70×70mm;

2. Machining the sheath made of aviation 7075 extruded pipe, the inner diameter of the machined sheath is 70mm, the thickness is 12mm, and then the blank obtained in step 1 is coated with lubricant and compounded with the sheath material to obtain a combined billet ;

3. Control the furnace temperature to 425-435°C, spray the combined billet obtained in step 2 with lubricant and install it in the furnace, keep it warm for 1.5-2 hours, then use a 1600-ton hydraulic press for isothermal upsetting, and the preheating temperature of the upper and lower cutting boards is 400-430°C , use the steel block to control the thickness of the billet;

4. Turn off the outer sheath of the upsetting billet until all the sheath materials are turned off to obtain a semi-finished forging;

5. Heat the semi-finished forging obtained in step 4 to 430°C, keep it warm for 1.5-2 hours, and carry out die forging. The die forging process parameters: the forging rate is 2-4mm/s, the mold preheating temperature is 400-430°C, the press The tonnage is 1600 tons, and a method of sheathing deformation of ultra-high-strength aluminum alloy is completed.

The beneficial effects of the present invention are:

(1) Change the equivalent stress state of the billet, transfer the tensile stress on the outer edge of the billet, effectively inhibit the crack initiation caused by the secondary tensile stress during the alloy deformation process, and improve the deformation capacity of the alloy;

(2) The limiting effect of the sheath material greatly increases the dislocation density in the alloy, promotes the formation of substructures, and effectively refines the deformed structure of the alloy;

(3) After being deformed by the sheath, the component structure is uniform and fine, with complete and ideal metal streamline characteristics, and the T6 state has excellent bidirectional mechanical properties.

The invention is used for sheath deformation of ultra-high-strength aluminum alloy.

Description of drawings

Fig. 1 is a schematic diagram of the deformation of the blank sheath in Embodiment 1.

detailed description

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific implementation mode 1: In this implementation mode, a method for sheathing deformation of an ultra-high-strength aluminum alloy is carried out according to the following steps:

1. Perform hot isostatic pressing pre-densification treatment on the spray-deposited billet whose composition is Al-(9～12.5)Zn-(2.0～3.0)Mg-(1.5～2.0)Cu-(0.1～0.3)Zr. The density of the post-spray deposition ingot is >99.7%, and then it is blanked by wire cutting. After blanking, the lathe is finished into a cylindrical blank with a size of Ф70×70mm;

2. Machining the sheath made of aviation 7075 extruded pipe, the inner diameter of the machined sheath is 70mm, the thickness is 12mm, and then the blank obtained in step 1 is coated with lubricant and compounded with the sheath material to obtain a combined billet ;

3. Control the furnace temperature to 425-435°C, spray the combined billet obtained in step 2 with lubricant and install it in the furnace, keep it warm for 1.5-2 hours, then use a 1600-ton hydraulic press for isothermal upsetting, and the preheating temperature of the upper and lower cutting boards is 400-430°C , use the steel block to control the thickness of the billet;

4. Turn off the outer sheath of the upsetting billet until all the sheath materials are turned off to obtain a semi-finished forging;

5. Heat the semi-finished forging obtained in step 4 to 430°C, keep it warm for 1.5-2 hours, and carry out die forging. The die forging process parameters: the forging rate is 2-4mm/s, the mold preheating temperature is 400-430°C, the press The tonnage is 1600 tons, and a method of sheathing deformation of ultra-high-strength aluminum alloy is completed.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the lubricant in step 2 is a mixture of engine oil and graphite. Others are the same as in the first embodiment.

Embodiment 3: This embodiment differs from Embodiment 1 or Embodiment 2 in that: in step 3, the temperature of the furnace is controlled to 430°C. Others are the same as in the first or second embodiment.

Embodiment 4: This embodiment differs from Embodiments 1 to 3 in that: in step 3, when the pier is thick, the side length or diameter of the upper and lower chopping boards is >240mm. Others are the same as those in the first to third specific embodiments.

Embodiment 5: This embodiment is different from Embodiment 1 to Embodiment 4 in that: in step 3, the thickness of the blank is controlled to be 20 mm. Others are the same as one of the specific embodiments 1 to 4.

Embodiment 6: This embodiment differs from Embodiment 1 to Embodiment 5 in that: in step 3, the thickness deformation rate of the pier is controlled to be ≤4 mm/s. Others are the same as one of the specific embodiments 1 to 5.

Embodiment 7: This embodiment is different from Embodiment 1 to Embodiment 6 in that: in step 4, turning starts from the outer diameter first, until the inner blank interface is completely exposed, then turning the upper and lower bottom surfaces, and then turning around. Others are the same as one of the specific embodiments 1 to 6.

