關(guān)于船舶無損檢測與iacsrec20標(biāo)準(zhǔn)說明(編輯修改稿)
2025-08-10 17:53 本頁面
【文章內(nèi)容簡介】 36455430Ⅴ點數(shù)多于Ⅳ（長徑尺寸大于t/2）“Number of point” more than IV (length dimension greater than t/2)長形缺陷（長寬比大于3，夾雜或長形氣孔）Length flaws (ratio of length VS width is greater than 3, slag or length of pore)單個長形缺陷限值Single limited length flaws長形缺陷在任意12t焊縫長度內(nèi)的限值Threshold level for length flaws existing on length as 12t at random評級Classification母材厚度Plate thickness≤12＞12~48＞48單個缺陷尺寸Size of single flawsⅠ≤4≤1/3t≤16不大于tNot greater than tⅡ≤6≤1/2t≤24Not greater than Ⅲ≤8≤2/3t≤32不大于2tNot greater than 2tⅣ≤10≤6/5t≤40不大于3tNot greater than 3tⅤ大于Ⅳ者The one greater than IV表3和表4比較 Results after paring Table 3 and Table 4：1. 裂紋、未焊透、未熔合等危害性缺陷在CB/T355894標(biāo)準(zhǔn)中是不接受的，在IACS Rec. 20標(biāo)準(zhǔn)中可以接受一定長度的未熔合和未焊透缺陷；Crack, inplete root penetration and lack of fusion etc. is not accepted as per CB/T355894, but certain length of inplete root penetration and lack of fusion (specified on IACS REC 20) could be accepted as per IACS REC 20.2. 在兩標(biāo)準(zhǔn)中夾渣的分級和評價，例如選取厚度為20mm的焊縫作缺陷評定，在IACS Rec. 20標(biāo)準(zhǔn)中可以接受的單個夾渣長度為20mm，在CB/T355894標(biāo)準(zhǔn)中II級和III級合格的夾渣的許可長度為10mm和13mm；間斷的累計缺陷允許長度分別為: REC 20 為40mm、CB/T355894為小于30mm、小于40mm；Regarding classifying slag flaws related to CB/T 355894 amp。 IACS REC 20, for example, selected plate thickness as 20 mm for classifying, single length of slag flaws as 20 mm could be accepted。 but acc. to CB/T 355894, accepted length of slag flaws for class II amp。 III are 10mm, 13 mm。 intermittent cumulative length are 40mm for REC 20, less than 30mm and less than 40mm for CB/T3558943. 一般來講，船廠或無損檢測公司在實際評片中使用的合格等級至少為II級（），所以CB/T355894標(biāo)準(zhǔn)的缺陷評價分級要嚴(yán)于IACS) Rec. 20標(biāo)準(zhǔn)的要求。General speaking, during normal classification practice, shipyard or NDT pany shall adopt lowest class as class II (Class III shall be accepted when out of L area), so classifying requirement of CB/T 355894 is much more stringent than that of REC 20.二、超聲波檢測Ultrasonic testing:表5 / Table 5：DAC曲線 / DAC curveCB/T355994 母材厚度Plate thicknessARL(判廢線）DRL（測長區(qū)分線）MRL（測長線）≤50Φ3Φ310dBΦ316dB＞50Φ3+2dBΦ36dBΦ312dBIACS Rec. 20測長線MRL評定線Evaluation Line大于100%的DAC曲線的波高（Φ3孔徑）Greater than 100% of DAC curve (Φ3)回波高度在DAC缺陷50~100%之間（Φ3孔徑）Greater than 50% but less than 100% of DAC curve (Φ3)低于33%的DAC曲線的波高（Φ310dB）Less than 33% of DAC curve (Φ310dB)表6 / Table 6：超聲波探傷焊縫質(zhì)量分級Acceptance criteria for Ultrasonic testingIACS Rec. 20CB/T355994回波高度ECHO Height接受標(biāo)準(zhǔn)Acceptance criteria評級Classification單個缺陷指示長度Indicated length for single flaw在6t或150mm 焊縫長度內(nèi)In length of 6t or 150 mm welding seamⅠt/3，最小8，最大24t/3, Min. 8, Max. 242t大于100%的DAC曲線的回波高度Greater than 100% of DAC curve單個缺陷最大接受長度t/2或25mm，兩者取小者；Max. length t/2 or 25 mm whichever is the lessⅡt/2，最小12，最大36t/2, Min. 12, Max. 36回波高度在DAC缺陷50~100%之間Greater than 50% but less than 100% of DAC curve單個缺陷最大接受長度t或50mm，兩者取小者；Max. length t or 50 mm whichever is the lessⅢ3/4t，最小16，最大483/4t, Min. 16, Max. 483t評估認(rèn)為是裂紋的，不管回波高度都是不接受Indications evaluated to be cracks are unacceptable regardless of ECHO heightⅣt，最小20，最大60t, Min. 20, Max. 604t在接頭的單面焊縫評估認(rèn)為是未焊透的，不管回波高度都是不接受Indications evaluated to be lack of root penetration in joints welded from one side are unacceptable regardless of ECHO heightⅤ大于Ⅳ者（裂紋、未焊透、未熔合）The one greater IV (Crack, lack of root penetration, lack of fusion)表表6 / Table 5, Table 6：1. 在CB/T355994標(biāo)準(zhǔn)中，根據(jù)缺陷的波高和指示長度及分布狀態(tài)，把焊縫質(zhì)量分為Ⅰ~Ⅴ級；高于ARL (判廢線）的缺陷回波均評定為Ⅴ級；低于或等
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