brass
Enable an AI agent to recognise brass, assess its material condition and suitability, and determine which uses, treatments or recovery routes are supported by evidence.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise brass, assess its material condition and suitability, and determine which uses, treatments or recovery routes are supported by evidence.
Brass is a copper-base alloy in which zinc is the principal alloying addition (typically about 5-45 wt%), optionally with lead, tin, aluminium, silicon, arsenic or other elements, forming α, α+β (duplex) or more complex phases that set colour, formability, machinability and corrosion behaviour.
It can be Identify and segregate brass using composition, grade and lot evidence.; Select forming, machining or joining candidates consistent with verified alloy and condition.; Inspect for dezincification, cracking and metal loss before accepting continued service.; Assess a proposed contact environment against grade-specific compatibility evidence.; Select cleaning or surface restoration methods after identifying coatings and degradation.; Route stock or scrap to reuse or recycling according to chemistry, contamination and traceability..
Distinguishing features
Use representative composition evidence to establish a copper-based alloy in which zinc is the principal alloying addition; colour or a trade name alone does not establish brass.
Distinguish solid brass from brass-plated substrates by checking whether surface observations represent the underlying material.
Distinguish brass from tin bronze and other copper alloys using composition and the applicable designation system, allowing for misleading commercial names.
Distinguish brass from gold-coloured coatings or other yellow metals through material analysis rather than appearance alone.
Distinguish grades of brass through measured chemistry and documented condition, since visually similar pieces can have different processing and service limits.
Scope
+ Evidence identifying the material as brass and establishing its grade or composition
+ Alloy additions, impurities and compositional variation within an item or lot
+ Product form, processing history and metallurgical condition
+ Corrosion, cracking, surface treatments and remaining material integrity
+ Suitability for specified fabrication, service and material recovery actions
- Complete assemblies, mechanisms and geometries of objects made from brass
- Copper, bronze and other neighbouring alloy families as independent materials
- Musical instruments and the orchestral meaning of brass
- Design and operation of casting, machining or joining equipment
- Complete fluid systems, electrical installations and their operating requirements
Characteristics
- Copper and zinc composition
- Mass percent of copper and zinc, with method, sampling location and uncertainty Supports brass identification and interpretation of grade, structure and behaviour.
- Additional elements and impurities
- Mass percent or detection limits for relevant elements, including lead, tin, arsenic, aluminium, silicon, iron and nickel Can affect machining, corrosion, joining, exposure constraints and recycling compatibility.
- Grade designation
- Designation plus standard and edition; claimed, verified or unknown Connects a material identity to requirements without assuming different naming systems are interchangeable.
- Represented material lot
- Links between the item, heat or lot, supplier certificate, sample and test report Determines whether composition and property evidence actually applies to the material being assessed.
- Product form and processing route
- Cast, wrought or unknown; sheet, strip, tube, bar, forging, casting, chips or mixed scrap Changes which defects, property evidence and fabrication routes require attention.
- Temper and working history
- Recorded temper designation, annealed or cold-worked condition, treatment history, or unknown Supports judgments about strength, ductility, forming and residual stress.
- Observed microstructure
- Documented phase constituents, grain features and inclusions, with examination method; unknown if unexamined Helps explain behaviour that composition or appearance alone cannot establish.
- Mechanical condition
- Hardness with scale, strength in MPa, elongation in percent, each with test conditions Provides evidence for forming and load-related decisions in the recorded condition.
- Surface and substrate relationship
- Bare brass, coated brass, brass plating on another material, or unresolved Controls interpretation of identification tests, corrosion observations and treatment options.
- Degradation condition
- Observed tarnish, metal loss, suspected or confirmed dezincification, cracking, or no detected damage within inspection limits Separates cosmetic change from possible loss of material integrity.
- Service exposure
- Links to contacting media, temperature history, stress conditions and electrically contacting metals Makes corrosion and compatibility judgments specific to the intended environment.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.brass-artifact
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Alloy identity Establishes whether the material is brass and how precisely its alloy identity is known.
Brass appearance and commercial naming cannot establish composition or distinguish a solid alloy from a plated object.
Composition and family
Connects representative chemistry to the brass classification.
Copper-zinc basis
Record evidence supporting a copper-zinc alloy identity, including additions and unresolved classification boundaries.
