磁粉探伤
MAGNETIC PARTICLE INSPECTION
1. INTRODUCTION 介绍
A. The data in this subject comes from Boeing process specification BAC5424. The data about magnetic rubber comes from MIL-I-83387.
本主题中的数据来自波音工艺规范 BAC5424。有关磁性橡胶的数据来自 MIL-I-83387。
B. The data is general. It is not about all situations or specific installations. Use it as a guide to help you write minimum standards.
数据为通用数据。并非适用于所有情况或特定安装。请将其作为帮助您编写最低标准的指南。
C. Refer to SOPM 20-00-00 for a list of all the vendor names and addresses.
请参阅 SOPM 20-00-00，了解所有供应商的名称和地址。
2. DESCRIPTION 描述
A. Magnetic particle examination can be done only on materials with ferromagnetic properties, usually low alloy steels and heat-treatable stainless steels. It is a sensitive nondestructive procedure to find surface and near-surface cracks and discontinuities.
磁粉检查仅适用于具有铁磁特性的材料，通常是低合金钢和可热处理不锈钢。它是一种灵敏的无损程序，用于发现表面和近表面裂纹及不连续性。
B. Magnetic particle examinations are generally specified in overhaul instructions or service bulletins. In-service cracks can be caused by fatigue, stress corrosion, hydrogen embrittlement, or loads and can start at or near a surface. In good conditions, the procedure can find relatively small, tight cracks.
磁粉检查一般是在大修说明或服务通告中规定的。使用中的裂纹可能由疲劳、应力腐蚀、氢脆或负载引起，并可能从表面或表面附近开始。在良好的条件下，该程序可以发现相对较小的紧密裂纹。
3. PRINCIPLES OF OPERATION 操作原则
A. Magnetic particle examination uses the property of magnetic lines of force, or flux, of an applied field to go more easily through metal than through air. A defect at or near the metal surface changes the distribution of the magnetic flux and some must come out through the metal surface. The field strength is increased in the area of the defect and opposite magnetic poles occur on each side of the defect. Fine magnetic particles applied to the part are pulled to these regions and make a pattern around the defect.
磁粉检测利用的是外加磁场的磁力线或磁通量比空气更容易穿过金属的特性。金属表面或其附近的缺陷会改变磁通量的分布，部分磁通量必须穿过金属表面。缺陷区域的磁场强度会增加，缺陷两侧会出现相反的磁极。施加在零件上的细小磁性颗粒会被拉到这些区域，并在缺陷周围形成图案。
B. To find a defect, the direction of magnetization must be adjusted to put the induced flux lines across the axes of possible defects. Two types of magnetization, circular (transverse) and longitudinal, are used to magnetize the part and cause perpendicular flux paths. On some configurations, local magnetization could be necessary to be sure the magnetic field direction is correct and the field strength is sufficient.
要找到缺陷，必须调整磁化方向，使感应磁通线穿过可能存在缺陷的轴线。圆形（横向）和纵向两种磁化方式用于对零件进行磁化，并造成垂直的磁通路径。在某些配置中，可能需要进行局部磁化，以确保磁场方向正确且磁场强度足够。
C. Examination of critical areas for defects could make necessary disassembly and complete removal of surface coatings, sealants and other such layers. Because the applied or residual magnetic fields could damage such delicate parts as instruments, bearings and mechanisms, removal of the parts could be necessary.
检查关键部位的缺陷可能需要拆卸并彻底清除表面涂层、密封剂和其他类似层。由于外加磁场或残余磁场可能会损坏仪器、轴承和机械装置等精密零件，因此可能有必要拆卸这些零件。
D. Some properties of the magnetic particle method could cause nonrelevant indications, because the magnetic field can be bent also by design features such as:
磁粉法的某些特性可能会导致不相关的迹象，因为磁场也可能因设计特性而弯曲， 例如：
(1) Small fillet radii, such as smaller than 0.10-inch radius.
圆角半径小，例如半径小于 0.10 英寸。
(2) Thread roots, keyways, drilled holes.
螺纹根部、键槽、钻孔。
(3) Sudden changes in geometry or in magnetic properties within the part.
零件内部几何形状或磁性的突然变化。
E. But the locations of these nonrelevant indications are also where many service induced defects can occur. Operators must know that nonrelevant indications can occur during examination. For correct analysis of indications in these areas, much skill and experience is necessary. Other procedures could be necessary before you can make a final evaluation. Special details are given below.
但这些非相关指示的位置也是许多因使用而产生缺陷的地方。操作人员必须知道在检查过程中可能会出现无关指示。要正确分析这些区域指示，需要大量的技能和经验。在进行最终评估之前，可能还需要其他程序。具体细节如下。
4. APPLICATIONS 应用
A. You can use magnetic particle examination on any clean surface that has access for visual examination. Typical parts for magnetic particle examination are:
您可以在任何可以进行目视检查的干净表面上使用磁粉检查。典型的磁粉检查零件有
(1) Steel fasteners and pins
钢制紧固件和销钉
(2) Important structural elements
重要的结构部件
(3) Linkages
连杆
(4) Landing gear components
起落架部件
(5) Splice and attach fittings
接头和连接件
(6) Actuating mechanisms
作动机构
B. During field repair operations, disassembly is frequently not necessary, unless the parts have critical areas or easily damaged installed components.
在现场修理作业中，除非零件有关键部位或容易损坏的安装部件，否则经常不需要拆卸。
C. During overhaul, a better examination is possible with stationary equipment in the shop on parts which are completely disassembled, cleaned and with all finishes removed.
大修时，在车间内使用固定设备对已完全拆卸、清洗和去除所有表面涂层的零件进行检查，可以获得更好的检查效果。
D. Examinations with magnetic rubber can be used in fastener holes and when:
在下列情况下，可在紧固件孔中使用磁性橡胶进行检查：
(1) The access is not easy.
不易进入。
(2) Particle suspensions could cause unwanted contamination.
颗粒悬浮物可能造成不必要的污染。
(3) A permanent record is necessary.
需要永久记录。
(4) The area cannot be examined visually.
无法目视检查该区域。
5. MATERIALS 材料
NOTE: These materials can be used in different methods of magnetic particle examination. These items do not include all of the products available. Equivalent substitutes can be used. You must make the final selection.
