U.S. Aluminum Foundries (Except Die-Casting): An Investor Primer

1. Overview

North American Industry Classification System (NAICS) code 331524 covers U.S. plants that buy aluminum, melt it and pour it into molds to make castings—excluding high-pressure die-castings.[1][2] Products range from industrial housings and marine-engine parts to aircraft components, vehicle structures and heavy-equipment parts.

This is a capital-intensive, cyclical industry in which utilization, casting yield, defects, energy consumption and machining content matter more than headline volume alone. Public-market access is indirect through diversified manufacturers and captive foundries. Private investors can obtain more focused exposure through independent foundries, consolidators, private credit and equipment financing.

2. What it is and how it is structured

Included processes principally comprise:

• Sand casting: flexible tooling for complex, large or lower-volume parts.
• Permanent-mold and low-pressure casting: reusable molds for repeat production.
• Investment casting: expendable ceramic molds for intricate, close-tolerance components.
• Lost-foam casting: foam patterns that evaporate when molten metal enters the mold.

Wisconsin Aluminum Foundry lists permanent mold, green-sand, air-set sand and low-pressure permanent-mold processes, while Stahl Specialty describes itself as one of the largest U.S. permanent-mold foundries and offers coremaking, machining, heat treatment and testing.[3][4]

Process choice is not simply "which foundry is cheapest": part size, annual volume, wall thickness, internal passages, tolerance, porosity limits and qualification requirements determine the economically feasible process.

Excluded adjacent industries include nonferrous die-casting foundries (331523), other nonferrous foundries (331529), primary and secondary aluminum smelting, aluminum rolling and extrusion, nonferrous forging (332112), and plants classified by the finished product they manufacture.[1] The most important boundary error is to equate this industry with all "aluminum casting." Automotive gigacasting and most high-pressure structural casting are die casting and are outside NAICS 331524.

Ownership is mixed. Independent contract foundries are mostly family-, employee- or sponsor-owned; public manufacturers frequently operate captive plants. Federal statistics therefore understate the physical footprint when aluminum casting occurs inside establishments classified as vehicle, engine or machinery manufacturers. County Business Patterns (CBP) also covers employer establishments, not nonemployers or most government activity, although this is not a government- or tiny-operator-dominated industry.[5][6]

3. How big it is

The supplied federal employer data report 261 establishments, 13,031 employees, $221.118 million of first-quarter payroll and $870.957 million of annual payroll in 2023.[5]

No usable shipment-value, firm-count, concentration-ratio or code-specific capacity-utilization figure was supplied, so none is stated. The supplied Small Business Administration (SBA) standard classified businesses with up to 500 employees as small for relevant federal programs in 2023; this administrative ceiling does not describe the actual ownership mix.[7]

4. Investable universe

There is no clean listed U.S. contract-foundry pure play. Available exposures are diluted inside larger companies:

General Motors is another downstream exposure: its Saginaw plant uses precision-sand and semi-permanent-mold aluminum casting, and the company announced a planned investment exceeding $150 million in 2026 for next-generation engine blocks and heads.[15]

Major private owners include:

• Consolidated Precision Products, a Warburg Pincus portfolio company with U.S. aluminum investment- and precision-sand-casting operations serving aerospace and defense.[16]
• Wisconsin Aluminum Foundry, a family-owned platform that acquired low-pressure specialist ATEK Metal Technologies in 2024 and aluminum-foundry tooling company Anderson Global in 2025.[3][17]
• Ligon Industries, a privately owned group whose aluminum businesses include Alcast, Harmony Castings, Premier Aluminum, Stahl Specialty and Watry Industries.[18]
• CaneKast, a private network of regional nonferrous sand- and permanent-mold foundries.[19]
• Angstrom Automotive Group, which acquired General Aluminum from Park-Ohio effective in 2023.[20]
• Amsted Industries, an employee-owned industrial group whose ConMet subsidiary produces aluminum castings for commercial vehicles.[21]
• Eck Industries, a family-owned specialist in high-strength aerospace, defense and industrial castings.[22]
• Bremer Manufacturing, a privately held aluminum sand caster.[23]

5. How the money works

Foundries earn revenue from the casting itself plus tooling, engineering, heat treatment, machining, coating, assembly and inspection. High-value operators deliver qualified, installation-ready components rather than commodity cast metal.

