The wear resistance of aluminum alloy profiles is an important technical means to ensure the profile quality. Appearance. In general, aluminum coated with a layer of protective film, the protective layer has a strong resistance to wear, the wear resistance is mainly in order to resist some friction force, make the coating hardness and cohesiveness combining comprehensive effect of the friction on the use of aluminum alloy profile caused great impact. The abrasion resistance of aluminum alloy profile coating can be expressed by the wear-resisting index. Usually, the abrasion resistance tester can be used to complete the measuring process.

Considering the use of aluminum profiles in construction projects, the commonly used testing methods for abrasion resistance of aluminum profiles coating in China mainly include:

(1) sand falling test method

(2) sand blasting test instrument method

(3) wheel grinding test instrument method

(4) Taber test method

1. Sand falling test method

Shakeout GB5237-2008 test method specifies the wear resistance of aluminum alloy profile test method, the natural quartz sand as the main shakeout wear-resisting material, adopt the principle of this test method is abrasive in free fall, a certain height to scouring of the surface of the specimen, the scour area of about 2 mm or so, using the free-falling abrasive wear resistance of aluminum alloy profile quality test.

GB5237-2008 abrasion by anodic oxidation profile specifies the shakeout test shall not be less than three hundred grams per micron, coefficient for different on the surface of aluminum alloy profiles, the processing method is completely different, but using the shakeout experiment method to test the wear resistance of aluminum alloy profiles, the principle of which is the same, but their use of test equipment, test methods and evaluation standard or there is a difference to a great extent. In the specific work will find that aluminum alloy profile coating wear resistance test with the sand falling test method is different, the use of sand falling test instrument is also different.

Preparation for sand fall test:

A. Prepare the test plate according to the standard requirements and conduct the test at the appropriate temperature and under appropriate conditions.

B. Pour a certain amount of sand into the funnel to check the sand flow falling from the lower end of the pipe. Use the bottom adjustment screw to calibrate the device until the two positions of 90c are observed, and the heart of the sand bundle falls right at the center of the sand flow. The distance from the pipe to the painted surface shall be adjusted by the high and low adjusting nut according to ASTM standard. When measuring in the vertical direction, the nearest point is 1 inch (25mm). The user shall adjust according to the thickness of his own sample.

Pour a certain volume of sand and measure the outflow time. The outflow velocity should be 2L. This speed comes from ASTM standard, and when using international standard sand for testing, our measured speed is over 7L per minute.

C. Attention should be paid during the test. After the sand falling, the machine should be slightly tilted to pour out the excess sand in the small box at the lower part of the funnel.

The sand falling test method is very simple and convenient in operation, but it takes a long time in the process of the experiment, and the reproducibility of the measured test results is very poor, and the impact of aluminum alloy profile abrasive on the test results is large. The reason is that the way to obtain abrasive is different, even in a certain degree can meet the basic requirements of abrasive particles in the abrasive, but the main shape and characteristics of abrasive particles are different, the wear of aluminum alloy profile is also different.

Therefore, in order to ensure the strong contrast of the experimental results, the abrasive obtained in the same way should be used in the specific experiment, and the quality of the abrasive should be checked before the use of abrasive, and at the same time, check whether the degree of drying of the abrasive meets the requirements of the experiment.

2. Sandblasting test method

The sand blasting tester method is to spray very dry silicon carbide particles on a small test area of aluminum alloy profile under favorable conditions of air drying until the metal is exposed. The wearability of aluminium alloy profile, namely the average wear-resisting degree of aluminium alloy profile, is decided by the quality of silicon carbide that gush grinds time and use.

Sandblasting tester is made of stainless steel, glass, brass, or a few more hard materials, mainly by two pipe combination form, between the two tubes are fixed by coaxial and gradually perfect, the connectivity of outer tube with compressed air generator, control valves to control the velocity of which provide effective control of gas and dry abrasive through the tube in the outlet after mixed with air, direct injection on the surface of the aluminum profile test.

In some countries on the aluminum alloy profile in the sand blasting test method by the standard is consistent, but there is a little difference in some of the details of the test, such as the sand blasting test in the grinding size of the provisions are different.

The time required by sandblasting test method in the test process is very short, and the test results are obtained by comparing the test results of sample and standard sample, so the obtained results have a strong reproducibility in the whole process. In addition, attention should be paid to whether the nozzle of the sandblasting experimental instrument is worn. If there is wear, the nozzle should be replaced in time to ensure the accuracy of the test results.

3.wheel grinding test instrument method

Grinding wheel tester method is also called the wheel wear tester method, also called the method of abrasion test at the same time, the basic principle of wheel grinding tester method is mainly follow certain test conditions, through the sample and friction wheel grinding sand paper on the outer edge of planar reciprocating movement, when after completion of reciprocating motion again and again, the grinding wheel will be through the rotation Angle, gradually formed a sandpaper, has not been used this new abrasive paper and test area formed by mutual contact, and then continue to grinding operation process. The wear resistance of wheel grinding tester is determined by the thickness of test and the quality of sample.

Grinding wheel tester method is only applicable to the surface is very smooth specimens, and easily to timely control of sample condition, did not appear in the process of the whole test dressing of grinding wheel need, at the same time not met grinding wheel aging phenomenon, therefore, the whole test for the repeatability of the result of the effect is very good, but in the process of sample need to be aware of the problem is to regularly to timely replacement of the grinding wheel test paper, avoid the grinding wheel test paper did not change in time to cause adverse effect to the test results.

4.Taber Abraser method

Taber Abraser method is also known as the rotating friction rubber wheel method. Taber Abraser is mainly used for testing wear resistance. After years of research, Taber abrasion tester has been widely used in many occasions, and has been widely used in industrial development in central Europe. The main structure of the tester is composed of a rotary table, a friction wheel and a loading device.

Taber test method can be widely used in coating, coating, metal, non-metallic materials wear resistance test, but in the specific test process needs to pay attention to the rubber grinding wheel timely maintenance, and timely replacement.

To sum up, there are many kinds of aluminum coating wear resistance test method, including a variety of methods are carried out in accordance with the relevant standard test, but our country there is no standard test of shakeout, and shakeout test workload is very big, need testing time is long, will have a big impact, the results of test does not guarantee the reproducibility of the test result. In the process of testing the abrasion resistance of aluminum profile coating, sandblasting test method, wheel grinding test method and Taber test method are rarely used, which requires further research on the testing method of abrasion resistance of aluminum profile coating in daily work.

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