EP3458207A1

EP3458207A1 - Method for producing a shaped body

Info

Publication number: EP3458207A1
Application number: EP17722801.2A
Authority: EP
Inventors: Thomas Grosserüschkamp; Michael Gövert; Thomas FLÖTH
Original assignee: ThyssenKrupp Steel Europe AG; ThyssenKrupp AG
Current assignee: ThyssenKrupp Steel Europe AG; ThyssenKrupp AG
Priority date: 2016-05-18
Filing date: 2017-05-11
Publication date: 2019-03-27
Also published as: MX2018014092A; CA3021235C; CA3021235A1; JP2019514699A; WO2017198544A1; KR102312107B1; DE102016208462B4; US20190151923A1; DE102016208462A1; CN109475914A; KR20190008886A

Abstract

The invention relates to a method for producing a shaped body (15, 15'), comprising the following steps: - providing a semifinished product (1) of a steel material that is preformed or in the form of a round blank, - heating at least certain regions of the semifinished product (1) to a first temperature, - shaping a hub (8) on the semifinished product (1) that is warm at least in certain regions to create a preform (3) with an upper geometry element in a first working step and/or tool (7) by means of roller spinning, - heating or reheating at least certain regions of the preform (3) with an upper geometry element to a second temperature, - shaping a bell cup (14) on the preform (3) with an upper geometry element that is warm at least in certain regions to create a preform (11) with an upper geometry element and at least one lower geometry element in a second working step and/or tool (12) by means of roller spinning, - heating or reheating at least certain regions of the preform (11) to a third temperature, - profiling the preform (11) that is warm at least in certain regions to create a shaped body (15, 15') in a third working step and/or tool (16, 20).

Description

Method for producing a shaped body

The invention relates to a method for producing a shaped body.

Methods for producing shaped bodies, in particular by means of flow-forming rollers, belong to the state of the art. Thus, for example, document US 2001/0035036 A1 describes a method for producing a rotationally symmetrical component, such as from a blank-shaped blank, a component having a hub by means of flow-forming rollers is produced. From other documents DE 10 2013 101 555 B3 and DE 10 2013 106 268 AI, for example, methods for producing articulated or journal by means of flow-forming are known, are made of substantially planar blanks from a steel material corresponding moldings in a multi-stage flow-forming process. The said methods have in common that high forming forces are required for the massive shaping and appropriately sized flow-forming plants are required.

Based on the prior art, the invention was based on the object, a method with reduced compared to conventional spinning drums

To provide forming forces.

The above object is achieved by a method comprising the following steps:

- Providing a Ronde-shaped or preformed semifinished product from a

Steel material,

At least partially heating the semifinished product to a first temperature,

Forming a hub on the at least partially warm semi-finished product for producing a preform with an upper geometric element in a first working step and / or tool by means of flow-forming rollers,

At least partially heating or reheating the preform with an upper geometrical element to a second temperature,

- Forming a bell on the at least partially warm preform with an upper geometric element to produce a preform with an upper and at least one lower geometric element in a second working step and / or tool by means of flow-forming rollers,

At least partially heating or reheating the preform to a third temperature,

- Profiling the at least partially warm preform for producing a shaped body in a third step and / or tool.

It has been found that a reduction of the forming forces in comparison to conventional spin forming is possible, in particular if the workpiece is heated to a certain temperature prior to molding and / or profiling. According to a first embodiment of the method according to the invention, the first temperature and / or second temperature are between 200 ° C and 700 ° C, in particular between 250 ° C and 580 ° C. In particular, at a temperature from 200 ° C, preferably from 250 ° C lower forming forces compared to conventional spin forming are thus necessary when molding in particular the hub on the semifinished product and / or the bell on the preform, since the material softer with increasing temperature and thus connected, is easier to mold. In a preferred use of hardenable steel materials, the temperature is limited depending on the alloying elements to a maximum of 700 ° C, in particular to a maximum of 580 ° C in order to suppress a structural change, for example in (partial) austenite, in the material substantially. The first and second temperatures may be the same or different from that mentioned

Temperature range can be selected, preferably in dependence on the material and the tools used and / or deformation.

