EP1321535A2 - Material with high ballistic protection - Google Patents

Abstract

Use of an alloy containing (in wt.%): 0.26-0.79 C, 0.2-1.2 Si, 0.2-0.9 Mn, 1.1-7.94 Cr, 0.56-3.49 Mo, 0.26-1.74 V and a balance of Fe as a material for products having a high ballistic protective action is new. The alloy contains P and S in a sum of less than 0.025 wt.%. The sum of the impurity elements As, Sb, Bi, Sn, Zn and B is less than 0.011. <??>Preferred Features: The alloy contains additions of (in wt.%): 0.36-0.64, preferably 0.41-0.58 C, 0.36-0.9, preferably 0.41-0.68 Si, 0.36-0.70, preferably 0.41-0.59 Mn, 1.1-7.94, preferably 2.61-5.2 Cr, 0.56-3.49, preferably 1.30-2.7 Mo, 0.26-1.74, preferably 0.39-0.83 V.

Description

The invention relates to the use of steel alloys known per se as Material for products with high ballistic protection.

A ballistic protective effect of objects, especially those flat material, is generally characterized by its security against a breakthrough of projectiles and splinters at high energy Weapon impact, with increasing protection and at the same time a reduced weight of the object or part with improved Economics of deployment are required.

At the beginning, the recognized expert opinion should be stated that the usual mechanical measurement data from a tensile and notch impact test none direct inference regarding the properties of a material in ballistic Allow stress. In many cases, however, the hardness, the impact strength and the strength of the material used to give at least one clue for a penetration resistance of a protective part. At long last however, mark the "held shots" of a sheet metal part thereof ballistic protection.

It is now approximated that the strength, hardness and toughness not change with the rate of stress, so it can it can be assumed that the material of the protective parts is both extremely hard must also have great toughness in order to destroy ballistic Withstand exposure and a refractive effect on projectiles exercise. Now these properties are taken into account for steels and alloys counter to their simultaneous maximization, so that next to one general improvement thereof a balance of toughness and Strength of the material, especially after thermal tempering is required according to the claim.

Depending on the desired property profile, products with ballistic Protective effect carbon steels, low and medium alloy steels, high alloy Steels and precipitation hardenable alloys with one if necessary Iron content of less than 55% by weight proposed and often a composite construction and / or a hard layer on the outer surface of the protective part is advantageous recognized.

For example, EP-A-180805 discloses a steel helmet made from a low alloyed boron steel, the steel helmet being sandblasted after tempering.

From EP-A-1052296 an armored sheet with a tempering structure is known, which has a yield strength of> 1100 N / mm ² and a hardness of> 400 HB and with a carbon content in% by weight of 0.15 to 0.2 im Essentially 1 to 2 wt% chromium (Cr), 0.2 to 0.7 wt% molybdenum (Mo), 1.0 to 2.5 wt% nickel (Ni), 0.05 to 0 , 25 wt .-% vanadium (V), balance iron (Fe).

A process for the production of thick armor plates is known from EP-A-580062 became known in which the above, increased in carbon and nickel content Alloy in slab form initially heated to a temperature of over 1150 ° C, Allow to cool increasingly and in the range from 1050 to 900 ° C with high temperatures Degree of deformation is rolled to the final thickness.

In EP-B-731332 is a steel armor plate with improved penetration resistance to projectiles, which contain a large number of inclusions, which Oriented essentially parallel to the plate surface and in a quarter up to three Quarter of the plate thickness are concentrated.

