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NAICS Code· 331511

NAICS 331511: Iron Foundries

This U.S. industry comprises establishments primarily engaged in pouring molten pig iron or iron alloys into molds to manufacture castings (e.g., cast iron manhole covers, cast iron pipe, cast iron skillets). Establishments in this industry purchase iron made in other establishments. Cross-References.Show more

NAICS 331511 – Iron Foundries encompasses the production of iron castings through molding and pouring processes, including gray iron, ductile iron, and malleable iron products used in heavy industrial, defense, and infrastructure applications. This sector supports the manufacture of components such as engine blocks, valve bodies, gear housings, structural brackets, and pipe fittings that require high strength, vibration damping, and thermal stability.

59
Active Contracts
$338K
Total Obligations (12mo)
7
Awarded Contracts (12mo)
6
Contractors Awarded (12mo)
2
Median Bidders per Award
-12.7%
YoY Growth

Industry Spending Overview

Federal obligations, top contractors and agencies, and related industry codes for NAICS 331511.

AI Industry Description

NAICS 331511 – Iron Foundries encompasses the production of iron castings through molding and pouring processes, including gray iron, ductile iron, and malleable iron products used in heavy industrial, defense, and infrastructure applications. This sector supports the manufacture of components such ...

NAICS 331511 – Iron Foundries encompasses the production of iron castings through molding and pouring processes, including gray iron, ductile iron, and malleable iron products used in heavy industrial, defense, and infrastructure applications. This sector supports the manufacture of components such as engine blocks, valve bodies, gear housings, structural brackets, and pipe fittings that require high strength, vibration damping, and thermal stability. In government contracting, iron foundries serve as critical suppliers to defense, aerospace, and transportation programs, providing foundational metal parts for military vehicles, naval equipment, and mechanical systems where precision casting and material integrity are non-negotiable. The industry operates at the intersection of metallurgical engineering and advanced manufacturing, often requiring adherence to military specifications (MIL-SPEC) and quality standards such as AS9100 or ISO 9001. No contractor data is available for this NAICS code, indicating limited visibility of prime contractors or subcontractors in the current federal award database. The competitive landscape likely includes a mix of small businesses with specialized casting capabilities and larger industrial manufacturers with vertically integrated foundry operations, though no dominant players are currently identifiable from procurement records. No agency data is available, suggesting that while iron foundries support mission-critical defense and logistics systems, their contracts may be embedded within broader procurement vehicles or awarded under indirect supply chain mechanisms rather than as standalone line items. The market context reflects low visibility in public award data, which may indicate that demand is fulfilled through long-term supplier agreements, indirect sourcing, or classified programs. Opportunities exist for certified small businesses with NADCAP or AS9100 accreditation seeking to enter the defense industrial base, particularly those capable of producing complex, high-integrity iron castings under strict quality control protocols.

Small Business Size Standard

The SBA threshold that decides who can bid NAICS 331511 work as a small business.

1,000 employees
Applies to the whole industry code

The SBA cap for this NAICS (13 CFR 121.201). A business at or under it can self-certify as small for work in this code, which is what makes it eligible for a small-business set-aside. The cap is set per NAICS, so the same company can be small in one code and not in another.

13 CFR 121.201, effective January 1, 2026. The SBA revises the table roughly once a year.

Top Contractors

Companies with the highest total award value under NAICS 331511, ranked by dollars won.

Ranked by total awards

Top Agencies

Federal agencies directing the most contract spending toward NAICS 331511.

Competition

How many companies historically bid on federal awards in NAICS 331511, from bidder counts reported on USAspending.

Fewer Bidders

Median under 3 bidders per reported award. · 805 reported awards

Median Bidders

2

Per reported award, all-time

Single-Bid Awards

40%

Share of reported awards with one bidder

10+ Bidder Awards

5%

Share of reported awards with 10+ bidders

Reported Awards

805

95% of 848 total awards

Bidder Count Distribution by Fiscal Year

Share of reported awards in each bidder-count bracket per federal fiscal year.

How this code compares up the NAICS hierarchy. Parent cohorts pool every code under their prefix, so they are the steadier baseline when a 6-digit sample is thin.

Industry FamilyCompetitionMedian BiddersSingle-BidBidder MixReported Awards
331511This Code
Iron Foundries
Fewer Bidders240%
80595% of 848
33151NAICS Industry
Fewer Bidders239%
3,03394% of 3,227
3315Industry Group
Foundries
Moderate Competition336%
8,13587% of 9,399
331Subsector
Moderate Competition325%
208,26883% of 251,042
33Sector
Manufacturing
Fewer Bidders244%
16,883,00469% of 24,369,785

Bidder counts reported on past federal awards in this NAICS (USAspending). An open opportunity has no bidders yet, so this is the historical norm for similar work, not a fact about this solicitation. Not all awards report bidder counts, and fewer bidders often means incumbent-held work rather than an easier win. Federal reporting of bidder counts fell from ~96% of awards (FY2016) to ~30% (FY2018 onward); the chart shows shares of reported awards, and washed-out stretches mark years with fewer than 30 of them.

Related NAICS Codes

Industries similar to Iron Foundries, by shared sector, subsector, and industry group.

Explore contracts across multiple NAICS codes Browse all NAICS Codes

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NAICS 331511 FAQ

Frequently Asked Questions

NAICS code 331511 covers Iron Foundries. This U.S. industry comprises establishments primarily engaged in pouring molten pig iron or iron alloys into molds to manufacture castings (e.g., cast iron manhole covers, cast iron pipe, cast iron skillets). Establishments in this industry purchase iron made in other establishments. Cross-References.

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