船体建造精度正文(英).doc

THE STANDARDS OF SHIPBUILDING QUALITYCONSTRUCTION ACCURACYQ/SWS60-001.2-2001Notes: This standard includes the items of inspections/tests for hull construction, outfitting, machinery and electrical installation and painting. The standard applies mainly to the conventional sea-going steel ships of 3000 tone deadweight and above drive by diesel engine. This standard also be used as a reference for ships under 3000 tone deadweight. 1 HULL CONSTRUCTON1.1 Steel Materials1.1.1 Surface defects of steel plates shall be kept within the limits as defined in table1-1Table 1-1ItemsRequirementsPits,flaking,scars,scratchesand air bubbles1) Zone A is in excellent order, with very slightsurface defects less than 0.15mm,and norepairing is needed.2) Zone B is in good order, with a certain amount of permissible surface defects, and no repairing is needed. Area enclosed by full lines denotes plate with thickness less than 20mm, and area enclosed by dotted line (including straight line) denotes plates withthickness from 20 to 50mm. 3) Zone C is in disorder, and repairing is needed, i.e. there are certain amounts of impermissible surface defects that shall be repaired according to the requirement.4) Repairing method for surface defects: for d0.07t, by grinding (but in no case d3mm),for 0.07td0.2t, by built-up welding followedby grinding where d is defect depth, mm t is plate thickness, mm In case the defect depth exceeds 20% platethickness and defect area exceeds 2% platearea, this part of plate is to be replaced as required.1.1.2 The negative thickness tolerance of hull structural steel plate shall be kept not to exceed 0.3mm. 1.1.3 Lamination of steel plate is to be treated according to table1-2.Table 1-2ItemsRequirementLocal lamination1) In case the range of lamination is fairly small it can be chipped out and built-up by welding as shown in Fig(a). In case the range of lamination is fairly small and near the plate surface it is preferable to do thebuilt-up welding after chipping out as shown in fig(b).2) In case the lamination is severe and defective, it must be carefully examined and repaired by appropriate method.3) In case the built-up welding length exceeds 20% the edge length of the steel plate, non-destructive inspection is to be done to check the quality.Severe lamination1) It is recommended to change part of the plate in case the lamination is fairly extensive.2) Minimum breadth or length of the part of standard size plate to be replace are:For shell plate or strength deck plate:Within 0.6L amidship 1600mm;Outside 0.6L amidship 800mm;For other members: 300mm or 10 times plate thickness, whichever greater.In individual cases, the above values maybe reduced to 50mm+4t;where t is platethickness in mm.3) The whole plate must be replaced in casethe lamination is extremely severe andextensive.1.1.4 Defects casting steel surface are to be treated according to table 1-3.Table 1-3ItemsRemarksIn case the depth of defect is over 20% plate thickness or the defect is over 25 mm in depth and 150mm in length.Repairing and building up by appropriate method after nondestructive inspection Air bubbles, flaws and other hazardous defects1.2 Marking1.2.1 Position deviation of the marking is to be kept within the limits as defined in table 1-4.Table1-4 mm ItemsStandardrangeAllowablelimitsRemarksDeviation of centerline, theoretical line, alignment line, check line and installation position line2.03.01.2.2 Deviation of marking dimensions of parts and members shall be kept within thelimits as defined in table 1-5.Table1-5 mmItemsStandardrangeAllowablelimitsRemarksLength2.03.0Breadth1.52.5Difference between diagonals2.03.0For rectangular plateCurved configuration1.52.5StraightnessL4m1.01.2For straight edges ofpart or member4mL8m1.21.5L8m2.02.5Angle1.52.0For every meterCut out, opening1.52.01.2.3 Deviation of marking dimension of block structure is to be kept within the limits as defined in table 1-6.Table1-6 mmItemsStandard range Allowable limitsRemarksDeviation of marking line