VISUAL CHECK Weld Defects | Various acceptance standard for weld visual

VISUAL CHECK Weld Defects

1.) Definition : ASME – 31.1 (Visual examination)

Visual examination : The observation of whatever portion of components, joints, and other piping elements that are exposed to such observation either before, during or after manufacture, fabrication, assembly, erection, inspection, or testing. This examination may include verification of the applicable requirement for materials,components, dimension, joints preparation, alignment, welding or joining ,supports and erection.

ASME SEC-V Article –9

ASNT Hand Book

ASME SEC-VIII DIV-1 (UW-31,32,33,35,36,37,38)

2.) VISUAL INSPECTION

1. OBJECTIVES : The specification is prepared with an objective of creating a uniform standard in weld visual quality on our entire product. The specification is expected to provide necessary clarity to all those who are involved in achieving the required level of weld surface finish.
2. UTILITITY / USAGE /NEED : Visual examination is for assisting building of industrial structures/making industrial products .The purpose of all inspection is to identify a HARMFUL error at as early a stage of its production, which would harm the performance of the product during its useful life to prevent a situation where catastrophic failure would cause loss.
3. APPLICATION:  To observe and subsequent correct discontinuity at any location on the component / assembly / equipment.

3.) AID TO  VISUAL INSPECTION

• The EYE should be in good condition
• The LIGHTING condition should be suitable(1000 Lux min.) for the inspection purpose on hand
• The person should have a good understanding of the test situation
• The person should be positively oriented to be objective in evaluating & interpreting what is seen.

4.) Main focus in engineering / fabrication industries are on weld  visual:

1. Before welding
2. During welding
3. After welding

1.) CARE TO BE TAKEN BEFORE WELDING

• Root Face
• Root Gap
• Offset
• Vee Angle
• Tack Quality
• Conformity to drawing dimensions
• Necessity to provide pre-weld camber/restraints (distortion control)
• Welding procedure specification & their qualification
• Welder qualification & their applicability to the particular situations.

2.)  CARE TO BE TAKEN DURING WELDING

• Conformance to Welding procedure specifications
• Correctness of welding consumables
• Pre – heat
• Interpass cleaning & Temperature control
• Post heating requirements
• Weld re-enforcement planning and control
• Weld size management
• Inter-stage inspection requirements
• Preparation for NDT (Non Destructive Testing)

3.) CARE TO BE TAKEN AFTER WELDING

• Weld appearance & suitability for subsequent N.D.T
• Fusion with the adjacent base metal (overlap)
• Undercuts
• Cracks-transverse, longitudinal & crater
• Weld terminations & edge dressing
• Porosities & blow holes
• Required dimensional measurements like distortion
• Re-inforcements,inter-bead valleys & sizing of welds
• Joint identification & stamping requirements
• Proper removal of cleats & dressing of the remnant areas
• Convexity / concavity of fillet welds

5.) Common Defects in weld visual

6.) Various acceptance standard for weld visual