RU2324000C1 - Method of thermal treatment of storage made of aluminium alloy d16 - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used under the hardiness of storages made of alloy D16 and the following producing of the high-precision parts of devices. The alloy is heated up to the temperature of hardiness. Then it is made the cooling from the temperature of hardiness to 430°C with the speed 130-150°C per hour and retention interval 3 minutes. The following cooling is made in the water under the temperature 80-100°C, and after under the temperature 20°C, and finally it is made the aging.

EFFECT: alloy deformation is reducing during hardiness and aging.

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Description

The present invention relates to the field of heat treatment and can be applied when quenching workpieces from alloy D16 for the subsequent manufacture of high-precision parts from them.

A known method of heat treatment of alloy D16, which consists in quenching from a temperature of 490 ° C, holding at this temperature, cooling in water with a temperature of 10-40 ° C and subsequent aging at a temperature of 190 ° C - 12 hours [1]. The method adopted as an analogue.

The cooling of the workpieces with this method is carried out directly from the quenching temperature in water. In this case, due to the large temperature difference, significant stresses arise, leading to deformation of the workpieces. These deformations have to be eliminated by processing (removal) of the left allowance by milling, which subsequently leads to a change in the shape and size of parts, and this is unacceptable, because requires an increase in significant allowance for further processing.

A known method of hardening of aluminum alloys, which consists in heating to a hardening temperature, holding at this temperature and cooling in water with a temperature of 80-100 ° C [2].

The method is taken as a prototype. With this method, the temperature during quenching is reduced to 390-410 ° C in comparison with the analogue method. However, this does not effectively reduce deformation, because stresses arise during cooling during quenching at temperatures above 480 ° C, when the yield strength (σ _0.2 ) of the aluminum alloy is very small (~ 10 kgf / mm ² ), which leads to significant deformations of the workpieces. These deformations are not eliminated during subsequent aging, and after machining to the specified dimensions, the parts spontaneously change their shape and dimensions. These resizing cannot be fixed. Therefore, this heat treatment method is also ineffective for the manufacture of high-precision parts of complex configuration (frames, brackets, cases, etc.).

The technical result achieved by the application of the proposed method is to reduce deformation during hardening and aging.

The technical result is achieved by the fact that in the proposed method of heat treatment of D16 alloy billets, including quenching in water with a temperature of 80-100 ° C in workshop water and aging, cooling from the quenching temperature is carried out at a speed of 130-150 ° C per hour to a temperature of 430 ° C, exposure to 3 minutes.

A distinctive feature of the proposed method is cooling from quenching temperature at a speed of 130-150 ° C per hour to 430 ° C, holding for up to 3 minutes at this temperature, which provides a technical result.

An example of practical application.

Samples of alloy D16 were quenched in various modes. The results of the study are shown in the table.