注：这些材料可用于不同的磁粉检查方法。这些项目不包括所有可用产品。可使用同等替代品。您必须做出最终选择。
A. Oil suspension liquid vehicle — Petroleum products per DOD-F-87935 or AMS 2641
油悬浮液载体 — 符合 DOD-F-87935 或 AMS 2641 标准的石油产品
B. Water suspension liquid vehicle — Water with rust inhibitor and wetting agent per AMS 3042 or AMS 3045
水悬浮液体载体 — 含有防锈剂和润湿剂的水，符合 AMS 3042 或 AMS 3045 标准
C. Magnetic particles
磁性颗粒
(1) Dry Powder Method
干粉法
(a) AMS 3040, Magnetic Particle, Nonfluorescent, Dry Powder
(2) Visible Wet Method
可见光湿法
(a) AMS 3041, Magnetic Particle Wet Method, Oil Vehicle, Ready to Use
(b) AMS 3042, Magnetic Particle Wet Method, Dry Powder
(c) AMS 3043, Magnetic Particle Wet Method, Oil Vehicle, Aerosol Packaged
(3) Fluorescent Wet Method
荧光湿法
(a) AMS 3044, Magnetic Particle Fluorescent Wet Method, Dry Powder
(b) AMS 3045, Magnetic Particle Fluorescent Wet Method, Oil Vehicle, Ready to Use
(c) AMS 3046, Magnetic Particle Fluorescent Wet Method, Oil Vehicle, Aerosol Packaged
D. Magnetic Rubber Material — Dynachek, V30256
磁性橡胶材料 — Dynachek, V30256
6. EQUIPMENT 设备
A. Electrical Magnetizing Equipment
电气磁化设备
(1) General
通用
(a) Stationary equipment that can supply 4000-6000 amps is typical in the aerospace industry for overhaul operations. Mobile equipment with equivalent current outputs is available for field examination of heavy structures such as landing gear cylinders and axles. Small parts and local areas of large components can be examined with small permanent magnets or electromagnetic yokes.
可提供 4000-6000 安培电流的固定设备通常用于航空航天工业的大修作业。具有同等电流输出的移动设备可用于起落架气缸和车轴等重型结构的现场检查。小零件和大型部件的局部区域可使用小型永久磁铁或电磁轭进行检查。
(b) The maximum rated output of the equipment must be greater than that necessary for the examinations, because the resistance load of the part could decrease the current through it by as much as 20% of the rated output.
设备的最大额定输出必须大于检查所需的输出，因为零件的电阻负载可能会使通过它的电流减少额定输出的 20%。
(2) Current Types
电流类型
(a) Three-Phase, Full-Wave Rectified Alternating Current — Large, stationary equipment of this type is preferred in major overhaul and repair facilities. This equipment sends a magnetic field deep into a part which is good for subsurface examination of repair welds, through plating or after shot peening.
三相全波整流交流电 — 这种类型的大型固定设备是大修和修理设施的首选。这种设备可将磁场送入零件深处，有利于通过电镀或喷丸后对修理焊缝进行次表面检查。
(b) Half-Wave Rectified Alternating Current — Mobile and portable equipment of this type is generally good for subsurface examinations.
半波整流交流电 — 这类移动和便携式设备通用于表面下检查。
(c) Alternating Current equipment is satisfactory to find defects which occur during service. Fields made by AC stay near the external surface, where such defects usually occur. Also, fields that are not deep are more easily removed by AC demagnetization.
交流电设备在发现使用过程中出现的缺陷方面令人满意。交流电产生的电场停留在外部表面附近，而这些缺陷通常就发生在外部表面。此外，交流退磁更容易消除不深的磁场。
B. Permanent Magnets and Electromagnetic Yokes
永磁体和电磁轭
(1) General
通用
(a) Permanent magnets and electromagnetic yokes are used for magnetic particle examination of small parts and local areas of large parts. These items can be used to examine local areas of installed parts, or after you use the larger stationary bench type equipment on local critical areas on large parts. AC-DC electromagnetic yokes can demagnetize small parts or local areas after the examination.
永磁体和电磁轭用于小零件和大零件局部区域的磁粉检查。这些设备可用于检查已安装零件的局部区域，或在使用较大的固定台式设备对大型零件的局部关键区域进行检查后使用。交直流电磁轭可以在检查后对小零件或局部区域进行消磁。
(b) See Table 1 for dead weight lift requirements of magnetic yokes. Do dead weight lift tests of the yokes at intervals of 6 months maximum.
有关磁轭的自重提升要求，请参见表 1。最多每隔 6 个月对磁轭进行一次自重提升测试。
(c) Typical examples:
典型示例：
1) Electromagnetic Yoke — Contour Probe Model DA-200, V26774
电磁轭 — 轮廓探头 DA-200 型，V26774
2) Permanent Magnets — Magnaflux Yoke YM-5, V37676
永久磁铁 — Magnaflux Yoke YM-5，V37676
C. Magnetization Indicator
磁化指示器
(1) Locally fabricated per Figure 1
根据图 1 就地制造
(2) Penetrameter — Model 500386, V23373
渗透仪 — 型号 500386，V23373
(3) Pie Field Indicator 169799, V37676
磁场指示器 169799，V37676
7. PREPARATION OF PARTS FOR EXAMINATION 要检查零件的准备
A. Be very careful to not let cleaning material or magnetic particles get where they cannot be removed. Removal of components such as bushings, bearings, or inserts from assemblies could be necessary before you clean and magnetic particle examine the unit.
要非常小心，不要让清洁材料或磁粉进入无法清除的地方。在对设备进行清洁和磁粉检查之前，可能需要从组件中拆下衬套、轴承或钢丝螺套等部件。
B. Magnetic particle examination of assembled bearings is not recommended because the bearings are not easy to demagnetize. If a bearing cannot be removed it must be given protection from the magnetic particle examination materials and locally magnetized with a magnetic yoke to limit the magnetic field across the bearing.
