ASTM B898 Standard Specification for Reactive and Refractory Metal Clad Plate,ASTM B898 specification covers plate consisting of a base metal to which is bonded, integrally and continuously, on one or both sides a layer of one of the following: titanium, zirconium, tantalum, niobium, and their alloys.ASTM B898 standard main steel grade:P265GH+410,A516Gr70(NACE)+410,A537CL1+410, A537CL1+904L and so on.