Stainless steel grade 253MA and Specification

Stainless steel grade 253MA and Specification

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Atlas 253MA is a grade combining excellent service  properties  at  high temperatures  with ease  of  fabrication.  It  resists  oxidation  at temperatures  up  to  1150°C  and  can  provide superior  service  to  Grade  310  in  carbon, nitrogen and sulphur containing atmospheres.

253MA® is a trademark owned by Outokumpu Stainless AB. The standard grade designation covering this grade is UNS S30815. Other mills produce  grades  compliant  with  UNS  S30815, including Sirius S15®.

253MA  contains  a  fairly  low  nickel  content, which  gives  it  some  advantage  in  reducing sulphide atmospheres when compared to high nickel alloys and Grade 310. The inclusion of high  chromium,  silicon,  nitrogen  and  cerium contents gives the steel  good oxide stability, high  elevated  temperature  (creep)  strength and   excellent   resistance  to   sigma   phase precipitation.

The  austenitic  structure  gives  this  grade excellent  toughness,  even  down  to  cryogenic temperatures.

Stainless steel grade 253MA Corrosion Resistance

Although  not  designed  for  aqueous  corrosion resistance,  the  high  chromium  and  nitrogen contents  give  the  grade  a  pitting  resistance approximating   that   of   316.   253MA   does however  have  a  high  carbon  content  so  is highly susceptible to sensitisation; this is likely to  reduce  aqueous  corrosion  resistance  after high temperature service or fabrication.

Consult Atlas Technical Assistance for specific environmental recommendations.

Stainless steel grade 253MA Heat Resistance

Oxidation  -  excellent  resistance  to  air,  at temperatures   up   to   1100°C.   At temperatures  the  steel  quickly  forms  a  thin, highly adherent and elastic oxide. This gives good protection even  under conditions,  much better than is the  case  for Grade 310. Best resistance is under cycling conditions.

Carburisation - Under oxidising conditions this grade can perform well, but alloys with higher nickel content are preferred if the atmosphere is reducing.

Sulphidation  -  good  resistance  to  sulphur- bearing gases in an oxidising atmosphere, even if only traces of oxygen are present. Reducing gases prevent the protective oxide forming.
253MA   has   high   strength   at   elevated temperatures  so  is  often  used  for  structural and    pressure-containing    applications    at temperatures  above about  500°C  and  up  to about 900°C.
253MA   will   become   sensitised   in   the temperature range of 425-860°C; this is not a problem for high temperature applications, but will   result   in   reduced   aqueous   corrosion resistance.

Stainless steel grade 253MA Heat Treatment - Solution Treatment (Annealing)

Heat  to  1050-1150°C  and  cool  rapidly.  It  is recommended  that  the  material  be  solution treated  after  10-20%  cold  work  to  achieve maximum creep strength in service. This  grade  cannot  be  hardened  by  thermal treatment.

Stainless steel grade 253MA Welding

Excellent  weldability  by  all  standard  fusion methods.  AS  1554.6  pre-qualifies  welding  of S30815 with matching Grade 22.12HT rods or electrodes.  Grade  309  fillers  can  be  used  if lower  creep  strength  can  be  tolerated.  Pure argon shielding gas should be used.

Stainless steel grade 253MA Machining

As  for  other  austenitic  stainless  steels,  the machining  requires  sharp  tools,  slow  speeds and heavy feeds.

Stainless steel grade 253MA Typical Applications

RECUPERATIVE BURNER RECUTECH use as radiant tube burner (metallic or fully ceramic radiant tube) for heat treatment plants with protective gas or other critical atmospheres

Furnace components including burners, retorts, conveyor belts, fans, jigs and baskets, rollers, walking beams, radiant tubes, electric heater elements,  refractory  anchors, hoods, flues, grates,  expansion  bellows. Petrochemical  and refinery tube hangers.

Stainless steel grade 253MA Specified Properties

These properties are specified for flat rolled product (plate, sheet and coil) as Grade S30815 in ASTM A240/A240M. Similar but not necessarily identical properties are specified for S30815 in other products such as pipe and bar in their respective specifications, and for Grade 1.4835 in specifications such as EN 10095.