CN112662906A

CN112662906A - Heat treatment process for aluminum alloy M174+ material piston

Info

Publication number: CN112662906A
Application number: CN202011280959.7A
Authority: CN
Inventors: 祝文明; 朱程程; 常帅
Original assignee: Shandong Zhenting Jinggong Piston Co ltd
Current assignee: Shandong Zhenting Jinggong Piston Co ltd
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-04-16

Abstract

The invention provides a heat treatment process of an aluminum alloy M174+ material piston, which comprises the following steps: (1) pretreating raw materials (2) and pouring a piston blank. (3) The piston blank is placed in a heat treatment cage, is placed in a pit type heat treatment furnace, is heated from 200 ℃ in the furnace for 3 hours to 520 DEG +/-5 DEG, is kept warm for 4 hours, is placed in a quenching pool with the water temperature of 60 DEG +/-10 DEG, is shaken up and down from left to right in the heat treatment cage, is cooled, is taken out and dried in the air, is placed in an aging furnace, has the furnace temperature of 50 DEG to 80 DEG, is heated for 1.5 hours to 255 DEG +/-5 DEG, and is kept warm for 5.5 hours. The piston produced by the process has the advantages of obviously improved normal-temperature tensile strength, high-temperature tensile strength, volume stability and metallographic structure, and meets technical requirements.

Description

Heat treatment process for aluminum alloy M174+ material piston

Technical Field

The invention belongs to the technical field of piston machining, and particularly relates to a heat treatment process of an aluminum alloy M174+ piston.

Background

The piston is a core part of an engine, high-speed linear motion is carried out at high temperature and high pressure in the engine, and lubrication is not easy to realize, so that the requirements on the material performance and the geometric dimension of the piston are very high, and the high-power piston is quickly added along with the development of a company, but the current high-power piston does not achieve good effects on the components, the metallographic structure, the tensile strength and the like of the piston, and a better heat treatment process is needed for optimization.

The M174+ aluminum alloy belongs to A1, Si, Cu and Mg series light aluminum alloy, and is a composite material with small mass, high strength and good toughness. The application is wider in piston manufacturing, and after a piston blank is formed, the heat treatment process determines bad good indexes, so that the correct heat treatment process is very important. The conventional treatment method comprises the following steps: the piston is solid-dissolved at 500 +/-5 ℃ for 3.5 hours, artificially aged at 206 ℃ for 8 hours, and made of M174+, the conventional heat treatment process cannot meet the technical requirements on normal-temperature tensile strength, high-temperature tensile strength, volume stability and metallographic structure, the tensile strength at the normal temperature is only about 275MPa, and a new heat treatment process needs to be explored.

Disclosure of Invention

In order to solve the technical problem, the invention provides a heat treatment process of an aluminum alloy M174+ piston.

The technical scheme adopted by the invention is as follows: a heat treatment process of an aluminum alloy M174+ material piston comprises the following steps:

(1) the raw materials are put into a smelting furnace and heated to 680-720 degrees, chemicals are added in a concentrated manner, the temperature section can fully exert the greatest effect of the chemicals, the aluminum liquid treatment reaches a relatively ideal state, and various properties of the piston are improved to the maximum, particularly the metallurgical structure uniformity and the product strength. Pressing the medicine into the aluminum liquid by using a bell jar, stirring, standing for 10 minutes after stirring, fishing out the slag on the surface of the aluminum liquid by using a colander, then putting the aluminum liquid into a turnover bag, putting the turnover bag into a heat preservation furnace at a production site for secondary chemical treatment, flushing nitrogen into the aluminum liquid by using a carbon rod while stirring by using a degassing vehicle, and standing for fishing out the slag.

(2) And (4) swinging away the oxide skin on the surface of the aluminum liquid by using a stainless steel cup spoon, scooping up the aluminum liquid at the position where the oxide skin is swung away, guiding the aluminum liquid into a water inlet of a piston mold of the casting machine, and casting a piston blank by using the casting machine.

(3) The piston blank is placed in a heat treatment cage, is placed in a pit type heat treatment furnace, is heated from 200 ℃ in the furnace for 3 hours to 520 DEG +/-5 DEG, is kept warm for 4 hours, is placed in a quenching pool with the water temperature of 60 DEG +/-10 DEG, is shaken up and down from left to right in the heat treatment cage, is cooled, is taken out and dried in the air, is placed in an aging furnace, has the furnace temperature of 50 DEG to 80 DEG, is heated for 1.5 hours to 255 DEG +/-5 DEG, and is kept warm for 5.5 hours.

