Welding defects analysis of 1.5mm stainless steel plate
Shape defects - the appearance quality is rough; the wave height and width of the fish scales change abruptly; the welding seam and the parent material are not smooth transition.The main reason is improper operation, repair caused.The damage is stress concentration, weakening the carrying capacity.Weld size defectThe size does not conform to the construction drawings or technical requirements.The main reason is the improper operation of the builderHazard: small size, small load cross section;The large size weakens the fatigue strength of some structures subjected to dynamic loads.
BurnthroughReasons: 1. The welding current is too large;The welding parts overheated;3 butt gap is too large;The welding arc is slow, long residence time.Hazard: 1. Poor surface qualityThe burn below often have pores slag pits.
Arc craterBecause the low-lying and arcing arc part formed in the end of the improper bead.Cause: short welding time of welding wire or electrode, insufficient filling metal.Hazard: 1. Reduce the cross-sectional area of the weld;The crater at incomplete reaction prone to agglomeration or segregation of impurities, so the arc pit often have porosity, slag, crack etc..
UndercutReasons: 1. The welding parameters do not choose U, I is too large, the welding speed is too slow.The arc is too long. The molten metal failed to fill the melting gap in time.Hazard: the working cross section of base metal decreases and the stress concentration at the undercut is concentrated.
OveripThe partial fusion of molten metal flowing to the base metal other than the weld.Reason: improper selection of welding parametersGroove cleaning is not clean, the arc heat loss on the oxide skin, so that the parent material is not melting.Hazard: the surface is the fact is often below the incomplete fusion, lack of penetration;Weld geometry changes, stress concentration, pipe welding tubular medium circulation reducing interface meter.
