CN103131976A - Heating processing technology of 7A12 aluminum alloy forge piece - Google Patents

Abstract

The invention belongs to the field of aerial metal material processing, and in particular relates to a heating processing technology of a 7A12 aluminum alloy forge piece. The technology comprises the following steps of blank washing, solution treatment, sizing, grading precipitation heat treatment and the like. The heating processing technology of 7A12 aluminium alloy lays a technological foundation for domestic independent guarantee of 1933 high-performance aluminum alloy for production. The perfection of the 7A12 aluminum alloy technology system is beneficial to the popularization and application of the 7A12 aluminum alloy, the 7A12 aluminum alloy with good anti-fatigue and corrosion resistance can be not only used for manufacture of plane bearing parts, but also used in research and production process of other manufacture industries, thus improving the property of the product.

Description

A kind of 7A12 aluminum alloy forge piece heat-treatment technology method

Technical field

The invention belongs to the airframe material process field, particularly relate to a kind of 7A12 aluminum alloy forge piece heat-treatment technology method.

Background technology

Along with the progress of Aviation Industry and investigation of materials, design and select material is constantly selected advanced material, introduces imported materials and items.Import Russia aluminium 1933 has excellent anti-fatigue performance, traumatic resistance energy and good processing performance, is the desirable candidate materials of Chinese large-sized military transportation airplane.But 1933 aluminium alloys rely on external import, can't satisfy Production requirement.7A12 is the production domesticization material of 1933 aluminium alloys, if can develop the production heat-treatment technology method of 7A12, just can realize the domestic self-support of this material.7A12 is the domestic newly material of development, there is no at present knowhow, therefore in most of situation, directly adopts the thermal treatment standard of 1933 aluminium alloys.The processing parameter invalidated research of 1933 aluminium alloys is used for the 7A12 aluminum alloy heat to be processed, and sometimes can not reach the technical qualification requirement, need to carry out repetition thermal treatment or directly scrap, and has affected production schedule.Through research trial, formulate and be applicable to 7A12 forging overaging heat treatment process test parameter, solved home made materials 7A12 present domestic without the difficult problem of thermal treatment with reference to system.

Summary of the invention

Goal of the invention: a kind of 7A12 aluminum alloy forge piece heat-treatment technology method is provided, establishes good technical foundation for producing with the domestic self-support of 1933 high-performance aluminium alloys.

Technical scheme:

A kind of 7A12 aluminum alloy forge piece heat-treatment technology method:

1, processing parameter is as follows:

(1), solid solution temperature: 460～475 ℃;

(2), I level timeliness holding temperature: 105～115 ℃, soaking time: 10～12h;

(3), II level timeliness holding temperature: 175～180 ℃, soaking time: if blank thickness＜300mm is incubated 7～8h; If blank thickness 〉=300mm, 8～9h;

(4), repeat the thermal treatment number of times: 2 times;

2, processing step is as follows:

Step 1, cleaning blank;

Step 2, solution treatment;

Step 3, school shape;

Step 4, classification artificial aging.

Beneficial effect: 7A12 belongs to high-strength deformation aluminium alloy, after adopting rational heat treating regime, has very excellent anti-fatigue performance, traumatic resistance energy and good processing performance, is the preferential selection of bearing member.In the research and production of existing aircraft, the part type selects high-purity Russia aluminium 1933 as the primary structure material of aircraft, but Russia's aluminum dependence on import, and development causes restriction to Aircraft Production.7A12 aluminum alloy heat treatment process of the present invention is established good technical foundation for producing with the domestic self-support of 1933 high-performance aluminium alloys.7A12 aluminium alloy process system perfect, be conducive to applying of 7A12 aluminium alloy, excellent antifatigue, corrosion resistance nature not only are used for the aircraft bearing member to be made, and use that can be in the research and production process of other manufacturing improves the performance of product.

Description of drawings

Fig. 1 is schema of the present invention.

Embodiment

The below is described in further details the present invention.