An armor plate with a base material made of tough steel, on which by Plate at least one hard steel pad facing the bombardment consisting of 0.6 to 1.0% by weight carbon (C), 0.2 to 2.0% by weight silicon (Si), 0.2 to 2.0 wt% manganese (Mn), 0.8 to 2.0 wt% chromium (Cr), 0.05 to 1.0 % By weight of molybdenum (Mo), 0.05 to 0.35% by weight of vanadium (V), remainder iron (Fe) and Steel companion is applied, discloses EP-B-247020. Between the Base material and the pad is an intermediate layer made of pure nickel or Pure iron with a thickness between 0.1 and 15% of the total sheet thickness arranged by roll cladding with the base material and the support connected is. The liner not only facilitates plating the Base material, but also prevents the support material from flaking off, which can be tempered to a hardness of 55 to 60 HRC, but is therefore evident has low toughness.

In addition to the above low and medium alloyed tempering steels high-alloy chrome steel alloys (CH-A-648354) and precipitation or martensitic hardening steels (AT-336659, DE-C-19921961, EP-A-1008659) as Single part or in composite construction with possibly a hard outer layer proposed for ballistic protection. Such steels with high Alloys up to 50% are used as a material for components highly effective ballistic protection can be used advantageously, but have the Disadvantage of high costs.

Here, the invention wants to create downhill and has the goal of materials indicate from which products with a high ballistic protective effect low weight, can be produced economically in a simple manner. This Products or parts are said to have a high bullet or flight part breaking effect possess, consist of an iron-based alloy, through a heat treatment adjustable toughness and strength properties have, with both characteristics maximized. Materials Technical a composite production or a multi-layer part production and a Surface hardening is possible and there is weldability.

This goal is achieved when using an alloy containing in% by weight: Carbon (C) 0.26 to 0.79 Silicon (Si) 0.2 to 1.2 Manganese (Mn) 0.2 to 0.9 Chrome (Cr) 1.1 to 7.94 Molybdenum (Mo) 0.56 to 3.49 Vanadium (V) 0.26 to 1.74 Iron (Fe) as well as accompanying elements and impurities as the remainder, with the alloying requirement that the value for the content of phosphorus (P) plus sulfur (S) is less than 0.025, P + S <0.025% by weight the concentration of nickel (Ni) is below 0.28 Ni <0.28% by weight and the sum of the contaminant elements arsenic (As),
Antimony (Sb), bismuth (Bi), tin (Sn), zinc (Zn) and boron (B) is less than 0.011 As + Sb + Bi + Sn + Zn + B <0.011% by weight as a material for the aforementioned products.

The advantages achieved with the invention according to the above characteristic are essentially to be seen in the fact that by restricting the content of the impurity elements sulfur (S) plus phosphorus (P) in combination to a value of less than 0.025% by weight, the prerequisite for a Achieving high material toughness is achieved if, as was found, the other impurity components arsenic (As) plus antimony (Sb) plus bismuth (Bi) plus tin (Sn) plus zinc (Zn) plus boron (B) have a total concentration that is less than 0.011% by weight. Because nickel (Ni) surprisingly, in interaction with the other alloy elements, in particular with molybdenum (Mo) and vanadium (V), increases the risk of grain boundary occupancy, the nickel content is below 0.28% by weight. limited to the top. These advantageous material properties achieved according to the invention, which are markedly pronounced in a shelling test due to a high proportion of shots held, are particularly evident in parts which have been tempered to a high strength of over 1900 N / mm ² . It has also been shown that a further improvement in the desired material properties is achieved with sulfur contents of less than 0.005% by weight.

In the case of a selection in which one or more element (s) has (have) the concentration (s) in% by weight: Carbon (C) 0.36 to 0.64, preferably 0.41 to 0.58 Silicon (Si) 0.36 to 0.9, preferably 0.41 to 0.68 Manganese (Mn) 0.36 to 0.7, preferably 0.41 to 0.59 Chrome (Cr) 1.7 to 5.95, preferably 2.61 to 5.2 Molybdenum (Mo) 1.05 to 2.9, preferably 1.3 to 2.7 Vanadium (V) 0.36 to 1.25, preferably 0.39 to 0.83 excellent results are achieved in the bullet test. As has been determined, this is due to the fact that, in close coordination with the other alloying elements, the respective concentration of the selected element (s) has a positive influence on the structural changes during thermal quenching, that is, it favors hardness assumption without interference areas at the grain boundaries and ensure a largely homogeneous remuneration structure when starting.

