锻件无损探伤工艺实操｜Non-Destructive Testing of Forgings in Practice

摘要：磁粉探伤检表面与近表面裂纹，超声探伤检内部裂纹、缩孔、夹杂。探伤时机、表面状态、磁化与探头校准决定检出率；探伤只负责检出，不能消除缺陷。
Abstract: Magnetic particle testing finds surface and near-surface cracks; ultrasonic testing finds internal cracks, shrinkage and inclusions. Timing, surface condition and calibration decide the detection rate, and no test removes a defect.

正文： 无损探伤不破坏锻件本体，检出肉眼难以发现裂纹缺陷。
Main text: Non-destructive testing finds cracks that the eye cannot, without cutting the forging.

一、磁粉探伤：查表面与近表面
1. Magnetic particle: surface and near-surface

适合铁磁性材料，主要检出表面、近表面裂纹。工艺要点：锻件表面要清理，氧化皮、厚油污会干扰磁痕；磁化方式、磁粉介质按照标准执行；探伤时机：锻件冷却到室温之后，温度太高不能做磁粉探伤；探伤完成做退磁处理。
Suited to ferromagnetic materials, it detects surface and near-surface cracks. The surface must be clean: scale and heavy oil interfere with the indication. Magnetisation method and the particle medium follow the standard. Timing matters — the forging has to be at room temperature, since a hot part cannot be inspected this way — and the part must be demagnetised afterwards.

二、超声波探伤：查内部
2. Ultrasonic: internal defects

主要检测锻件内部缺陷，内部裂纹、缩孔、夹杂。工艺要点：锻件表面粗糙度不能太差，粗糙表面耦合不好；做好探头校准；参考对应行业标准做缺陷当量判定。
Ultrasonic testing looks inside the forging for cracks, shrinkage cavities and inclusions. Surface roughness has to be reasonable — a rough surface couples badly. Calibrate the probe, and judge defect size against the equivalent reflectors defined in the applicable industry standard.

三、工艺管控三件事
3. Three control decisions

• 明确哪些锻件需要探伤、探伤比例（全检还是抽检）；
  Decide which forgings are tested and at what rate — full inspection or sampling.
• 规定探伤工序放在哪个节点：锻后？热处理之后？大部分重要锻件热处理完成之后探伤；
  Fix where the test sits in the route. After forging, or after heat treatment? Most critical forgings are tested after the final heat treatment.
• 探伤记录保存，记录批次、探伤结果；不合格锻件隔离标识。
  Keep the records: batch, result, and isolation and marking of any rejected forging.

注意：探伤只是检出手段，不能消除缺陷，发现批量缺陷，需要回头优化锻造热处理工艺。
One point worth stating plainly: a test detects, it does not correct. A batch of indications is a signal to go back and change the forging or heat treatment process.

小结 磁粉查表面裂纹，超声查内部缺陷；控制锻件表面状态，严格按照标准执行探伤，完整留存探伤记录。
In short. Magnetic particle for surface cracks, ultrasonic for internal ones. Control the surface condition, run the test to the standard, and keep the records complete.