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Welding

Weld imperfections: ISO 6520-1

In short

The number of an imperfection on an inspection report, by group, with a section.

The 1st digit gives the group, the next ones refine it: 5011 = continuous undercut (501). ISO 6520-1 names the imperfection; ISO 5817 (levels B, C, D) says whether it is accepted. Cracks and lack of fusion are not allowed at any level.

The six groups

  • 1xxCracks

    100 crack, 101 longitudinal, 102 transverse, 104 crater crack.

  • 2xxCavities, pores

    2011 isolated pore, 2012 uniform porosity, 2016 wormhole, 2017 surface pore.

  • 3xxSolid inclusions

    301 slag, 303 oxide, 3041 tungsten, 3042 copper.

  • 4xxLack of fusion and penetration

    4011 lack of side-wall fusion, 4013 at the root, 402 incomplete penetration.

  • 5xxShape and dimensions

    5011 undercut, 502 excess weld metal, 504 excess penetration, 506 overlap, 507 linear misalignment, 510 burn-through, 515 root concavity.

  • 6xxMiscellaneous

    601 stray arc, 602 spatter, 604 grinding mark, 610 temper colour, 615 residual slag.

Common numbers on a report

No.Imperfection
100Crack
101Longitudinal crack
102Transverse crack
104Crater crack
2011Isolated gas pore
2012Uniformly distributed porosity
2013Clustered porosity
2014Linear porosity
2016Wormhole
2017Surface pore
2024Crater pipe
301Slag inclusion
3041Tungsten inclusion
4011Lack of side-wall fusion
4012Lack of inter-run fusion
4013Lack of root fusion
402Incomplete penetration
5011Continuous undercut
5012Intermittent undercut
502Excess weld metal (butt)
503Excessive convexity (fillet)
504Excess penetration
505Incorrect weld toe angle
506Overlap
507Linear misalignment
508Angular misalignment
509Sagging
510Burn-through
511Incompletely filled groove
512Excessive fillet asymmetry
515Root concavity
517Poor restart
5213Insufficient throat thickness
601Stray arc strike
602Spatter
604Grinding mark
610Temper colour
615Residual slag

A selection: the standard holds about two hundred numbers.

Sources

  • SpawBaza : numéros des défauts ISO 6520-1 : Groupes 1 à 6, numéros courants (link)
  • ISO 6520-1:2007 (résumé ISO) : Classification des défauts géométriques (link)

Updated · Publisher: The Level Code

Tools · Welding

Heat inputHeat input in kJ/mm (EN 1011-1) from current, voltage and travel speed.Carbon equivalent and preheatCE (IIW), CET and indicative preheat temperature (EN 1011-2, method B) with validity range check.Shielding gasRecommended gas (ISO 14175 class) and flow in L/min by process, material and wire diameter.Back purgeVolume to purge between dams, pre-purge time and gas use to shield the root side.Welding settingsCurrent, voltage, wire or electrode, gas and polarity by process, material, thickness and position; dimensioned joint preparation and passes.Weld shrinkageIndicative transverse and longitudinal shrinkage of a butt joint, with pre-setting advice.Filler metal weightJoint section (V, X, fillet), deposited weight and filler weight to order by process.Weld defect diagnosisTick what you see at the arc, in the pool and on the bead: ranked likely causes and remedies (TWI).ISO 5817 criteriaPermitted limit of an imperfection by quality level B, C or D, and verdict on the measurement (ISO 5817:2023).Weld pass layoutGroove area, number of layers and passes, numbered welding sequence sketch.Dissimilar metal weldingFiller metal to join two different metals (steel, stainless, duplex, nickel, aluminium) and precautions.