作为生经理、项目经理、质量经理或工程师，您可以在产品、部件或工件中遇到残余磁性。
在其他事物中，如电机和齿轮零件、滚动或滑动轴承、整个加工中心以及医疗技术中的注射针或制表行业的精密零件中，都存在残余磁性。越来越多的公司正在其图纸中指定规定的残余磁性限制，其组件必须遵守这些限制。冲压和折弯机制造商可使用高达 20 A/cm 的工具。部件的清洁或电镀要求通常更高，零件允许的最大值为 2-8 A/cm。
Residual magnetism can be found, among other things, in motor and gear parts, in rolling or sliding bearings, in entire machining centres, and also in injection needles in medical technology or in precision parts in the watchmaking industry. More and more companies are specifying defined residual magnetism limits in their working drawings, which their components must comply with. Manufacturers of stamping and press brakes accept up to 20 A/cm on tools. Cleaning of parts or electroplating is generally more demanding, with parts being allowed to have a maximum of 2-8 A/cm.
01
什么是残余磁性？
当铁磁性材料暴露在外部磁场中时，工件的磁化程度或多或少取决于材料和形状。磁化分三个阶段进行。首先，布洛赫墙移动并开始熔断。后来，材料的基本磁铁与外部磁场对齐，最后固定在材料（磁偶极子）中。例如，当磁铁粘附在部件上或使用磁性夹紧设备时，就会发生此情况。磁场强度在单位 A/m（安培/米）中以场强度 H 为单位进行测量。去除外部磁场后，元件中仍保留一定量的磁化。此部分称为声词;根据区间的不同，使用 A/m、A/cm、mT（米利特拉）或高斯单位。
When a ferromagnetic material is exposed to an external magnetic field, the workpiece is magnetized to a greater or lesser extent, depending on the material and shape. The magnetisation takes place in three stages. First, the Bloch walls shift and begin to fuse. Later, the elementary magnets of the material align themselves with the external magnetic field and are finally anchored in the material (magnetic dipole). This happens, for example, when a magnet adheres to the component or when magnetic clamping devices are used. The strength of the magnetic field is measured as field strength H in the unit A/m (ampere/meter). After removal of the external magnetic field, a certain amount of magnetisation remains in the component. This part is known as remanence or residual magnetism; depending on the economic area, the units A/m, A/cm, mT (millitesla) or Gauss are used here.
不同类型的残余磁性及其成因
02
对部件的第一次磁力影响已在钢厂中发生。退火或轧制过程后，铁磁钢可以在地球磁场的影响下在冷却过程中磁化。铁磁成分中可出现以下三类残余磁性： 1、具有主极形成的元件的二极磁化2、精细极磁化，这是具有小范围的磁场的零件表面的磁化3、两种磁化的混合形式在组件的不同部分
The first magnetic influence on the component already occurs in the steel mill. After the annealing or rolling process, ferromagnetic steels can be magnetized during cooling under the influence of the earth’s magnetic field. The following three categories of residual magnetism can occur in ferromagnetic components:
1、Dipole magnetization of the component with a main pole formation
2、fine-polar magnetization, that is a magnetization at the part surface with a small range of the magnetic stray field
3、Mixed form of both types of magnetisation in different parts of the component
借助磁性观察器（1）可以看到由于硬化过程而导致的滚珠轴承壳上的残留磁性。
组件上的细极磁化强度（例如通过磁性螺丝起子），通过磁查看器（1）可见以及近距离泄漏磁通的示意性截面图（2）
组件的偶极磁化强度（例如在检测到磁性裂纹后），用磁查看器（1）可视化并显示扩展漏磁通量的示意性截面图（2）
钢铁厂中的工艺往往不会使原料磁化。这样的部件甚至可以具有中性的磁性结构，这从磁性的观点来看是理想的。
联系到磁性提升和夹紧装置接触会破坏理想的磁性状态，在工业上广泛使用磁性裂纹检测。
细极剩磁会在进一步的制造过程中产生：零部件可能会与随机极性强磁场接触无数次。这些可以来自各种来源或过程，例如线性振荡器，切削工具，硬化过程或类似过程。这样的磁效应趋向于导致部件的细极性磁化。
The processes in the steelworks tend not to magnetize the raw material. Such parts can even have a neutral magnetic structure which is ideal from a magnetic point of view.
Contact with magnetic lifting and clamping devices destroys the ideal magnetic state and the magnetic crack detection widely used in industry.
Fine-pole residual magnetism is created in the course of a further manufacturing process: a component can come into contact countless times with more or less strong magnetic fields of random polarity. These can come from various sources or processes, such as linear oscillators, cutting tools, hardening processes or similar. Such magnetic effects tend to lead to a fine-polar magnetization of the component.
下面的列表显示了哪些过程会导致残余磁性，以及这有多高。剩余磁性取决于通过该过程的组件的材料。给出的值为使用霍尔探头在0.5 mm的测量距离处测得的标准值。 >100 A/cm 裂纹测试（磁性颗粒和通量泄漏测试）>100 A/cm 使用负载提升或处理磁铁（永久或电气）50×>100 A/cm 使用夹紧装置（永久或电气）50×>100 A/cm 放下磁性支架（例如拨号表）30~60 A/cm 焊接工艺30~50 A/cm 加工，带磁化工具、夹紧装置等。30×40 A/cm 使用磁化工具、支架、夹持器等进行处理10~20 A/cm电镀和电腐蚀工艺（镀铬、侵蚀等）5~15 A/cm 部分PVD涂层工艺（如磁龙溅射）5~15 A/cm 成型工艺（材料结构变化）
不同的场强度值在实践中意味着什么下面是一些特定词值如何影响对象的示例：
> 1000 A/cm = 永磁体的强度 20~200 A/cm = 接触磁性夹紧板后磁化，具体取决于材料性能> 10 A/cm = 组件开始相互粘附> 8 A/cm = 金属芯片粘附> 4 A/cm = 最小的金属部件粘附并污染工件> 2 A/cm = 研磨灰尘粘附> 1.5 A/cm = 电子束焊接受到影响~ 0.4 A/cm 大约地球磁场的磁场强度
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