- What measured composition supports identifying this material as brass rather than another copper alloy? measurement
- Which designation system resolves the alloy family if its commercial name or additional elements make classification ambiguous? boundary
Surface versus bulk
Determines whether brass identification applies to a surface layer or the underlying material.
Representative identification
Record how coatings, plating, tarnish or selective corrosion affect the representativeness of identification evidence.
- Does the brass identification describe the bulk material, a plated layer or only the tested surface? boundary
- What examination or sampling evidence distinguishes the surface composition from the underlying alloy? measurement
Grade and metallurgical condition Connects brass chemistry and processing history to its present material condition.
A brass grade alone does not establish the properties of a cast, annealed or cold-worked piece.
Grade and lot evidence
Defines the reach and reliability of grade claims.
Traceable grade claim
Record the claimed grade, its governing specification and the evidence linking it to this item or lot.
- Which brass designation, standard and edition are claimed, and which certificate or test supports that claim? provenance
- How is the assessed piece linked to the heat, lot or sample represented by that evidence? provenance
Processing and properties
Captures the effects of production, working and thermal history on present behaviour.
Present metallurgical state
Record product route, temper and available property or microstructure evidence without inferring them from colour or grade alone.
- What casting, cold-working, annealing or subsequent heating history establishes the present condition? provenance
- Which hardness, strength, ductility or microstructure observations verify the condition needed for the proposed action? measurement
Corrosion and integrity Distinguishes surface appearance from degradation that affects brass integrity.
Brass assessment must account for selective zinc loss and environment-associated cracking as well as ordinary surface change.
Selective corrosion
Examines suspected dezincification and remaining sound material.
Dezincification evidence
Record observations and tests that distinguish superficial discolouration from selective zinc loss and porous material.
- What evidence distinguishes tarnish or deposited material from suspected or confirmed dezincification? measurement
- How far does affected material extend, and what sound section remains within the limits of the inspection? measurement
Cracking and exposure
Relates cracking observations to stress and environmental history.
Stress-corrosion assessment
Record crack evidence, residual or applied stress and relevant chemical exposure, including ammonia-bearing environments where applicable.
- What cracking has been detected, by which method, and with what inspection coverage? measurement
- What stress and exposure history supports investigating stress-corrosion cracking rather than assigning a cause from appearance alone? provenance
Fabrication and treatment Bounds processing and restoration actions using the actual brass alloy and condition.
Brasses differ in forming, machining and joining behaviour, and processing can change their condition or surface chemistry.
Forming and machining
Assesses candidate operations against grade, temper and required final properties.
Operation suitability
Record evidence for proposed deformation or cutting operations, including relevant alloy additions and condition changes.
- What grade- and temper-specific evidence supports the proposed bend, draw, forge or machining operation? action
- What post-operation checks are needed to establish acceptable cracking, hardness and ductility? measurement
Joining and surface treatment
Assesses thermal joining, cleaning and finishing against brass chemistry and existing surfaces.
Treatment compatibility
Record an applicable treatment procedure and its implications for zinc, alloy additions, temper and coatings.
- What procedure supports the proposed joining or heating action for this brass, including control of zinc loss and relevant emissions? action
- Which cleaning or finishing method is compatible with the brass, any coating and the observed corrosion condition? action
Service and material disposition Connects verified brass condition to a specified use, reuse decision or recovery route.
A brass identity does not establish suitability for every contact medium, regulated application or recycling stream.
Contact and service qualification
Links material evidence to the requirements of a defined operating environment.
Application-specific acceptance
Record compatibility evidence, applicable material requirements and unresolved limits for the proposed service.
- What evidence supports this brass grade and condition in the specified medium, temperature, stress and contacting-metal combination? boundary
- For a regulated contact use, which applicable requirements and test or certification evidence establish material acceptance? action
Reuse and recovery
Determines whether brass can retain its identity in reuse or enter a defined recovery stream.
Chemistry-aware disposition
Record remaining condition, alloy segregation, attached materials and contamination relevant to reuse or recycling.
