无损检测工艺规程（磁粉检验）

NJBST Co Ltd QCD 014Rev 0Page 1 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION 磁磁 粉粉 检检 验验 操操 作作 工工 艺艺 规规 程程 CONTROLLED 在控本 UNCONTROLLED 非在控本 COPY NO 副本编号 PREPARED BY 编制 DATE 日期 REVIEWED BY 审核 DATE 日期 APPROVED BY 批准 DATE 日期 NJBST Co Ltd QCD 014Rev 0Page 2 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION DEMONSTRATION CERTIFICATION This is to certify that this procedure has been demonstrated on a test specimen with known defects to the satisfaction of the Authorized Inspector according to T 150 of ASME Code Section V as required by Appendix 6 of Section Div 1 Test Specimen No Demo Report No NDE Level AI NJBST Co Ltd QCD 014Rev 0Page 3 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION 1 General 1 1 This procedure is applied to the magnetic particle examination of ferromagnetic materials and welds for ASME Code items 1 2 The magnetic particle examination method is suitable for detecting cracks and other discontinuities on or near the surface in ferromagnetic materials 1 3 This procedure is applied to wet continuous magnetization by yoke which shall only be applied to detect discontinuities that are open to the surface of the part 1 4 This procedure shall be demonstrated to the satisfaction of the AI prior to implementation 2 Personnel 2 1 The NDE personnel who engage in magnetic particle examination shall be qualified and certified according to NJBST Co Ltd s Written Practice for NDE Personnel Training Examination Qualification 直流电磁轭提升力至 少为 40lb 177N 最大磁轭间距 5 检验介质 NJBST Co Ltd QCD 014Rev 0Page 4 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION ferromagnetic particles which have high permeability and low retentivity The size and shape of the magnetic particles shall be suitable for forming magnetic particle indications 5 2 The black magnetic particles HK 1 400or 350 made by yixin Citong Co Ltd shall be used 5 3 The fluid medium for the magnetic suspension fluid shall be transformer oil smelless kerosene or water The temperature of the wet particle suspension and the surface of the part shall not exceed 1350F 570C 5 4 Concentration of wet magnetic particle suspensions 5 4 1 The initial bath concentration of suspended magnetic particles should be as specified of as recommended by the manufacturer and should be checked by settling volume measurements and maintained at the specified concentration on a daily basis If the concentration is not maintained properly test results can vary greatly 5 4 2 The bath concentration shall be maintained within 1 2 to 2 4 ml per 100ml of vehicle for nonfluorescent particles unless otherwise specified by the particle manufacturer 5 4 3 Bath concentration is normally determined by measuring its setting volume through the use of an ASTM Pear shaped centrifuge tube with a 1 5 ml stem 0 1 ml divisions for nonfluorescent suspensions Before sampling run the suspension through the recirculating system for at least 30 min to assure thorough mixing of all particles which could have settled on the sump screen and along the sides or bottom of the tank Take a 100 mL portion of the suspension from the hose or nozzle and allow it to settle for approximately 30 min The volume settling out at the bottom of the tube is indicative of the particle concentration in the bath If the bath concentration is low in particle content add a sufficient amount of particle materials to obtain the desired concentration If the suspension is high in