Fused Element Artillery Projectile Manufacture: Modularization and Decentralization Enhancement for Modern Warfare

Abstract

A method for manufacturing artillery projectiles is disclosed, involving forging a steel base and welding it to a separately formed body using Gas Tungsten Arc Welding / Tungsten Inert Gas (GTAW / TIG) welding. This hybrid approach offers performance comparable to that of fully forged projectiles while reducing the need for large forging presses, thereby lowering production costs and enabling decentralized, scalable manufacturing with modular and mobile facilities. By forging only the base, the method simplifies production, enhances quality control, and increases resilience against supply chain disruptions.

Description

BACKGROUND

[0001] Artillery projectiles are critical for military operations, demanding reliability and safety under extreme conditions. Traditional all-forged projectiles, such as those in U.S. Pat. No. 1,358,199 (Abbott et al., 1920), use large, multi-stage forging presses to create monolithic steel bodies with uniform grain structures, ensuring in-bore integrity at pressures exceeding 60,000 psi (e.g., M795 155 mm projectile). However, these methods depend on costly, centralized facilities with presses often exceeding 10,000 tons, resulting in long lead times, production bottlenecks, and supply chain vulnerabilities.

[0002] Alternatives like cast bodies in U.S. Pat. No. 2,314,342 (Campbell, 1943) suffer from inconsistent material properties, compromising safety and fragmentation. Composite designs, such as U.S. Pat. No. 4,644,867 (Hellner et al. 1987), use metallurgically bonded fragments but lack the forging efficiency and decentralized focus of this invention. Powder metallurgy approaches, like US20140020590A1 (Ronn et al., 2014), produce preformed fragmentation casings but do not incorporate a forged base or enable decentralized production.

[0003] This invention addresses these challenges by introducing a hybrid method that combines a forged base with a separately formed body, welded using GTAW / TIG, to maintain safety and performance while enabling decentralized, resilient manufacturing.A. Field of the Invention

[0004] This invention pertains to artillery projectile manufacturing, specifically enhancing the production of caseless rounds, such as the M795 155 mm projectile, through a hybrid forged / welded design and decentralized facilities.B. Description of Related Art

[0005] All-forged projectiles, foundational to modern artillery, rely on techniques from U.S. Pat. No. 1,040,924 (Friedrick, 1912), U.S. Pat. Nos. 1,358,199, and 1,407,254 (Cox, 1922), using large presses to shape steel billets into robust, monolithic bodies. These approaches, while effective, tether production to centralized facilities, escalating costs and risks. Alternatives like powder metallurgy in U.S. Pat. No. 2,401,483 (Hensel et al., 1946) and US20140020590A1 offer body formation options, with the latter focusing on sintering with embedded fragment bodies for fragmentation control. However, these methods fail to ensure in-bore safety at high pressures or improve scalability through decentralized production.

[0006] Composite designs, such as U.S. Pat. No. 4,644,867, feature metallurgically bonded fragments in a non-compressible casing but do not limit forging to the base nor enable modular or mobile plants. Fragmentation enhancements, such as liners in U.S. Pat. No. 7,886,667B1 (Baker et al., 2011), US2017067833A1 (Jennett et al., 2017), and U.S. Pat. No. 8,272,329B1 (Hsieh et al., 2012), improve performance yet remain tied to conventional manufacturing constraints. Modern techniques, like electrical discharge machining (EDM) for fragmentation casings in U.S. Pat. No. 11,454,480B1 (Algoso et al., 2022), introduce innovative approaches but lack the hybrid forged / welded structure and decentralized production of this invention. Additionally, U.S. Pat. No. 11,614,311B1 (Bonnstetter et al., 2023) describes a prefragmented warhead with concentric layers of preformed fragments held in binding materials, designed to optimize fragmentation through an expanding curtain effect upon detonation. While effective for fragmentation control, it relies on a layered assembly process without this invention's forged base or decentralized manufacturing focus.

[0007] This invention's method uniquely integrates a forged base with a separately formed body, welded via GTAW / TIG, to maintain safety while enabling decentralized, scalable manufacturing.SUMMARY OF THE INVENTION

[0008] This invention provides a method for manufacturing artillery projectiles by:

[0009] 1. Forging a steel base from a heated High-Strength Low-Alloy (HSLA) steel billet using a closed-die press.