- What evidence supports reuse while preserving knowledge of the brass grade, condition and previous exposure? action
- Which alloy additions, coatings, attached metals or contaminants determine segregation and acceptance by the intended recycler? boundary
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Alpha (cold-working) brasses, including cartridge brass ~70Cu/30Zn (UNS C26000, EN CW505L)
- Alpha-beta / duplex / hot-working brasses, including Muntz metal ~60/40 (C28000, CW509L)
- Leaded free-cutting and forging brasses (C36000, C37700, EN CW614N / CW617N)
- Low-zinc red and gilding brasses (Zn ≲ 15-20%; C21000-C23000)
- Naval and Admiralty tin brasses (C46400, C44300) used in marine and condenser service
- Aluminium brass (C68700 / CW702R) for seawater heat-exchanger tubes
- Dezincification-resistant and lead-free plumbing brasses (CW602N; silicon Eco Brass CW724R / C69300)
- Cast red, semi-red and yellow brasses (UNS C83300-C85800), including 85-5-5-5 red brass
- Which of these kinds and varieties hold for the sense of brass this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q34095 - Item for brass as the copper-zinc alloy.
- UNS (wrought) - C21000-C28000 (binary Cu-Zn); C31200-C38500 (leaded); C40400-C48600 (tin brasses); also C66400-C69710 - Unified Numbering System families used in North America.
- UNS (cast) - C83300-C84800 (red/semi-red); C85200-C85800 (yellow); C86100-C86800 (manganese bronze / high-strength yellow brass) - Cast brass families; silicon brasses occupy C87300-C87800.
- EN designation - CWnnnL/N/R plus chemical symbol, e.g. CW505L (CuZn30), CW614N (CuZn39Pb3), CW724R (CuZn21Si3P) - European number and symbol pair under EN 1412 / CEN/TS 13388.
- ISO chemical symbol - CuZnx or CuZnxPby[As|Sn|Al|Si…], e.g. CuZn30, CuZn39Pb3, CuZn20Al2As - Composition-based designation used in ISO/EN product standards.
- Legacy national codes - BS CZ106 etc.; JIS C2600; DIN Werkstoff 2.0265; obsolete German MS58 - Still seen on drawings and stock lists; map to EN/UNS rather than treating as current primary IDs.
- Which of these identifiers and schemes hold for the sense of brass this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- CEN/TS 13388 (CEN) - composition compendium for copper and copper alloys, including brass groups A/B/C under EN 1412.
- EN 12164 / EN 12167 / EN 12449 / EN 1652 (CEN) - wrought brass rod, bar, tube and plate product standards.
- ASTM B16, B36, B124, B135 and related ASTM B-series (ASTM International) - US mill-product specifications for brass rod, sheet, forgings and tube.
- ISO/R 426 (ISO, 1965 recommendation) - classification and composition of brasses, leaded brasses, special and high-tensile brasses.
- ISO 15608 group 32 / 32.2 (ISO) - PED material grouping for copper-zinc alloys.
- ISO 6509 (ISO) - laboratory test for dezincification resistance of copper-zinc alloys.
- NSF/ANSI/CAN 61 and NSF/ANSI 372 (NSF International) - drinking-water contact and lead-content criteria; NSF expects DZR performance for fittings with >15% Zn.
- U.S. Safe Drinking Water Act as amended by the Reduction of Lead in Drinking Water Act (U.S. EPA / Congress) - "lead-free" wetted surfaces, 0.25% Pb weighted average (California AB 1953 aligned).
- EU Drinking Water Directive (EU) 2020/2184 - tightening lead in water and driving lead-free DZR fittings (with national schemes WRAS, DVGW, ACS, KIWA).
- California Proposition 65 (OEHHA) - lead-exposure warnings that have forced lower-Pb keys and consumer brass hardware.
- Which of these standards and regulation hold for the sense of brass this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Deep-drawn ammunition cartridge cases and similar severe cold-formed parts in C26000.
- Machined plumbing valves, faucets, meter bodies and fittings, now shifting from leaded CW617N/C360 to DZR lead-free grades such as CW724R/C69300.
- Locks, hinges, screws, zippers, hose couplings and low-friction bearings and gears.
- Trumpets, trombones, horns and other brass-instrument tubing, plus harmonica reeds and some percussion.
- Architectural hardware and trim (doorknobs, kick plates); trade "architectural bronze" C38500 is a leaded brass.
- Condenser and heat-exchanger tubes in Admiralty (C443) or aluminium brass (C68700) for marine and power-plant water.
- Electrical terminals, connectors, lamp caps, waveguides and non-sparking tools near flammable atmospheres.
