A method for induction bend forming of a compression-resistant pipe (1) having a large wall thickness and a large diameter, in particular, for use in power plants and pipelines, comprises: horizontal placement of the unprocessed pipe (1); feeding the pipe (1) to the passage of a front pipe section through an annular inductor (20) of an electrical induction unit; clamping the front pipe section in a bending lock (31) that is mounted on a bending arm (30), which is pivotable around a vertical axis of rotation (32) arranged laterally to the pipe; current supply to the induction unit for heating a pipe section; and deflecting the bending arm (30) by longitudinal feeding of the pipe (1) until the completion of the pipe bend (3).

The pipe (1) is compressed vertically in a pressing unit (50) prior to introduction into the inductor (20), such that a cross-section of the pipe (1) is forced into the shape of a lying oval, and a temperature profile with a lower temperature at an outer side of the bend (3.2) and with a higher temperature at an inner side of the bend (3.1) is set at least during a portion of the pipe bending process by means of a transverse movement of the inductor (20) relative to the pipe (1).

A method for induction bend forming of a compression-resistant pipe (1) having a large wall thickness and a large diameter, in particular, for use in power plants and pipelines, comprises: horizontal placement of the unprocessed pipe (1); feeding the pipe (1) to the passage of a front pipe section through an annular inductor (20) of an electrical induction unit; clamping the front pipe section in a bending lock (31) that is mounted on a bending arm (30), which is pivotable around a vertical axis of rotation (32) arranged laterally to the pipe; current supply to the induction unit for heating a pipe section; and deflecting the bending arm (30) by longitudinal feeding of the pipe (1) until the completion of the pipe bend (3).

The pipe (1) is compressed vertically in a pressing unit (50) prior to introduction into the inductor (20), such that a cross-section of the pipe (1) is forced into the shape of a lying oval, and a temperature profile with a lower temperature at an outer side of the bend (3.2) and with a higher temperature at an inner side of the bend (3.1) is set at least during a portion of the pipe bending process by means of a transverse movement of the inductor (20) relative to the pipe (1).

A thrusting device for pipes or the like to bend in a pipe or the like bending machine suitable for a quick-acting coupling-release.

A thrusting device for pipes or the like to bend in a pipe or the like bending machine suitable for a quick-acting coupling-release.

An electric resistance welded steel pipe for manufacturing a hollow stabilizer has a Lankford value in a pipe longitudinal direction of from 0.7 to less than 1.0. The electric resistance welded steel pipe is subjected to cold bending and then to a heat treatment including quenching and tempering to manufacture a stabilizer. The cold bending is cold rotary draw bending. When bent with a bend radius of from 1.0 times to 3.0 times an outer diameter of the pipe before cold bending, a flattening ratio is from 0% to 10%, a thickness reduction rate on a bending outside and a thickness increase rate on a bending inside are from 0% to 10%, and additionally, a circumferential length change of a bending center portion is from 0% to 10%. A Vickers hardness of the stabilizer after the heat treatment is adjusted to from 400 HV to less than 580 HV.

An electric resistance welded steel pipe for manufacturing a hollow stabilizer has a Lankford value in a pipe longitudinal direction of from 0.7 to less than 1.0. The electric resistance welded steel pipe is subjected to cold bending and then to a heat treatment including quenching and tempering to manufacture a stabilizer. The cold bending is cold rotary draw bending. When bent with a bend radius of from 1.0 times to 3.0 times an outer diameter of the pipe before cold bending, a flattening ratio is from 0% to 10%, a thickness reduction rate on a bending outside and a thickness increase rate on a bending inside are from 0% to 10%, and additionally, a circumferential length change of a bending center portion is from 0% to 10%. A Vickers hardness of the stabilizer after the heat treatment is adjusted to from 400 HV to less than 580 HV.

A pipe bend die unit includes a bend die that comprises a clamp member and a counter pressure member, wherein the clamp member has a first groove part of half-circular cross section and a fitting recess extending in a peripheral direction by a first predetermined length on a planar surface perpendicular to a rotary axis. A fitting protrusion of the counter pressure member is positioned in the fitting recess to form a pipe-receiving groove of half-circular cross section, so that the counter pressure member and the clamp member are hingedly connected to one another about the rotary axis so as to be rotated relative to each other. The fitting recess possesses width expanding end face areas, where a clearance between opposing end faces is enlarged in a predetermined distance range including at least a radially outer end portion, from the rotary axis toward a radial outside.

A pipe bend die unit includes a bend die that comprises a clamp member and a counter pressure member, wherein the clamp member has a first groove part of half-circular cross section and a fitting recess extending in a peripheral direction by a first predetermined length on a planar surface perpendicular to a rotary axis. A fitting protrusion of the counter pressure member is positioned in the fitting recess to form a pipe-receiving groove of half-circular cross section, so that the counter pressure member and the clamp member are hingedly connected to one another about the rotary axis so as to be rotated relative to each other. The fitting recess possesses width expanding end face areas, where a clearance between opposing end faces is enlarged in a predetermined distance range including at least a radially outer end portion, from the rotary axis toward a radial outside.

A bend die comprises a clamp member having a first groove part of half-circular cross section on its outer peripheral surface with a fitting recess formed on the first groove part and extending in a peripheral direction by a first predetermined length on a planar surface perpendicular to a rotary axis, and a counter pressure member having a second groove part of half-circular cross section formed on its outer peripheral surface, and a fitting protrusion extending in a peripheral direction by a second predetermined length from a tip end portion of the second groove part. The fitting protrusion is positioned in the fitting recess so that a pipe-receiving groove of half-circular cross section is formed. The first and second groove parts are hingedly connected to one another about the rotary axis so as to be rotated relative to each other.

A bend die comprises a clamp member having a first groove part of half-circular cross section on its outer peripheral surface with a fitting recess formed on the first groove part and extending in a peripheral direction by a first predetermined length on a planar surface perpendicular to a rotary axis, and a counter pressure member having a second groove part of half-circular cross section formed on its outer peripheral surface, and a fitting protrusion extending in a peripheral direction by a second predetermined length from a tip end portion of the second groove part. The fitting protrusion is positioned in the fitting recess so that a pipe-receiving groove of half-circular cross section is formed. The first and second groove parts are hingedly connected to one another about the rotary axis so as to be rotated relative to each other.