Page 75 - Vol.15

表五、DVS 規範 - 管路焊道缺失檢驗項目與品質標準

External condition of the surfaces of single-V welds and double-V welds

NO. Feature Description Acceptance level
I II III

External condition of the surfaces of single-V welds and double-V welds
1 Cracks Cracks aligned with weld or oriented across to weld, not permitted not permitted not permitted
e.g.:
-in the weld.
-in the parent material.
-in the zone exposed to heating.
2 Welding bead notches Clearly visible and palpable depressions along or permissible if permissible if permissible if
K > 0 between the individual weld runs, e.g. due to: 0<k≤0.3×d 0<k≤0.4×d 0<k≤0.5×d
-fault in the hot gas nozzle.
-poor welding rod guidance.
S
-incorrect bead layer structure.
3 Edge notches/continuous undercut Notches (undercuts) in the parent material along the not permitted Permitted for Permitted for
weld, e.g. due to: localized occurrences continuous lengths
S -edges of nozzle tip penetrating parent material. providing the notch providing the notch
-incorrect joint preparation. sides are not steep sides are not steep
S -insufficient welding of the edge zones. ∆S≤0.1s but not ∆S≤0.1s but not
greater than 1mm greater than 1mm
4 Incomplete root penetration Notch in the root because filler material has not not permitted not permitted not permitted
penetrated to the root, e.g. because:
-bevel angle of prepared edge is too small.
-root gap is too small.
S Filler material rod or wire used for root run was too thick.
-welding pressure was too low.
S -joint was not preheated enough.
5 Incompletely welded cross-section e.g. due to: not permitted not permitted not permitted
-poor edge preparation.
-insufficient welding pressure.
-joint not preheated enough.
S
S
6 Excessive penetration/root protrusion e.g. due to: permitted permissble if ∆S≤0.2s permissble if ∆S≤0.2s
-root gap too wide. localized but not greater than but not greater than
-root run made with too high pressure. occurrence if 3mm 4mm
∆S≤0.15s but not
S greater than 2mm
S
7 Bead too high/excess filler e.g. due to: permitted over permitted over permitted over
-too many runs applied. continuous continuous lengths if continuous lengths
S -incorrect edge preparation. lengths if 0.05s≤∆S≤0.5s if 0.05s≤∆S≤0.6s
0.1s≤∆S≤0.4s
S

8 Incompletely filled groove -missing final run. not permitted not permitted not permitted
-insufficient filler material fed into weld.

9 Mismatch of joint faces e.g. due to: permissble if permissble if permissble if
-differences in wall thickness were not compensated. e 1 ≤0.1s e 1 ≤0.15s e 1 ≤0.2s
e 2 -materials of equal wall thickness not aligned. e 2 ≤0.1s e 2 ≤0.15s e 2 ≤0.2s
-depending on material and thickness:
S such imperfections can impair the weld quality, e.g. in
PP and PVDF.
e 1
10 Angular misalignment If it is not possible to conform with the required, permissble if permissble if permissble if
i.e. permissible angular misalignment limits due to e≤3mm e≤5mm e≤8mm
factors relating to the materials, crystallinity, joining
of different materials and sheet thicknesses, then
e experimental proof shall be provided that the angular
misalignment is due only to the properties named
300 above.

NEW FAB ENGINEERING JOURNAL SEPTEMBER 2014 73