DD270087A1 - METHOD FOR THE THERMAL SURFACE HARDENING WITH ENERGY RAYS - Google Patents

Abstract

The method for thermal surface hardening with energy beams serves to produce hardened webs, in particular raceways of guide rails of machine tools. According to the invention, a compensating hair track is produced on the Haertebahn opposite side in accordance with the energy transfer conditions dependent delay characteristic of the component prior to energy transfer to the Haertebahn. After temperature compensation, the residual distortion is measured and, after comparison with the permissible values, one or more additional compensation hair sheets are produced until the permissible delay value is reached.

Description

For this 1 page drawings

Field of application of the invention

The invention relates to a method for producing energlestrahlharärtet webs on preferably prismatic components with a great length · to cross-sectional ratio, in particular for electron beam curing of the tracks of guide rails and compact guide rails of machine tools.

Characteristic of the known technical solutions

It is known to modify the material properties in the sense of improving the performance properties in near-surface boundary layers of metallic components by thermal energy beam processes that take place in the solid or liquid phase. The localized energy transfer associated with enforcing material conversion leads to changes in shape, d. H. a delay of the component. This can in particular take on disturbing proportions when it comes to components with a comparatively large cross-section length, such. B. in leadership and compact guide rails of machine tools, acts.

From other methods, such as. As the surface induction hardening, it is known to minimize by biasing the remaining after treatment delay. In the case of the component geometry mentioned, however, this can not meet the high demands made with regard to the remaining component distortion. It has already been proposed to produce hardness tracks on the stressed running surfaces with energy beams. To minimize the distortion during curing

at the same time additional hardness tracks, also called compensation hardnesses, applied to the workpiece. This method has the disadvantage that when using electron beams, the technical equipment expense is very high due to the required additional electron gun and the associated facilities. In addition, the residual distortion remaining from part to part due to the different internal stresses of the component, which scatters strongly, is not eliminated in accordance with the high requirements.

Object of the invention

The process should reduce the distortion of the components to be provided with hardness tracks to a tolerable minimum without increased expenditure on equipment technology and energy.

Explanation of the essence of the invention

The invention has for its object to provide a method for the thermal surface hardening of components of great length, but comparatively to this small cross-section. The distortion of the component should be limited to a small value relative to the depth of hardness.

According to the invention, the object is deflected with an energy number, preferably electron beam, perpendicular to the workpiece movement direction in the region of the hardness web to be produced and achieved by applying at least one compensation hardness, depending on the unavoidable initial distortion of the component and on the default of the energy balance conditions of the component, preferably before the energy transfer to serving as a utility path hardness web on one of these opposite Bautoilseite a compensation hardness with up to the parameters taken from the delay characteristic parameters hardness track identical parameters is applied. The energy input takes place in such a way that the component distortion after energy transfer to the hardness web is certainly not overcompensated. After the temperature compensation over the component cross-section of the residual distortion is measured and after comparison with the allowable value, if necessary, and if not sufficient after renewed temperature compensation with the allowable value more compensation hardnesses preferably generated on both sides of the first Kompem tion hardness track shares. In this case, except for the parameters taken from a draft path, the procedure is repeated until the permissible distortion value is reached. In an advantageous embodiment of the method, the component is at least perpendicular to the longitudinal direction during de. Thermally insulated insulated recorded and the center deflection of the component detected as a measure of the component distortion. As a variable parameter of the compensation hardnesses and the delay characteristics, the web width is expediently selected and each compensation hardness web is arranged to be thermally interacting with the previously produced ones. The second and possibly further compensation hardnesses are advantageously carried out using the known principles of jumping beam technology or beam splitting with orbital shares on both sides of the already existing compensation hardnesses that the selectable ratio of the partial web widths according to dimensions of the component distortion in the r.'r main draft direction vertical plane is set.

In order to carry out the method in an automated manner, it is expedient to start from a coarse delay characteristic obtained from the preliminary tests or from extrapolation of experience with other components and to use the measured values recorded for the continuous improvement of the distortion characteristic stored in the control of the device. It is also expedient to carry out the energy beam process on a plurality of components arranged in a receiving device in order to continue the energy beam process on other components during the necessary temperature compensation times.

embodiment The accompanying drawing shows in

Fig. 1: a Queischnitt a guide rail with electron beam hardened webs, Fig. 2: a default characteristic of Baueils «ernäß Fig. 1 schematise.