In addition to a high purity or a low content of Impurity elements of the material used according to the invention acts As has been recognized, the technology of manufacturing also relies on a ballistic Protective effect from parts made from it. The manufacturing technology Measures as set out in claim 3 can be individually and in Combination improving the ballistic protection through parts manufactured in this way affect, because it promotes in particular the isotropy of the material. Remuneration can lead to higher strength values with improved Material toughness take place, whereby the product is significantly increased Resists projectile breakdown.

If the material with the remuneration technical requirement that it has a strength of greater than 1800 N / mm, preferably greater than 2000 N / mm ² , in particular greater than 2100 N / mm ² , with a toughness at room temperature of greater than SEP 150 J , preferably greater than 185 J, in particular of about 245 J as measured by (S e teel isen rüfblatt P) in September 1314, has the highest breakdown products resistors and the like are the same strength achievable at low alloy cost.

Using examples and from FIG. 1, the invention according to claims 1 to 4 are explained in more detail, wherein Fig. 1 shows the percentage of shots held Depends on the sheet thickness.

Example 1:

A sheet according to the invention made of an ESR block with a sheet thickness of 6.6 mm and a composition in% by weight of 0.49 carbon (C), 0.59 silicon (Si), 0.3 manganese (Mn), 0.004 Sulfur (S), 0.019 phosphorus (P), 3.23 chromium (Cr), 1.37 molybdenum (Mo), 0.29 vanadium (V) and 0.19 nickel (Ni), remainder iron (Fe) and accompanying elements (Arsenic (As), Antimony (Sb), Bismuth (Bi), Tin (Sn), Zinc (Zn), Boron (B)) with a total concentration of 0.008 was tempered to a hardness of 56 + 1 HRC and a shot test with Subjected to 100 rounds, of which 93 rounds were held A sheet made from tempered carbon steel, which held 57 shots, was tested under the same bombardment conditions.

Example 2:

A sheet made of Cr-Mo-V steel, which was treated by ladle metallurgy and was vacuum-degassed, with a composition in% by weight of 0.45 carbon (C), 0.62 silicon (Si), 0.64 manganese (Mn) , 0.016 phosphorus (P), 0.007 sulfur (S), 3.35 chromium (Cr), 1.62 molybdenum (Mo), 0.32 vanadium (V) was rolled from a slab to a thickness of 7.5 mm. Samples were made from the sheet, the same was tempered and tested with different technologies. Table 1 shows the remuneration parameters and the mechanical values achieved. Sample No. Härtetemp. ° C Antasser ° C number rm Rp _0.2 A Kertischlag hardness N / mm ² N / mm ² % J MW HRC A 930 300 1 1941 1441 6.2 167 180 166 171 55 B 930 300 1 1872 1471 7.6 64 209 160 151 53 C 950 300 1 1975 1576 5.6 61 201 171 144 55

From the results, the effects are obviously different Remuneration parameters on the mechanical properties of the material evident, which clearly indicates an easy setting according to the invention indicates the desired product data.

In comparison with tempered carbon steel of the same thickness, Shot test from the sheet metal according to the invention held by about 60% more shots.

In a further test, a comparison was made of sheets according to the invention with those made of carbon steel and martensitic steel with regard to held shots. Set the values indicated or drawn in Fig. 1 represent mean values of results from at least three shots each.

In Fig. 1, the percentage of shots held is dependent on the Sheet thickness shown. From a sheet thickness of 6 mm upwards it is the same energetic conditions of shelling the percentage of shots held from an inventive and one from a martensitic steel manufactured sheet metal practically the same. With regard to economy, it must be determined that that the material according to the invention has an alloy content of approx. 6%, that of the martensitic steel (comparison material) has 41.5% and thus has significantly higher costs.