[0010] 2. Forming a separate body through methods such as forging, squeeze casting, additive manufacturing, or composite construction.

[0011] 3. Welding the base to the body using Gas Tungsten Arc Welding / Tungsten Inert Gas (GTAW / TIG) welding and a filler material with a tensile strength exceeding that of the HSLA steel base (e.g., ER80S or higher) to ensure joint strength exceeds that of the base material.

[0012] This hybrid design achieves the safety and performance of all-forged projectiles while requiring significantly smaller forging presses (e.g., 1,500-3,000 tons vs. 10,000 tons). This increases production rates and enables the creation of modular and even mobile manufacturing facilities capable of producing over 100 rounds daily and relocating within two hours. This provides ammunition availability in disrupted or combat scenarios, offering a cost-effective, resilient alternative to centralized, large-scale forging methods at the end of long supply chains.A. Advantages of the Invention1. Production Efficiency: Forging only the base increases output by leveraging smaller presses with capacities reduced by at least 70% compared to traditional methods, enabling higher throughput with less equipment strain.

[0014] 2. Cost Reduction: Smaller presses and broader supplier access lower capital and operational costs by at least 50%, cutting energy, maintenance, and labor expenses while enhancing economic viability.

[0015] 3. Cost and Time Efficiency with Smaller Forging Presses: Smaller presses reduce costs and enable faster, cheaper design changes through quick die swaps, enhancing production agility and reducing downtime.

[0016] 4. Decentralized Manufacturing: Modular and mobile plants improve scalability, resilience, and flexibility, mitigating supply chain risks and supporting rapid production adjustments.

[0017] 5. Performance Parity: Ensures in-bore safety and ballistic equivalence to all-forged designs, validated at pressures exceeding 60,000 psi, while simplifying manufacturing complexity.

[0018] 6. Design Flexibility: Facilitates advanced fragmentation patterns and diverse body configurations, enhancing tactical adaptability and supporting innovative, mission-specific designs.

[0019] 7. Improved Quality Control (QC): Simplifies manufacturing by focusing on the base, reducing complexity and defect rates compared to all-forged methods, ensuring consistent quality.

[0020] 8. Improved Inspection: Features an open-walled body and straight weld seams, enabling easier, more thorough inspections that streamline quality assurance and reduce undetected defects.

[0021] 9. Reduced Production Time: The hybrid method reduces manufacturing complexity and setup times, enabling faster production cycles compared to traditional all-forged approaches.

[0022] 10. Improved Consistency: By simplifying the forging process and enabling easier inspection, the method ensures more consistent projectile quality and performance across production runs.

[0023] 11. Maximizes Automation: The hybrid method uses smaller presses and modular steps to boost machine efficiency, cutting labor costs and improving safety.DescriptionA. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1: Perspective view of the M795 fused projectile (forged base, welded body).

[0025] FIG. 2: Cross-sectional view showing dimensions and explosive cavity.

[0026] FIG. 3: Comparison of all-forged vs. fused-element designs.

[0027] FIG. 4-8: Fragmentation embodiments (grooves, holes, liner, composite).

[0028] FIG. 9: Modular plant layout.

[0029] FIG. 10: Mobile plant layout (21 vehicles).B. DETAILED DESCRIPTION

[0030] This invention outlines a manufacturing process for artillery projectiles, exemplified by the M795 155 mm, combining a forged base with a separately formed body to enhance production flexibility and resilience.1. Forming the Projectile Base

[0031] A heated HSLA steel billet is forged at 1,000° C. to 1,200° C. in a closed-die press (1,500-3,000 tons) into a base—e.g., a 60-mm segment (FIG. 3). One side features a convex propellant bowl designed for pressures over 60,000 psi, while the other is flat for welding. This reduces press capacity by at least 70% compared to full-body forging in U.S. Pat. No. 1,358,199, simplifying quality control through a straightforward convex geometry.