Furthermore, the chemicals are a slag remover, a refining agent and an aluminum-silicon-phosphorus intermediate alloy modifier.

Further, the slag remover comprises: the TC-LQJ1 slag remover changes the wettability of slag and aluminum liquid, increases the surface tension on an aluminum interface, makes aluminum difficult to wet the slag, effectively separates the aluminum liquid from the slag under the condition of stirring, makes the slag become dry powdery slag, effectively reduces the aluminum content in the slag, reduces the amount of aluminum liquid brought out during slag removal, reduces the loss of aluminum, and increases economic benefits.

Further, the refining agent is: the Xuzhou Lida refining agent removes hydrogen and floating oxidation slag inclusion in the aluminum liquid, so that the aluminum liquid is purer and has the function of a slag remover.

Part of components in the refining agent are easy to decompose at high temperature, and the generated gas is easy to react with hydrogen, has strong adsorption force with slag inclusion and can quickly escape from a melt. Other components also have the function of slag remover.

Further, the aluminum-silicon-phosphorus master alloy modifier is as follows: A1SP4.5 AlSiP master alloy modifier is used to refine crystal grains and improve structure to improve material performance.

According to the invention, when the material is treated in the early stage, chemicals are added in two times, when the chemicals are added for the first time, impurities in the aluminum liquid are removed, various elements of the aluminum liquid are fused closely and uniformly, the addition amount for the second time is small, the chemicals are mainly subjected to degassing treatment, gas caused by turnover and flow is removed, and the aluminum liquid is subjected to further pure treatment, so that the metallographic structure is more compact, the temperature is 680-720 ℃, the performance of the chemicals can be fully exerted, and the aluminum liquid is better treated.

During solution treatment, the temperature is gradually increased to 520 ℃ from 200 ℃ for 3 hours, the piston blank is not deformed due to local uneven heating in the slow temperature increasing process, faults are not generated locally due to temperature difference, the temperature is kept for 4 hours at 520 ℃, the internal structure of the piston reaches a stable state, and the temperature of each part is more balanced. The aging temperature is 255 degrees, and at the temperature, all parts of the piston have certain toughness and are not so brittle and hard, so that the internal stress of all parts is eliminated, and the piston is deformed in the operation process.

TABLE 1 comparison of three material performance indexes

Comparing the three materials:

1. the M174+ room temperature tensile strength is slightly more superior than ZT11 and slightly inferior to ZL 109.

2. M174+ tensile strength at high temperature is slightly more advantageous than the other two materials.

3. The hardness and temperature decay is obviously superior to those of ZL109 and slightly better than that of ZT 11.

3. M174+ has slightly poor volume stability but meets GB

In view of the above, in combination,

m174+ has certain performance advantages over ZT11 ZL 109.

Drawings

FIG. 1 shows a grade 2 upper product of metallographic structure of the treatment process of the invention;

FIG. 2 shows the grade 2 lower product of metallographic structure of the conventional heat treatment process.

Detailed Description

The following examples further describe embodiments of the present invention in detail.

Example 1:

a heat treatment process of an aluminum alloy M174+ material piston comprises the following steps:

(1) 900Kg of raw materials are put into a smelting furnace and heated to 680-720 degrees, chemicals are added in a concentrated manner, 3Kg of Xuzhou Lida refining agent, 2.5Kg of TC-LQJ1 slag removal agent and 2.0Kg of A1SP4.5 aluminum silicon phosphorus intermediate alloy modifier are added, and the temperature section can fully play the greatest role of the chemicals, so that the aluminum liquid treatment reaches a relatively ideal state, and all properties of the piston are improved to the maximum, particularly the uniformity of a metallographic structure and the strength of a product. Pressing the medicines into the aluminum liquid by using a bell jar, stirring, standing for 10 minutes after stirring, fishing out the slag on the surface of the aluminum liquid by using a strainer, then putting the aluminum liquid into a turnover bag, respectively putting the turnover bag into 3 heat preservation furnaces of a production field for secondary chemical treatment, flushing nitrogen into the aluminum liquid by using a carbon rod while stirring by using a degassing vehicle, flushing 300L in 20 minutes, and statically fishing the slag, wherein 0.5Kg of a refining agent, 1Kg of a TC-LQJ1 slag removing agent and 0.3Kg of a A1SP4.5 aluminum silicon phosphorus intermediate alloy modifier in each heat preservation furnace.