According to a further embodiment of the method according to the invention, the third temperature is between 400 ° C and 1000 ° C, in particular between 480 ° C and 950 ° C. In addition to the lower for the profiling of the molded body to be produced

Forming forces in comparison to conventional spin forming can be cured at least in regions during or after profiling according to a preferred embodiment of the inventive method of molding. Hardening during profiling requires that the third temperature be at least Acl for partial austenitizing, preferably at least Ac3 for complete austenitizing. Alternatively, curing may take place after profiling take place, wherein the third temperature is then limited to a maximum of 700 ° C, in particular to a maximum of 580 ° C. As a result, according to an alternative embodiment of the method according to the invention, at least in some areas, a surface hardening is carried out on the shaped body, in particular in the inner area of the bell. Particularly preferred hardenable steel materials are used, which have at least a hardness of 50HRC in the tempered state. The steel material preferably consists of the following alloy constituents in% by weight:

0.15 <= c <= 0.8,

0.1 <= Si <= 1.2,

0.3 <= Mn <= 1.8,

0.1 <= Cr <= 1.8,

0.05 <= Mo <= 0.6,

0.05 <= Ni <= 3.0,

0.0005 <= B <= 0.01,

AI <= 0.15,

Ti <= 0.04,

P <= 0.04,

S <= 0.03,

N <= 0.03,

Remaining iron and unavoidable impurities. HRC is the Rockwell hardness and the hardness test is regulated in DIN EN ISO 6508-1.

According to a further embodiment of the method according to the invention, the semifinished product in the first working step and / or tool and / or the preform with an upper geometrical element in the second working step and / or tool are actively tempered during molding. This can ensure that even after inserting or arranging the warm workpiece, the workpiece is held at a predetermined temperature in the tool by means of suitable arranged and / or integrated means, so that a rapid cooling of the workpiece compared to a cold tool can be avoided.

According to a further embodiment of the method according to the invention, the shaping and / or profiling can each take place in one or more work steps. Depending on the complexity of the shaped body to be produced, the generation of the desired (pre-) form can take place in one or more tools.

According to a preferred embodiment of the method according to the invention, a shaped body is produced in the form of a pivot pin or journal, wherein the profiling in the third tool at least partially in the lower geometric element respectively the bell of the warm preform takes place and at least one embodiment comprises a cage track and / or ball tracks. The profiling in the third tool can take place by means of flow-forming rollers, wherein the profiling takes place, for example, by means of at least one rolled beam and / or at least one profiling roll or cumulatively or alternatively in a profiling tool which has, for example, at least one sliding element.

According to a further embodiment of the method according to the invention, the heating takes place inductively. Inductive heat sources are easy and economical to operate and can at least partially workpieces heat, in particular, the heat treatment depth can be targeted and relatively easily controlled.

Preferably, the heating of the respective workpiece is carried out before placing or inserting in the respective tool and / or before carrying out the respective work step. Alternatively, other heat sources are conceivable, for example heating the workpiece in an oven. The heating outside of the tool is particularly preferred and the cycle time can be increased thereby.

In the following the invention will be explained in more detail with reference to some embodiments illustrative drawing. Identical parts are provided with the same reference numerals. It shows

1): a schematic representation of an embodiment at the time of heating a semifinished product,

FIG. 2): a schematic representation of an exemplary embodiment at the time of the generation of a preform with an upper geometric element, FIG. 3): a schematic representation of an exemplary embodiment at the time of heating a preform with an upper geometric element,

FIG. 4): a schematic representation of an exemplary embodiment at the time of the generation of a preform with an upper and at least one lower geometric element,

FIG. 5): a schematic representation of an exemplary embodiment at the time of heating a preform with an upper and at least one lower geometric element,

Figure 6): a schematic representation of a first embodiment of the

Time of production of a shaped body,

Figure 7): a schematic representation of a second embodiment of the

Time of production of a shaped body.