Table.
The results of the study of alloy D16 after various heat treatment modes. No. Grade Hardening mode Resize ± mm after The properties Note after hardening Aging 190 ° C - 12 hours Hardening Aging 190 ° C 12 hours σ _in kgf / mm ² δ% σ _in kgf / mm ² δ% one 2 3 four 5 6 7 8 9 10 Plate ≠ 35 mm Heating to 490 ° C, exp. 1.5 hours, cooling: Analogue Method one a) in water with a temperature of 20 ° C +0.58 -0.06 36 17 42 fifteen b) in water with a temperature of 90 ° C +0.25 -0.04 37 19 41 17 Prototype method Plate ≠ 20 mm but) -"- +0.68 -0.05 37 19 42 eighteen Analogue Method b) - "- +0.18 -0.06 38 16 43 fifteen Prototype method Plate ≠ 35 mm Heating to 490 ° C, exp. 1.5 hours, cooling. with a furnace at a speed +0.08 -0.02 40 17 42 fifteen Suggested Mode 2 Plate ≠ 20 mm 130 ° C per hour to 430 ° C, issue 3 min, cooling. in water with a temperature of 90 ° C, vyd. 3 min, cooling. in water with a temperature of 20 ° C +0.05 -0.02 41 16 43 fourteen Plate ≠ 35 mm Heating to 490 ° C. issue 1.5 hours, cooling. with a furnace at a speed +0.09 -0.02 40.5 16 42 fifteen Suggested Mode 3 Plate ≠ 20 mm 150 ° C per hour to 430 ° C, issue 3 min, cooling. in water with a temperature of 90 ° C, vyd. 3 min, cooling. in water with a temperature of 20 ° C +0.06 -0.03 41.5 eighteen 43 fourteen Plate ≠ 35 mm Heating to 490 ° C, exp. 1.5 hours, cooling. with a furnace at a speed +0.07 -0.01 37 eighteen 38 17 The way beyond the proposed four Plate ≠ 20 mm 120 ° C per hour to 430 ° C, issue 3 min, cooling in water with a temperature of 90 ° C, vyd. 3 min, cooling in
water with tamper. 20 ° C. +0.05 -0.01 38 19 39 eighteen Plate ≠ 35 mm Heating to 490 ° C, exp. 1.5 hours, cooling. with oven with +0.01 0.01 33 twenty 34 19 - "- 5 Plate ≠ 20 mm speed of 150 ° C per hour to 400 ° C, vyd. 3 minutes, cooling in water with a temperature of 90 ° C, vyd. 3 minutes, cooling in water with a temperature of 20 ° C +0.01 0 34 21 35 twenty

для повышения точности измерения длины образцов.
3. На каждый режим термической обработки использовали по три образца, вырезанные из каждой плиты Д16 согласно ГОСТ 17232-99.
4. Результаты измерения размеров (длины) образцов являются среднеарифметическим результатом измерения 3-х образцов. Измерения длины (60 мм) образцов выполняли с точностью ±0,001 мм.
5. Охлаждение деталей и образцов со скоростью 130-150°С в час производили вместе с печью.
6. Температура закалки обеспечивалась с точностью ±5°С.
Из результатов таблицы следует, что предлагаемый режим обеспечивает уменьшение деформации образцов более чем в 6 раз после закалки и более чем в 2 раза после старения при практически равных механических свойствах (σ_в; δ).Notes to the table.
1. The exposure to heat treatment was counted after the samples reached a predetermined temperature.
2. During the heat treatment, samples of type III GOST1497-84 were used. The ends of the samples were roughened

to increase the accuracy of measuring the length of the samples.
3. For each heat treatment mode, three samples were used, cut from each plate D16 according to GOST 17232-99.
4. The results of measuring the size (length) of the samples are the arithmetic mean of the measurement of 3 samples. Measurements of the length (60 mm) of the samples were performed with an accuracy of ± 0.001 mm.
5. The cooling of parts and samples at a speed of 130-150 ° C per hour was carried out together with the furnace.
6. The hardening temperature was ensured with an accuracy of ± 5 ° C.
From the results of the table it follows that the proposed mode provides a reduction in the deformation of the samples by more than 6 times after quenching and more than 2 times after aging with almost equal mechanical properties (σ _in ; δ).

Using the proposed method allows you to:

1. Significantly reduce deformation both after hardening and after aging (190 ° C - 12 hours).

2. To produce parts (frames, cases, brackets) of complex configuration with exact dimensions from plates, profiles, bars of alloy D16.

Information sources

1. Production instruction PI 1.2A510-98 p.15-20. Heat treatment of semi-finished products and parts from aluminum and aluminum deformed alloys, VIAM.

2. RF patent №2125618. The method of heat treatment of castings from aluminum alloys.

Claims (1)

The method of heat treatment of blanks from aluminum alloy D16, including heating the alloy to a quenching temperature, cooling from a quenching temperature to 430 ° C at a speed of 130-150 ° C per hour and holding for 3 minutes, cooling in water with a temperature of 80-100 ° C and then in water with a temperature of 20 ° C and aging.