【正文】 ss of detail due to poor screentofilm contact. e. false indications due to defective screens. 7. Evaluation of Radiographs Prior to evaluating the radiographs, the NDE level ⅡorⅢ shall check if the information in radiographing record and the exposure location drawing of the ponent or product are plete and correct. Prior to being interpreted, the radiographs shall be checked whether their own quality is conformed to the specified requirements. Otherwise, the radiograph has to be retaken. In addition to the requirement described in Paragraph , the requirement of radiograph quality also includes: Density Limitation The transmitted film density near the discernible minimum wire of an IQI on radiograph and the area to be interpreted shall be within the limitations specified in Table 8. “B” Mark. The bright image of “B” mark shall not appear on a darker background of the radiograph. If dark image of “B” appears on the lighter background, it should not be taken as a reason that radiograph quality is unaccepted. IQI The IQI images and designated wire of wire IQI specified shall appear on the radiograph so as to ensure the quality level of inspection meeting the requirement of Table T276 of Section .Ⅴ 8. Acceptance Standards Acceptance standards for the radiographic examination of welds shall refer the following: Section Ⅷ,UW51(full RT) and UW52(spot RT)for pressure Vessels. Indications shown on the radiographs of welds and characterized as imperfections are unacceptable for pressure vessel welds that are full radiographed under the following conditions . a. Any indication characterized as a crack or zone of inplete fusion or penetration. b. Any other elongated indication on the radiograph which has a length greater than: 1/4in. for t up to 3/4in. 沖洗質(zhì)量要求 沖洗的底片應無機械、化學或其它污損，這些污損包括(但并不限于)： a. 灰霧 b. 沖洗缺陷，如條痕、水跡、或化學污染 c. 劃痕、指印、卷曲、靜態(tài)斑紋、污跡、或撕裂。 d. 因增感屏與膠片貼合不良而造成的細節(jié)損失。 e. 因增感屏有缺陷而造成的偽缺陷。 7. 評片 評片前，NDEⅡ級或Ⅲ級人應檢查射線照相記錄數(shù)據(jù)和工件或產(chǎn)品曝光定位圖是否完整、正確。 評片前，應檢查底片自身質(zhì)量是否符合規(guī)定的要求，否則，底片必須重拍。 ，底片質(zhì)量要求還包括： 黑度范圍 射線底片上象質(zhì)計最小可識別絲附近的底片黑度和評定區(qū)黑度應在表8規(guī)定的范圍內(nèi)。 “B ” 標記 在底片較暗背景上不應出現(xiàn)明亮的“B”標記的較淡影像。若在淡背景上出現(xiàn) “B”的暗影，則不能作為底片判廢原因。 象質(zhì)計 象質(zhì)計影像和線型象質(zhì)計規(guī)定的應識別線應在底片上出現(xiàn)，以保證檢測質(zhì)量符合第Ⅴ卷表T276的要求。 8. 合格標準 焊縫射線照相檢測合格標準如下： 壓力容器：第Ⅷ卷第1冊，UW51(全部RT)和UW52(局部RT) 作全檢的壓力容器焊縫，底片上出現(xiàn)的影象定為下列缺陷時，則評為不合格； a. 任何定為裂紋、未熔合或未焊透的顯示； ； t≤3/4in(19mm): 1/4in() t3/4in(19mm)~ 21/4in(57 mm): 1/3t****** Co.,Ltd.焊縫檢驗規(guī)程4Rev.:0Page:13 of 14Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS 1/3 t for t from 3/4in. to 2 1/4in. 3/4in. for t over 2 1/4in. where t is the thickness of the weld excluding any allowable reinforcement. c. Any group of aligned indications that have an aggregate length greater than t in a length of 12t, except when the distance between the successive imperfections exceeds is the length of the longest imperfection in the group. d. Rounded indications in excess of those specified by the acceptance standards given in Appendix 4 of Section Ⅷ for pressure vessels. For pressure vessels, the acceptability of welds examined by spot radiography shall be judged by the following standards. a. Welds in which indications are characterized as cracks or zones of inplete fusion or penetration shall be unacceptable. b. Welds in which indications are characterized as slag inclusions or cavities shall be unacceptable if the length of any such indication is greater than 2/3t (t: weld thickness) excluding any allowable reinforcement. c. If several indications within the above limitations exist in line, the welds shall be judged acceptable if the sum of the longest dimensions of all such indications is not more than t in a length of 6t and if the longest indications considered are separated by at least 3L of acceptable weld metal (L: length of the longest indication). d. The maximum length of acceptable indications shall be 3/4 in. (19mm). Any such indications shorter than 1/4in. (6mm) shall be acceptable for any plate thickness. e. Rounded indications are not a factor in the acceptability of welds not required to be fully radiographed. 9. Records The records shall include the Radiographic Examination Report, RT Interpretation Sheet, Radiographic Sketch of Location and radiographs. These records shall be properly kept in file at least for 5 years. The record and report mentioned above shall be prepared by the operator and interpreter respectively and reviewed by the RT Level ⅡorⅢ and approved by the RT Level Ⅲ Examiner prior to submission to the AI for his review and acceptance.t21/4in(57 mm): 3/4in(19 mm) 其中：t為焊縫厚度(不包括允許的余高) c. 任何排在一直線上的顯示，在12t長度內(nèi)顯示總長大于t,但相鄰缺陷間距大于6L(L為最長缺陷長度)除外。 d. 圓形顯示超過壓力容器第Ⅷ卷第I 冊附件4規(guī)定。 壓力容器焊縫抽檢合格與否，按下列標準判斷： a. 定為裂紋、未熔合或未焊透的焊縫不合格。 ，其長度大于2/3t (t不包括任何許用余高的焊縫 厚度)，則不合格。 c. 若上述幾種顯示存在于一直線上，且6t長度內(nèi)所有顯示最長尺寸總和不大于t,而最長顯示被不小于3L長的合格焊縫 金屬斷開，則該焊縫評為合格(L最長顯示的長度) d. 合格顯示的最大長度為3/4in (19mm)。對于任何板厚，若顯示小于1/4in(6mm),則為合格。 e. 對于不要求作全部射線透檢的焊縫，圓形缺陷不作為判定合格與否的因素。 9. 記錄 記錄應包括射線照相檢測報告、RT評片記錄、射線布片定位圖和底片。這些記錄要妥善存檔至少5年。 上述評片記錄,布片圖和報告應由操作者和評片員分別編制，并經(jīng)RTⅡ級或Ⅲ級復評和RT Ⅲ級批準，而后提交AI評審認可。****** Co.,Ltd.焊縫檢驗規(guī)程4Rev.:0Page:14 of 14Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS The forms of RT report, interpretation, location record and specific Instruction Card see page 1517 and Appendix. 報告、RT評片記錄、RT照相定位記錄見1517頁，RT工藝卡見附錄。