METHOD FOR PRODUCING A COMPONENT, COMPONENT AND PRESS FOR PRODUCING A COMPONENT

Abstract

A method to produce a component from a workpiece via a press which includes at least one die to form the workpiece. The workpiece comprises at least one of a metal, a metal alloy and a coating and has a form of a hollow part. The method includes internal high-pressure forming and/or hydraulic back-pressure forming the workpiece via a fluid and the at least one die at a temperature below a first hardening temperature of the workpiece, and subsequently partially or completely hardening the workpiece by heating the workpiece above the first hardening temperature and then immediately cooling the workpiece. The heating and the cooling are each essentially conducted without a forming so that a fabricated component results.

Claims

1-11. (canceled)

12. A method to produce a component from a workpiece via a press which comprises at least one die to form the workpiece, wherein the workpiece comprises at least one of a metal, a metal alloy and a coating and has a form of a hollow part, the method comprising: internal high-pressure forming and/or hydraulic back-pressure forming the workpiece via a fluid and the at least one die, the internal high-pressure forming and/or the hydraulic back-pressure forming being conducted at a temperature below a first hardening temperature of the workpiece; and subsequently partially or completely hardening the workpiece by heating the workpiece above the first hardening temperature and then immediately cooling the workpiece, the heating and the cooling each being essentially conducted without a forming so that a fabricated component results.

13. The method as recited in claim 12, wherein, the first hardening temperature is below a melting point of zinc phases; and the heating of the workpiece above the first hardening temperature is to a temperature of above 700 C.

14. The method as recited in claim 13, wherein the temperature is above 840 C.

15. The method as recited in claim 12, wherein the fluid comprises at least one of water, an oil, a mixture of water and the oil, and a gas.

16. The method as recited in claim 15, wherein the gas is a shielding gas.

17. The method as recited in claim 12, wherein the internal high-pressure forming and/or hydraulic back-pressure forming is performed above a vaporization point of the fluid.

18. The method as recited in claim 17, wherein the vaporization point is above 100 C.

19. The method as recited in claim 12, wherein the heating of the workpiece is performed via an inductive heating using an induction coil.

20. The method as recited in claim 12, wherein the immediate cooling of the workpiece is performed via a cooling device arranged inside or outside of the press.

21. The method as recited in claim 12, wherein the coating of the workpiece comprises zinc.

22. The method as recited in claim 21, wherein the partial or complete hardening of the workpiece is performed by, heating the workpiece above the first hardening temperature in an oven, and cooling the workpiece in the at least one die, so that the component is essentially free of cracks.

23. The method as recited in claim 12, wherein, when the workpiece is an uncoated workpiece, at least one of, the partial or complete hardening of the workpiece is performed in a sealed space or in an oven in a shielding gas atmosphere, and the immediate cooling of the workpiece is performed in a cooling device in the shielding gas atmosphere so that the workpiece is free of burn-off.

24. The method as recited in claim 12, further comprising: at least one of bending and pre-forming the workpiece prior to the internal high-pressure forming and/or hydraulic back-pressure forming.

25. A component manufactured pursuant claim 12, wherein, the component is a zinc-coated hollow part or an uncoated hollow part, and the component is manufactured so as to be free of at least one of a burn-off and cracks.

26. The component as recited in claim 25, wherein the zinc-coated hollow part is a zinc-coated pipe, and the uncoated hollow part is an uncoated pipe.

27. A press configured to produce the component pursuant to the method as recited in claim 12, the press comprising: a first device for the internal high-pressure forming and/or hydraulic back-pressure forming; and a second device for subsequently partially or completely hardening the workpiece by heating the workpiece above the first hardening temperature and then immediately cooling the workpiece.

28. The press as recited in claim 27, wherein the second device is at least one of an induction coil, a liquid spray, and a bath of a liquid.

Description

[0077] FIG. 1 a schematic cross-sectional view of a press with closed die for the internal high-pressure forming of an uncoated pipe and

[0078] FIG. 2 a schematic cross-sectional view of the press with opened die and cooling of a fabricated catalytic converter housing by means of a water spray.