The main profit drivers are:

• Utilization: furnaces, molding lines, maintenance crews and environmental systems create substantial fixed costs.
• Yield: gates, runners, risers, rejected parts and machining losses must be remelted or scrapped. Metal yield is central to profitability; trade literature notes that melt loss varies materially with furnace and charge practice and argues that recovering aluminum from dross can be worth more than energy savings.[24] One reported green-sand installation reduced weekly scrap from 4–5% to less than 2%, illustrating why mold consistency, melt cleanliness and process control can matter more than headline tonnage (that is a single-plant case, not an industry average).[25]
• Quality: porosity, inclusions, dimensional errors and heat-treatment failures create rework, warranty and customer-loss risk.
• Value-added content: machining, testing and assembly generally earn better margins than pouring alone.
• Input pass-through: aluminum is commonly priced from the London Metal Exchange (LME) price plus a regional premium. Contractual surcharges reduce exposure, but recovery can lag. Howmet says it generally seeks to pass higher raw-material and energy costs through contractual price increases, while warning of delay and incomplete recovery.[9]
• Program durability: customer-owned tooling and lengthy qualification processes can make relationships sticky, especially in aerospace, defense and safety-critical transportation.
• Working capital: metal inventories, tooling, work-in-process and long approval cycles consume cash.

Energy is material but not equivalent to the exposure of upstream primary aluminum smelting. The Energy Information Administration's national 2022 ratios for aluminum foundries excluding die casting were 497.5 million Btu per employee, 3.9 thousand Btu per dollar of value added, and 2.3 thousand Btu per dollar of shipments. These are survey ratios, not the industry's total energy bill.[26]

The American Foundry Society's late-2025 cross-industry survey found demand, chemical/energy/material inflation and labor among foundries' leading concerns; those results cover all metalcasters, not just NAICS 331524.[27]

Investors should track good castings shipped—not merely pounds melted—alongside scrap and rework rates, energy per good pound, furnace uptime, labor productivity, on-time delivery, backlog, customer concentration and maintenance capital expenditure.

6. Demand drivers

Transportation is the largest broad U.S. aluminum end market, accounting for 36% of estimated aluminum consumption in 2025; that is an aluminum-wide measure, not a 331524 revenue share.[28] Foundry demand also comes from aerospace and defense, commercial vehicles, agriculture, construction machinery, marine engines and general industrial equipment.

Key drivers are vehicle and equipment production, aircraft build rates, defense spending, replacement-parts demand and manufacturers' efforts to reduce weight. The Department of Energy states that a 10% vehicle-weight reduction can improve fuel economy by 6–8%, and gives aluminum and aluminum-matrix composites a potential mass reduction of 30–60% versus conventional materials, depending on the application.[29] Aerospace offers attractive pricing and switching barriers but demanding qualification and inspection requirements.

Electric vehicles create a mixed outcome. Lightweight structures and battery systems support aluminum use, but many large "gigacast" components use excluded high-pressure die-casting. Meanwhile, declining internal-combustion engine volumes could reduce demand for some sand- and permanent-mold blocks and heads. General Motors' Saginaw investment shows that profitable conventional-engine programs can nevertheless remain material.[15]

Input conditions are important: U.S. aluminum spot-ingot prices rose 39% in 2025, while net import reliance was 60%.[28] Foundries without timely metal pass-throughs face the greatest margin risk.

7. Regulation

Qualifying area-source aluminum foundries are regulated under National Emission Standards for Hazardous Air Pollutants (NESHAP) in 40 Code of Federal Regulations Part 63, Subpart ZZZZZZ. Requirements address hazardous pollutants—including beryllium, cadmium, chromium, lead, manganese and nickel—furnace practices, scrap selection and, for covered larger facilities, particulate controls.[30]

Plants that process secondary scrap, use particular fluxes or operate covered furnaces may instead or additionally fall under the secondary-aluminum NESHAP in Subpart RRR. Applicability depends on the charge material, furnace and operating practices—not NAICS classification alone.[31]

Sand handling and finishing can expose workers to respirable crystalline silica. Occupational Safety and Health Administration (OSHA) rules set an eight-hour permissible exposure limit of 50 micrograms per cubic meter and an action level of 25 micrograms per cubic meter.[32] OSHA has issued enforcement guidance specific to foundry silica exposure and maintains alliance materials with the American Foundry Society addressing broader foundry safety hazards.[33][34] Molten metal, heat, machinery and combustible aluminum dust create additional safety and insurance risks.

Spent foundry sand may be recycled beneficially, but baghouse dust, dross, sludge and contaminated wastes require separate testing and disposal analysis under federal and state rules.[35]

Trade policy cuts both ways. The U.S. raised Section 232 aluminum and steel tariffs to 50% effective June 4, 2025, and modified the regime in April 2026 with differentiated treatment for products made wholly or substantially from covered metals.[36][37] As of June 2026, the regime generally imposed additional duties of 50% on covered primary metal products and 25% on predominantly metal derivative products, subject to product- and origin-specific adjustments.[38] Tariffs can protect domestic castings while raising imported-ingot costs; the net effect depends on tariff classification, domestic scrap use and customer pass-through clauses.

