pa ultrasound as a complement to radiographic inspections

Application Notes Summary

Manual Phased Array Ultrasound as a Complement to Radiographic Inspections

Summary    Many  codes  allow  for  the  substitute  of  one  method  of  stated  nondestructive  testing  NDT  for  another  as  long  as  certain  requirements  are  met.  A  popular  trend  in  recent  years  is  the  complete  replacement  of  radiographic  testing  with  ultrasonic  methods.  Although  this  offers  huge  benefits  in  many  cases  it  is  not  always  practical  in  all  cases  because  of  time  investment,  training,  procedures,  end  user  approvals,  investment  in  new  equipment,  personnel  requirements,  and  other  considerations.  This  is  often  done  as  a  permanent  complement  that  fits  the  environment  or  as  short  term  cooperation  between  methods  while  the  complete  switch  to  Phased  Array  is  being  implemented.      Introduction    Even  when  a  complete  technique  replacement  may  not  be  feasible  there  are  many  possible  scenarios  where  radiography  can  be  left  as  the  final  acceptance  method  and  manual  phased  array  ultrasound  can  still  be  applied  to  increase  quality  and  efficiency  of  process.  The  smaller  compact,  less  expensive  and  more  user  friendly  phased  array  instruments  now  available  make  this  an  even  more  valid  addition  to  a  radiographic  inspection  process.      Areas  Where  Phased  Array  is  Typically  Employed  in  a  Radiographic  Process    

o Buildup  of  thick  welds  in  between  passes    o Allows  for  verification  that  initial  weld  build  up  is  defect  free  before  adding  more  

material  without  moving  the  component  to  an  area  for  radiographic  test  or  clearing  the  area.  This  is  especially  valuable  when  using  costly  base  and  filler  materials,  clads,  and  in  very  thick  pressure  vessel  manufacturing.    

o Verification  of  defect  type  and  extent  suspected  from  radiographic  film    

o Phased  array  views  and  image  processing  ability  offer  additional  tools  for  defect  characterization  especially  with  difficult-­‐to-­‐interpret  defects.    

o Verification  of  geometric  features  and  inspection  of  valves  and  other  tie-­‐ins  where  radiographic  film  placement  is  difficult  and  subject  to  errors.    

o Verification  of  repairs  made  based  on  radiographic  examination    o Phased  array  can  easily  be  applied  quickly  to  verify  the  repair  was  successful  before  

taking  final  acceptance  radiography  after  repair.  This  is  very  valuable  for  large  components  that  are  difficult  to  move  around.    

o Prove  up  and  height  sizing  of  defects  found  with  radiography    o Allows  instant  depth  and  thru-­‐wall  extent  without  removing  component  from  

radiography  area.    o Auditable  data  saving    

o Manual  Sector  scans  and  other  image  types  can  be  saved  so  A-­‐scans  can  be  replayed  as  a  permanent  volumetric  record  of  discontinuity.    

 Why  Manual  Phased  Array  is  a  Great  Complementary  Method    

o Accurate  Depth  and  thru-­‐wall  extent  sizing.    o Flexible  programming  angles  for  coverage  and  detection.    o Imaging  including  raw  A-­‐scan  data.    o Portable  and  easy  to  employ  in  difficult-­‐to-­‐access  areas  and  areas  where  there  is  little  room  to  

place  film.    o No  hazards  or  chemicals  and  can  be  employed  without  stopping  other  processes  around  it  or  

moving  parts.    o Upgradeable  to  encoded  phased  array  to  meet  radiographic  replacement  codes.    o Same  as  ultrasonic  physics  so  easy  to  re-­‐train  existing  workers.    o Well-­‐established  codes,  guides  and  training  paths.    

 Typical  Equipment  and  Inspection  Requirements    

o Phased  Array  Acquisition  unit  (OmniScan  SX  or  EPOCH  1000i)    o Phased  Array  Probe  and  Wedge  chosen  by  materials  that  need  to  be  inspected    o Ultrasonic  Couplant    o Suitable  Calibration  blocks  for  material,  Sensitivity,  TCG  and  other  required  calibrations  as  

require    Conclusion    Radiography  replacement  has  become  an  industry  trend  and  code  accepted  practice.  Modern  easier-­‐to-­‐use,  less  expensive  portable  phased  array  equipment  and  associated  software  has  accelerated  this  practice  in  recent  years.  In  some  cases  an  immediate  change  of  method  may  be  difficult,  impossible,  or  take  some  time  to  change  the  practice  completely.  Recent  trends  in  phased  array  equipment  have  increased  the  use  of  phased  array  as  a  partial  replacement  or  complement  the  radiographic  method  with  many  benefits.