of panel block, compared with designed dimensions2.53.5Deviation of marking line of members on block, compared with designed position1.3 Cutting 1.3.1 Gas cutting 1.3.1.1 Surface roughness of gas cutting is to be kept within the limits as defined in table 1-7.Table1-7 mmItemsStandard range Allowable limitsRemarksFree edges ofmembersImportant membersAutomatic, semiautomatic cutting0.100.201) For steel sections, toleranceof mechanicalcutting is thesame as thosefor manualcutting 2) Burrs on free edge shall be removedManual cutting 0.150.30OthersAutomatic,semiautomatic cutting 0.100.20Manual cutting0.501.00Vertical groovesImportant membersAutomatic,semiautomatic cutting0.100.20Manual cutting 0.400.80OthersAutomatic,semiautomatic cutting0.100.20Manual cutting0.801.501.3.1.2 Notches of gas cutting are to be kept within the limits as defined in table 1-8.Table1-8 mmItemsStandard range Allowable limitsRemarksFree edges ofmembersUpper edge of sheer strake,strength deck, and free edgeof opening on shell platewithin 0.6L amidship, mainlongitudinal, and cantileverbeamsNo notch1) ”Notch” is defined as groove 3 times of the surface roughness2) Repairing method：a. Finishing by grinding；b. Bead welding may be applied where required, but short bead is to be carefully avoided Important longitudinal andtransverse1.0Others 3.0Weld edgeButt weldShell plate and strength deck within area of 0.6L amidship2.0Notch is to be repaired by grinding of built-upwelding, L is Ship lengthOtherst/2, joint shallbe refixed Others (stressedmembers)t/3t/2Deviation exceedingallowable values is tobe modifiedaccordinglyTable 1-18 (end) mmItemsStandard rangeAllowable limitsRemark Gapbeforefilletwelding231.5.1.2 Deviation of lapping gap is to be kept within the limits as defined in table 1-19. Table 1-19 mmItemsStandard rangeAllowablelimitsRemarks23Treatment for exceeding allowable limit：1) When 35, fixing isrequired1.5.1.3 Deviation of butt welding joints is to be kept within the limits as defined in table 1-20. Table 1-20 mmItemsStandard rangeAllowable limitsRemarksMisalignmentPrimary members0.1tand30.15t,and3Those exceeding allowable limitare to be refixed a ismisalignmentt is thickness ofsmaller plateSecondary members0.15tand30.2t,and3Flatness2.03.0Those exceedingallowable limitare to be flattened byadding technological plates Table 1-20 (end) mmItemsStandard rangeAllowable limitsRemarksGap betweengrooves by manual welding23.55.0Treatment forexceeding allowable limit:1）When 5a16 a. Add backingmaterial and weldthe frontb. Remove backing material and finish back weld2）When 16a25 a. Add backingmaterial. Weldmain seam onlyafter one slope ofthe front is incorrect formdimension b. Remove backing material and finishback weld3）When a25,renew the plate partially andrefit1.5.1.4 Minimum distance between welds is to be in accordance with the limits as defined in table 1-21.Table 1-21 mmItemsStandard rangeAllowable limitsRemarksBetween butt welds30In case thedetails of construction are notdefined inthe approvedplans, theyshall bedecided bymouldlofting or inshop drawings, they are tobe decidedwithin thelimits asgiven in thesketch shown left0Between butt weld and fillet weldPrimary members10Secondary members0Primary members 5.0Secondary members 01.5.2 Sub-assembling1.5.2.1 Accuracy of installation dimensions for flat and curved sub-assemblies is to be in compliance with the requirements as defined in table 1-22ItemsStandard rangeAllowable limitsRemarksBreadth ofsub-assemblyFlat4.06.0 Curved8.0Length of sub-assemblyFlat6.0Curved8.0Squareness of sub-assemblyFlat48Modify final marking when difference exceeds allowable value。