(2) And (4) shaking the oxide skin on the surface of the aluminum liquid by using a stainless steel cup spoon, scooping the aluminum liquid into a water inlet of a piston mold of the casting machine at the position of shaking the oxide skin, and pouring a piston blank by using the casting machine.

(3) The piston blank is placed in a heat treatment cage, the piston blank is placed in a pit type heat treatment furnace, the piston blank is heated from 200 ℃ in the furnace for 3 hours to 520 DEG +/-5 DEG, the temperature is kept for 4 hours, the piston blank is placed in a quenching tank with the water temperature of 60 DEG +/-10 DEG, the heat treatment cage is shaken left and right and up and down, the air is dried after 2-3 minutes, the piston blank is placed in an aging furnace, the temperature of the aging furnace is 50-80 DEG, the piston blank is heated for 1.5 hours to 255 DEG +/-5 DEG, and the temperature is kept for 5.

The method of the invention and the conventional treatment method are respectively adopted to treat the piston, and the conventional treatment method comprises the following steps: and (3) performing solution treatment on the piston at 500 +/-5 ℃ for 3.5h, and performing artificial aging treatment at 206 ℃ for 8 h.

TABLE 2 comparison of various performance indexes of M174+ conventional heat treatment process and heat treatment process of the present application

The comparison of various performance indexes of the piston after treatment is shown in a table 2, various technical indexes in the table show that the material and the heat treatment process can be used as a large-discharge large-size piston production process, and the new heat treatment process has obvious advantages in the detection comparison of items such as normal-temperature tensile strength, high-temperature tensile strength, volume stability, metallographic structure, 280 ℃ attenuation test and the like.

Claims

1. A heat treatment process of an aluminum alloy M174+ material piston is characterized by comprising the following steps:

(1) putting raw materials into a smelting furnace, heating to 680-720 ℃, adding chemicals in a centralized manner, pressing the chemicals into aluminum liquid by using a bell jar, stirring, standing for 10 minutes after stirring, fishing out residues on the surface of the aluminum liquid by using a strainer, then putting the aluminum liquid into a turnover bag, putting the turnover bag into a heat preservation furnace of a production site for secondary chemical treatment, using a degassing vehicle, using a carbon rod to flush nitrogen into the aluminum liquid while stirring, and standing for fishing out residues;

(2) after the slag is fished, swinging away oxide skin on the surface of the aluminum liquid by using a stainless steel cup spoon, scooping the aluminum liquid at the position where the oxide skin is swung away, pouring the aluminum liquid into a water inlet of a piston mold of the casting machine, and pouring a piston blank by the casting machine;

(3) the piston blank is placed in a heat treatment cage, is placed in a pit type heat treatment furnace, is heated from 200 ℃ in the furnace for 3 hours to 520 DEG +/-5 DEG, is kept warm for 4 hours, is then placed in a quenching pool with the water temperature of 60 DEG +/-10 DEG to be cooled, enables the heat treatment cage to shake left and right and up and down, is taken out after 2-3 minutes and dried, is placed in an aging furnace, the temperature of the aging furnace is 50-80 DEG, is heated for 1.5 hours to 255 DEG +/-5 DEG, and is kept warm for 5.5 hours.

2. The heat treatment process of the aluminum alloy M174+ piston as claimed in claim 1, wherein the chemicals are a slag remover, a refining agent, an aluminum-silicon-phosphorus intermediate alloy modifier.

3. The heat treatment process of the aluminum alloy M174+ piston as claimed in claim 2, wherein the slag remover is: TC-LQJ1 slag remover.

4. The heat treatment process for the aluminum alloy M174+ piston as claimed in claim 2, wherein the refining agent is: xuzhou Lida refining agent.

5. The heat treatment process of the aluminum alloy M174+ piston as claimed in claim 2, wherein the modifier of the Al-Si-P master alloy is: A1SP4.5 AlSiP master alloy modifier.