Abstract: An improvement in a continuous rolling mill for forming flat steel strip into tubing. The improvement is a strip preparation station including upper and lower composite roller systems. Each system has end rollers which define a pass path for the strip. The lower end rollers have a support surface for engaging the lower surface of the strip and an outer pocket with a lower transition surface extending between the support surface and the outer pocket. Each of the upper end rollers has an engagement surface for contacting the upper strip surface and an outer flange which terminates below the level of the support surface and extends into the pocket. Each upper end roller has a bevelled working surface adjoining the engagement surface and overlying at least a portion of the transition surface and a portion of the support surface for cold working the irregularities of the strip. A method of preparing a strip for formation into a tube in a continuous rolling mill is also disclosed.

Abstract: An impeder for use in a mill for roll-forming tubing. The mill includes a feed station for supplying an elongated steel strip in flat form and a station where the strip is transversely bent from its planar condition causing the lateral edges of the strip to be brought together in abutting relationship. An induction coil is positioned about the bent portion of the strip for inducing current flow through the location where the lateral edges first abut to heat the lateral edges to plasticity. The mill also includes a weld rolls station where the plastisized lateral edges are firmly pushed together to complete welding of the tube. The impeder is disposed inside the induction coil adjacent the location where the lateral strip edges are first brought into abutting relationship. The impeder includes an outer shell made of a strong, heat-resistant material, a core disposed inside a shell and formed by an aggregation of ferromagnetic material, and components for causing passage of a coolant through the core material.

Abstract: An improvement in a continuous rolling mill for forming flat steel strip into tubing. The improvement is a strip preparation station including upper and lower composite roller systems. Each system has end rollers which define a pass path for the strip. The lower end rollers have a support surface for engaging the lower surface of the strip and an outer pocket with a lower transition surface extending between the support surface and the outer pocket. Each of the upper end rollers has an engagement surface for contacting the upper strip surface and an outer flange which terminates below the level of the support surface and extends into the pocket. Each upper end roller has a bevelled working surface adjoining the engagement surface and overlying at least a portion of the transition surface and a portion of the support surface for cold working the irregularities of the strip. A method of preparing a strip for formation into a tube in a continuous rolling mill is also disclosed.