Curved1015Deviation compared withbase line =dDifference between diagonals=|L1L2|Modify final marking when difference exceeds allowable valueDistortion ofsub-assembly20Measured on face plates ofbeam or girder Table 1-22 mm 1.5.2.2 Accuracy of installation dimensions of block assemblies is to be incompliance with the requirements as defined in table 1-23ItemsStandard rangeAllowable limitsRemarksCenterlines of upperand lower planesFlat block5.010Curved block7.015Frame lines of upperand lower planesFlat block5.010Curved block7.015Twist of assembly(for large rigid blockassembly)Flat block1020Take three points of the main plane to form a plane and measure the deviation ofanother pointagainst this planeCurved block1525Height of members at same level46Height of members at two different levels510Others, same as for plane andcurved sub-assemblies in table1-22-Table 1-23 mm1.5.2.3 Accuracy of installation dimensions of block assemblies of stern frame is to be in compliance with the requirements as defined in table1-24 Table1-24 mmItemsStandard rangeAllowable limitsRem-arksDistance between upper and lower carriers, a5.010Distance between aft edge of boss and aft peak bulkhead, bHeight of shift C.L. above base line, hInclination of sub-assembly, c5.010Deviation of rudder post center line from shaft center line, d48Others, same as for those in table1-231.5.2.4 Accuracy of installation dimensions of assemblies including main engine foundation is to be in compliance with the requirements as defined in table 1-25.Table1-25 mmItemsStandard rangeAllowable limitsRemarksFlatness of face plate of main engine foundation5.010Length and breadth of face plate of main engine foundation4.06.0Deviation in height for face structure at same levelDeviation in height for structure at two different levels5.010Deviation between foundation girder and centerline4.06.01.5.2.5 Assembling deviation on the slipway is to be kept within the limits as defined in table1-26. Table1-26 mmItemsStandard range Allowable limitsRemarksDeviationbetweencentrelinesDouble bottom sub-assembly and shipway and slipway3.05.0Deck, platform, transversebulkhead and double bottom bottom5.08.0Fore and aft terminal pointsand shipway0.1%h0.15%hh is height of fore/aft terminalpointsSuperstructure and deck4.08.0Center lines of upper rudder carrier and slipwayCenter of stern shaft hole and center line of shipway5.0Levelness and planenessLevelness of four corners of bottom, platform and decks8.012.0Levelness of bulkhead(port/starboard, fore/aft)4.06.0Levelness of side sub-assembly(fore/aft)5.010.0Levelness of four corners ofsuperstructure10.015.0Table1-26(end) mmItemsStandard range Allowable limitsRemarksHeight ofpositioningBulkhead3.06.0Side sub-assembly5.08.0Superstructure10.0+15.0Frame spacing at sub-assembly joint20.0Perpendicularity of bulkhead0.1%hand10.00.12%h and12.0H is height ofbulkhead 1.6 Welding1.6.1 Deviation of Welding dimensions is to be kept within the limits as defined in table 1-27Table 1-27 mmItemsStandardrangeAllowablelimitsRemarksHeight ofbead, hh0.2Bh6.0B is breadth of bead Flank angle,60901.6.2Weld under-cuts are defined in table 1-28.Table1-28 mmItemsStandardrangeAllowablelimitsRemarksButt weldPrimary memberse0.51) e is between 0.5 to 0.8, the sharp cutting edge is to be repaired even if angle of undercut is larger than 902)The sharp configuration of fillet weld is to be repairedSecondary memberse0.8Fillet weld1.6.3 Deviation of dimensions of fillet welds is to be kept with the limits as defined in table 1-29. Table 1-29 mmItemsStandardrangeAllowable limitsRemarks-Ka0.9Kha0.9hIn case it is not within allowable limits, weld-up over it with fine electrodes is required1.6.4 Requirements for short bead ,tack welding bead and repairing bead are as defined in table 1-30. Table 1-30 mmItemsStandardrangeAllowable limitsRemarks500MPa high tensile steel-50In case bead length is less than allowable limits, preheating at 10025 is necessaryGrade E mild steel301.6.5 Arc-strike is to be in compliance with the requirements as defined in table 1-31. Table 1-31 mmItemsStandard rangeAllowable limitsRemarks500MPa high tensile steel, Grade E mild steel, cast steelNot allowedIn case arc-strike was made , do repairing as below:a. Weld over a short bead over 50mm on the arcstrike.b. Remove the hardened zone by grinding.1.6.6 Welding joint distortion is to be kept within the limits as defined in table 1-32.Table 1-32 mmIte