KR100201545B1 - Aluminum-manganes alloy with high strength - Google Patents

Abstract

The present invention relates to a high-strength, high-conductivity Al-Mn-based alloy which is a material of an air-cooled heat exchanger. It is about.

An object of the present invention is the development of a new aluminum alloy material that satisfies the formability, cutting properties, corrosion resistance, etc. according to the pin-tube integrated at the same time.

Therefore, in the present invention, Al, Mn-based A3003 alloy was used as a basic composition, and Cu, Mn, and Ti were added for the purpose of thinning due to the improvement of strength, and Pb was added to improve the machinability.

Description

High strength, high conductivity aluminum-manganese alloy for heat exchangers

The present invention relates to a high-strength, high-conductivity Al-Mn-based alloy, which is a material of an air-cooled heat exchanger. It is about.

In general, in selecting the use of aluminum alloys by material, it is necessary to comprehensively examine the properties such as strength, corrosion resistance, and workability.

It is difficult to satisfy all of these items, and the necessary characteristics and priorities must be determined and reviewed.

When selecting materials only for strength, the strength is generally increased in the order of pure aluminum, Al-Mg, Al-Mg-Si, Al-Cu, and Al-Zn-Mg. Al-Mn-based A3003 alloy In the case of, it can be expected to improve the strength by about 10% compared to the general alloy A1100, which has a purity of 99.0% or more.

If the aluminum alloy material is selected in terms of corrosion resistance, the alloy material used in medicine and food containers and plants may use pure Al-based alloys, and high purity aluminum alloys may be used when more corrosion resistance is required.

In freshwater, on the other hand, Al-Mn-based A3003 alloys, rather than pure Al, generally produce good results.

In terms of processability, A1100, A3003, and A3004 alloys are generally used where a complicated shape is required, such as household articles.

These materials are complex in shape and require special consideration in the components and manufacturing process.

Since aluminum alloy has excellent hot workability, it is possible to produce a material having various cross-sectional shapes by extrusion processing.

When the material is selected in consideration of the thermal conductivity, high Al A6101 representing 66% IACS, A1060, and high strength A6101 representing 55% IACS are used.

On the other hand, the A3003 alloy has a value of about 50-55% IACS.

Considering the above criteria, the characteristics of the aluminum alloy material for the tube-fin integral heat exchanger can be summarized as follows.

First, the cooling water circulates inside the tube, so it is always exposed to the corrosive environment and must be an alloy having high corrosion resistance. Second, in order to manufacture a heat exchanger in which the tube and the fin are integrated, the flesh of the fin is added to the outside of the tube in advance. Extrusion should be performed using bridge dies, so hot workability should be excellent. Third, in order to make the product thinner and more efficient, it should be a high-strength alloy with a tensile strength of about 13Kg / mm2 or more. In addition to the pre-extruded pin portion to be cut and shaved through a shaving process, it must be an alloy having excellent machinability.

In the present invention, Al-Mn-based A3003 alloy was adopted as a base alloy in order to develop an alloy that satisfies all the above requirements.

The A3003 alloy is an aluminum alloy that has excellent corrosion resistance, stress corrosion cracking resistance, formability, and weldability along with A1100 alloy.

However, the A3003 alloy has a weakness compared to the A2014 alloy or the A7075 alloy in terms of machinability, and this disadvantage causes a problem in the shaving process of the tube-fin integral heat exchanger.

An object of the present invention is the development of a new aluminum alloy material that satisfies the formability, cutting properties, corrosion resistance, etc. according to the pin-tube integrated at the same time.

Therefore, in the present invention, Al, Mn-based A3003 alloy was used as a basic composition, and Cu, Mn, and Ti were added for the purpose of thinning due to the improvement of strength, and Pb was added to improve the machinability.

The chemical composition of the aluminum alloy material of the present invention is shown in Table 1 and shown in Table 2 with reference to the chemical composition of the conventional commercial alloy A3003 alloy.

By adding Mn to Al, hardening of the material can be induced by the solid solution strengthening effect and the dispersion of fine precipitates, and the addition of Ti serves to distribute the precipitates of the alloy more finely and evenly.

Hereinafter, the configuration of the present invention will be described as the process examples.

Alloys having the composition of Alloy 1, Alloy 2, and Alloy 3 shown in Table 1 were prepared into billets by a general casting method, homogenized at 550 ° C. for 12 hours, and then preheated to 470 ° C., 500 ° C., and 530 ° C. Hot extrusion was performed.

A bridge die designed to fabricate a fin-tube integral heat exchanger was used, and after shaping, the shaving process was carried out to form a fin on the outside of the tube after calibration. The cutting speed was 0.2m / min.

After the shaving process, the tube side was bent at a bending angle of about 90 ° and the bending method was press.

The pressure on the press was about 35 Kgf.

As a result of the extrusion process, the alloy of the present invention was found to have a very good moldability so that the thickness of the inner tube can be compressed to about 1 mm, and the cutting process does not cause the wear of the cutting edge or the bad cutting surface. And the like.

Table 3 shows the mechanical properties of each alloy developed in the present invention.

Claims (3)

0.6 wt% Si, 0.5 wt% Fe, 0.1 wt% Cu, 0.5 wt% Mn, 0.25 wt% Ti, 0.4 wt% Zn, 0.2 wt% Pb and the remainder consists of aluminum and inevitable impurities High strength, high conductivity aluminum-manganese alloy for heat exchanger, characterized by high tensile strength of 15Kg / mm2, yield strength of 7.0Kg / mm2, elongation of 24% or more, Brinnel hardness of 38 or more, and excellent machinability. 0.6 wt% Si, 0.5 wt% Fe, 0.1 wt% Cu, 0.1 wt% Mn, 0.25 wt% Ti, 0.4 wt% Zn, 0.2 wt% Pb and the rest consists of aluminum and inevitable impurities High strength, high strength aluminum-manganese alloy for heat exchanger, characterized by high tensile strength of 16Kg / mm2, yield strength of 8.0Kg / mm2, elongation of 24% or more, Brinnel hardness of 38 or more, and excellent machinability. 0.6 wt% Si, 0.5 wt% Fe, 0.1 wt% Cu, 0.1 wt% Mn, 0.4 wt% Ti, 0.4 wt% Zn, 0.2 wt% Pb and the rest consists of aluminum and inevitable impurities High strength, high strength aluminum-manganese alloy for heat exchanger, characterized by high tensile strength of 15Kg / mm2, yield strength of 7.0Kg / mm2, elongation of 21% or more, Brinnel hardness of 39 or more, and excellent machinability.