不建议对装配好的轴承进行磁粉检查，因为轴承不容易去磁。如果轴承无法拆卸，则必须对其进行保护，使其免受磁粉检查材料的影响，并用磁轭对其进行局部磁化，以限制轴承上的磁场。
C. Parts must have no grease, oil, rust, scale or other substances which could be a problem with the examination. If necessary, vapor degrease, or solvent, alkaline or abrasive clean per SOPM 20-30-03. Use abrasive cleaning only as necessary to completely remove scale or rust. Too much blasting of parts can change examination results.
零件上不得有油脂、油、锈、垢或其他可能影响检查的物质。如有必要，可按照 SOPM 20-30-03 进行蒸汽脱脂或溶剂、碱性或研磨剂清洗。仅在必要时使用研磨剂清洁，以彻底清除水垢或铁锈。对零件喷砂太多会改变检查结果。
D. A water-break-free surface is necessary for parts to be examined by water suspension methods. If the suspension completely wets the surface, the surface is satisfactory.
采用水悬浮法检验的零件必须有无水破损的表面。如果悬浮液完全浸湿表面，则表面合格。
E. For in-service inspection, removal of coatings and plating will be necessary before the magnetic particle examination for the conditions that follow:
对于在役检查，在进行磁粉检查之前必须去除涂层和镀层，以满足以下条件：
(1) The coating or plating is damaged.
涂层或镀层受损。
(2) The coating or plating thickness prevents a satisfactory magnetic particle examination of the part.
涂层或镀层厚度妨碍对零件进行令人满意的磁粉检查。
(3) The coating or plating thickness is more than 0.005 inch, unless specified in Paragraph 7.E.(4).
涂层或镀层厚度超过 0.005 英寸，第 7.E.(4)段规定的除外。
(4) The coating or plating thickness is more than 0.006 inch, if a 0.006 inch coating or plating thickness is permitted by the design limit of the part.
涂层或电镀层厚度超过 0.006 英寸，但零件设计极限允许涂层或电镀层厚度为 0.006 英寸。
F. If necessary, remove protective coatings as specified in SOPM 20-30-02. Unless otherwise specified, the magnetic particle examination must be done before you shot peen, before you apply finishes such as primer and paint, and also before you apply metallic coatings such as electroplate, flame spray, or vacuum deposition of 0.002 inch or thicker. Unless specified by the overhaul instructions, magnetic particle examine parts with electroplate by the sequence specified in Table 2.
如有必要，按 SOPM 20-30-02 规定的除去保护涂层。除非另有规定的，磁粉检查必须在喷丸、涂底漆和油漆等表面处理之前进行，也必须在电镀、火焰喷涂或真空沉积等 0.002 英寸或更厚的金属镀层之前进行。除非大修说明有规定，否则应按照表 2 规定的顺序对带有电镀层的零件进行磁粉检查。
8. METHODS OF EXAMINATION 检查方法
A. Magnetic particle examination usually has these steps:
磁粉检查通常有以下步骤：
(1) Application of magnetic particles.
应用磁粉。
(2) Magnetization, circular or longitudinal.
环向或纵向磁化。
(3) Measurement of field strength.
测量磁场强度。
(4) Examination for, and interpretation of indications.
检查并解释迹象。
(5) Demagnetization and post-examination cleaning.
去磁和检查后清洁。
B. Magnetic Particles: The magnetic particles used can be nonfluorescent or fluorescent (as applicable to the examination specified) and are applied as a suspension in a vehicle. Fluorescent particles are preferred due to their higher sensitivity.
磁性颗粒： 所使用的磁性微粒可以是无荧光或荧光的（适用于规定的检查），并以悬浮物的形式置于载体中。荧光颗粒因其灵敏度较高而更受青睐。
C. Wet Continuous Method: Unless shown differently, use only the wet continuous AC or DC fluorescent or nonfluorescent methods as follows:
湿式连续法： 除非另有说明，否则只能使用以下湿式连续交流或直流荧光或非荧光方法：
(1) In the wet continuous method, the particle suspension is applied to wet all surfaces of the part. The magnetizing current is applied at the instant the suspension is diverted from the part. Apply a minimum of two shots of magnetizing current, each 1/2-second long.
在湿式连续法中，使用颗粒悬浮液润湿零件的所有表面。磁化电流在悬浮液偏离零件的瞬间施加。至少施加两次磁化电流，每次 1/2 秒。
(2) Wet suspensions of fluorescent particles, in water or oil, are recommended for most overhaul and in-service examinations unless not permitted by the material, size, or shape of the part.
除非零件的材料、尺寸或形状不允许，大多数大修和在役检查都建议使用水或油中的荧光颗粒湿悬浮液。
(3) Water, with a suitable rust inhibitor and wetting agent, can be used as a liquid vehicle if the magnetic examination equipment can be used with water as the vehicle.
如果磁性检查设备可以用水作为载体，则可以使用含有适当防锈剂和润湿剂的水作为液体载体。
(4) It is acceptable to use the residual magnetization method (Paragraph 8.H.) as an alternative to the continuous method when you examine bores for cracks with a central conductor.
在检查有中心导体的孔洞裂纹时，可使用残余磁化法（第 8.H 段）替代连续法。
D. Dry Continuous Method: The dry continuous method is not recommended for airplane components because of its lower sensitivity level.
干式连续法： 由于干式连续法的灵敏度较低，不建议用于飞机部件。
E. Circular Magnetization: Circular magnetization is put in the part by one of these methods:
环形磁化法： 通过以下方法之一对零件进行环形磁化：
(1) Central Conductor Method (Figure 2):
中心导体法（图 2）：
(a) Send the current through a central conductor that goes through the part. For examination of inside and outside surfaces of cylindrical and hollow parts, use a central conductor with as large a diameter as possible. for other shapes, use a central conductor for circular magnetization when you can.
通过穿过零件的中心导体发送电流。对于检查圆柱形和空心零件的内外表面，使用直径尽可能大的中心导体。对于其他形状的零件，在可能的情况下使用中心导体进行圆周磁化。
(b) When the full circumference is not magnetized at one time, examine the circumference with a series of magnetizations and inspections, one after another, with the cylinder in one position after another as necessary to do a full circle magnetization.