Embodiment 8: This embodiment differs from Embodiments 1 to 7 in that: in step 5, the forging rate is 2-4 mm/s, and the mold preheating temperature is 410-420°C. Others are the same as one of the specific embodiments 1 to 7.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment one:

In this embodiment, a method for sheathing deformation of an ultra-high-strength aluminum alloy is specifically carried out according to the following steps:

1. Perform hot isostatic pressing pre-densification treatment on the spray-deposited billet whose composition is Al-11Zn-2.65Mg-1.5Cu-0.18Zr. After blanking, the lathe is finished into a cylindrical blank with a size of Ф70×70mm;

2. Machining the sheath made of aviation 7075 extruded pipe, the inner diameter of the machined sheath is 70mm, the thickness is 12mm, and then the blank obtained in step 1 is coated with lubricant and compounded with the sheath material to obtain a combined billet ;

3. Control the furnace temperature to 430°C. Spray the combined billet obtained in step 2 with lubricant and install it in the furnace, keep it warm for 2 hours, and then use a 1600-ton hydraulic press for isothermal upsetting. The upper and lower cutting boards are preheated at 400°C and controlled by steel pads. The thickness of the blank, the thickness of the blank is 20mm;

4. Turn off the outer sheath of the upsetting billet until all the sheath materials are turned off to obtain a semi-finished forging;

5. Heat the semi-finished forging obtained in step 4 to 430°C, keep it warm for 2 hours, and carry out die forging. The die forging process parameters: the forging rate is 3mm/s, the mold preheating temperature is 400°C, and the tonnage of the press is 1600 tons. A sheathing deformation method of an ultra-high-strength aluminum alloy.

In the step 2, the lubricant is a mixture of machine oil and graphite;

Step 3 When the middle pier is thick, the side length of the upper and lower cutting boards is 250mm;

In step 3, the coarse deformation rate of the pier is controlled to be 3mm/s.

The schematic diagram of the deformation of the blank sheath in this embodiment is shown in FIG. 1 .

The technical effect that this embodiment reaches:

(1) Change the equivalent stress state of the billet, transfer the tensile stress on the outer edge of the billet, effectively inhibit the crack initiation caused by the secondary tensile stress during the alloy deformation process, and improve the deformation capacity of the alloy;

(2) The limiting effect of the sheath material greatly increases the dislocation density in the alloy, promotes the formation of substructures, and effectively refines the deformed structure of the alloy;

(3) After being deformed by the sheath, the component structure is uniform and fine, with complete and ideal metal streamline characteristics, and the T6 state has excellent bidirectional mechanical properties.

Claims (8)

1. a method for sheathing deformation of an ultra-high-strength aluminum alloy, characterized in that the method is specifically carried out in the following steps: 1. Perform hot isostatic pressing pre-densification treatment on the spray-deposited billet whose composition is Al-(9～12.5)Zn-(2.0～3.0)Mg-(1.5～2.0)Cu-(0.1～0.3)Zr. The density of the post-spray deposition ingot is >99.7%, and then it is blanked by wire cutting. After blanking, the lathe is finished into a cylindrical blank with a size of Ф70×70mm; 2. Machining the sheath made of aviation 7075 extruded pipe, the inner diameter of the machined sheath is 70mm, the thickness is 12mm, and then the blank obtained in step 1 is coated with lubricant and compounded with the sheath material to obtain a combined billet ; 3. Control the furnace temperature to 425-435°C, spray the combined billet obtained in step 2 with lubricant and install it in the furnace, keep it warm for 1.5-2 hours, then use a 1600-ton hydraulic press for isothermal upsetting, and the preheating temperature of the upper and lower cutting boards is 400-430°C , use the steel block to control the thickness of the billet; 4. Turn off the outer sheath of the upsetting billet until all the sheath materials are turned off to obtain a semi-finished forging; 5. Heat the semi-finished forging obtained in step 4 to 430°C, keep it warm for 1.5-2 hours, and carry out die forging. The die forging process parameters: the forging rate is 2-4mm/s, the mold preheating temperature is 400-430°C, the press The tonnage is 1600 tons, and a method of sheathing deformation of ultra-high-strength aluminum alloy is completed. 2. The sheathing deformation method of a super-high-strength aluminum alloy according to claim 1, characterized in that the lubricant in step 2 is a mixed solution of machine oil and graphite. 3. A method for sheathing deformation of an ultra-high-strength aluminum alloy according to claim 1, characterized in that in step 3, the furnace temperature is controlled to 430°C. 4. A method for sheathing deformation of an ultra-high-strength aluminum alloy according to claim 1, characterized in that the side length or diameter of the upper and lower cutting boards is greater than 240mm when the pier is thick in step 3. 5. A method for sheathing deformation of an ultra-high-strength aluminum alloy according to claim 1, characterized in that in step 3, the thickness of the blank is controlled to be 20mm. 6. A method for sheathing deformation of an ultra-high-strength aluminum alloy according to claim 1, characterized in that in step 3, the coarse deformation rate of the pier is controlled to be ≤4mm/s. 7. The sheathing deformation method of a super-high-strength aluminum alloy according to claim 1, characterized in that during turning in step 4, turning starts from the outer diameter first, turning until the inner blank interface is completely exposed, then turning the upper and lower bottom surfaces, and then turning Turn around. 8. A method for sheathing deformation of an ultra-high-strength aluminum alloy according to claim 1, characterized in that in step 5, the forging rate is 2-4mm/s, and the mold preheating temperature is 410-420°C.