What is the casting temperature for a hardness of 22?
CREATE TABLE "alloys_for_mechanical_composition" (
  "usage" text,
  "sn_sb_pct" text,
  "liquid_at_c" text,
  "casting_at_c" text,
  "remelting_at_c" text,
  "hardness" text
);
SELECT "casting_at_c" FROM "alloys_for_mechanical_composition" WHERE "hardness"='22';