A kind of 7A12 aluminum alloy forge piece heat-treatment technology method:

1, main technologic parameters is as follows:

(1), solid solution temperature: 460～475 ℃;

(2), I level timeliness holding temperature: 105～115 ℃, soaking time: 10～12h;

(3), II level timeliness holding temperature: 175～180 ℃, soaking time: if blank thickness＜300mm is incubated 7～8h; If blank thickness 〉=300mm, 8～9h;

(4), repeat the thermal treatment number of times: allow 2 times;

2, processing step, as shown in Figure 1:

1) forging oil removing, frame up

The forging of heat-treating, its surface has not allowed dirt, kish and oil stain, and not allowing significantly affects the scuffing of quality and damages.The greasy dirt on surface need clean.

Forging should fill basket or colligation before shove charge, when parts fixation and placement, should consider salt made from earth containing a comparatively high percentage of sodium chloride inflow and outflow smoothly.Work, the fixture that can design as required and adopt, the binding forging must adopt aluminium wire or aluminium strip, and other material bans use of.

For the larger forging of deadweight, pad aluminium foil on steel clamps, forbid the parallels silk screen, with anti-pinch, scratch part.Should adopt rational support and fixture to yielding forging, in case part distortion and warpage.Do not allow clamping overstocked, pile up to place or closely connect and place.

Little open die forgings (less than 30kg) can divide two rows to be placed on the screen cloth that is installed on rack.For heavy froging work in-process and part (greater than 30kg), do not allow two-layer placement, complex-shaped part should single placement.Spacing thickness between part: nitrate groove be forging thick+30mm.

2) quenching heat tracing

Part adopts get the tempreture and set furnace, and Heating temperature and soaking time are as shown in table 1 below:

Table 1

Allow the different forging of equal state, same process parameter to manage with furnace treatment.But should each band with the same code name of forging, with the sample of heat (batch) number.

3) quench and clean

The forging quenching shift time must not surpass 15s.

Nitrate groove heating quenching tank should be supplied with fresh mobile tap water (10 ℃～40 ℃) or refresh the water periodically.Before quenching, water temperature should not surpass 32 ℃, and after quenching, water temperature must not be higher than 40 ℃.In order to reduce distortion, out-of-shape and became uneven and large-scale forging can adopt in the hot water of 40～80 ℃ and quench.

When forging quenches, the water-immersed time length should keep it fully cooling, and namely forging is immersed in the water after boiling stops and keeps at least 2min.In quenching process, quenchant can stir with pressurized air or alternate manner, also can make the upper and lower motion of quenching basket, to improve speed of cooling.

Forging should clean in warm water after quenching in the nitre groove, and scavenging period is no more than two minutes.

4) school shape

The 7A12 aluminum alloy part that need to correct shape need to be under new as-quenched condition carries out in hold-time of plasticity.Quenching and the break period between artificial aging that the energy assurance obtains optimum performance are 240h.

5) part frames up

Parts fixation and 3) with, component clearance during artificial aging: forging is thick+50mm.

6) institution of prescription

Institution of prescription sees Table 2.

Table 2 institution of prescription

The artificially aged soaking time should record thermopair from minimum one of temperature in the heating installation workspace and reach and begin in limited time under the regulation aging temp to calculate.

After I level artificial aging is completed, directly heat up and carry out II level artificial aging temperature, need not to come out of the stove.After II level artificial aging, the air cooling of coming out of the stove.

In the situation that ag(e)ing process occur to be interrupted (as having a power failure etc.), allow each independent soaking time summation as total soaking time.

7) repeat thermal treatment

Allow twice repetition thermal treatment.

8) performance after thermal treatment

The full following technical qualification of specific conductivity and conventional mechanical property after testpieces thermal treatment, specific as follows shown in:

1. specific conductivity is not less than 40.5%IACS(23.5MS/m);

2. hardness: HB 〉=110;

3. mechanical property: the room temperature tensile mechanical property of forging should meet the regulation of table 3;

Table 3

4. microstructure: without burning.

Claims (1)

1. 7A12 aluminum alloy forge piece heat-treatment technology method is characterized in that:

1, processing parameter is as follows:

(1), solid solution temperature: 460～475 ℃;

(2), I level timeliness holding temperature: 105～115 ℃, soaking time: 10～12h;

(3), II level timeliness holding temperature: 175～180 ℃, soaking time: if blank thickness＜300mm is incubated 7～8h; If blank thickness 〉=300mm, 8～9h;

(4), repeat the thermal treatment number of times: allow 2 times;

2, processing step is as follows:

Step 1, cleaning blank;

Step 2, solution treatment;

Step 3, school shape;

Step 4, classification artificial aging.

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