[0079] A press 101 has a drive 102 and a ram 104. A jig 105 which holds the upper half of the die 106 is arranged on the ram 104. The lower half of the die 108 is arranged on a press bed 109. An uncoated pipe 107 made of 22MnB5, whose pipe ends 112 are in contact with a first axial sealing punch 110 and with a second axial sealing punch 112 lies in the lower half of the die 108. The first axial sealing punch 110 has a fluid feed 111. Induction coils 113 follow the inner contour of the upper half of the die 106 and the lower half of the die 108 within both the upper half of the die 106 and the lower half of the die 108.

[0080] A water spray 114 is arranged outside on the underside of the jig 105, and a transport rail 115 is arranged on the press bed 109 below the water spray.

[0081] The following processing steps are realized with the press 101 by cold internal high-pressure forming at a room temperature of 20 C. and complete hardening:

[0082] The upper half of the die 106 and the lower half of the die 108 are opened in the press 101. An uncoated pipe 107 is put into the lower half of die 108 by means of a gripper tool which is not shown. The upper half of the die 106 and the lower half of the die 108 are closed and a pressing force of 35,000 kN is applied.

[0083] Parallel to the increase in the pressing force, the first axial sealing punch 110 and the second axial sealing punch 112 are moved towards the ends of the uncoated pipe 107 and seal the pipe 107. Nitrogen as the pressure medium and shielding gas is fed into the inside of the uncoated pipe 107 via the fluid feed 111 of the first axial sealing punch 110. This causes a pressure of 800 bar to build up.

[0084] The uncoated pipe 107 is compressed by the first axial sealing punch 110 and the second axial sealing punch 112, while the axial flow of material and the expansion and the close fitting of the uncoated pipe to the inner contour of the upper half of the die 106 and the lower half of the die 108 is carried out by the nitrogen pressure medium.

[0085] By setting the calibration pressure of 1,000 bar, the uncoated pipe is formed so as to be a perfect fit so that it assumes the inner contour of the upper half of the die 106 and the lower half of the die 108 as its outer contour. The formed, uncoated pipe 107 is subsequently heated in the closed upper half of the die 106 and lower half of the die 108 by means of the induction coils 113 to a hardening temperature of 900 C. within 3 seconds.

[0086] The pressing force is then relieved and the upper half of the die 106 and the lower half of the die 108 are opened. The second axial sealing punch 112 is moved to outside the press and the formed uncoated pipe 107 is brought onto the transport rail 115 by means of a gripping tool which is not shown here. The transfer time here is 3 seconds.

[0087] As soon as the formed, uncoated pipe 107 is on the transfer rail 115, the water spray 114 is triggered automatically, the formed, uncoated pipe 107 is completely cooled down and thus hardened.

[0088] This produces the catalytic convertor housing 116 fabricated from the uncoated pipe 107 by forming and hardening. The catalytic convertor housing 116 fabricated is a high-strength, high-quality component with a yield point of 750 MPa and with very little scaling and low burn-off so that a further process step of shot peening is not necessary. Neither does the catalytic convertor housing 116 warp with this fabrication method.

[0089] In an alternative, the processing steps described are carried out in the press 101 using a zinc-coated pipe 107 in a warm internal high-pressure forming with argon as the pressure medium and shielding gas at a temperature of 500 C., which is above the vaporization point of water and below the melting point of zinc phases. The pipe is thus formed at this temperature. Subsequently, the pipe is heated to 800 C. and quenched so that a hardened and zinc-coated pipe is produced.

KEY

[0090] 101 press [0091] 102 drive [0092] 104 ram [0093] 105 jig [0094] 106 upper half of die [0095] 107 uncoated pipe [0096] 108 lower half of die [0097] 109 press bed [0098] 110 first axial sealing punch [0099] 111 fluid feed [0100] 112 second axial sealing punch [0101] 113 induction coil [0102] 114 water spray [0103] 115 transport rail [0104] 116 fabricated catalytic convertor housing