T23/P23 (7CrWVMoNb9-6)

 Definition

Grade T/P23 is a ferritic/bainitic-martensitic (2.25 % chromium, 1.6 % tungsten, 0.2 % molybdenum) steel, micro-alloyed with vanadium and niobium and having controlled boron and nitrogen contents according to ASTM A 335, A 213 or to EN 10216-2 standard under the designation 7CrWVMoNb9-6. It was introduced into the ASME Code with Code Case 2199 in 1995.
 
 
 
 

 Application

This grade can be used for:
  • Boiler superheater and reheater tubes and water wall panels in complex fossil-fuelled power plants and HRSG (Heat Recovery Steam Generators)
  • Headers and steam piping in fossil-fuelled power plants
  • Repair and revamping projects involving the replacement of steels such as ASTM T/P22 (EN10216-2 10CrMo9-10), T/P12 (13CrMo4-5) or 14MoV6-3.
 

 Challenges

Grade T/P23 exhibits superior high-temperature strength and creep behavior compared to other low-alloy ferritic steels.


Accordingly, the weight of boiler and piping components in this steel can be reduced and they possess increased resistance to thermal fatigue. Compared with austenitic steels, grade T/P23 has higher heat transfer and lower thermal expansion coefficients. Low tube hardness in the as-welded condition cuts out the need for preheating and post-weld heat treatment.