1范围
本部分是有关喷射清理用金属磨料的抽样和试验的国家标准GB/T19816的一个部分。
金属磨料的类型和对每种类型的要求均包含在ISO 11124的各个部分中。
ISO 11124和 CB/T19816系列是有关喷射清理用金属磨料的一套密切相关的标准。有关这两个系列标准的所有信息可参见附录A。
GB/T19816的本部分规定了喷射清理用金属磨料的维氏硬度的测定方法。
本部分所述方法不宜用于颗粒尺寸小于0.3mm的磨料测试。
注:对0.3 mm 以下的颗粒（颗粒等级为S 040/G 050）的精准测定是非常困难的。
2规范性引用文件
下列文件中的条款通过GB/T19816的本部分的引用而成为本部分的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本部分，然而，鼓励According to本部分达成协议的各方研究是否可使用这些文件的新的版本。凡是不注日期的引用文件，其新的版本适用于本部分。
GB/T 4340.2—1999金属维氏硬度试验第﹖部分:硬度计的检验( idtISO 6507—2:1997)
GB/T19816.1—2005涂覆涂料前钢材表面处理喷射清理用金属磨料的试验方法惇第l部分:抽样（ISO 11125—1:1993，IDT)
3设备
3.1硬度试验机
具备高达10N的测试力和可将硬度试验压痕放大至少200倍的光学装置。
3.2硬度比照板
具有与被测试产品相近的硬度范围。
3.3金相样品固定材料
硬化温度低于140℃。
注:固定材料的拉伸极限值至少应是因施加试验力而在试样上产生的压应力值的2倍。
示例:公称直径0.4mm的颗粒具有大约0.126mm2的面积，在施加9.807N试验力时，产生约80N/mm2的压应力，固定介质的拉伸极限值应大于160N/mm2。
注:使用硬化温度高于140C的金相固定材料，会对测试样品的材质产生回火作用而影响所测得的硬度值。
3.4金相样品模具
直径至少25 mm。
4抽样
According to the provisions of GB/T19816.1-2005, take representative samples of the tested products.
5 Sample preparation
A monolayer of abrasive grains is laid on the bottom of the metallographic sample mold (3.4) and embedded in the metallographic sample holding material (3.3). The test samples thus obtained can be ground and polished. The samples were wet ground until half the nominal diameter of the particles was exposed. The fixed support surface and the test surface shall be parallel.
Note 1: Each test sample shall provide sufficient abrasive particles as far as possible to ensure that at least half of the test surface is covered by abrasive particles after grinding and polishing.
Note 2 to entry: These metallographic samples prepared for hardness testing can also be used for the determination of grain defects and microstructure as described in International Standard ISO 11125-5 (see Appendix A).
6 steps
Take duplicate samples for measurement.
6.1 Perform all hardness measurements at the ambient temperature specified in GB/T 4340.2-1999. 6.2 Before measuring the hardness of the sample, it should be calibrated with a hardness comparison plate (3.2) similar to the product to be tested.
6.3 When the diameter of the abrasive particles to be tested is greater than 0.5 mm, measure the hardness of the sample with a test force of 9.807N, which is equivalent to HVI. When the diameter of the abrasive particle to be tested is 0.3mm~0.5mm, the hardness of the sample is measured with a test force of 4.904 N, which is equivalent to HVO.5. The test time is 10s~15s.
6.4 Do not measure the particles located less than 3 mm from the edge of the test sample, and make a hardness indentation at half the length between the center and the edge of each particle.
Metal abrasives sometimes contain undetected internal shrinkage defects and voids beneath the surface of fixed and polished metallographic specimens. These hidden voids create inconsistent hardness indentations and give false hardness readings. These hardness indentations shall be ignored.
Note: The definition of defects is given in the corresponding test material part of the international standard ISO 11124.
6.5 Make 10 available hardness indentations on different particles of each test sample, omit all indentations whose length difference between the two diagonals is greater than 5%, and record the obtained 10 hardness values.
7 Expression of results
Calculate the percentage consistent with the requirements specified in the corresponding part of the international standard ISO 11124 (see Appendix A) from the obtained 10 hardness values.
Note: The arithmetic mean can be calculated, although it is not necessary when using this method to assess conformity with the corresponding part of the International Standard ISO 11124 (see Appendix A).
8 conversion of hardness value
There is no general method for accurately converting Vickers hardness to other hardness or tensile strength. Such conversions should therefore be avoided unless a reliable basis for these conversions can be obtained through comparative experiments.
Rigorous comparison of hardness values is only possible with equivalent test forces.
9 test report
The test report should at least include the following:
a) identify all details necessary for the product under test as specified in the corresponding part of the international standard ISO 11124;
b ) The standard number of this part (GB/T19816.3-2005);
c) test results;
d) deviations from specified test methods;
e) test date;
f) Testers.