In a first step of the method according to the invention, a blank-shaped semi-finished product (1) made of a steel material, for example hot-rolled, boron-alloyed steel materials is provided. In order to reduce the deformation forces in comparison to conventional spin forming, the workpiece / semifinished product (1) on a first

Temperature, which is between 200 ° C and 700 ° C, at least partially heated, in particular before the semi-finished product (1) is processed in a first step and / or inserted or arranged in a first tool (7). Preferably, the at least partially heating inductively by means of an inductor (2). The semifinished product (1) is for example supplied to a device correspondingly equipped with at least one inductor (2) [FIG. 1] or the inductor can be arranged on a supply device, not shown here, which the first tool (7) equipped with the semi-finished product (1).

The warm semi-finished product (1) is placed in the first tool (7), in particular arranged in a correspondingly shaped die (4). The die (4) is actively rotatably disposed in the first tool (7). After inserting the warm Semi-finished product (1) is a pin-shaped hold-down (5) centered on the semi-finished (1) equipped die (4) lowered and fixes the semi-finished product (1) against rotation in the die (4). At least one spinning roller (6, 6 ') is lowered onto the warm, rotating semi-finished product (1) and presses material radially from outside to inside, whereby the pushed-on material first accumulates on the pin-shaped holding-down device (5) and the spinning roller (6, 6 ') is driven so that the accumulated material in the further process along the pin-shaped blank holder (5) is pushed up to produce a hub / pin (8). Preferably, two pressure rollers (6, 6 ') are provided, which are arranged diametrically, so that the lateral action forces on a, for example, with the die (4) connected and not shown here

Main spindle to the rotating drive, symbolized by the rotating

Arrow depiction, can be substantially compensated. This results in a preform (3) with an upper geometric element (hub / pin) in a first step and / or tool (7) by means of flow-forming [Fig. 2]. In order to prevent premature cooling of the preform (3) to be produced, the die (4) can be equipped with means for tempering. In the course of production or after the

Production of the preform (3) can in the region of the upper geometric element not shown here additional functional elements preferably in the first step or a downstream, separate process step, for example teeth, in particular inside and / or outside in the hub (8), grooves, threads, etc. by means Pressure rollers are molded. Furthermore, the die (4) can be thermally decoupled from further components (not shown), for example the main spindle of the first tool (7) connected to the die (4), in order to substantially prevent heating of the further components of the tool (7) , which may have a negative effect on the life of these components in particular.

In a further step of the method according to the invention, the preform (3) with an upper geometric element or hub / pin (8) to a second

Temperature, which is between 200 ° C and 700 ° C, at least partially heated, in particular before the preform (3) is processed with an upper geometric element in a second step and / or arranged or inserted in a second tool (12). Preferably, the at least partially Heating inductively by means of an inductor. The preform (3) with an upper

Geometry element is for example supplied to a corresponding equipped with at least one inductor (2) device [Fig. 3] or the inductor can be arranged on a feed device, not shown, which the second

Tool (12) equipped with the preform (3).

The warm preform (3) with an upper geometric element is transferred to the second tool (12) and, for example, clamped against rotation between a tool core (13) and a holding-down device (9). The tool core (13) and the hold-down device (9) are actively rotatably arranged in the second tool (12), symbolized by the rotating arrow display. At least one spinning roller (6, 6 ') is lowered onto the warm, rotating preform (3) with an upper geometrical element and presses material radially from the inside outwards starting from the hub / pin (8) of the preform (3) Material is pushed along the tool core (13), symbolized by the arrow, wherein the spinning roller (6, 6 ') is driven such that a bell (14) is generated. This creates a

Preform (11) with an upper geometric element respectively hub / pin (8) and at least one lower geometric element or bell (14) in a second step and / or second tool (12) by means of flow-forming [Fig. 4]. To prevent premature cooling of the preform (11) to be produced, the

Tool core (13) equipped with means for temperature control. Furthermore, the tool core (13) can be thermally decoupled from further components (not shown), for example a main spindle of the second tool (12) connected to the tool core (13), in order to substantially prevent heating of the further components of the tool (12) , which may have a negative effect on the life of these components in particular.