The stated goal is also achieved when using an alloy containing in% by weight: Carbon (C) 0.3 to 0.6 Silicon (Si) 0.08 to 0.59 Manganese (Mn) 0.1 to 0.6 Chrome (Cr) 0.9 to 1.5 Nickel (Ni) 2.4 to 5.5 Iron (Fe) as well as accompanying elements and impurities as the remainder, with the alloying requirement that the value for the content of phosphorus (P) plus sulfur (S) is less than 0.025, P + S <0.025% by weight the concentration of molybdenum (Mo) is below 0.34 and that of tungsten (W) is below 0.29, the total value of molybdenum (Mo) plus tungsten (W) broken by two not exceeding 0.38. Mo <0.28% by weight W <0.29% by weight Mon + W 2 <0.38% by weight and the sum of the grain boundary impurity elements arsenic (As), antimony (Sb), bismuth (Bi), tin (Sn), zinc (Zn) and boron (B) is less than 0.011 As + Sb + Bi + Sn + Zn + B <0.011% by weight as a material for the products mentioned at the beginning.

The achieved according to the invention with the immediately aforementioned characteristics The main advantages are that, on the one hand, by choosing the Alloy elements and their respective concentration one by means of a thermal tempering created desired high material strength is achievable. On the other hand, a high toughness of the material, as has been found, can do so by means of three further alloying measures. By a Limiting the total content of sulfur (S) and phosphorus (Ph) upwards, which elements cause inclusion and embrittlement through grain boundary assignments, can at least interact created the requirement for high toughness of the material. The Elements Molybdenum (Mo) and tungsten (W) individually and in combination, which in itself strengthening in alloys can, however, have the Tendency of brittle grain boundary enrichment in the material, so that a Limitation of salary mentioned above has a toughening effect. It it was also found that the impurity elements arsenic (As), antimony (Sb), bismuth (Bi), tin (Sn), zinc (Zn) and boron (B) in small amounts Concentrations cause a steep drop in material toughness if there is too abruptly effective high mechanical loads on the material, such as for example, when a part made from it is shot at, comes from what the determination of the highest total content according to the invention results. How also mentioned at the beginning, can be determined with material tests mechanical material properties with high-energy weapon impact change significantly, so strictly speaking, only through a bullet test Penetration resistance of bullets or fragments and cracking behavior of protective parts can be evaluated. According to the invention in the Alloy characterized as a material for products with high demands Ballistic protection effect not only of the improved properties in this regard because of, but also for economic reasons special advantages because of The proportion of alloying elements in the steel is less than 8.8% by weight thermal coating is feasible and adequate weldability of the Materials for a component production, for example for a Limousine armor.

In a further development of the alloy, one or more elements of which have (have) the concentration (s) in% by weight: Carbon (C) 0.3 to 0.54, preferably 0.41 to 0.49 Silicon (Si) 0.11 to 0.39 Manganese (Mn) 0.18 to 0.49, preferably 0.25 to 0.38 Chrome (Cr) 1.15 to 1.4 Nickel (Ni) 2.9 to 4.9, preferably 2.56 to 3.9 For use as a material for the aforementioned products, improved properties can be achieved in the bombardment test. At this point, it should also be noted that a further increase in the property level is achieved by lowering the sulfur content to below 0.005% by weight.

The advantageous material properties achieved according to the invention are increasingly pronounced in the case of bombardment if the parts are tempered to higher strength values of over 1900 N / mm ² . This is also due to the fact that a narrower range of the concentration of a respective alloy element in interaction with the other constituents of the alloy has a favorable influence on the conversion and the formation of the structure of the material in the thermal treatment, whereby the hardness acceptance and the tempering behavior are improved and such extensive isotropy with low residual stresses.

