DE1810883A1 - Process for the production of molded parts with high density - Google Patents

Description

. « ₄ Düsseldorf, November 25, 1968

Dr. ing. Eichenberg Cecilienallee 76 Ill / Sch.

Dipl.-Ing. Sauerland

Dr. Ing.King Our files; 24 429

Sintermetallwerk Krebsöge G _e m _e b _e Ho, 5608 Krebsöge / Rhld.

"Process for the production of high-density molded parts"

The invention relates to a method for producing high-density parts by compacting or forming a heated preform in a preheated tool.

It has already been proposed to heat, consisting of iron powder, for the most part preforms without sintering treatment at 800 to 1100 ⁰ C and preheated in a 300 to 35O ⁰ C, repacked at a constant temperature held tool. Such molded iron parts are characterized by a comparatively high density of 7.4 to 7.8 g / cm3. It is essential that the production is carried out such highly compacted parts from a preform without Übliohe time-dependent sintering, namely by simply heating dee preform at 800 to 1100 ⁰ C and then re-pressing the Vorpreßlinga in a 300 to 35O ⁰ C preheated tool, the gradient between the tool temperature and the compact temperature remains approximately constant. The constant temperature relationship between the pressed part and the tool during re-pressing leads to always glaiohan RakriataUiaationabadln-

which is found above all in mass production βηΐ-

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having a divisive effect, "in which the pre-pressings in a and the same tool can be re-compacted in quick succession.

It has now been found that the above-mentioned process for producing molded parts of high density is not only suitable for molded parts consisting predominantly of iron powder, but also in an excellent manner for molded parts made of non-malleable or difficult-to-malleable alloys and is also suitable for low-density alloys perform mold temperature can * It is therefore proposed according to the invention, set for the pre-press an existing high-alloy, difficult or impossible malleable materials metal powder mixture to be used and the mold temperature to 150 to 35O ⁰ C.

The re-pressing of the with a pressure of about 6 t / cm Pre-pressed moldings are expediently carried out under a pressure of 8 t / cm. Maintaining the preheating temperature of the tool during re-pressing takes place through controlled cooling.

The method according to the invention is, so to speak, a "powder forging", which in comparison to the conventional Forging processes, for example die forging, the production of molded parts materials that are difficult or impossible to forge allows good strength properties. In addition, the method according to the invention enables in contrast to the well-known forging process a waste and burr-free ι production of format parts mil; a Maigs " accuracy. which are higher than the other Sehraiedeveas » drive is. In particular, long-lasting broths can be used here

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and achieve complex outer contours with high dimensional accuracy. Finally, the hot deformation is too with less deformation work than with any other forging process.

According to the invention, a 4 to 5 hour G!
Connect vacuum.

4 to 5 hours annealing of the molding at 125O ⁰ O im

The method according to the invention is explained in more detail below with reference to exemplary embodiments

example 1

Of a mixture of electrolytic iron powder with 5 # chromium powder, 59 $ nickel powder and 2656 molybdenum powder was pressed under a pressure of 6 t / cm, a compact prepared heats this to 85O ⁰ C and in an at 35O ⁰ C pre-heated and held tool having a pressing

pressure of 8 t / cm. After this treatment, the molded part had a density of 8.51 g / cm. The molded part was then annealed for four and a half hours at 1250 ^° C. in a vacuum. After the annealing, the molding had m

a tensile strength of 48 kgf / mm.

Example 2

A compact was produced from a mixture of electrolyte iron powder with chromium powder, 57 # nickel powder, 17 # molybdenum powder and 4 ° C. tungsten powder with a pressing pressure of 6 t / cm. The compact was preheated to 850 ⁰ C and preheated in a to 35O ⁰ C and overall

holding tool with a pressing pressure of 8 t / cm hot pressed. After annealing for four and a half hours at 125O ⁰ C in a vacuum, the body had a density of 8.78 g / cm *, a tensile strength of 39 kp / mm ² , a

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Elongation at break of 6.4 $ and a Brinell hardness of 120 «

Example 3

Of a mixture of electrolytic iron powder with \ $> Ghr.ompulver, 65 $ nickel powder and 30 $ molybdenum powder at a pressure of 6 t / cm, a compact prepared, heated to 850 ⁰ C and in an at 35O ⁰ C pre-heated and held tool under a press pressure

repressed by 8 t / cm. After a four and a half-hour annealing at 125O ⁰ C in vacuo, the compact exhibited at a density of 8.35 g / cnr a tensile strength of

57 kp / mm and an elongation at break of 4 #.

Example 4

A compact was produced from a mixture of 20 $ fine chrome powder, 79 $ carbonyl nickel powder and 1 $ titanium carbide powder with a pressing pressure of 6 t / cm. The compact was then heated to 850 ⁰ C and pre-heated in a 35O to ⁰ C and held tool with

re-pressed with a pressure of 8 t / cm. After a viereinhalbsttindigen annealing at 1250 ⁰ C in vacuo, the compacts had a density of 7.6 g / cm., His

Tensile strength was 30 kp / mm, ί 16.5 $ and its Brinell hardness was 105,

Tensile strength was 30 kgf / mm, its elongation at break

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Claims (1)

Sintermetallwerk Krebsöge G.moboH., 5608 Krebsöge / Rhld. Patent claims: Process for the production of molded parts of high density by re-compacting or reshaping a heated torprim in a preheated tool, characterized in that a powder mixture consisting of high-alloy, non-forgeable or difficult-to-forge metals is heated ^{to 800 to 1100 ° C. after pressing without sintering} repressing is carried out in a tool preheated to 150 to 35O ⁰ O and kept at a constant temperature during repressing. Method according to claim!, Characterized in that that the pressing of the pre-pressed with a pressure of about 6 t / cm under a pressure of about 8 t / cm takes place 3. The method according to claims 1 and 2, characterized in that the re-pressing is followed by an annealing of the molded part for about four to five hours at 125O ⁰ C in a vacuum. 009887/0680