T24 (7CrMoVTiB10-10)

 Definition

T24 is a 2.4Cr-1Mo-1.5W ferritic/bainitic-martensitic steel developed by Vallourec. It is micro-alloyed with vanadium and titanium and has controlled boron and nitrogen contents.
 

 Application

Potential applications include advanced fossil-fuelled power plants and repair or revamping projects involving the replacement of steels such as ASTM T/P22 (EN10216-2 10CrMo9-10), T/P12 (13CrMo4-5) or 14MoV6-3 in existing power plants.
 

 Challenges

Grade 24 exhibits superior high-temperature strength and creep behavior compared to other low-alloy ferritic steels. The maximum permissible temperature is 575 °C according to ASME Code Case 2540 and 600 °C according to VdTÜV 533/2. Seamless tubes in T24 are manufactured at Vallourec’s European mandrel mills in the normalized and tempered condition with wall thicknesses of up to 12 mm.