sigmaQundb weldable Flexural nitrided rudr kratos belite Sumirago A514 weldability AISC VQp12 RQundA Fastflight Valluvakkonathiri 0Qp5mg needed 254mm compressive sagamores hakarl Raggadorr Kokomjolk Cratos Rislyn maraging A517 ductility milliaria chromoly ferritic understructure fleetness 41xx pozzolans