particle content add sufficient vehicle to obtain the desired concentration 5 4 4 If the settled particles appear to be loose agglomerates rather than a solid layer take a second sample If still agglomerated the particles may have become magnetized replace the suspension 6 Magnetization Procedure 6 1 Yoke Technique 6 1 1 The direct alternating current electromagnetic yokes or permanent magnet yokes shall be used for localized magnetization to form a longitudinal magnetic field 6 1 2 The alternating current electromagnetic yoke shall have a lifting power of at least 10 lb 4 5kg at maximum pole spacing The direct current electromagnetic yoke shall have a lifting power of at least 40 lb 18 1kg at the maximum pole spacing 6 1 3 The field strength of yokes can be empirically determined 5 1 检验介质是具有高导磁率和低顽 磁性的细铁磁粉 其尺寸和形状必 须易于形成磁粉显示 5 2 应使用宜兴磁通探伤材料公司 生产的黑磁粉 HK 1 400 或 350 5 3 磁悬液的液体介质必须是变压 器油 无味煤油或水 磁悬液的温 度和工件表面温度均不得超过 1350F 570C 5 4 湿磁粉悬浮液的浓度 5 4 1 磁悬液浓度应按制造厂推荐 用沉淀量值验证 务使日常浓度一 定 浓度不当 会大大影响探伤结 果 5 4 2 除制造厂另有规定外 非荧 光磁粉悬浮液浓度应为每 100ml 1 2 2 4ml 的水平 5 4 3 槽中磁悬液浓度通常是用 ASTM 的梨形离心管测定其沉淀值 来确定的 对非荧光磁粉悬液为 1 5ml 芯柱 0 1ml 刻度 的沉淀柱 在取样以前 将悬浮液在再循环系 统中至少流动 30 分钟 以保证所有 磁粉的完全混合 否则磁粉可能在 油盘滤网和沿槽的壁或底沉淀下来 从软管或管嘴取 100ml 悬浮液并使 它沉淀大约 30 分钟 大管底沉淀的 体积 是槽液磁粉浓度指示值 假如 磁悬液中磁粉浓度大低 加足够量 的磁粉以获得所需浓度 假如磁悬 液中磁粉浓度大高 则加足够的液 体介质以获得所需浓度 5 4 4 假如沉淀磁粉表现为松散的 团块 而不是紧密的敷层 则应作 第二次取样试验 如果还是团块 说明磁粉可能已被磁化 这时需更 换悬浮液 6 磁化过程 6 1 磁轭法 6 1 1 可采用直流的 交流的电磁 轭或永久磁轭 来磁化一个局部区 域 形成一个纵向磁场 6 1 2 交流电磁轭的提升力应至少 在两极间距离最大时为 10 磅 4 5 公 斤 6 1 3 经验磁轭式磁场强度可测量 它 NJBST Co Ltd QCD 014Rev 0Page 5 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION by measuring its lifting power 6 1 4 Direction of magnetization At least two separate examinations shall be carried out on each area The second examination shall be with the lines of magnetic flux approximately perpendicular to those used for the first examination in that area 6 1 5 The area to be examined shall be restricted to the area which is equal to 1 4 maximum pole spacing on both sides of the line through two poles The pole spacing shall at least have 1in 25mm overlap each time 7 Magnetic Field Strength 7 1 The special carbon steel copper plate type field indicator is used to verify that an adequate field strength and direction for the surface of part is obtained If the clear magnetic particle pattern is shown on the copper plate side of the field indicator it indicates that adequate field strength is obtained 8 Examination Requirements 8 1 Surface Preparation 8 1 1 Satisfactory results are usually obtained in the as welded as rolled as cast or as forged conditions However surface preparation by grinding or machining may be necessary where surface irregularities could mask indications due to discontinuities 8 1 2 Prior to magnetic particle examination the surface to be examined and all adjacent areas within at least 1in 25mm shall be dry and free of all dirt grease lint scale welding flux and spatter oil or other extraneous matter that could interfere with the examination 8 1 3 Cleaning may be accomplished using detergents organic solvents descaling solution paint removers vapor degreasing sand or grit blasting or ultrasonic cleaning methods 8 1 4 If coatings are left on the part in the area being examined it must be demonstrated that indications can be detected through the existing maximum coating thickness applied When AC yoke technique is used the demonstration must be in accordance with Mandatory Appendix of Article 7 