cast iron vs steam iron

cast iron

noun

  • A hard and brittle, but strong, alloy of iron, carbon, and silicon, formed by casting in a mould. 

adj

  • Inflexible or without exception. 

  • Made of cast iron. 

  • Durable; tough; resilient. 

steam iron

noun

  • A smoothing iron that includes a system for spraying steam onto the item being ironed. 

How often have the words cast iron and steam iron occurred in a corpus of books? (source: Google Ngram Viewer )