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Your location: Home > Related Articles > What types of wear tests are commonly used in the world? This is the case

What types of wear tests are commonly used in the world? This is the case

Author: Released in:2022-12-08 Click:41

 

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In today's society, there are four types of test instruments that are widely used in the field of wear resistance: wear tester, scratch tester, oscillation tester and linear wear tester. The establishment of standards for coating abrasion resistance test methods unifies and standardizes the detection methods and quality requirements of various materials, and also provides a design basis to be followed for the development and development of various standard abrasion resistance test instruments. Below, Shanghai Qianshi will introduce some commonly used wear tests for you.

Rotating friction rubber wheel method (Taber test)

National standard GB/T1768- Although the method and the instrument specified in -79(89) have the same working principle, is the rotational speed of the rotgrinding wheel not clearly specified, and the test results are based only on the mass loss of the coating (weight loss method) after grinding with the specified number of grinding rotations. method representation. The rotating friction rubber wheel method can be widely used in coatings, coatings and wear resistance testing of metal and non-metal materials, but the rubber grinding wheel used for grinding needs to be trimmed regularly and timely updated. The international standard ISO 7784.2--97 stipulates that the wear resistance of the coating is measured by the method of rotating friction rubber wheel, that is, under the specified test conditions of the rotating speed of the rotating disc at 60r/min and the pressure arm reaching a certain load, the rubber wheel embedded with emery is used. The hard rubber friction wheel of the abrasive wears the surface of the coating, and the wear resistance can be calculated bythe average value of the mass loss of the coating (weight loss method) after grinding at a certain number of grinding revolutions, or by the average grinding required to wear a certain coating thickness. There are two ways to express and evaluate the number of revolutions (speed method). Compared with the two, the weight loss method has strict requirements on the sample weighing accuracy, but is not affected by the thickness of the coating; while the revolution method is intuitive and convenient in measuring, without weighing, but the measurement of coating grinding thickness requires very strict.

Test method for abrasion resistance of coatings

Abrasion resistance of coatings refers to the ability of the coating surface to resist a certain mechanical action is usually measured by grinding wheel or sand impact test. It is one of the important characteristics of coatings often subject to mechanical wear during use, and it is related to the hardness and other physical properties such as strength and flexibility are closely related. Commonly used test methods for coating wear resistance at home and abroad and their main technical characteristics.

Test method for falling sand

Using this test method, the natural abrasive The choice has a direct effect on the test results and thus on the hardness, grain size and geometry of the sand grains. The requirements are strict. The national standard GB/T5237.5-2000 stipulates that the standard sand that meets the requirements of the standard GB/T 178-77 must be used as an abrasive. ASTMD 968-93 stipulates that the abrasion resistance of organic coatings should be measured by a falling sand abrasion tester, that is, the natural quartz sand of the specified place of origin is used as scrental agent and that it falls freely from a certain height through the test tube to abrade the surface of the sample, and the wear resistance is determined by the wear. The volume (L) of abrasive consumed by the coating per unit thickness of the area, and the abrasion resistance of the coating is evaluated by calculating the abrasion resistance coefficient. It should be noted that in the above two standards using the falling sand erosion test method, although the wear resistance tester is used with the same main technical parameters, because the particle size of the natural sand abrasive used is different, the isotropic outflow volume is 2L abrasive The flow rate is not the same, the former is specified as 21 ~ 23.5s and the latter is specified as 16 ~ 18s.

Sandblasting impact test method

ASTM D 658 -81(86) regulation Blast abrasion (sandblasting) test is used to determine the abrasion resistancen organic coatings. This method is to adjust the output pressure of the air pump so that the air flow rate at the nozzle of the tester is 0.07 m3 /min to ensure the average spray rate per minute. ( 44 ± 1 ) g of diamond rays affect the coating and coating abrasion resistance The wear is evaluated by calculating the abrasion resistance coefficient based on the mass (g) of abrasive consumed per unit thickness of the coating by sanding a given area. Therefore, silicon carbide with a particle size range of 75-90 μm should be selected as an abrasive according to the standard, and the output pressure of the air source and the uniform spraying speed of the abrasive become the decisive factors influencing the test results.

Reciprocating wear test method

Layer thickness (µ m ) or layer mass (mg ) decrease and the abrasion resistance of the coating is evaluated by theto calculate wear resistance. Both ISO 8251-87 and JIS H8682 specify the measurement of abrasion resistance of anodized films on aluminum and aluminum alloys using a friction wheel wear tester. This test method is to make the coating layer and abrasive sandpaper glued to the outer edge of the friction wheel go back and forth in a plane under the specified test conditions, and the friction wheel rotates at a small angle (0.9o) after each double stroke ). The test conditions are easy to control, and there are no problems such as grinding wheel dressing, aging, sand flow rate, sandblasting shape, etc., which are difficult to control in other methods, so the repeatability of the test results is good. It is widely used in the abrasion resistance test of plastic, rubber and metal materials.

my country already has a national standard GB/T1768-79(89) "Paint film resistanceIn recent years, GB/T5237.5-2000 stipulates that the abrasion resistanceof fluorocarbon paint film on the surface of aluminum alloy building profiles should be determined by falling sand abrasion resistance testing machine. In summary, it is not difficult to see that there are various methods of paint coating abrasion resistance test at home and abroad, each with its own characteristics.Although people have different views on the above different testing methods and the evaluation of their application performance, as for the development and promotion of multiple detection methods, the rotating friction rubber wheel method, the falling sand method and the sandblasting method are still used. law is more common.

Until now, industrially developed countries have corresponding wear test methods for different materials. For example, the Japanese industrial standard JIS H8503 defines the test method for the abrasion resistance of metal films; JIS H8615 Describes the abrasion resistance test of thechrome plating layer; another example is the standard ASTM D 968-93 and ASTM D 658-81(86) of the American Society for Testing and Materials, which states that the abrasion resistance of organic coatings should be measured by the falling sand method and the sandblast method. ; while the international standard SO7784.2-97 uses the rotating friction rubber wheel method to measure the abrasion resistance of paints and varnishes; in IKS08251-87 and JISH8682, it is stipulated that the friction wheel wear tester is used to measure the anode of aluminum and aluminum alloy surfaces. The abrasion resistance coefficient of the oxide film.

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