8. Competitive dynamics and consolidation

Competitive advantages come from metallurgical knowledge, proprietary tooling, stable process control, customer approvals, certifications, delivery performance and integrated machining. Freight and service favor regional suppliers for some industrial work, while aerospace and large transportation programs compete nationally or globally.

Entry is difficult because a new plant needs furnaces, molding and finishing equipment, permits, skilled labor and enough volume to absorb fixed costs. Switching can also require new tooling, destructive testing and customer requalification.

Recent acquisitions by Wisconsin Aluminum Foundry, Ligon, CaneKast, Angstrom and Linamar show consolidation around broader process capability, machining, tooling and geographic coverage.[3][12][17][18][19][20] Even so, ownership remains fragmented among specialist private plants and captive operations. With no supplied federal concentration measure, the degree of concentration should not be quantified.

9. Risks

• Cyclicality: vehicle, machinery, marine and construction demand can fall quickly.
• Fixed-cost leverage: weak utilization can turn modest volume declines into large profit declines.
• Metal and energy inflation: pricing formulas may recover costs slowly or incompletely.
• Customer concentration: losing one qualified program can strand dedicated tooling and capacity.
• Technology substitution: forgings, fabricated parts, composites, additive manufacturing and excluded high-pressure die-casting can replace conventional castings. Advanced high-strength steel, magnesium and plastics also compete for applications.
• Quality failures: defects can cause scrap, recalls, warranty claims or permanent disqualification.
• Environmental liabilities: old furnaces, waste areas and contaminated sites can require substantial remediation.
• Labor and safety: experienced foundry and machining workers are difficult to replace.
• Private-company leverage: acquisition debt can compound normal operating cyclicality.
• Misclassification: businesses marketed as aluminum foundries may derive much of their revenue from die-casting, smelting, machining or finished-product manufacturing outside 331524.

10. How to invest and outlook

Public investors should treat Howmet and Berkshire as aerospace-oriented indirect exposures, Linamar as a mixed North American casting platform, and Brunswick or General Motors as captive-foundry exposures. Valuation should be based on each company's broader business rather than applying a foundry multiple to consolidated earnings.

Private investors can pursue control acquisitions, minority stakes, private credit, equipment leases and industrial sale-leasebacks. Diligence should prioritize plant-level utilization, yield, customer and tooling ownership, pass-through formulas, certification status, maintenance needs, environmental history, pension and union obligations, and debt headroom.

Outlook: selective rather than uniformly bullish. Reported facts support aerospace and defense demand, continued investment in domestic engine programs and consolidation among capable private operators.[8][15][17] Conversely, expensive metal, shifting vehicle architectures and the migration of some structural parts toward high-pressure die-casting remain headwinds.[28]

Our forward-looking judgment is that the strongest investments will be qualified specialty foundries with high machining content, contractual metal recovery and durable aerospace, defense or safety-critical programs. Undifferentiated automotive capacity, weak utilization and unresolved environmental liabilities deserve a substantial discount.