In a further step of the method according to the invention, the preform (11) with an upper geometric element or hub / pin (8) and at least one lower geometric element or bell (14) to a third temperature which is between 400 ° C and 1000 ° C, at least partially heated, in particular before the preform (11) is processed in a third step and / or inserted or arranged in a third tool (16, 20). Preferably, the at least partially heating inductively by means of an inductor, preferably by means of a ring inductor (2 '), which, as shown in FIG. 5, is arranged externally, in particular, over the bell (14) of the preform (11) and heats the bell (14) at least in regions. Alternatively, a ring inductor can be inserted inside the bell of the preform to heat the bell from the inside. A line inductor can also be arranged from the inside or from the outside in the area of the bell and at least heat the region of the bell of the preform. The preform (11) with an upper and at least one lower geometric element is for example supplied to a device correspondingly equipped with at least one inductor (2 ') [FIG. 5] or the inductor can be arranged on a feed device, not shown, which a third tool (16, 20) with the preform (11) equipped with an upper and at least one lower geometric element.

The warm preform (11) with an upper and at least a lower one

Geometry element is transferred according to a first embodiment to a third tool (16) and, for example, clamped against rotation on a tool core (22). The tool core (22) is actively rotatably arranged in the third tool (16), symbolized by the rotating arrow display. With at least one roll bar (23) and / or at least one profiling roll (17), which in each case have the outer contour in the region of the bell (14) of the molded body (15) to be produced, the tool core (22), which forms the inner contour in the region of the bell (14) of the molded body (15) to be produced, by the action of the at least one rolling beam (23) and / or at least one profiling roll (17) and the tool core (22) on each other ball tracks (24) and / or a cage track (25 ) profiled in the bell (14) by means of flow-forming rollers. Alternatively and not shown here can be used for profiling two or without two 90 ° offset support rollers not shown for profiling or other two to four profiling rollers without or with two offset 90 ° to each other, not shown support rollers for profiling. If hardening is to be carried out during profiling, heating the preform (11) at least in regions to a third temperature of at least Acl for a partial austenitizing, preferably to at least Ac3 for a complete

Austenitizing required. Profiling should be essentially complete before the shaped body (15) reaches the temperature of martensite start (Ms) and the hardening or transformation of the austenite microstructure into martensitic microstructure has taken place. Depending on the design of the tool (16), at least the tool core (22) can be equipped with means for active cooling to the required

Provide cooling rate for conversion to martensite.

Alternatively or cumulatively, means for tempering can also be provided.

Alternatively, the hardening can take place after profiling, wherein the third temperature is then limited to a maximum of 700 ° C, in particular to a maximum of 580 ° C. Furthermore, the tool core (22) of further, not shown

Components, for example one connected to the tool core (22)

Main spindle of the third tool (16) thermally decoupled to a

Heating of the other components of the tool (16) to avoid substantially, which may adversely affect in particular the life of these components. Hardening can then be carried out in a further process step by austenitizing the shaped body (15), for example in an oven and quenching, for example in a water or oil bath. Furthermore, according to a further alternative embodiment, an edge layer hardening, in particular in the interior region of the profiled bell (10), can be carried out at least in regions, preferably at least in the area of the ball tracks (24). The molded body (15) has at least one hub / pin (8), which further

Functional elements may comprise at least one profiled bell (10).

The warm preform (11) with an upper and at least a lower one

Geometry element is transferred according to an alternative second embodiment to a third tool (20) and clamped against rotation, for example, on a tool core (21). The tool core (21) is non-rotatably arranged in the third tool (20). With at least one, preferably a plurality of radially movable mold sliding elements (18), symbolized by the arrow, which are arranged between die elements (19) and the outer contour in the region of the bell (14) of the shaped body to be generated (15 ') and the tool core (21 ), which has the inner contour in the region of the bell (14) of the molded body (15 ') to be produced, are produced by the action of the at least one molded sliding element (18) and / or at least one die element (19). and tool core (21) on each other ball tracks (24 ') and / or a cage track (25') in the bell (14) profiled. The drive of the at least one mold sliding element (18) takes place, for example, mechanically by means of appropriately designed slides and / or by means of hydraulics. If hardening is to be carried out during profiling, it is necessary to at least partially heat the preform (11) to a third temperature of at least Acl for partial austenitizing, preferably to at least Ac3 for complete austenitizing. The profiling should be done essentially before reaching the temperature of martensite (Ms) in the

