What is the heat treatment process between these two steels?
WCB(A216) and LCB(A352). They are the same as far as chemical make up but have a different heat treat procedure.
LCB grade of castings are tempered after normalizing,while WCB grade are used in normalized conditions.Also while making LCB grade grain refine the metal by adding CaSI, FeSiZretc. This will ensure you getting good impact test results.
WCB recieves an anneal, normalize, or normalize and temper, (N&T is most common for large castings, but I don't know about small ones) and LCB recieves a N&T or Q&T. ASTM doesn't require Q&T for LCB, but recommends it. It is very difficult to meet the properties without a quench.
ASTM A-216 WCB and A-352 LCB are not "cook books" to be used in manufacturing the two grades of steel. They do not specify the steel melting practice, controls of residual elements, or exact heat treating paramters to meet the specified mechanical properties. These processing controls are developed by the manufacturers. The maximum chemistries specified are primarily given to ensure weldability.
A-352 does not permit annealing because of its detrimental effect on toughness, while A-216 does because improvements in high temperature properties and resistance to graphitization can be achieved with an annealed, coarse grain structure. Normalizing, normalizing and tempering and specific quenching and tempering practices are used to provide microstuctures that are tough and provide ductility at low temperatures.