Sources

1. U.S. Census Bureau, "2022 NAICS Definition: 331524 Aluminum Foundries (except Die-Casting)," 2022, https://www.census.gov/naics/?details=33&input=33&year=2022
2. Bureau of Labor Statistics, "NAICS to SIC Concordance," 2026, https://www.bls.gov/ppi/additional-resources/naics-to-sic-concordance-331111-to-332510.htm
3. Wisconsin Aluminum Foundry, "Processes and Locations," 2026, https://wafco.com/
4. Stahl Specialty Company, "Capabilities," 2026, https://stahlspecialty.com/
5. U.S. Census Bureau, "331524—Aluminum Foundries (except Die-Casting): County Business Patterns Profile," 2023, https://data.census.gov/profile/331524_-_Aluminum_foundries_(except_die-casting)?codeset=naics~331524
6. U.S. Census Bureau, "County Business Patterns Methodology," 2026, https://www.census.gov/programs-surveys/cbp/technical-documentation/methodology.html
7. U.S. Small Business Administration, "Table of Size Standards," 2023, https://www.sba.gov/document/support-table-size-standards
8. Howmet Aerospace, "2025 Annual Report," 2026, https://www.howmet.com/annualreport/
9. Howmet Aerospace, "Annual Report on Form 10-K," 2025, https://www.sec.gov/Archives/edgar/data/4281/000000428126000012/hwm-20251231.htm
10. Precision Castparts, "Investment Cast Products," 2026, https://www.precast.com/operations/pcc-investment-cast-products/
11. Berkshire Hathaway, "2025 Annual Report," 2026, https://berkshirehathaway.com/2025ar/2025ar.pdf
12. Linamar, "Linamar Completes Acquisition of Aludyne North America Assets," 2025, https://www.linamar.com/linamar-completes-acquisition-of-aludyne-north-america-assets/
13. Brunswick Corporation, "Our History: Mercury Marine Lost-Foam Foundry," 2026, https://www.brunswick.com/our-company/our-history
14. Brunswick Corporation, "Annual Report on Form 10-K," 2025, https://www.sec.gov/Archives/edgar/data/14930/000001493026000027/bcorp-20251231.htm
15. General Motors, "GM to Invest More Than $150 Million in Saginaw Metal Casting Plant," 2026, https://news.gm.com/home.detail.html/Pages/news/us/en/2026/apr/0401-GM-invest-150-million-Saginaw-Metal-Casting.html
16. Consolidated Precision Products, "Company and Operating Locations," 2026, https://www.cppcorp.com/
17. Wisconsin Aluminum Foundry, "ATEK and Anderson Global Acquisitions," 2024–2025, https://wafco.com/about/history/
18. Ligon Industries, "About Us and Acquisitions," 2026, https://ligonindustries.com/acquisitions/
19. CaneKast, "Non-Ferrous Foundry Network," 2026, https://canekast.com/
20. Park-Ohio Holdings, "Annual Report on Form 10-K," 2024, https://www.sec.gov/Archives/edgar/data/76282/000007628225000013/pkoh-20241231.htm
21. Amsted Industries, "Commercial Vehicle and Metal Castings," 2026, https://www.amsted.com/products-and-services/commercial-vehicle/
22. Eck Industries, "About Eck Industries," 2026, https://www.eckindustries.com/
23. Bremer Manufacturing, "About Us," 2026, https://www.bremermfg.com/about-us/
24. Foundry Management & Technology, "Aluminum Metal Still More Expensive Than Energy," 2026, https://www.foundrymag.com/melt-pour/article/21931943/aluminum-metal-still-more-expensive-than-energy
25. Foundry Management & Technology, "Green Sand Molding for High-Quality Nonferrous Castings," 2026, https://www.foundrymag.com/molds-cores/article/21281074/green-sand-molding-for-high-quality-nonferrous-castings-disa
26. U.S. Energy Information Administration, "2022 MECS Table 6.3: Energy Intensity," 2024, https://www.eia.gov/consumption/manufacturing/data/2022/pdf/Table6_3.pdf
27. Modern Casting, "Industry Pulse Check Survey," 2026, https://www.moderncasting.com/index.php/articles/2026/01/05/industry-pulse-check
28. U.S. Geological Survey, "Mineral Commodity Summaries 2026: Aluminum," 2026, https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf
29. U.S. Department of Energy, "Lightweight Materials for Cars and Trucks," 2026, https://www.energy.gov/cmei/vehicles/lightweight-materials-cars-and-trucks
30. U.S. Environmental Protection Agency, "Aluminum, Copper and Other Nonferrous Foundries: National Emission Standards," 2026, https://www.epa.gov/stationary-sources-air-pollution/aluminum-copper-and-other-nonferrous-foundries-national-emission
31. U.S. Environmental Protection Agency, "Secondary Aluminum Production: National Emission Standards for Hazardous Air Pollutants," 2026, https://www.epa.gov/stationary-sources-air-pollution/secondary-aluminum-production-national-emission-standards
32. Occupational Safety and Health Administration, "Crystalline Silica—General Industry and Maritime," 2026, https://www.osha.gov/silica-crystalline/general-industry-maritime
33. Occupational Safety and Health Administration, "Enforcement Guidance for Respirable Crystalline Silica," 2026, https://www.osha.gov/enforcement/directives/cpl-02-02-007
34. Occupational Safety and Health Administration, "OSHA/AFS Alliance," 2026, https://obis.osha.gov/dcsp/alliances/afs/afs.html
35. U.S. Environmental Protection Agency, "Beneficial Uses of Spent Foundry Sands," 2026, https://www.epa.gov/smm/beneficial-uses-spent-foundry-sands
36. Federal Register, "Adjusting Imports of Aluminum Into the United States," 2025, https://www.federalregister.gov/documents/full_text/html/2025/06/09/2025-10524.html
37. White House, "Strengthening Actions Taken to Adjust Imports of Aluminum, Steel and Copper," 2026, https://www.whitehouse.gov/presidential-actions/2026/04/strengthening-actions-taken-to-adjust-imports-of-aluminum-steel-and-copper-into-the-united-states/
38. White House, "Further Adjusting the Tariff Regimes for Imports of Aluminum, Steel, and Copper," 2026, https://www.whitehouse.gov/presidential-actions/2026/06/further-adjusting-the-tariff-regimes-for-imports-of-aluminum-steel-and-copper-into-the-united-states/