GB2255936A - Tungsten projectiles - Google Patents
Tungsten projectiles Download PDFInfo
- Publication number
- GB2255936A GB2255936A GB9202528A GB9202528A GB2255936A GB 2255936 A GB2255936 A GB 2255936A GB 9202528 A GB9202528 A GB 9202528A GB 9202528 A GB9202528 A GB 9202528A GB 2255936 A GB2255936 A GB 2255936A
- Authority
- GB
- United Kingdom
- Prior art keywords
- penetrator
- tungsten
- accordance
- weight
- acid mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/26—Acidic compositions for etching refractory metals
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B12/00—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material
- F42B12/72—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the material
- F42B12/74—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the material of the core or solid body
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Powder Metallurgy (AREA)
- ing And Chemical Polishing (AREA)
- Weting (AREA)
Description
2 2 5 -SY 3 0 1 - TITLE ProJectiles This invention relates to a method for
the production of a penetrator projectile primarily intended for use against armour.
In DE 3438 547-C2 there is described a heat treatment process for a prealloyed two-phase tungsten powder having a high. proportion of tungsten wherein a porous pre-form of compressed powder is sintered in the solid phase, with the sintering being followed by a heat treatment of between two and ten minutes in or with a liquid phase. The heat treatment in the liquid phase causes a rounding of the tungsten particles in order to increase their strength which is not accompanied by any appreciable granular growth.
Despite the increase in the strength of the starting material of the penetrator, however, mechanical processing such as turning or grinding unavoidably causes cracks in the tungsten particles close -'L.o the surface, and these fractures propagate themselves undbr loads so that the penetrator prematurely becomes useless.
An object of this invention is to provide a simple and economical process L?y which the propagation of cracks r_ in a penetrator can be avoided.
According to this invention there is provided a method for the production of a penetrator from tungsten heavy metal, in which method outer tungsten particle layers are removed by a corrosive process from the surface of the penetrator after processing to the final external geometrical shape.
This invention is primarily based on a simple method of removing the outer tungsten layers from the surface of the penetrator after the latter has been machined. Cutting operations on the external geometry of the penetrator can cause surface cracks in individual tungsten particles. Particularly with slender penetrators having a considerable length-todiameter ratio, the cracks in the particles concerned propagate themselves under tensile stresses accompanying the firing operation, under vbrational and flexural stresses occurring during the flight and also as a result of impact with a target, so that they cause the penetrator to fail prematurely. Laboratory tests have shown that when the outer granular layers are removed by a corrosive action process in accordance with the invention the notch impact strength of the penetrator is increased by about 20%.
This invention is explained and described in greater i 1 3 detail with reference to an example and the accompanying drawings.
In the drawings:
Figure 1 shows a penetrator wherein the external surface has undergone the final processing, and Figure 2 shows an enlarged diagram of a section of the penetrator referenced 1 in Figure 1.
Figure 1 shows a penetrator 10 which is made of bungsten heavy metal and of which the outer contour has been subject to a finishing process. The penetrator has a nose 12 and is---Laperedin a rear zone 14 to enable- a. tail unit (not shown) to be secured thereto. For force transmission by means of a sabot (not shown) the central part 16 of the penetrator is provided with positive interlocking means 18 comprising, for example, screw threading or annular grooves. The penetrator 10 is produced by a cutting process from a cylindrical body. This process is accompanied by the formation of notches and cracks in tungsten particles close to the surface and when subjected to stresses the cracks propagate themselves from these particles so that the penetrator shatters prematurely. Microscopic examination shows that particles in which initial cracks occur are mainly to be found in the two uppermost layers while the processing machinery causes no damage to the layers situated lower down. This is illustrated in Figure which is an enlarged diagram of the zone 1 of the penetrator 10 which is adjacent to the surface. The reference number 22 denotes the tungsten particles which are situated in the top two layers and which have suffered initial cracking, while the number 24 indicates the undamaged tungsten particles in the layers lower down.
According to this invention two layers are etched away from the surface of the penetrator. A chemical erosion process which has proved particularly advantageous is one with which the choice of acid mixture and the time for which it reacts with the penetrator material enables a certain defined rate of surface removal to be achieved.
The element tungsten is highly acid-resi-Sting. The maximum attack on the material is effected by a mixture of nitric acid (HNO3) and hydrofluoric acid (HF), the rate of removal depending largely on the concentration. A mixed acid of 50% by weight of HF and 50% by weight of HNO3 for example, is found to attack the heavy metal structure excessively, so that a corrosion process intended to ensure a defined rate of removal is difficult to control. An easily controllable reaction, on the 0 other hand, can be achieved by the use of the acid with a composition of 90% by weight of HF (industrial purity) and 10% by weight of HNO3 (industrial purity) for the corrosive processing.
During the said corrosion operation the acid mixture is at a temperature of between 20 and 50o C. This offers the advantage of enabling any change in the original strength properties in consequence of thermal action on the material to be avoided. The removal of material from the surface is governed not only by the composition of the acid mixture but also by the reaction time. For the corrosive removal of at least two tungsten granular layers, corresponding to a reduction of 100,,mrri in a penetrator of 120 mm calibre, a suitable time d be about 3 for the reaction with the acid mixture minutes. The penetrator is then rinsed under running water, and any tungsten particles not adhering thereto are removed with a brush.
6
Claims (7)
1. Method for the production of a penetrator from tungsten heavy metal, in which method outer tungsten particle layers are removed by a corrosive process from the surface of the penetrator after processing to the final external geometrical shape.