Shaped body (15 ') must be completed before the hardening or transformation of the austenite microstructure into martensitic structure. Depending on the design of the tool (20), at least the tool core (21) can be provided with means for active cooling

be equipped to provide the required cooling rate for conversion to martensite can. Alternatively or cumulatively, means for tempering can also be provided. Alternatively, the hardening can take place after profiling, wherein the third temperature is then limited to a maximum of 700 ° C, in particular to a maximum of 580 ° C. Furthermore, the tool core (21) may be thermally decoupled from further components, not shown, in order to substantially prevent heating of the further components of the tool (20), which may adversely affect, in particular, the service life of these components. Hardening can then be carried out in a further, separate process step by austenitizing the shaped body (15 '), for example in an oven and quenching, for example in a water or oil bath. Furthermore, according to a further alternative embodiment, an edge layer hardening can be carried out at least in regions, in particular in the inner region of the profiled bell (10 '), preferably at least in the region of the ball tracks (24'). The molded body (15 ') has at least one hub / pin (8), which may comprise further functional elements with at least one profiled bell (10').

The invention is not limited to the embodiments shown in the drawing, but other particular rotationally symmetrical

Moldings are produced by the method according to the invention. Ronde-shaped semi-finished product

, 2 'inductor

Preform with an upper feature

die

pin-shaped hold-down

, 6 'spinning roller

first tool

Upper geometric element, hub, pin

Stripper plate

0, 10 'profiled bell, lower profiled geometric element1 preform with upper and lower geometrical elements2 second tool

3, 21, 22 Tool core

4 lower geometric element, bell

5, 15 'molded body

6, 20 third tool

7 profiling roller

8 sliding mold element

9 die element

3 rolling beams

4, 24 'ball tracks

5, 25 'cage rail

Claims

claims

A method for producing a shaped article (15, 15 '), comprising the following

Steps:

Providing a blank-shaped or preformed semifinished product (1) made of a steel material,

- At least partially heating the semifinished product (1) to a first

Temperature,

Forming a hub (8) on the at least partially warm semi-finished product (1) for producing a preform (3) with an upper geometric element in a first working step and / or tool (7) by means of spin forming,

At least partially heating or reheating the preform (3) with an upper geometric element to a second temperature,

Forming a bell (14) on the at least partially warm preform (3) with an upper geometrical element for producing a preform (11) with an upper and at least one lower geometrical element in a second working step and / or tool (12) by means of spin forming;

At least partially heating or reheating the preform (11) to a third temperature,

- Profiling the at least partially warm preform (11) for producing a shaped body (15, 15 ') in a third step and / or tool (16, 20).

2. The method according to claim 1,

characterized in that

the first temperature and / or the second temperature between 200 ° C and 700 ° C, in particular between 250 ° C and 580 ° C.

3. The method according to claim 1 or 2,

characterized in that

the third temperature is between 400 ° C and 1000 ° C, in particular between 480 ° C and 950 ° C.

4. The method according to any one of the preceding claims,

characterized in that

during the molding, the semi-finished product (1) in the first step and / or

Tool (7) and / or the preform (3) with an upper geometric element in the second step and / or tool (12) are actively tempered.

5. The method according to any one of the preceding claims,

characterized in that

the shaping and / or profiling can each take place in one or more work steps.

6. The method according to any one of the preceding claims,

characterized in that

a shaped body (15, 15 ') is produced in the form of a pivot pin or journal, the profiling taking place at least in regions in the lower geometric element or the bell (14) of the warm preform (11) and at least one formation of a cage track (25, 25'). ) and / or ball tracks (24, 24 ') in the third step and / or tool (16, 20).

7. The method according to any one of the preceding claims,

characterized in that

the shaped body (15, 15 ') is hardened at least in regions during or after profiling.

8. The method according to any one of the preceding claims,

characterized in that

the heating is done inductively.

9. The method according to any one of the preceding claims,

characterized in that

hardenable steel materials are used in the tempered state

have at least a hardness of 50HRC. Method according to one of the preceding claims,

characterized in that

on the molding (15, 15 ') at least partially an edge hardening, in particular in the inner region of the profiled bell (10, 10') is performed.