On the guide strip 1 of a machine tool shown in cross-section in FIG. 1, on one side a hardness web 2 of width b is to be produced over a depth h with electron beams. It is predetermined that the guide strip 1 after curing on the side of the hardness web 2 a concave deflection up to a maximum value z, z, < h may not exceed. Curing should be carried out according to the known principle of isothermal energy transmission by two-dimensional high-frequency beam deflection.

From preliminary tests, the delay characteristic shown in Fig. 2 is known. It gives the measured signed delay values z _H after execution of a compensation hardness 3, the connected version of the hardness course 2 and temperature compensation over the cross section of the guide strip 1 as a function of the width ratio <% of the tracks with negligible output delay of the guide rail 1. It states that owing to unknown influencing factors, such as internal stresses in the component, a distortion in the limits -z _H -... + z _{H +} remains with a track width ratio α _Λ = a _V Kmi _n ··· ανιοη «χ. The value required for exact distortion compensation can therefore not be predetermined. The compensation hardness 3 is therefore executed in a width bvxmtn = Ov _K min b. After generating the compensation hardness 3 and the hardness sheet 2 and after temperature compensation over the component cross-section of the residual distortion is measured, because of the choice made the width of the compensation hardness 3 in the limits 0 s zA z z _{H +}

lies. In the present case, ΐμ> z ₍ .) Therefore, a weather compensating hardness 4 r lit is performed on the two divisors 4a and 4b lying symmetrically to the compensation hardness 3. Their total width is selected in taalogy to that explained above Measured, with which the delay compensation is completed.

In the case of components which have already warped with Z ₀ before the energy beam process, warping characteristics which are dependent on the predrawing result, which essentially result in a value ανκπίη M dependent on z _o , resulting in a web width bvKmin (z ₀ ) which depends on Z ₀ .

Claims (7)

1. A method for thermal surface hardening with energy beams, preferably an electron beam, which is deflected high frequency perpendicular to the workpiece movement direction according to the width of the hardness web to be generated and generating at least one compensation hardness, characterized in that depending on the initial delay of the component and in accordance with the of the energy transfer conditions dependent delay characteristic of the component before the energy transfer to the hardness on a opposite side of a compensation hardness with identical except for one of the delay characteristic parameters identical energy transfer conditions is generated such that the component distortion is not overcompensated by the energy transfer to the hardness path with certainty that after energy transfer to measured the hardness and temperature compensation over the cross section of the component of residual distortion and after comparison with the permissible value optionally one or after renewed temperature compensation, Verzuyserfassung and comparison with the permissible value further Kornpenaationshärtebahnen turn up to the delay characteristic extracted parameters are generated with identical to the hardness of energy transfer conditions until the allowable default value is ei ι eicht. 2. The method according to claim 1, characterized in that in the generation of further. Compensation hardnesses are generated to an already generated compensation hardness on both sides of these web shares. 3. The method according to claim 1 and 2, characterized in that the component is absorbed during the energy transfer process and the temperature compensation time at least perpendicular to its longitudinal direction heat insulated and that the center deflection of the component is detected as a measure of the Bauverteilverzug. 4. The method according to claim 1 to 3, characterized in that the compensation hardnesses are generated with up to the web width identical energy transfer conditions and that the web width is carried out in accordance with the delay compensation characteristic and the delay to be compensated. 5. The method according to claim 1 to 4, characterized in that the second and further compensation hardnesses are carried out using known principles of jumping beam technology or beam splitting on both sides of the already existing compensation hardness or paths and no significant thermal interaction with them. 6. The method according to claim 1 to 5, characterized in that the partial web widths are carried out according to the delay in a direction perpendicular to the main drafting axis plane. 7. The method according to claim 1 to 6, characterized in that the energy beam process is carried out in batches, wherein the energy transfer and the temperature compensation for the components of a batch are time-interleaved.