[0032] The method improves quality control by simplifying the forging process compared to all-forged projectiles with monolithic enclosed bases and elongated bodies, which require complex manufacturing and stringent oversight to avoid high failure rates. Forging a base with a simple convex geometry on one side reduces complexity, enhances process control, and results in a lower defect rate, ensuring consistent performance.2. Forming the Projectile Body

[0033] The body is formed separately via forging, squeeze casting, powder metallurgy with embedded fragments (e.g., US20140020590A1), or composite construction with preformed steel fragments in a polymer shell (FIG. 6). These methods achieve all-forged performance while offering versatility distinct from traditional sintering, as described in U.S. Pat. No. 2,401,483. Tapering of the projectile body is performed either during the body's creation or afterward, depending on the preferred production and fragmentation preforming methods.3. Preforming the Fragmentation Profile

[0034] This invention features an enhanced fragmentation formation process that dramatically simplifies and accelerates the creation of precise fragmentation patterns, a critical advancement over traditional methods. By employing an open-ended, heat-softened projectile body, the process eliminates the labor-intensive and complex machining required through the tapered openings of conventional all-forged projectiles, such as those in U.S. Pat. No. 1,358,199. Direct access to the interior surface allows for swift, efficient application of fragmentation techniques prior to welding the body to the forged base, reducing production time and enhancing manufacturing flexibility.

[0035] The projectile body is preformed to establish a tailored fragmentation pattern through one of these innovative methods:

[0036] a) Direct Structural Modification: Using a grooving tool with a raised grid roll to preform fragmentation grooves (FIG. 4) or a perforating tool with a spiked roll to create partial-depth holes (FIG. 5), both applied to the heat-softened interior profile. These techniques generate irregular stress concentrations that precisely redirect explosive forces, ensuring controlled fragment sizes and patterns upon detonation.

[0037] b) Liner Insertion: Inserting a plastic or metal liner with irregular grid openings (FIG. 7 and FIG. 8) into the open-walled body to guide fragmentation, offering precise control over the resulting pattern without altering the body's structural integrity.

[0038] These methods draw on prior art but adapt and improve upon them for this hybrid design. U.S. Pat. No. 7,886,667B1 uses patterned plastic liners tied to traditional manufacturing, US20170167833A1 uses liners made of metal alloys, while U.S. Pat. No. 8,272,329B1 employs hole-patterned insert sleeves for selectable lethality; here, these concepts are streamlined for direct application to an accessible, open-walled body, bypassing complex assembly steps. In contrast, U.S. Pat. No. 11,454,480B1 relies on electrical discharge machining (EDM) to form fragmentation casings, a costly and equipment-intensive process compared to the simple, tool-based approach of this invention. Similarly, U.S. Pat. No. 11,614,311B1 describes a prefragmented warhead with concentric layers of preformed fragments in binding materials for an expanding curtain effect, differing significantly from this invention's direct structural modification or liner insertion within a single, open-walled body. This step is rendered unnecessary when using a composite body with sandwiched preformed steel fragments (FIG. 6), where the wall design inherently dictates the desired fragmentation pattern—a concept echoing U.S. Pat. No. 11,614,311B1's wall structure focus but uniquely integrated here via composite construction without additional layering.

[0039] These techniques markedly enhance fragment size control, simplify production compared to all-forged tapering, and leverage the open-walled design's accessibility to reduce costs and improve scalability, aligning with the invention's decentralized manufacturing goals.4. Greater Design Flexibility

[0040] The hybrid method enables advanced projectile configurations, supporting modern warfare demands while preserving the strength of forged components.5. Welding Base and Body

[0041] The base is welded to the body using GTAW / TIG. A filler material with a tensile strength exceeding that of the HSLA steel base (e.g., ER80S or higher) is employed, combined with controlled heat input and argon shielding gas, to ensure the weld joint's strength equals or surpasses the base material, providing superior in-bore integrity beyond simpler welds.6. Finishing Steps

[0042] This method simplifies inspection by employing a forged base featuring a straightforward convex impression on one side and a flat opposing surface, allowing for easier defect evaluation compared to the intricate structure of a monolithic all-forged projectile. Furthermore, examining an open-walled cylindrical body—whether forged or non-forged—is streamlined due to its readily accessible interior surfaces. Both can be thoroughly inspected to ensure they meet QA requirements before they are welded together so that the only inspection needed after the projectile is completed is the straight weld itself. The use of straight weld seams also supports efficient and reliable inspection, contributing to superior quality assurance. Following inspection, CNC machining is applied to refine tolerances and tap the fuze well, followed by heat treatment to achieve HF1 fragmentation standards while preserving preformed patterns. Subsequent finishing processes, including painting and marking, adhere to conventional techniques consistent with prior art.

