A tube diameter expanding method includes: rotating a tube having one end fixed to a turntable about a center axis of the tube; inserting a rod-like roller which extends in an axial direction of the tube into the tube from another end of the tube, and bringing the rod-like roller into contact with a forming region extending from the other end to a predetermined position of the tube; heating the forming region of the tube; cooling at least a section located near the forming region and within a non-forming region extending from the predetermined position to the one end of the tube; and moving the rod-like roller in a state of contacting the forming region of the tube, in a direction from the one end of the tube toward the other end of the tube and outward in a radial direction of the tube.

The present disclosure relates to the field of idler, and in particular, to a welded idler and manufacturing method thereof. The method comprises steps of (1) separately manufacturing at least two parts; (2) friction welding, (3) spin forming, (4) turning an inner circle and an outer end surface, (5) turning another end surface, (6) surface treatment, (7) installing a bearing, (8) installing a bearing cover, (9) painting.

The present disclosure relates to the field of idler, and in particular, to a welded idler and manufacturing method thereof. The method comprises steps of (1) separately manufacturing at least two parts; (2) friction welding, (3) spin forming, (4) turning an inner circle and an outer end surface, (5) turning another end surface, (6) surface treatment, (7) installing a bearing, (8) installing a bearing cover, (9) painting.

Method for forming a collar in a muffler shell including: providing a muffler shell made of a metal sheet and forming a muffler housing, the muffler shell having an exhaust gas opening, providing a collar forming head having a rotational axis and at least two movable expanders, introducing a collar forming head into a muffler housing, moving the expanders of the collar forming head introduced into the muffler shell radially away from the rotational axis of the collar forming head from a retracted position to an expanded position rotating the collar forming head around the of the collar forming head, bringing the rotating expanded collar forming head in contact with the metal sheet forming an outwardly projecting collar around the exhaust gas opening by flaring the edge of the metal sheet.

The present application discloses an on-line induction heating device for a wheel blank, consisting of a frame, a servo motor, guide posts I, guide sleeves I, a lower fixed plate, a lifting top plate, a bearing seat, a jacking cylinder, a piston connecting rod, a top cone, reset springs, radial positioning blocks, upper fixed plates, induction heating cylinders, connecting rods, double-head fastening nuts, fixed slide rails, mounting plates, outer protective jackets, induction coils, a displacement sensor I, a compression cylinder, a guide sleeve II, a guide post II, a gland, pressure sensors, asbestos, a displacement sensor II, water inlet pipes, water outlet pipes, a roller bed, transverse sliding tables, positioning cylinders, a supporting plate and lifting cylinders.

The present application discloses an on-line induction heating device for a wheel blank, consisting of a frame, a servo motor, guide posts I, guide sleeves I, a lower fixed plate, a lifting top plate, a bearing seat, a jacking cylinder, a piston connecting rod, a top cone, reset springs, radial positioning blocks, upper fixed plates, induction heating cylinders, connecting rods, double-head fastening nuts, fixed slide rails, mounting plates, outer protective jackets, induction coils, a displacement sensor I, a compression cylinder, a guide sleeve II, a guide post II, a gland, pressure sensors, asbestos, a displacement sensor II, water inlet pipes, water outlet pipes, a roller bed, transverse sliding tables, positioning cylinders, a supporting plate and lifting cylinders.

In a method for closing open ends of tubes, an open tube end is closed using spin-tubing methods known in the art. Following the tube end closing, a concavity is formed in the tube end in a tube end forming machine. The tube end is brazed with the tube end facing upright, so that the braze alloy pools in the concavity, strengthening the tube end.

A spinning forming device according to one aspect, a receiving jig supporting a central portion of a plate to be formed is attached to a rotating shaft, and a transform target portion of the plate is pressed by a processing tool and locally heated by a heater that performs induction heating. The heater includes an electric conducting pipe in which a cooling liquid flows. The electric conducting pipe includes: a coil portion extending in a circumferential direction of the rotating shaft and having a doubled circular-arc shape facing the plate; and a pair of lead portions extending from the coil portion outward in a radial direction of the rotating shaft. Each of the pair of lead portions is retreated father away from the plate than the coil portion at its end portion adjacent to the coil portion.

A spinning forming device according to one aspect, a receiving jig supporting a central portion of a plate to be formed is attached to a rotating shaft, and a transform target portion of the plate is pressed by a processing tool and locally heated by a heater that performs induction heating. The heater includes an electric conducting pipe in which a cooling liquid flows. The electric conducting pipe includes: a coil portion extending in a circumferential direction of the rotating shaft and having a doubled circular-arc shape facing the plate; and a pair of lead portions extending from the coil portion outward in a radial direction of the rotating shaft. Each of the pair of lead portions is retreated father away from the plate than the coil portion at its end portion adjacent to the coil portion.

The disclosure discloses a spinning process of a magnesium alloy wheel hub, which comprises the following steps: step 1, heating a magnesium alloy bar at 350-430? C. and keeping the temperature for 20 minutes; step 2, initially forging and forming on the bar under a forging press, wherein the forging down-pressing speed is 6-15 mm/s; step 3, finally forging and forming on the bar under a forging press, wherein the forging down-pressing speed is 5-8 mm/s; step 4, stress relief annealing on the final forged magnesium alloy blank; step 5, solid dissolving on the annealed magnesium alloy blank; step 6, taking out the solid-dissolved blank and directly spinning by a spinning machine; step 7, heating treatment and aging treatment. The magnesium alloy wheel hub with excellent performance is obtained by the process, and the spinning process and processing efficiency are greatly improved.