如果不能一次对整个圆周进行磁化，则要对圆周进行一系列的磁化和检查，一个接一个，根据需要将圆柱体放在一个接一个的位置上，以便进行全圆磁化。
1) Keep the control conductor adjacent to one side of the part. This will magnetize a distance (or arc) along the circumference approximately 3 times the diameter of the central conductor. (For cylindrical parts, the number of magnetizations necessary to go around the total circumference will be equal to the part diameter divided by the conductor diameter.)
让控制导体紧贴零件的一侧。这样沿圆周磁化的距离（或弧度）约为中央导体直径的 3 倍。(对于圆柱形零件，绕整个圆周所需的充磁次数等于零件直径除以导体直径）。
2) The number of magnetizations (segments of the full circle) multiplied by the current per segment magnetization must be no less than the magnetization current necessary for a full circle magnetization of the outside diameter. Do not use too much current or you could get false indications.
磁化次数（全圆的分段）乘以每段磁化电流，必须不小于外径全圆磁化所需的磁化电流。不要使用过大的电流，否则会产生错误的指示。
(c) When a number of small parts are examined at one time, put sufficient space between each piece to permit satisfactory coverage (with particles), magnetization and examination.
当一次检查多个小零件时，每个零件之间要留出足够的空间，以便能够进行满意的覆盖（带颗粒）、磁化和检查。
(2) Direct Contact Method: Send current through the part mounted horizontally between contact plates. Be very careful not to burn the part at the electrode contact areas. Burns and arcs can be caused by:
直接接触法： 将电流通过水平安装在接触板之间的零件。要非常小心，不要在电极接触区域烧伤零件。烧伤和电弧可能由以下原因造成：
(a) Too small a contact area
接触面积太小
(b) Too low a contact pressure
接触压力太小
(c) Dirty or coated contact areas
接触区域不干净或有涂层
(d) Electrode removal during current flow
电流流动过程中电极脱落
F. Longitudinal Magnetization
纵向磁化
(1) To put longitudinal magnetization in a part, put the part inside a current carrying coil or between the poles of an electromagnetic yoke.
要对零件进行纵向磁化，可将零件放在载流线圈内或电磁轭的两极之间。
(2) When you use a coil, best results occur when:
使用线圈时，在以下情况下效果最佳：
(a) The part to be examined is two or more times as long as it is wide.
要检查的零件长度是宽度的两倍或两倍以上。
(b) The long axis of the part is parallel to the axis of the coil opening.
零件的长轴与线圈开口的轴平行。
(c) The area of the coil opening is a minimum of 10 times the cross sectional areas of the part.
线圈开口的面积至少是零件横截面积的 10 倍。
(d) The part is put near the side of the coil.
零件放在靠近线圈的一侧。
(e) Handheld coils, made of electrical cables wrapped around the part, have three to five turns.
手持式线圈由缠绕在零件上的电线制成，有三到五圈。
(f) Long parts are magnetized and examined in increments of 12-18 inches, because approximately 6-9 inches on either side of the coil vertical centerline will be magnetized.
长零件以 12-18 英寸为增量进行磁化和检查，因为线圈垂直中心线两侧约 6-9 英寸将被磁化。
(g) The intensity of the longitudinal shots is kept just below the level that starts to make leakage fields across sharp changes of section, such as radii under bolt heads, threads, and other sharp angles in parts, unless this is to look for grinding cracks in chrome plate.
除非是为了寻找铬板上的磨削裂纹，否则纵向拍击的强度应保持在刚好低于开始在截面急剧变化处产生漏磁场的水平，如螺栓头下半径、螺纹和零件上的其他锐角。
(3) When you use a yoke, the area of the part between the ends of the yoke completes the path of the magnetic lines of force. This gives a magnetic field between the points of contact.
使用磁轭时，磁轭两端之间的零件区域完成了磁力线的路径。这就在接触点之间产生了磁场。
G. Use of Permanent Magnets and Electromagnetic Yoke
永磁体和电磁轭的使用
(1) For a stable magnetic field from permanent magnets, you must shake the oxide particles within the field. The wet method is most satisfactory. Use a plastic squirt bottle for best results.
要使永久磁铁产生稳定的磁场，必须摇动磁场中的氧化物颗粒。湿法最令人满意。使用塑料喷壶效果最佳。
(2) When you do not know the direction of possible cracks in a suspect area or if the cracks could possibly be not perpendicular to the lines of force between the poles of the magnet, move the magnet and try again. The part must be demagnetized between each magnetization when the field direction is changed.
如果不知道可疑区域可能出现裂纹的方向，或者裂纹可能不垂直于磁铁两极之间的力线，则应移动磁铁再试一次。改变磁场方向时，每次磁化之间必须对零件进行退磁。
H. Residual Magnetization Method
残余磁化法
(1) This method is generally used only for subsequent analysis of indications found by the wet continuous method. It can be used to help tell the difference between microsegregations (Paragraph 14.A.(3)) and other defects.
此方法通用于对湿式连续法发现的指示进行后续分析。它可用于帮助区分微偏析（第 14.A.(3)段）和其他缺陷。
(2) In this method, the part is magnetized and the magnetizing current then cut off. Apply three shots of the magnetizing current, each 1/2-second long. Then apply the magnetic particles.
在此方法中，对零件进行磁化，然后切断磁化电流。施加三次磁化电流，每次半秒。然后使用磁性颗粒。
(3) Good results are a function of the strength of the applied field, the direction of magnetization, and the shape of the part.
良好的效果取决于施加磁场的强度、磁化方向和零件的形状。
I. Field Strength Determination
磁场强度的确定
(1) Factors such as part size, shape, magnetic properties of the material and the method of magnetization will affect the field strength made within a part by a given applied magnetizing force. The factors do not make it easy to give rules for magnetizing during examination. Technique requirements are best determined on actual parts having known defects.
零件的尺寸、形状、材料的磁性和磁化方法等因素都会影响给定的外加磁化力在零件内形成的场强。由于这些因素的影响，在检查过程中不易给出磁化规则。最好根据已知缺陷的实际零件来确定技术要求。
(2) Use the magnetization indicator (Figure 1), or an equivalent method, to make sure the magnetic flux strength is sufficient. It shows you the internal field, the field direction, and the quality of the particle suspension during magnetization. Lay the indicator, copper side up, on the part in the area of interest as you apply the magnetizing force. An easy-to-see clear line of magnetic particles will occur across its face when sprayed with or put in the particle suspension.
