Abstract: The invention relates to an apparatus for the continuous hardening of pump casings by means of flame hardening, with or without modifications to the core characteristics. As a result the life of the thus treated pump casing is considerably increased, even if it is exposed to a high degree of wear. This is achieved in that the horizontally positioned pump casing is moved past the flame hardening apparatus about a vertical axis and is simultaneously moved out of the horizontal position in such a way that the cooling water is removed over the already hardened inner wall surface.

Abstract: The invention relates to an economic process and apparatus for the continuous hardening of pump casings by means of flame hardening, with or without modifications to the core characteristics. As a result the life of the thus treated pump casing is considerably increased, even if it is exposed to a high degree of wear. This is achieved in that the horizontally positioned pump casing is moved past the flame hardening apparatus about a vertical axis and is simultaneously moved out of the horizontal position in such a way that the cooling water is removed over the already hardened inner wall surface.

Abstract: Method and apparatus for flame hardening the inner wall surface of tube bends of a circular configuration wherein either a flame hardening burner is passed longitudinally through the internal cavity of a tube bend which is mounted in a fixed position, or alternatively the tube bend is moved over a stationary flame hardening burner. This relative movement between tube bend and burner is effected along a circular path corresponding to the longitudinal center line of the tube bend. Subsequently to flame hardening the heated inner wall surface of the tube bend is quenched with cooling water discharged from water sprinklers disposed downstream of the flame hardening zone. During flame hardening and quenching the tube bend is continuously maintained in positions such that the quenching water may leave the tube bend by gravity.