哈尔滨彩涂钢板的铅笔硬度试验

固化膜的硬度是评价薄膜质量的关键指标，也是研究线圈涂层能否加工成型的重要指标。固化涂层硬度的测试方法有摆锤硬度、铅笔硬度、肖氏硬度等，由于铅笔硬度简单易操作，在彩钢板工业中得到了广泛的应用。

彩钢板涂层硬度通常与涂层配方组成和固化条件有关。此外，涂层厚度对固化膜的硬度也有显著影响。当涂层较薄时，温度吸收更均匀，固化均匀彻底，涂层整体硬度高；厚涂层的吸热效应有梯度效应，固化不均匀，整体硬度较低。
彩涂钢板的涂层硬度试验通常采用铅笔压痕硬度计测定，即用6h-6b范围内14个等级的已知硬度的铅笔芯来破坏涂层，其中6h最硬，6b最软。有两种测定方法：手工铅笔法和仪器铅笔法。

手笔法
用卷笔刀将铅笔削尖，露出4-6mm圆柱芯，握住铅笔使其垂直于400砂纸表面，在砂纸上打磨至端面平整，边缘锋利。然后将铅笔与涂层保持45°的角度，向下和向前施加足够的均匀压力，以折断铅笔边缘或犁削涂层。铅笔的笔划是6.5毫米。测试应从标记最硬的铅笔开始，依次测试每支标记铅笔。每级铅笔应刮5次，直到5次中至少4次刮不破涂膜铅笔为止。铅笔的硬度是被测涂层的铅笔硬度。
B仪器铅笔法
彩钢板铅笔经手工铅笔法加工后，固定在仪器小车上，使铅笔尖能与样品表面自由接触。推动手推车，使其在样品上移动6.5米。与手动方法一样，依次测试每支记号笔。每级铅笔应刮5次，直到5次中至少4次刮不破涂膜铅笔为止。铅笔的硬度是被测涂层的铅笔硬度。
到目前为止，铅笔硬度计的规格有很多，如qhq（台式）和qhq-a（便携式）等，许多厂家生产的铅笔划痕硬度计应该在市场上有售，可以作为本次测试的配套仪器。

The hardness of the cured film is the key index to evaluate the quality of the film, and it is also an important index to investigate whether the coil coating can be processed and formed. The methods to test the hardness of solidified coating include pendulum hardness, pencil hardness, shore hardness, etc. Because pencil hardness is simple and easy to operate, it is widely used in color coating industry.

The hardness of coating is usually related to the composition of coating formula and curing conditions. In addition, the thickness of the coating also has a significant effect on the hardness of the cured film. When the coating is thin, the temperature can be absorbed more evenly, the curing is even and thorough, and the overall hardness of the coating is high; the heat absorption effect of the thick coating has gradient effect, the curing is uneven, and the overall hardness is relatively low.
The coating hardness test of color coated steel plate is usually determined by pencil indentation hardness tester, that is to say, the pencil core with known hardness from 14 grades in 6h-6b range is used to break the coating, of which 6h is the hardest and 6b is the softest. There are two methods for determination: manual pencil method and instrument pencil method.
A hand pencil method
Use a pencil sharpener to sharpen the pencil to expose the 4-6mm cylindrical core, hold the pencil so that it is perpendicular to the 400 sandpaper surface, and grind it on the sandpaper until the end surface is flat and the edge is sharp. Then hold the pencil at an angle of 45 ° with the coating, and apply enough uniform pressure downward and forward to break the edge of the pencil or plow the coating. The stroke of the pencil is 6.5mm. The test shall start with the pencil with the hardest mark, and test each mark pencil in turn. Each grade of pencil shall be scratched 5 times, until at least 4 times of the 5 times can't break the coating pencil. The hardness of this pencil is the pencil hardness of the tested coating.
B instrument pencil method
After the pencil is processed by hand pencil method, it is fixed in the instrument trolley, so that the pencil tip can contact the sample surface freely. Push the trolley so that it can move 6.5m on the sample. As with the manual method, test each marking pencil in turn. Each grade of pencil shall be scratched 5 times, until at least 4 times of the 5 times can't break the coating pencil. The hardness of this pencil is the pencil hardness of the tested coating.

Up to now, there are many specifications of pencil hardness tester, such as QHQ (desk type) and qhq-a (portable type), etc. pencil scratch hardness tester produced by many manufacturers should be available in the market and can be used as the supporting instrument for this test.