使用磁化指示器（图 1）或类似方法确保磁通强度足够。它可以显示内部磁场、磁场方向以及磁化过程中磁粉悬浮液的质量。在施加磁化力时，将指示器铜面朝上放在所关注区域的零件上。喷上或放入磁粉悬浮液后，其表面会出现一条易于观察的清晰磁粉线。
(3) The level of magnetization necessary to find service related defects frequently can be lower than that necessary for material and manufacturing control. Where conditions are good, AC magnetizing currents of the order of 50% of the DC amperage recommended for overhaul will give good results for surface cracks. For example, 400-600 amps AC per inch of diameter will usually be sufficient for circular magnetization, but use the magnetization indicator (Figure 1) to make sure the field is sufficient.
发现与维修有关的缺陷所需的磁化水平往往低于材料和制造控制所需的水平。在条件良好的情况下，交流磁化电流约为大修建议直流安培数的 50%，就能很好地发现表面裂纹。例如，每英寸直径 400-600 安培交流电通常足以进行圆形磁化，但要使用磁化指示器（图 1）来确保磁场足够大。
(4) If you must do the examination with a decreased current because of part size or equipment limitations, you can adjust for lower field strength. Examine a smaller area for each magnetization, or use electromagnetic yokes. Examine only 4 inches on either side of a coil instead of 6 or apply more magnetizations along the wall of a hollow cylinder when you use an internal conductor.
如果由于零件尺寸或设备限制而必须用较小的电流进行检查，可以调整较低的磁场强度。每次磁化时检查较小的区域，或使用电磁轭。只检查线圈两侧的 4 英寸而不是 6 英寸，或者在使用内部导体时沿着空心圆柱体的壁施加更多磁化。
9. SPECIAL EXAMINATION TECHNIQUES 特殊检查技术
A. Magnetic Rubber Method (Ref MIL-I-83387)
磁性橡胶法（参考 MIL-I-83387）
(1) Use this procedure as an alternative to the usual magnetic particle suspension when the access is not easy or if you must have a permanent record of the defect indication.
在不易接近或必须永久记录缺陷迹象时，可使用此程序替代通常的磁粉悬浮法。
(2) The magnetic rubber material contains black magnetic particles in a room temperature vulcanizing (RTV) liquid rubber vehicle.
磁性橡胶材料包含室温硫化 (RTV) 液态橡胶载体中的黑色磁性颗粒。
(3) General procedure:
通用程序：
(a) Fully clean the surfaces to be examined. Be sure to completely remove all magnetic particles from previous examinations.
充分清洁待检表面。确保彻底清除以前检查时留下的所有磁性颗粒。
(b) Prepare the area to get and contain the liquid rubber material. Use mylar or cellophane tape to close the lower opening of vertical holes. Make dams around flat surfaces with compatible plastic materials such as Duxseal putty. On horizontal holes, put tape over one opening and make a cup dam at the other. Make a hole in the tape at the upper edge to let caught air get out.
准备获取和容纳液体橡胶材料的区域。用胶布或玻璃纸胶带封住垂直孔的下部开口。用兼容的塑料材料（如 Duxseal 油灰）在平坦表面周围筑坝。在水平孔上，用胶带封住一个开口，在另一个开口处做一个杯状挡板。在上边缘的胶带上开一个孔，以便排出空气。
CAUTION:MANUFACTURER’S INSTRUCTIONS, SHELF LIFE AND POT LIFE TIMES MUST BE OBEYED.
注意：必须遵守制造商的说明、保质期和使用时间。
(c) To prepare the magnetic base material, stir or shake the container to make sure the ferromagnetic particles are in good suspension. Add the specified amount of catalyst. Mix fully.
准备磁性基料时，搅拌或摇晃容器，确保铁磁性颗粒处于良好的悬浮状态。加入规定量的催化剂。充分混合。
(d) Put the mixed liquid rubber into the examination area. You can use a plastic syringe with the needle removed to put the liquid rubber in tight areas or into small fastener holes. Do not apply more material than can be magnetized during its pot life.
将混合好的液体橡胶放入检查区。可使用去掉针头的塑料注射器将液体橡胶注入狭小区域或紧固件小孔中。不要使用超过其罐内寿命可磁化的材料。
(e) Apply a constant magnetic field for 30 seconds in the desired direction and of sufficient strength after you apply the rubber base material. Use a stronger field strength than that recommended for the oil or water suspension method, because the residual magnetism moves the particles through the rubber to collect as the indications as the rubber cures. Too strong a field could cause nonrelevant indications. You can apply the magnetic field with the usual procedures and equipment. The residual method is satisfactory for parts heat-treated above 180 ksi. You can use permanent magnets or DC electromagnetic yokes big enough to span the examination area. Because the residual magnetism must be strong, do not use alternating or swinging vector fields.
在涂抹橡胶基材后，按所需方向施加足够强度的恒定磁场 30 秒钟。使用比油或水悬浮法建议更强的磁场强度，因为残余磁力会使颗粒穿过橡胶，在橡胶固化时收集指示。太强的磁场可能导致不相关的指示。您可以使用常规程序和设备应用磁场。残余法适用于热处理超过 180 ksi 的零件。您可以使用足够大的永久磁铁或直流电磁轭来横跨检查区域。由于剩磁必须很强，因此不要使用交变或摆动矢量场。
(f) If you know the load path or possible crack locations and directions, one magnetization in the correct direction is sufficient. When cracks are in different locations or angles, two or more examinations will be necessary with a new application of magnetic rubber. Demagnetize the area after each application. Fastener holes can be examined for radial cracks with one circumferential magnetization with DC current sent through a central conductor put through the hole.
如果知道负载路径或可能的裂纹位置和方向，在正确的方向上进行一次磁化就足够了。如果裂缝位于不同位置或角度，则需要使用新的磁性橡胶进行两次或更多次检查。每次使用后都要对该区域进行消磁。紧固件孔的径向裂纹可通过一根穿过孔的中心导体发送直流电进行一次圆周磁化检查。
(g) To get sensitivity equivalent to that of the wet continuous particle suspensions, mix in an amount of catalyst to the liquid rubber to make the rubber cure in 2 hours or more. Longer cure times up to 6 hours will make the indications easier to find because more particles can continue to move to their final locations.
