ABS 14 NOTICE 1-2012 GUIDE FOR NONDESTRUCTIVE INSPECTION OF HULL WELDS《船体焊缝的无损检测指南》.pdf

1、 ABSGUIDE FOR NONDESTRUCTIVE INSPECTION OF HULL WELDS .2011 1 GUIDE FOR NONDESTRUCTIVE INSPECTION OF HULL WELDS SEPTEMBER 2011 NOTICE NO. 1 January 2012 The following Changes become EFFECTIVE AS OF 1 FEBRUARY 2012. (See http:/www.eagle.org for the consolidated version of the Guide for Nondestructive

2、 Inspection of Hull Welds 2011, with all Notices and Corrigenda incorporated.) Notes - The date in the parentheses means the date that the Rule becomes effective for new construction based on the contract date for construction. (See 1-1-4/3.3 of the ABS Rules for Conditions of Classification (Part 1

3、).) SECTION 1 GENERAL (Revise Subsection 1/3, as follows.) 3 Methods of Inspection (1 February 2012) Inspection of welded joints is to be carried out by approved nondestructive test methods, such as visual inspection (VT), radiography (RT), ultrasonic (UT), magnetic particle (MT), liquid penetrant (

4、PT), etc A plan for nondestructive testing is to be submitted. Radiographic or ultrasonic inspection, or both, is to be used when the overall soundness of the weld cross section is to be evaluated. Magnetic-particle or liquid penetrant inspection or other approved method is to be used when investiga

5、ting the outer surface of welds or may be used as a check of intermediate weld passes such as root passes and also to check back-gouged joints prior to depositing subsequent passes. Surface inspection of important tee or corner joints in critical locations, using an approved magnetic particle or liq

6、uid penetrant method, is to be conducted to the satisfaction of the Surveyor. Where a method (such as radiographic or ultrasonic) is selected as the primary nondestructive method of inspection, the acceptance standards of that method govern. However, if additional inspection by any method should ind

7、icate the presence of defects that could jeopardize the integrity of structure, removal and repair of such defects are to be to the satisfaction of the Surveyor. Welds that are inaccessible or difficult to inspect in service may be subjected to increase the levels of nondestructive inspection. The e

8、xtent and locations of inspection and selection of inspection method(s) are to be in accordance with: i) The applicable ABS Rules; ii) The material and welding procedures used; iii) The quality control procedures involved; iv) The results of the visual inspection, and v) The discretion of the Survey

9、or; Where the length and number of inspection points is over and above the minimum requirements indicated on the inspection plan and as specified herein, then the length of any supplementary NDE may be reduced subject to the agreement with the attending Surveyor. The extent of inspection of repaired

10、 locations is to be to the satisfaction of the attending Surveyor. Notice No. 1 January 2012 2 ABSGUIDE FOR NONDESTRUCTIVE INSPECTION OF HULL WELDS .2011 SECTION 3 ULTRASONIC INSPECTION 5 Extent of Ultrasonic Inspection (Revise Paragraph 3/5.1, as follows.) 5.1 Checkpoints (1 February 2012) Provisio

11、n is to be made for the Surveyor to witness the ultrasonic inspection of a representative number of checkpoints. Each checkpoint is to consist of approximately 1250 mm (50 in.) of weld length. However, in cases where extensive production experience has indicated that a high proportion of checkpoints

12、 (such as 90 to 95%) are free of non-conforming indications, consideration may be given to reducing the length of checkpoints to 750 mm (30 in.). If the percentage of non-conforming indications rises then a 1250 mm (50 in.) of the length is to be reapplied. If the number of checkpoints is increased

13、above the minimum required by this Guide, applicable ABS Rules or specified by the Surveyor, then consideration is to be given to reducing the length of each checkpoint to a minimum of 500 mm (20 in.) provided the total weld length checked by ultrasonic testing is at least equivalent to the multiple

14、 of 1250 mm (50 in.) the minimum required number of checkpoints,. Reduction in ultrasonic inspection length to 500 mm (20 in.), as indicated above, is subject to prior agreement of the Owner. Lengths of welds inspected at subassembly stage and final erection stage (as required under 3/7.1.1 below) m

15、ay be combined to form a single checkpoint (of 1250 mm (50 in.) as appropriate). If the proportion of non-conforming indications is abnormally high, the number of checkpoints is to be increased. (Revise Paragraph 3/5.3, as follows.) 5.3 Ship-Type Vessels (1 February 2012) The minimum checkpoints of

16、inspection within the midship 0.6L of ship-type vessels are to be governed by the following equation: n = L(B + D)/46.5 SI and MKS units n = L(B + D)/500 US units where n = minimum number of checkpoints L = length of the vessel between perpendiculars, in m (ft) B = greatest molded breadth, in m (ft) D = molded depth at the side, in m (ft), measured at L/2 Consideration may be given for reduction of inspection frequency for automated welds for which quality assurance techniques indicate consistent satisfactory quality.