The manufacturing technical requirements regarding the material, as in Claim 7 are listed, act individually and in combination to improve the ballistic protection from parts made from it, because of this Requirements regarding the isotropy of the material, including the micro segregation, is promoted. In this way, even with remuneration for higher strengths of the Material increase in material toughness in all directions and resistance to projectile penetration.

If the material with the remuneration technical requirement that it has a strength of greater than 1800 N / mm ² , preferably greater than 2000 N / mm ² , in particular greater than 2100 N / mm ² , with a toughness at room temperature of greater than SEP 150 J, preferably having greater than 185 J, in particular of about 245 J as measured by (S e teel isen rüfblatt P) in September 1314, are derived products or protection components with the highest breakdown resistance buildable.

Using examples and by means of Fig. 2, the invention according to the claims 5 to 8 are also explained in more detail, with FIG. 2 again the percentage of shots held depending on the sheet material thickness shows.

Example 3:

From a slab of vacuum-treated steel with a composition of in% by weight 0.5 carbon (C), 0.32 silicon (Si), 0.45 manganese (Mn), 0.017 phosphorus (P), 0.006 sulfur (S ), 1.25 chromium (Cr), 0.18 molybdenum (Mo), 0.21 tungsten (W), 3.97 nickel (Ni) and with a sum of arsenic (As) plus antimony (Sb) plus bismuth ( Bi) plus tin (Sn) plus boron (B) = 0.0085, a sheet with a thickness of 6.8 mm was rolled, which rolled material was mechanically tested after using different tempering technologies. The results of the tests are summarized in Tab. 2. Sample No. Härtetemp. Anlsesen number rm Rp _0.2 A Korbethlag hardness ° C ° C N / mm ² N / mm ² % J MW HRC AA 840 120 1 2229 1207 6.1 225 245 226 232 55.5 BB 870 120 1 2227 1133 8.6 220 245 216 227 56 CC 840 120 1 2282 1306 5.5 95 233 173 167 57

During the shooting test it was found that the sheet with the sample designation AA had a shot retention capacity of 95, but an equally thick tempered one Carbon steel sheet withstood only 56 out of 100 shots.

Example 4:

A sheet made of ladle-treated steel with a composition in% by weight of 0.52 carbon (C), 0.12 silicon (Si), 0.22 manganese (Mn), 0.014 phosphorus (P), 0.003 sulfur ( S), 1.42 chromium (Cr), 0.11 molybdenum (Mo), 0.09 tungsten (W), 0.004 (As + Sb + Bi + Sn + Zn + B), which was then remelted electroslag, with a thickness of 7.5 mm and tempered to a hardness of 57 HRC, at a hardness temperature of 880 ° C and air cooling after tempering at 200 ° C, the material had a yield strength of Rm = 2265 N / mm ² with a notched bar impact work of on average 202 J. In the shelling test compared to tempered carbon steel under otherwise identical conditions, a 68.7% higher number of shots was recorded.

In one of the further tests, a comparison of the invention was carried out Sheets and those made of carbon steel that have been tempered to the highest values and martensitic hardening steel using a bullet test. 2 is the Percentage of shots held depending on the sheet thickness shown. From a sheet thickness of 5 mm to 10 mm proportionately that of martensitic steel and that of Steel shots according to the invention held essentially the same with low Advantages of the material according to the invention in the range over a sheet thickness of 6 mm.

It is therefore characteristic that the use of a material according to the invention on the one hand from such Carbon steel with the same product forms and stress criteria has significantly higher ballistic protection and on the other hand a significantly lower proportion of a hardenable steel Alloy elements and thus economic advantages in the creation Has.