为获得与湿式连续颗粒悬浮液相同的灵敏度，在液体橡胶中混入一定量的催化剂，使橡胶在 2 小时或更长时间内固化。固化时间延长至 6 小时会使指示更容易找到，因为更多的颗粒可以继续移动到其最终位置。
(h) Let the rubber fully cure. Then remove the cast, and examine it under white light with 30-power magnification for indications of defects. These will stay permanently in position in the rubber and the casts can be identified and kept as a permanent record.
让橡胶完全固化。然后取下铸模，用 30 倍放大镜在白光下检查缺陷迹象。这些缺陷将永久保留在橡胶中，铸模可作为永久记录进行识别和保存。
B. Critical Examinations
关键检查
(1) A critical examination is necessary for defects at sudden changes in part shape or thickness, such as threaded parts, splines, gear teeth roots, because these sudden shape changes cause nonrelevant indications during usual examinations. This procedure is the most sensitive to find the start of in-service fatigue cracks in sharp, internal radii.
对于零件形状或厚度突然变化处的缺陷，如螺纹零件、花键、齿轮齿根，必须进行临界检查，因为这些突然的形状变化在通常的检查中会造成不相关的迹象。该程序对发现尖锐内半径处的在役疲劳裂纹起始点最为敏感。
(2) You can use the usual magnetic particle examination equipment (Paragraph 6.) but alternating fields cannot always give the necessary high level of residual magnetism.
可以使用通常的磁粉检查设备（第 6.段），但交变磁场并不总能提供必要的高水平剩磁。
(3) Fluorescent particle suspensions are recommended for the critical examination procedure. Oil base suspensions are preferred rather than water base.
建议在关键检查程序中使用荧光颗粒悬浮液。最好使用油基悬浮液而不是水基。
(4) Optical aids are necessary to get the maximum sensitivity possible by this magnetic particle procedure. Low-power (10X to 30X) binocular microscopes are recommended. As a minimum, pocket magnifiers of 7 to 10 power can be used.
要使磁粉程序达到最高灵敏度，必须使用光学辅助设备。建议使用低倍（10 倍至 30 倍）双目显微镜。至少可使用 7 至 10 倍的袖珍放大镜。
(5) General procedures:
通用程序：
(a) Fully clean the part in the areas of the sharp radii and fillets where dirt can collect, and where they could be ignored during a too quick an examination.
充分清洁零件的尖锐半径和圆角区域，因为这些区域可能会聚集污垢，而且在过快检查时可能会被忽略。
(b) The residual method can help in some problem areas, although it is not always best in most other instances. Start with wet continuous methods for general examination, then use the residual method only for local examination of the sharp radii. Use it only where nonrelevant indications are a problem in the initial examination.
残留法可以帮助解决某些问题，但在大多数其他情况下并不总是最佳方法。首先使用湿连续法进行通用检查，然后仅在尖锐半径的局部检查中使用残留法。只有在非相关指示成为初步检查问题的情况下才使用这种方法。
(c) Use the same methods of magnetization as in the standard procedures, but:
使用与标准程序相同的磁化方法，但：
1) Do not use alternating fields.
不要使用交变磁场。
2) Use a higher than usual level of magnetizing force to be sure of a higher residual field within the part.
使用比通常水平更高的磁化力，以确保零件内有更高的残余磁场。
(d) After magnetization, apply particles in a liquid suspension. Use a good amount, and apply them to cause maximum particle buildup. (A good method for small parts such as rod end fittings is to put them in a container of suspension that was stirred for approximately 30 seconds.)
磁化后，在液体悬浮液中涂抹颗粒。用量要适中，并使颗粒最大限度地堆积。(对于杆端配件等小零件，一个好的方法是将其放入搅拌了约 30 秒的悬浮液容器中）。
(e) Look for collected particles in the sharp radii. Be sure you used a sufficient level of magnetization and amounts of the particle application to cause nonrelevant indications.
在尖锐半径处寻找收集的颗粒。确保您使用了足够的磁化水平和颗粒应用量，以导致非相关指示。
(f) Wash the parts in clean suspension vehicle only sufficiently to remove the weakly held particle accumulations that make the nonrelevant indications. Particles at actual defects will be more strongly held and will stay there if you are careful. To do this, apply a light flow or stream of liquid vehicle over the part, or, for a small component, lightly stir the part in a container of the vehicle. Carefully monitor the removal of the collected nonrelevant particles in the area to be examined. If not, you could also wash away the smaller defect indications. Try a few times to get the best method and time.
在清洁的悬挂车辆中清洗零件，只需充分去除造成不相关迹象的微粒积聚。实际缺陷处的微粒附着力较强，如果小心操作，微粒会留在那里。要做到这一点，可在零件上轻轻喷洒液体悬浮液，或者，对于小零件，可在悬浮液容器中轻轻搅拌零件。仔细观察待检查区域内收集的无关颗粒的清除情况。否则，较小的缺陷迹象也会被冲走。多试几次以获得最佳方法和时间。
(g) Look for defect indications with optical magnification and good light. The smallest indications which are possible with this procedure cannot always be seen without such help.
用光学放大镜和良好的光线寻找缺陷指示。如果没有这种帮助，就不一定能看到这种程序所能看到的最小指示。
10. POST-EXAMINATION REQUIREMENTS 检查后的要求
A. Demagnetization
退磁
(1) Demagnetize between each magnetization of the same part to let you find defects in all directions, and whenever the residual magnetism becomes a problem with the interpretation of the indications. Also demagnetize all parts and materials after you are done with magnetic particle examination.
在同一零件的每次磁化之间进行退磁，以便让您发现所有方向的缺陷，并在残磁成为解释指示的问题时进行退磁。完成磁粉检查后，还要对所有零件和材料进行退磁。
(2) Demagnetize to a level of 3 oersteds (Gauss) or less as read by a standard magnetic field indicator. Measure the field at different locations, on the part and at all important changes in geometry. Demagnetize again if you see the field indicator needle move.
