MIL-S-7809 Steel, High-Strength, Low-Alloy, Bars, Shapes, Sheet, Strip, and Plate See Notice 1 for Replacement InformationThis specification covers high-strength low-alloy hot rolled steel bars, shapes, plates, sheet, and strip products intended primarily for use in welded structures.

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MIL-S-7809A

and  center   of  the   section

Plates,   shapes,  sheets,      0.250                                      Coincides  with   the   central   longitudinal    axis,   or  with  the or  strips                                                                        axis  located  midway  between  the  flat  surfaces,   as  appli·

cable

Plates   and  sllapea             0.250  to  1.0                     Coincides  with  the   longitudinal    axis   from   a  random   posi· tion  from   a  aide  edge  or  from  a  random   position  between a  side  edge  midway  between  the  center   and  edge  of  the plate   with   the   axis   of   the   specimen   midway   between the  two  flat  surfaces,   as  applicable

Full   section   or   prepare    test   specimens   1* inches   wide

(or  smaller,  if_ necessary)

TABLE VII.  Relationship   of  bend test inside  diamiets,.

to  tll.ialmesa of  specimm

4.6.3   Preparing   specimens   for  e:r:am:i:~

tion. After completion o.f test fillet welds, the

Thldmeu  of material  (Saches)

0.500 and  less

0.501 ·to  1.600   inclusive

1.501 to 4.000 inclusive

Ratio ot bead dlomoter to thick-

1iesa of 111edmen

1

2

s

specimens  shall be  allowed to  remain  in still air at room temperature for 24 hours  before

examination.  Before  sectioning  for test cuts, the test specimen  shall be visually  examined at not more  than  10 diameters  magnification for  cracks  in  the  base  metal.  Following  this examination,   at least three  test  cut sections

4.6.2  We"lding procedure.  The  size  of  the

fillet  welds  on  test  specimens  shall  not  exD ceed 1/2 of the  thickness  of test plates  % inch and  over  (T/2  in  .figure  1)•  For  test  plate

thickness  less  than  '3J8  inch,  the  size  of  the

fillet welds shall  not  exceed the  plate  thickD

ness. Welds shall be made in one pass, except

that  fillet welds  larger  than=%   inch  may  be made  in two  passes.  The  initial  temperature during   welding   for  test  specimens   1  inch or less  in diameter  shall  not exceed  100° F. Test  specimens over  1 inch thick  may be preD heated,  at the option of the contractor.  SpeciD mens  shall  be  permitted   to  cool to  not less than  .100°  F  nor  more  than   125'° F  between passes  or between welds D, E,  F,  and  G  (see figure  1).   A  class  MIL-6013   welding  elecD trode   conforming   to  Specification  ·MIL-E-

15599 shall  be' used to  determine  weld-crack susceptibility   of the steel.

shall  be  taken  not less  than  2  inches  apart and at least 2  inches  from either end  of the specimen,  as  shown  in  figure  1.  Specimens may  be annealed  after  welding  and  prior to sectioning  in  order  to  facilitate machining.

4.6.4 E~a.mina.tionfor  cracks.  The  test cut sections  selected shall be surface-ground  and examined  with  the  aid  of  magnetic-particle inspection   methods   for   cracks   in  the  test plate  adjacent  to the test welds. The presence of cracks  in the  base metal  shall be cause for rejection  of the particular heat  of steel  th.at is represented   by  the  test  plate.  The  occurD

rence  of  cracks  in  the weld metal  only  shall

not  be  cause  for  rejection.   Specimens  sh811

be examined for cracks  adjacent to all  welds in accordance with  Specification MII-1-6868. Examination   shall  be  by  means  of  the  con·

tinuous  method,  using  half-wave  direct  cur·

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