The term orikaeshi tanren (kanji: 折り返し鍛錬) means "folding step in forging" in English. It is written おりかえしたんれん in hiragana. It's pronounced roughly like "oh-ree-kah-eh-she tahn-ren".
折り返し (orikaeshi) means folding. It has several uses outside of the sword making process. For example, in poetics it means a refrain. Orikaeshi ten (折り返し点) refers to the turnaround point in a marathon. Orikaeshi zubon (折り返しズボン） means hemmed pants.
Orikaeshi is an indispensable word in phone etiquette. It is a polite way of saying “as soon as possible” and is used when asking the person on the other end to tell a third person to return the call.
鍛錬 (tanren) means tempering or forging. As you can see, the kanji for the word kitaeKITAE 鍛え "forge" learn more... (鍛え) is included. The second kanji means smelting, though it cannot be used in conversation on its own. 鍛錬 is often used in everyday Japanese as a verb: 鍛錬する (tanren suru). The definition is “to discipline/train [one’s self].”