去磁至标准磁场指示器读取的 3 oersteds（高斯）或更低的水平。在零件上的不同位置以及几何形状的所有重要变化处测量磁场。如果看到磁场指示器指针移动，则再次消磁。
(3) AC method
交流法
(a) Hold the part approximately 1 foot in front of the AC demagnetizing coils and then move the part slowly and smoothly through the coils and approximately 1 foot behind the coils.
将零件放在交流消磁线圈前约 1 英尺处，然后缓慢平稳地将零件穿过线圈，并在线圈后约 1 英尺处移动。
(b) Do this until the residual magnetism is gone.
这样做直到残磁消失。
(c) Turn and tilt parts of complex configuration as they are passed through the coils.
当复杂结构的零件通过线圈时，应转动和倾斜这些零件。
(4) DC method
直流法
(a) Put the part in the same relative position as when you magnetized it, and apply reversing DC current.
将零件放在与磁化时相同的相对位置，然后施加反向直流电流。
(b) Gradually reduce the current to zero.
逐渐将电流降至零。
(c) Do this until the residual magnetic field is gone.
直到残余磁场消失为止。
(5) When you use a magnetic yoke such as the Parker Research Contour Probe, you can remove the magnetized areas with the probe in the AC mode.
使用磁轭（如 Parker Research Contour Probe）时，可以用交流模式下的探头去除磁化区域。
B. Cleaning
清洁
(1) When you used oil suspensions, solvent clean or vapor degrease the part until all magnetic particles are gone.
如果使用的是油悬浮液，则应进行溶剂清洗或蒸汽脱脂，直至磁性颗粒全部清除。
(2) When you used water suspensions, completely remove the water, such as with an air blast, to make sure that the parts are dried immediately when done. Fully rinse the part with a detergent base cleaner until the magnetic particles are all gone. Then rinse in a solution of water and rust inhibitor.
如果使用的是水悬浮液，则应彻底清除水分，如用气喷，确保完成后立即将零件擦干。用洗涤剂基底的清洁剂充分冲洗零件，直到磁性颗粒全部消失。然后在水和防锈剂溶液中冲洗。
(3) On cadmium plated parts you can use an air-water vapor blast to remove remaining magnetic particles.
对于镀镉的零件，可以使用空气-水蒸气喷射法去除残留的磁性颗粒。
C. After magnetic particle examination, replace removed finishes as specified by overhaul instructions.
磁粉检查后，按照大修说明规定的方法更换去除的饰面。
D. After the parts are clean and dry, use temporary protective coatings per SOPM 20-44-02 as necessary to prevent corrosion.
在零件清洁干燥后，根据需要按照 SOPM 20-44-02 使用临时保护涂层，以防止腐蚀。
11. EQUIPMENT CONTROL 设备控制
A. Regularly do tests of magnetic particle examination equipment as necessary to be sure of satisfactory operation.
定期对磁粉检查设备进行必要的测试，以确保其运行令人满意。
B. When fluorescent magnetic particle suspension is used, the black light intensity must be a minimum of 1000 microwatts per square centimeter measured at the surface of the part. The ambient white light level must be no more than 2 foot candles (20 lux).
使用荧光磁粉悬浮液时，在零件表面测量的黑光强度必须至少为每平方厘米 1000 微瓦。环境白光亮度不得超过 2 foot candles (20 lux)。
C. When nonfluorescent particles are used, the white light intensity must be a minimum of 100 foot candles (1000 lux) measured at the surface of the part.
使用非荧光颗粒时，在零件表面测量的白光强度必须至少为 100 foot candles (1000 lux) 。
D. Use special lighting equipment and optical devices, as necessary, when you examine the inside diameters of holes, tubing, cylinders, and other surfaces where the access is not easy.
在检查孔、管道、圆筒和其他不易接近的表面的内径时，必要时使用特殊照明设备和光学设备。
12. MATERIAL CONTROL 材料控制
A. Make tests of the magnetic substance concentration (wet method) regularly and control as shown in Table 3.
定期检测磁性物质浓度（湿法），并按表 3 所示进行控制。
B. When water suspension systems are used, do regular tests to make sure there is sufficient wetting agent and rust inhibitor.
使用水悬浮系统时，应定期进行测试，确保有足够的润湿剂和防锈剂。
C. If adjustment of water suspensions is necessary to get a water break-free surface, keep the pH in the 6.0-10.0 range. Use nonionic wetting agents when possible.
如果需要调整悬浮水以获得无水表面，则应将 pH 值保持在 6.0-10.0 范围内。尽可能使用非离子润湿剂。
13. PROCESS CONTROL 过程控制
A. When magnetic particle examination is specified, do it after all overhaul/repair operations but these:
规定进行磁粉检查时，除以下操作外，应在所有大修/修理操作后进行：
(1) Before shot peening and protective finishing such as priming, painting and plating more than 0.002 inch thick.
在进行喷丸和保护性表面处理（如涂底漆、油漆和厚度超过 0.002 英寸的电镀）之前。
(2) Both before and after nitriding and the application of 0.002-inch or more of chrome or nickel plate. This lets you find surface defects in the base metal under the plating.
在氮化和镀 0.002 英寸或更厚的铬或镍之前和之后。这样可以发现镀层下基体金属的表面缺陷。
B. If you think there are indications, start at the lowest current possible to let you find relevant indications. Then increase the current until you get the best amperage for the particular part.
如果您认为有迹象，请从尽可能低的电流开始，以便找到相关迹象。然后再增加电流，直到获得适合特定零件的最佳安培数。
C. Do the magnetic particle check with sufficient magnetization and number of examinations to be sure that you can find discontinuities with axes in any direction.
用足够的磁化率和检查次数进行磁粉检查，以确保能找到任何方向的轴不连续性。
D. On tubular parts, use a central conductor and turn the part on the conductor with a separate magnetization and examination at each position. Use one turn for approximately 7 inches of part circumference.
对于管状零件，使用中心导体，在导体上转动零件，在每个位置分别进行磁化和检查。大约 7 英寸的零件周长转一圈。
14. ACCEPTANCE CRITERIA 验收标准
A. General (All Classes)
通用（所有级别）
(1) The following are not acceptable:
以下情况不予接受：
(a) Defects caused during service, such as cracks or corrosion.