2. Method in accordance with Claim 1, wherein at least two tungsten particle layers are etched away from the surface.
3. Method in accordance with Claim 'L or 2, wherein the corrosion process is effected chemically.
4. Method in accordance with any one of Claims 1, 2 or 3, wherein the corrosive process is carried out at a temperature of between 20 and 50o C.
5. Method in accordance with any one of the preceding claims, wherein the penetrator which has been finally processed in the required external geometry is immersed in an acid mixture, removed from the said mixture after a preselected period and rinsed with water, any tungsten particles riot adhering to the surface of the penetrator being removed from the said surface by brushing.
6. Method in accordance with any preceding claim, wherein the corrosive process is effected by an acid mixture prepared from 1-0% by weight of HNOs and 90% by weight of HF.
7. Method for the production of a penetrator substantially as described herein and exemplified with reference to the drawings.
8 A penetrator produced by the method of any preceding claim.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19914113177 DE4113177C2 (en) | 1991-04-23 | 1991-04-23 | Process for making a penetrator |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9202528D0 GB9202528D0 (en) | 1992-03-25 |
GB2255936A true GB2255936A (en) | 1992-11-25 |
Family
ID=6430147
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9202528A Withdrawn GB2255936A (en) | 1991-04-23 | 1992-02-06 | Tungsten projectiles |
Country Status (2)
Country | Link |
---|---|
DE (1) | DE4113177C2 (en) |
GB (1) | GB2255936A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8580188B2 (en) | 2005-10-18 | 2013-11-12 | Rheinmetall Waffe Munition Gmbh | Method for producing a penetrator |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005021982B4 (en) * | 2005-05-12 | 2007-04-05 | Rheinmetall Waffe Munition Gmbh | Process for the preparation of a penetrator |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3232803A (en) * | 1963-04-16 | 1966-02-01 | North American Aviation Inc | Chemical etching of tungsten |
GB1074203A (en) * | 1963-06-24 | 1967-06-28 | Egyesuelt Izzolampa | Polishing the surface of tungsten bodies |
DE2534213A1 (en) * | 1975-07-31 | 1977-02-17 | Licentia Gmbh | Alkaline hexacyanoferrate etch soln. - contains a silicate for etching and forming chromium, molybdenum and tungsten |
US4353780A (en) * | 1980-10-01 | 1982-10-12 | United Technologies Corporation | Chemical milling of high tungsten content superalloys |
DE3438547C2 (en) * | 1984-10-20 | 1986-10-02 | Dornier System Gmbh, 7990 Friedrichshafen | Heat treatment process for pre-alloyed, two-phase tungsten powder |
DE3932383C2 (en) * | 1989-09-28 | 1995-01-05 | Rheinmetall Gmbh | Projectile body |
-
1991
- 1991-04-23 DE DE19914113177 patent/DE4113177C2/en not_active Expired - Fee Related
-
1992
- 1992-02-06 GB GB9202528A patent/GB2255936A/en not_active Withdrawn
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8580188B2 (en) | 2005-10-18 | 2013-11-12 | Rheinmetall Waffe Munition Gmbh | Method for producing a penetrator |
Also Published As
Publication number | Publication date |
---|---|
DE4113177C2 (en) | 1993-10-21 |
GB9202528D0 (en) | 1992-03-25 |
DE4113177A1 (en) | 1992-10-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Nesterenko et al. | Shear localization and recrystallization in high-strain, high-strain-rate deformation of tantalum | |
AU569034B2 (en) | Zirconia ceramic materials and method of making same | |
US5069869A (en) | Process for direct shaping and optimization of the mechanical characteristics of penetrating projectiles of high-density tungsten alloy | |
Lim et al. | Solidification microstructure of electrodischarge machined surfaces of tool steels | |
US4305324A (en) | Projectile charges | |
FR2521982A1 (en) | ALUMINUM ALUMINUM COMPOSITE AND PROCESS FOR PRODUCING THE SAME | |
Gurevitch et al. | Characterization and comparison of microstructures in the shaped-charge regime: copper and tantalum | |
Murr et al. | Microbands and shear-related microstructural phenomena associated with impact craters in 6061-T6 aluminum | |
GB2255936A (en) | Tungsten projectiles | |
UA58628C2 (en) | Billet for barrel of fire-arms, method of its production and barrel of fire-arms | |
Sanz et al. | Study of surface integrity of rapid manufacturing parts after different thermal and finishing treatments | |
Melton et al. | Fatigue life of CuZnAl alloys | |
Hoeppner | The effect of grain size on fatigue crack propagation in copper | |
Güngör et al. | Effect of surface texture on the initiation and propagation of small fatigue cracks in a forged 6082 aluminium alloy | |
US3958063A (en) | Composite particle having surface recessing or indentation | |
Dörr et al. | Microcracks in fatigued FCC polycrystals by interaction between persistent slip bands and grain boundaries | |
US3402024A (en) | Method of treating alumina | |
AT393120B (en) | METHOD FOR PRODUCING ALUMINUM OXIDE CERAMICS HAVING INCREASED ABRASION RESISTANCE | |
D'Andrea et al. | Refractory-Lined Composite Pressure Vessels | |
Kerwien | Metallurgical post-mortem analysis of the cannon caliber electromagnetic gun: Rails and insulating sidewalls | |
DE1646483C3 (en) | Process for the production of shaped structures from zirconium corundum | |
Tankins et al. | Properties of a Retrogressed and Re-Aged 7075 Aluminum Alloy | |
EP2260978A1 (en) | Method of manufacturing screw joint product | |
Chan et al. | Experimental evidence for sulfur induced loss of ductility in copper shaped-charge jets | |
RU1801061C (en) | Method for manufacturing cathodes of electric arc evaporators |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |