QATM的布氏硬度计范围包括显微和宏观硬度测试型号。除了布氏硬度测试外,所有型号也都适用于多种测试方法,范围从半自动操作到全自动化。QATM产品的特点是操作舒适、精细的工程设计和准确的结果。
Johann August Brinell(瑞典)在1900年巴黎的世界展览上展示了他新的硬度测试方法。 在该方法中,一个碳化物球以一定的力垂直地压入样品的表面。这将在样品表面中形成一个压痕。压痕的直径d是使用测量显微镜确定的,然后计算出布氏硬度值或参考相应的表格。
布氏硬度的计算公式:
对于布氏硬度测试, 适宜的测试参数的选择起着决定性的作用。
对于非常小或非常大的压入深度,布氏测试方法会变得不精确。出于这个原因, 必须选择测试力以满足下面的平均压痕直径条件:
0,24 * D < d <0,6 * D
为满足这些条件, 引入了“应力水平 B”。这取决于要测试的材料分类。
应力水平根据下面的表格来选择:
材料 | Stress level B [N/mm²] | 球径D [mm] | 测试力F [N] | Recordable Hardness Range [HBW] |
钢和铸钢 镍和钛合金 铸铁 ≥ 140 HBW 铜及铜合金 ≥ 200 HBW | 30 | 1 | 2,94,2 | 95 – 650 |
轻金属及其合金 ≥ 35 HBW
| 15 | 1 | - | 48 – 327 |
Cast iron < 140 HBW
| 10 | 1 | 98,07 | 32 – 218 |
铜及铜合金 < 35 HBW 轻金属及其合金 ≥ 35 < HBW < 80 | 5 | 1 | 49,03 | 16 – 109 |
轻金属及其合金 ≥ 35 HBW | 2,5 | 1 | 24,52 | 8 – 55 |
铅和锡 | 1 | 1 | 9,807 | 3 – 22 |
根据标准DIN EN ISO 6506
只有 >1 mm直径的球可以用来测试铸铁
确定应力程度后,可根据表格确定测试力F和球直径D。原则上,球的直径应尽可能大,以便覆盖尽可能大的区域从而尽可能代表样品表面的一部分。
在相同载荷程度下,不同球直径确定的硬度值只能在有限程度内进行比较。用相同的球直径但不同的载荷程度确定的硬度值没有可比性。因此,在给出硬度值时,必须始终给出所有参数。
根据标准DIN EN IS 6506-1,布氏硬度测试的结果按下面形式表示 :
310 HBW 2,5 / 187,2 / 20 ⇒ 布氏硬度值
310 HBW 2,5 / 187,2 / 20 ⇒ 布氏硬度缩写
310 HBW 2,5 / 187,2 / 20 ⇒ 球直径,单位mm
310 HBW 2,5 / 187,2 / 20 ⇒ 测试力 [N] = 9.807 * 测试力规格
310 HBW 2,5 / 187,2 / 20 ⇒
为符合硬度测试标准,需满足更多的先决条件:
测试温度
压痕间和压痕到边缘的距离
A Brinell hardness tester is used to determine the hardness of materials by pressing a hard steel or carbide ball into the surface under a specific load. It's commonly used for testing metals and alloys to assess their suitability for various applications.
The test involves pressing a ball of a specific diameter into the material's surface under a predetermined load. The diameter of the indentation left on the surface is then measured, and the Brinell hardness number (BHN) is calculated using the load and the indentation size.
Brinell hardness testing is ideal for metals and alloys with coarse or uneven grain structures, such as cast iron, aluminum, and steel. It's particularly useful for materials that might not provide reliable results with other hardness testing methods.
The Brinell test is advantageous for its ability to test large samples and materials with coarse grain structures. It provides a broader average of hardness due to the size of the indentation, making it less affected by surface conditions.
Accuracy can be influenced by factors such as the surface finish of the specimen, the alignment of the tester, the consistency of the applied load, and the precise measurement of the indentation diameter. Proper calibration and maintenance of the equipment are essential for accurate results.