使用过程中造成的缺陷，如裂纹或腐蚀。
(b) Indications of material defects caused by or shown during any processing step, unless permitted by Paragraph 14.A.(2), Paragraph 14.A.(3) below. Examples of defects are cracks, laps, coldshuts, laminations, seams, tears, blowholes, flakes, forging bursts, embedded scale, linear porosity, pipes, corrosion pits, crazing, galling. Examples of processing steps include grinding, plating, welding, machining.
任何加工步骤所造成或显示的材料缺陷迹象，除非下文第 14.A.(2)段和第 14.A.(3)段允许。缺陷的例子包括裂缝、搭接、冷沟、层压、接缝、撕裂、气孔、薄片、锻造爆裂、嵌入鳞片、线性气孔、管道、腐蚀坑、裂纹、咬合。加工步骤包括打磨、电镀、焊接、机加工。
NOTE: Some service bulletins, maintenance manuals, or overhaul instructions specify an acceptance class, such as Class A critical. Acceptance classification is not necessary for overhaul inspections. It is used for newly-made parts to specify permitted discontinuities such as material inclusions or phase segregation. If you inspect a newly-made part or must evaluate material inclusions or phase segregation, refer to BAC5424 for the acceptance criteria.
注：某些服务通告、维护手册或大修说明规定的验收等级，如Class A critical。大修检查时不需要验收等级。它用于新制造的零件，规定允许的不连续性，如材料夹杂物或相位偏析。如果检查新制造的零件或必须评估材料夹杂物或相偏析，请参阅 BAC5424 了解验收标准。
(c) Indications of any length that extend over or into an edge, chamfer, corner, radius, fillet, or hole. But do not reject the part if the indications are because of microsegregation (alloy segregation). Refer to Paragraph 14.A.(3) below.
任何延伸至边缘、倒角、转角、半径、圆角或孔内的长度指示。但如果这些迹象是由于微偏析（合金偏析）造成的，则不要拒收该零件。请参阅下文第 14.A.(3)段。
(d) Parts with arc burns.
有电弧烧伤的零件。
(2) Indications of metallic phase segregations in precipitation hardened corrosion resistant steel:
沉淀硬化耐腐蚀钢中的金属相偏析迹象：
(a) are not acceptable in springs and material used for springs.
不得用于弹簧及弹簧材料。
(b) are acceptable in parts other than springs, made from sheet no thicker than 0.125 inch.
除弹簧外，厚度不超过 0.125 英寸的板材制成的零件可接受。
(c) must not be more than the limits of the material procurement document in parts made from materials thicker than 0.125 inch. If the procurement document does not contain limits, use the criteria for linear inclusions contained in BAC5424.
在厚度大于 0.125 英寸的材料制成的零件中，不得超过材料采购文件的限值。如果采购文件没有限制，则使用 BAC5424 中的线性夹杂物标准。
(3) Indications of microsegregation (alloy segregation) are acceptable. Microsegregation is a condition in which small changes in material chemistry could cause a banded microstructure in wrought items. When magnetic particle examined, microsegregation could be seen as very narrow lines, usually long and straight, on the surfaces of parts.
微偏析（合金偏析）的迹象是可以接受的。微偏析是指材料化学性质的微小变化会导致锻造物品出现带状微观结构。磁粉检查时，可在零件表面看到微偏析为非常狭窄的线条，通常是长而直的线条。
(a) Indications are microsegregation if these two conditions occur:
如果出现以下两种情况，则表明存在微偏析：
1) Indications do not reappear when the part is examined by the residual method, in BSS7040, and
在 BSS7040 中，用残留法检测零件时，指示不再出现，以及
2) Indications do not reappear when the part is demagnetized, cleaned, and then magnetic particle examined again at one-half the recommended current levels.
在对零件进行退磁、清洁，然后以二分之一的建议电流水平再次进行磁粉检查时，指示不会再次出现。
(b) If the indications reappear, reject the part.
如果指示再次出现，则剔除该零件。
B. For Classes A, B, and C, see BAC5424.
关于 A、B 和 C 级，请参见 BAC5424。
15. IN-PROCESS CORRECTION 过程中校正
A. If Class A examination was specified, parts which are not satisfactory are not acceptable for in-process correction.
如果规定的是 A 级检验，不合格的零件不能接受过程中校正。
(1) If you made the part but the Class A examination found defects in it, you must stop the process and reject the part.
如果是你制造的零件，但 A 级检查发现其中有缺陷，你必须停止工序并报废该零件。
(2) If this is a part that was in service and the Class A inspection found defects in it, get help from Boeing.
如果这是一个正在服役的零件，而 A 级检查发现其中有缺陷，请向波音公司寻求帮助。
B. For all other cases (Classes B, C, and when no class is specified), removal of indications from cracks or nonmetallic inclusions is permitted within limits given by overhaul procedures.
对于所有其他情况（B 级、C 级以及没有规定的级别），允许在大修程序规定的限度内去除裂纹或非金属夹杂物的迹象。
C. When permitted, repair all parts in the final heat-treated condition as follows:
当允许时，在最终热处理状态下修理所有零件如下：
(1) Remove surface indications by procedures and equipment that will not change the metallurgical structure of the adjacent material. Examples are hand filing, rotary filing, etc.
以不会改变邻近材料冶金结构的程序和设备清除表面痕迹。例如手工锉、旋转锉等。
(2) Blend out the repaired areas into the adjacent material with as large a radius as possible. A minimum of 1 inch radius is recommended.
以尽可能大的半径将修理过的区域与邻近材料混合。建议半径至少为 1 英寸。
(3) Make the surface finish of the repaired areas equal to or smoother than that specified by overhaul instructions.
使修理区域的表面光洁度等于或光滑于大修说明规定的光洁度。
(4) Do not grind.
切勿研磨。
(5) Examine the repaired areas by this procedure and the overhaul instructions.
按本程序和大修说明检查修理部位。
(6) Refinish the required areas as specified by the overhaul instructions.
按大修说明书规定的要求重新修整。