Claims (8)

Use of an alloy known per se as a material for products with a high ballistic protective effect containing in% by weight: Carbon (C) 0.26 to 0.79 Silicon (Si) 0.2 to 1.2 Manganese (Mn) 0.2 to 0.9 Chrome (Cr) 1.1 to 7.94 Molybdenum (Mo) 0.56 to 3.49 Vanadium (V) 0.26 to 1.74 Iron (Fe) as well as accompanying elements and impurities as the remainder, with the alloying requirement that the value for the content of phosphorus (P) plus sulfur (S) is less than 0.025, P + S <0.025% by weight the concentration of nickel (Ni) is below 0.28 Ni <0.28% by weight and the sum of the grain boundary impurity elements arsenic (As), antimony (Sb), bismuth (Bi), tin (Sn), zinc (Zn) and boron (B) is less than 0.011. As + Sb + Bi + Sn + Zn + B <0.011% by weight Use of an alloy according to claim 1, wherein one or more elements have the same concentration (s) in% by weight: Carbon (C) 0.36 to 0.64, preferably 0.41 to 0.58 Silicon (Si) 0.36 to 0.9, preferably 0.41 to 0.68 Manganese (Mn) 0.36 to 0.7, preferably 0.41 to 0.59 Chrome (Cr) 1.7 to 5.95, preferably 2.61 to 5.2 Molybdenum (Mo) 1.05 to 2.9, preferably 1.3 to 2.7 Vanadium (V) 0.36 to 1.25, preferably 0.39 to 0.83 Use of an alloy according to claim 1 or 2 as a material for Products with high ballistic protection with the manufacturing technology Provided that it is ladle metallurgy and / or vacuum treated and / or vacuum-melted or remelted and / or, optionally under pressure, is electroslag remelted and / or produced by powder metallurgy. Use of an alloy according to claims 1 to 3 as a material with a high ballistic protective effect with the remuneration technical requirement that it has a strength of greater than 1800 N / mm ² , preferably greater than 2000 N / mm ² , in particular more than 2100 N / mm ² a strength at room temperature of greater than 150 J September, preferably greater than 185 J, in particular about 245 J measured according September 1314 (S e teel isen rüfblatt P) has. Use of an alloy known per se as a material for products with a high ballistic protective effect containing in% by weight: Carbon (C) 0.3 to 0.6 Silicon (Si) 0.08 to 0.59 Manganese (Mn) 0.1 to 0.6 Chrome (Cr) 0.9 to 1.5 Nickel (Ni) 2.4 to 5.5 Iron (Fe) and accompanying elements and impurities as the remainder, with the alloying requirement that the value for the content of phosphorus (P) plus sulfur (S) is less than 0.025 P + S <0.025% by weight the concentration of molybdenum (Mo) is below 0.34 and that of tungsten (W) is below 0.29, the total value of molybdenum (Mo) plus tungsten (W) broken by two not exceeding 0.38 Mo <0.28% by weight W <0.29% by weight Mon + W 2 <0.38% by weight and the sum of the grain boundary impurity elements arsenic (As), antimony (Sb), bismuth (Bi), tin (Sn), zinc (Zn) and boron (B) is less than 0.011 As + Sb + Bi + Sn + Zn + B <0.011% by weight Use of an alloy according to claim 5, wherein one or more element (s) thereof has the concentration (s) in% by weight: Carbon (C) 0.36 to 0.54, preferably 0.41 to 0.49 Silicon (Si) 0.11 to 0.39 Manganese (Mn) 0.18 to 0.49, preferably 0.25 to 0.38 Chrome (Cr) 1.15 to 1.4 Nickel (Ni) 2.9 to 4.9, preferably 2.56 to 3.9 Use of an alloy according to claim 5 or 6 as a material for Products with high ballistic protection with the manufacturing technology Provided that the alloy is ladle metallurgy and / or vacuum treated and / or vacuum-melted or remelted, optionally under pressure, electroslag remelted or powder metallurgy. Use of an alloy according to claims 5 to 7 as a material with a high ballistic protective effect with the technical requirement that it has a strength of greater than 1800, preferably greater than 2000, in particular greater than 2100, N / mm ² with a toughness at room temperature SEP 150 J, preferably has greater than 185 J, in particular about 245 J measured according September 1314 (S e teel isen P rüfblatt).

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