【正文】 ent undercuts separated by a distance shorter than the shortest undercut should be regarded as a single continuous undercut.表7 / Table 7：1. 評估認(rèn)為是裂紋、未焊透、未熔合的，兩者都不接受；Both of IACS REC 20 and CB/T 355994 not accept that Indications evaluated to be cracks, lack of root penetration and lack of fusion.2. 在CB/T39582004標(biāo)準(zhǔn)中，任何長度大于3mm的線狀缺陷、任何單個(gè)直徑大于4mm的圓形缺陷，不接受；As per CB/T 39582004, not accept any length over 3 mm for lined flaws and any dia. over 4 mm for rotundity flaws.3. 在IACS Rec. 20標(biāo)準(zhǔn)中，表面氣孔可以接受的尺寸為在對接接頭上的單個(gè)氣孔直徑≤（角焊縫的單個(gè)氣孔直徑≤)，但最大直徑3mm；；在CB/T39582004標(biāo)準(zhǔn)中，~（II級合格）和＞2~4（III級合格）；As per IACS REC 20, acceptance criteria for single pore diameter d≤185。) for butt welds (d≦185。) for fillet welds) with Max. diameter 3 mm。 as Min. distance to adjacent pore。 As per CB/T 39582004, acceptance criteria for “Indicated length for single flaw” is ~ (Class II) and 2~4 (Class III).4. 船廠或無損檢測公司一般至少采用CB/T39582004標(biāo)準(zhǔn)的II級為合格；Shipyard or NDT pany at least to adopt “Class II” as accepted class ac. to CB/T 39582004.5. 所以磁粉/滲透檢測標(biāo)準(zhǔn)即CB/T39582004高于IACS Rec. 20標(biāo)準(zhǔn)的要求。So MT/PT requirement of CB/T39582004 is much more stringent than that of REC 20.中國船舶工業(yè)無損檢測標(biāo)準(zhǔn)（CB/T）與IACS Rec. 20標(biāo)準(zhǔn)的比較結(jié)(Conclusion): 1. 射線探傷： 接受標(biāo)準(zhǔn)采取中國船舶工業(yè)射線照相(CB/T355894) 標(biāo)準(zhǔn)是高于IACS Rec. 20中相關(guān)要求的。但在進(jìn)行射線照相時(shí)應(yīng)注意以下2個(gè)事項(xiàng)。 RT – the acceptance criteria in CB/T355894 is stringent then IACS Re. 20, however following 2 items should be taken into full consideration at the process of performing radiographic test: a) 關(guān)于射線照相透照靈敏度（發(fā)現(xiàn)金屬絲指數(shù)）：船廠或無損檢測公司可以使用CB/T355894標(biāo)準(zhǔn)的普通級要求，但同時(shí)需充分考慮并滿足IACS Rec. 20規(guī)定的要求，即在X射線片子上看到相應(yīng)要求（較高部分）的金屬絲指數(shù)， 詳見下表。Regarding wire number visible on the film (nominal diameter): shipyard or NDT pany may adopts CB/T355894 with full consideration of IACS REC 20, viz. the required wire number visible on the film (nominal diameter) should display the stringent ones as required in CB/T355894 and IACS REC 20, details as mentioned in the Table in below:b) 關(guān)于黑度：比較CB/T355894標(biāo)準(zhǔn)中，γ射線照相底片密度能夠滿足IACS Rec. 20標(biāo)準(zhǔn)；如船廠或無損檢測公司沒有γ射線源，在實(shí)際使用X射線照相時(shí)，操作人員應(yīng)通過使用適當(dāng)設(shè)備或增加曝光量等，使底片密度達(dá)到IACS REC 20的要求(根據(jù)ISO17636的表5的要求，經(jīng)各方商定，)，這樣就可以滿足IACS Rec. 20標(biāo)準(zhǔn)對底片密度的要求。即，使用X射線照相時(shí)RT底片黑度可接受范圍為： ~。Regarding density: paring CB/T355894 with IACS REC 20, yray can meet requirement of film density stipulated on IACS REC 20。 in case shipyard or NDT pany don’t has γray, during normal practice of Xray, NDT operator should choose suitable Xray equipment or increase exposal etc. to meet IACS Rec. 20 requirement on film density, (Acc. to table 5 of ISO17636, density may be reduced to if specified, . in an application standard), then could meet requirement of film density stipulated on IACS REC 20, viz, the acceptance range for the density of Xray firm is ~.2. 超聲波探傷：中國船舶工業(yè)超聲波的標(biāo)準(zhǔn)(CB/T 355994)嚴(yán)于IACS Rec. 20標(biāo)準(zhǔn)的要求。Chinese shipbuilding UT standard (CB/T 355994) is much more stringent than that of REC 20.磁粉和著色探傷：中國船舶工業(yè)磁粉/滲透的標(biāo)準(zhǔn)(CB/T 39582004)嚴(yán)于IACS Rec. 20標(biāo)準(zhǔn)的要求。Chinese shipbuilding MT/PT standards (CB/T 39582004) is much more stringent than that of REC 20..（.....）成立于2004年，專注于企業(yè)管理培訓(xùn)。提供60萬企業(yè)管理資料下載，詳情查看：...../提供5萬集管理視頻課程下載，詳情查看：...../zz/提供2萬GB高清管理視頻課程硬盤拷貝，詳情查看：...../shop/2萬GB高清管理視頻課程目錄下載：...../高清課程可提供免費(fèi)體驗(yàn)，如有需要請于我們聯(lián)系。咨詢電話：020.值班手機(jī)：.網(wǎng)站網(wǎng)址：.....（.....）成立于2004年，專注于企業(yè)管理培訓(xùn)。提供60萬企業(yè)管理資料下載，詳情查看：...../提供5萬集管理視頻課程下載，詳情查看：...../zz/提供2萬GB高清管理視頻課程硬盤拷貝，詳情查看：...../shop/2萬GB高清管理視頻課程目錄下載：...../高清課程可提供免費(fèi)體驗(yàn)，如有需要請于我們聯(lián)系。咨詢電話：020.值班手機(jī)：.網(wǎng)站網(wǎng)址：....3.10 / 10