[0043] By incorporating these advanced manufacturing steps, the process significantly enhances production speed, operational efficiency, and adaptability, while maintaining exceptional performance and robustness in the face of supply chain challenges.7. Optional Nosing for Aerodynamic Shaping

[0044] The method may optionally include using a nosing press to shape the projectile body into an ogival or curved profile, enhancing its aerodynamic performance. Alternatively, certain body manufacturing processes, such as squeeze casting, can form the desired aerodynamic profile directly, eliminating the need for a separate nosing press step.8. Decentralized Production

[0045] This invention enables maximum automation throughout the manufacturing process, reducing personnel exposure to operational risks and facilitating continuous, around-the-clock production. Automated systems can handle forging, body formation, fragmentation patterning, welding, and finishing, enhancing efficiency and safety in decentralized facilities.

[0046] Mobile plants (FIG. 10) produce over 100 rounds daily and relocate within two hours, offering strategic flexibility over vulnerable and well-known static facilities (e.g., Scranton). The operational modular facilities can be placed in warehouses, on ships, and even on trains to shorten the supply chain to where the projectiles are needed.9. Performance and Production Benefits

[0047] The projectile matches all-forged designs in mechanical and ballistic properties, with forging only the base reducing press capacity by 70% and costs by 50%. Mobile plants enhance resilience, supporting production near combat zones.

Claims

1. A method for manufacturing an artillery projectile with safety and performance properties equivalent to all-forged projectiles, comprising:a) forging a steel base from a heated High-Strength Low-Alloy (HSLA) steel billet in a closed-die press, the base having a convex impression on one side configured to withstand propellant pressures of at least 60,000 psi and a flat surface on the opposite side;b) forming a separate open-walled body using a method selected from forging, casting, additive manufacturing, or composite construction;c) welding the flat surface of the base to the body using Gas Tungsten Arc Welding / Tungsten Inert Gas (GTAW / TIG) with a filler material having a tensile strength equal to or exceeding that of the HSLA steel base material, achieving a joint strength greater than the base material's tensile strength.

2. The method of claim 1, further comprising preforming an interior fragmentation pattern on the sidewall of the separate projectile body that remains open on both sides before it is welded to the base. This enables direct access to the interior sidewall for applying a fragmentation pattern selected from grooves formed by a grooving tool with a raised grid roll or partial-depth holes formed by a perforating tool with a spiked roll, reducing manufacturing complexity compared to forming a fragmentation pattern through a tapered opening of an all-forged projectile.

3. The method of claim 1, further comprising inserting a fragmentation liner with grid openings configured as regular or irregular into the body before welding the body to the base, enabling liner placement to guide a fragmentation pattern tailored to a specific target type upon detonation.

4. The method of claim 1, further comprising forging the steel base with a single convex impression on one side to enhance quality control, wherein the simplified forging process reduces manufacturing complexity and defect rates compared to forging a monolithic all-forged projectile with an enclosed base and elongated body.

5. The method of claim 1, further comprising inspecting the forged steel base and the separate body prior to welding, wherein the base's convex impression on one side and flat surface on the other, combined with the body's open-walled configuration, facilitates defect detection with greater accuracy compared to inspecting a monolithic all-forged projectile with an enclosed base and elongated body.

6. The method of claim 1, wherein the reduced size of the base enables the use of forging presses with capacities reduced by at least 70% compared to presses required for all-forged projectiles.

7. The method of claim 1, implemented in a mobile manufacturing facility capable of producing at least 100 projectiles daily and relocatable within two hours.

8. The method of claim 1, further comprising heat-treating the projectile post-welding to enhance mechanical properties without altering the fragmentation pattern.

9. The method of claim 1, further comprising CNC machining the projectile to tap a fuze well and achieve tolerances compliant with artillery projectile standards.

10. The method of claim 1, where the projectile body can be tapered before or after the installation of the preformation fragmentation pattern.

11. The method of claim 1, wherein the base and body may be produced by separate suppliers, enhancing production flexibility.

12. The method of claim 1, further comprising non-destructive testing of the base, body, and weld to verify structural integrity meets in-bore safety requirements exceeding 60,000 psi.

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