of ASME Code Section 8 2 Unless specified on the drawings or other technical documentation the magnetic particle examination shall be carried out on the parts with finished surface condition or finished machined condition and final heat treatment condition 8 3 The small opening slots or holes in the parts can be blocked to prevent the magnetic particle from getting into 8 4 Examination shall be conducted with sufficient overlap 的提升力来确定 6 1 4 根据经验磁轭式磁场强度可测量它 的提升力来确定 6 1 4 磁化方向 每一区域应至少进行两次分别检验 在第二次检验中 磁通线的方向应大致 与第一次检验区域所采用的方向相垂直 6 1 5 受检区域应限制在两磁极连线的双 侧 相当于 1 4 最大磁极间距的范围内 磁极间距每次至少有 1 英寸 25 毫米 的搭接 7 磁场强度 7 1 使用专用的碳钢 铜板磁场指示器来 校验零件表面的磁场强度和方向是否满 足要求 如果铜板边有清晰的磁粉线条 则表明磁场强度是足够的 8 检验要求 8 1 表面制备 8 1 1 经焊接 轧制 铸造 锻造等加工 的零件 一般会取得满意的效果 然而 表面不平 不均匀 会掩饰缺陷的显示 则这些地方要通过打磨或机加工进行表 面制备 8 1 2 在磁粉检验之前 被检验的表面及 其附近至少 1 英寸 25mm 的区域内应 实干燥的 并且没有任何污垢 纤维屑 锈皮 焊剂和焊接飞溅 油污或其他能 妨碍检验的外来物 8 1 3 可使用去污剂 有机溶剂 除绣剂 除绣液 去漆剂 蒸气除油 喷沙或超 声波清洗等方法达到清洁的目的 8 1 4 如果在被检验部件表面存在漆层等 覆盖物 必须进行演示实验 使缺陷能 透过覆盖层最厚处显示出来 使用磁轭 法时 应按 ASME 法规第 卷第 7 章强 制性附录 之要求 验证涂层厚度的影 响 8 2 除非图纸或其他技术文件中另有规 定 任何零件均应在完工的表面状态 或最终机加工状态 或最终热处理状态 下进行磁粉探伤 8 3 零件上的小开口 槽或孔 应在检 验前堵塞好以防磁粉进入 8 4 检验时应有足够的重叠 至少 10 保证受检零件在规定的灵敏度下能得到 100 的履盖 NJBST Co Ltd QCD 014Rev 0Page 6 of 8 Title PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION at least 10 to assure 100 coverage at the established sensitivity 8 5 The repaired area shall be reexamined according to the original examination procedure 8 6 The intensity of the visual light at the surface of the part work piece undergoing examination shall be a minimum of 50fc 500lx 9 Evaluation of indications and acceptance standards 9 1 Evaluation of indications Indications will be revealed by retention of magnetic particles All such indications are not necessarily imperfections however since excessive surface roughness magnetic permeability variations such as at the edge of heat affected zones etc may produce similar indications An indication is the evidence of a mechanical imperfection Only indications which have any dimension greater than 1 16in 1 6mm shall be considered relevant a A linear indication is one having a length greater than three times the width b A rounded indication is one of circular or elliptical shape with a lenth equal to or less than three times the width c Any questionable or doubtful indications shall be reexamined to determine whether or not they are relevant d Broad areas of particle accumulation which might mask indications from discontinuities are prohibited and such areas shall be cleaned and reexamined 9 2 Acceptance standards per Appendix 6 of Section Div 1 These acceptance standards shall apply unless other more restrictive standards are specified for specific materials or applications All surfaces to be examined shall be free of a relevant linear indications b relevant rounded indications greater than 3 16in 4 8mm c four or more relevant rounded indications in a line separated by 1 16in 1 6mm or less edge to edge d an indication of an imperfection may be larger than the imperfection that causes it however the size of the indication is the basis for acceptance evaluation 10 Demagnetization When residual magnetism in the part could interfere with subsequent processing or usage the part shall be demagnetized any time after completion of the examination 11 Cleaning Post test cleaning is necessary where magnetic particle material could interfere with subsequent processing or usage 8 5 受检工件上经返修的区域 应按原 来的检验程序重新检验 8 6 受检工件表面