Classification, characteristics, cutting process and surface preparation of aluminum tubes

Aluminum tubes are mainly divided into the following categories

According to the shape, it can be divided into square tube, round tube, riffled tube, profiled tube and universal aluminum tube.

It can be divided into seamless aluminum tube and ordinary extruded tube according to extrusion mode

According to the precision, ordinary aluminum tubes and precision aluminum tubes are classified. The precision aluminum tubes generally need to be re processed after extrusion, such as cold drawing, fine drawing and rolling

By thickness: ordinary aluminum tube and thin-walled aluminum tube

Performance: corrosion resistance, light weight.

characteristic

It is a kind of high-strength duralumin, which can be strengthened by heat treatment. It has medium plasticity in annealing, hard quenching and hot state, and good spot welding. When gas welding and argon arc welding are used, the aluminum tube tends to form intergranular cracks; The machinability of aluminum tube is good after quenching and cold work hardening, but it is not good in the annealing state. The corrosion resistance is not high. Anodic oxidation and painting methods are often used or aluminum coating is added on the surface to improve the corrosion resistance. It can also be used as die material.

Advantages of aluminum pipe: First, advantages of welding technology: thin wall copper aluminum pipe welding technology suitable for industrial production is called a world-class problem, and is the key technology of replacing copper with aluminum for connecting pipe of air conditioner.

Second, the advantage of service life: from the perspective of the inner wall of the aluminum tube, since the refrigerant does not contain water, the inner wall of the copper aluminum connecting tube will not be corroded.

Third, energy saving advantages: the lower the heat transfer efficiency of the connecting pipeline between the indoor unit and the outdoor unit of the air conditioner, the more energy will be saved, or the better the insulation effect, the more power will be saved.

Fourth, excellent bending performance, easy to install and move

Cutting process

Aluminum pipe steel brush, slag hammer and sand wheel on aluminum pipe are strictly prohibited to share with carbon steel pipe. The special NC blade for processing stainless steel produced by aluminum tube manufacturers cannot be shared with carbon steel. The stainless seamless steel pipe shall not be marked with sewing needle or paint, but with chlorine free black ink. Some damages caused in the production process of aluminum tubes, such as welding spatter, arc damage, dental plaque and mechanical equipment scratches, should be completely removed as far as possible (after rough grinding with sand wheel pieces, polish with grinding and polishing machine).

Aluminum tube manufacturers produce and process many aluminum tube parts and carry out several kinds of cutting. For example, aluminum tubes have bores, bores, cones, etc. In addition, in addition to turning, some thick walled steel pipes also need to be milled, planed, clamped and cut. Therefore, when turning aluminum tubes, it is necessary to consider the overall situation, fully consider the relationship between the processing procedures of each part of aluminum tubes, formulate reasonable processes and production processing methods, and avoid one-sided.

For example, in the production and processing of thick walled steel tubes of shaft type, in addition to turning, CNC lathe operators must also provide convenience for the grinder: for example, CNC lathe operators must leave appropriate machining allowance for cutting, because the allowance is too small to cut, and the allowance is too much, which will increase the cutting time and easily burn the surface of British aluminum tubes.

In addition, drilling and milling qualified center holes is the basis of internal hole cutting. If there is no good center hole, the shaft parts of aluminum tube that meet the requirements cannot be cut.

Surface preparation

Research on rapid detection method of corrosion resistance of aluminum tube surface, deposit a layer of silane/corrosion inhibitor composite film on the aluminum tube surface according to the immersion method, and use a variety of experiments to investigate its corrosion resistance.

As a fluid medium for the transportation of aluminum pipe, its anti-corrosion treatment has become a major research topic in the material industry. The anti-corrosion measures such as chromate passivation, anodic oxidation and silane treatment have achieved corresponding results. However, the online production inspection of corrosion resistant coatings has never been a breakthrough.

experiment

1. Preparation of aluminum pipe surface

Cut the industrial pure aluminum tube with a diameter of 7.8mm and a thickness of 1.0mm into several samples with a length of 5cm, and seal both sides of the sample with modified material methyl ester. Fully consider that the surface of aluminum pipe may be polluted, and prepare it according to the following process:

Ultrasonic cleaning for 10min → purified water cleaning → alkaline solution cleaning → purified water cleaning → drying.

2. Preparation of working solution

Mix silane, long-chain ester corrosion inhibitor, ethanol and purified water according to the corresponding volume ratio, use a magnetic stirrer to stir at a uniform speed at room temperature until silane is completely hydrolyzed, and leave it for standby.

3. Preparation of corrosion resistant film

Composite films of silane synergistic corrosion inhibitor modified materials were prepared by impregnation method. Soak the prepared sample in the silane/corrosion inhibitor composite solution above 40 ℃, take it down at an average speed after 1 minute, dry it with compressed air in a drying oven at 60 ℃ for 3-4 hours, and then paint the film for inspection.

Source: Network

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