【文章內(nèi)容簡介】 tank. Take a 100mL 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. 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 bee magized, replace the suspension. 6. Magization Procedure Yoke Technique The direct, alternating current electromagic yokes or permanent mag yokes shall be used for localized magization to form a longitudinal magic field. The alternating current electromagic yoke shall have a lifting power of at least 10 lb. () at maximum pole spacing. The direct current electromagic yoke shall have a lifting power of at least 40 lb. () at the maximum pole spacing. The field strength of yokes can be empirically determined 檢驗(yàn)介質(zhì)是具有高導(dǎo)磁率和低頑磁性的細(xì)鐵磁粉，其尺寸和形狀必須易于形成磁粉顯示。 應(yīng)使用宜興磁通探傷材料公司生產(chǎn)的黑磁粉 HK1400 或 350。 磁懸液的液體介質(zhì)必須是變壓器油、無味煤油或水。磁懸液的溫度和工件表面溫度均不得超過 1350F (570C) 。 濕磁粉懸浮液的濃度 磁懸液濃度應(yīng)按制造廠推薦，用沉淀量值驗(yàn)證，務(wù)使日常濃度一定。濃度不當(dāng)，會大大影響探傷結(jié)果。 除制造廠另有規(guī)定外，非熒光磁粉懸浮液濃度應(yīng)為每 100ml 的水平。 槽中磁懸液濃度通常是用ASTM 的梨形離心管測定其沉淀值來確定的，對非熒光磁粉懸液為 芯柱 ( 刻度 )的沉淀柱；在取樣以前，將懸浮液在再循環(huán)系統(tǒng)中至少流動 30 分鐘，以保證所有磁粉的完全混合，否則磁粉可能在油盤濾網(wǎng)和沿槽的壁或底沉淀下來，從軟管或管嘴取 100ml 懸浮液并使它沉淀大約 30分鐘 ，大管底沉淀的體積 是槽液磁粉濃度指示值；假如磁懸液中磁粉濃度大低，加足夠量的磁粉以獲得所需濃度；假如磁懸液中磁粉濃度大高，則加足夠的液體介質(zhì)以獲得所需濃度。 假如沉淀磁粉表現(xiàn)為松散的團(tuán)塊，而不是緊密的敷層，則應(yīng)作第二次取樣試驗(yàn)，如果還是團(tuán)塊，說明磁粉可能已被磁化，這時(shí)需更換懸浮液。 6. 磁化過程 磁軛法 可采用直流的、交流的電磁軛或永久磁軛、來磁化一個(gè)局部區(qū)域、形成一個(gè)縱向磁場。 交流電磁軛的提升力應(yīng)至少在兩極間距離最大時(shí)為 10 磅 ( 公斤 )。 經(jīng)驗(yàn)磁軛式磁場強(qiáng)度可測量它 更多免費(fèi)資料下載請進(jìn)： 好好學(xué)習(xí)社區(qū) ****** Co.,Ltd. 焊縫檢驗(yàn)規(guī)程 3 Rev.:0 Page:5 of 7 Title: PROCEDURE FOR MAGNETIC PARTICLE EXAMINATION by measuring its lifting power. Direction of magization: At least two separate examinations shall be carried out on each area. The second examination shall be with the lines of magic flux approximately perpendicular to those used for the first examination in that area. 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. Magic Field Strength 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 magic particle pattern is shown on the copper plate side of the field indicator, it indicates that adequate field strength is obtained. 8. Examination Requirements Surface Preparation Satisfactory results are usually obtained in the aswelded, asrolled, ascast, o