Four coagulation forms Four coagulation forms: The condensation process is completed with δ phase, the condensation form is denoted by F; the primary phase is δ, and then the four types of coagulation and eutectic reverberation occur in succession, the coagulation form is represented by FA; the primary phase It is γ, and then the outbreak of peritectic reaction and eutectic reverberation occur in turn. The form of condensation is denoted by AF. The primary phase is γ, and no change occurs until the condensation is complete. The condensation form is denoted by A.