- Recycled as a non-ferromagnetic copper-alloy scrap stream (industry claims a very high recycle fraction).
- Which of these real-world use hold for the sense of brass this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Zinc content (commercial brasses) - 5-45 - wt%
- Density - 8.4-8.73 - g/cm³
- Melting / liquidus range (composition-dependent) - 900-940 - °C
- Tensile strength (wrought binary brasses, annealed to hard) - 240-630 - MPa
- Electrical conductivity (low-zinc alpha brasses CuZn5-CuZn15) - 37-56 - % IACS
- Lead in free-cutting grades (legacy) - 1-4.5 - wt% Pb
- Lead in current potable-water "lead-free" brass - ≤0.10 (EU market practice) to ≤0.25 weighted average (US) - wt% Pb
- Dezincification susceptibility threshold (uninhibited) - risk rises above ~15 - wt% Zn
- Which of these typical measurements hold for the sense of brass this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Dezincification: selective leaching of zinc in aggressive or soft, high-sulphate waters, leaving a weak porous copper sponge and causing leaks in fittings and tubes.
- Season cracking: ammonia-induced stress-corrosion cracking of residual-stressed cold-worked brass (classic cartridge-case failures).
- Lead leaching from free-cutting grades into drinking water and from handled objects (keys) above Proposition 65 limits.
- Galvanic attack of brass when coupled to more noble metals (gold, silver, some stainless) in an electrolyte; brass itself can drive corrosion of zinc or steel.
- Surface sulphide tarnish and, in urban rain, green-blue carbonate patina that may or may not be protective.
- Unmodified yellow brass is a poor choice in seawater; zinc is leached unless tin, aluminium and/or arsenic (naval, Admiralty, aluminium brass, DZR) are present.
- Even labelled DZR fittings can dezincify after long service in very aggressive water if microstructure, iron contamination or inhibitor levels are off.
- Which of these failure modes and hazards hold for the sense of brass this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- North America names mill products by UNS Cxxxxx and trade names (cartridge brass, free-cutting C360); Europe uses EN CW numbers and CuZn chemical symbols; the UK still quotes old BS CZ codes on older drawings.
- "Red brass" is ambiguous: wrought C23000 is ~85Cu/15Zn, while cast C83600 "red brass" is 85-5-5-5 Cu-Sn-Pb-Zn.
- German trade name MS58 (CuZn39Pb3) is obsolete in the standard but still used colloquially; Kupferverband notes the grade as specified in DIN 17660:1954 no longer exists as such.
- US architectural-trade "bronze" (C38500 architectural bronze) and "manganese bronze" / "commercial bronze" (C22000, 90/10) are brasses, not bronzes.
- Museums increasingly catalogue historical objects as "copper alloy" because brass/bronze labelling was inconsistent; West African "Benin bronzes" and Ife heads are often leaded zinc-brass.
- Potable-water alloy choice splits by market: EU/UK/Australia lean on intrinsically DZR silicon brass CW724R; US/Canada also use bismuth-bearing lead-free grades such as C6802 alongside NSF 61 listing.
- Which of these regional variation hold for the sense of brass this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Bronze (tin bronze) - Principal addition is tin, not zinc. Separate by bulk chemistry (XRF/OES): high Sn and low Zn indicates bronze; high Zn and little Sn indicates brass. Historical names overlap.
- Nickel silver (German silver) - Cu-Ni-Zn alloy, silvery white. Detect nickel (typically ~10-20% Ni); binary brass contains no intentional Ni and is yellow to red-gold.
- Copper - Commercially pure copper has ≳99% Cu, redder colour and much higher conductivity; brass shows several percent zinc by analysis.
- Aluminium bronze - Principal addition is aluminium (not zinc). Check Al vs Zn; aluminium bronze is stronger and usually a duller gold, and is grouped in UNS C6xxxx aluminium-bronze ranges.
- Gunmetal / ounce metal - High-tin red alloys (~88Cu-8-10Sn-2-4Zn, or 85-5-5-5). Tin is a major constituent, not a ~1% inhibitor; colour is redder than yellow brass.
- Architectural bronze (trade) and manganese bronze - Both are brasses (leaded Cu-Zn or high-strength Cu-Zn-Mn-Fe-Al). Do not treat the word "bronze" as diagnostic; read the UNS/EN number and Zn as the major addition.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of brass this model covers, and on what evidence? provenance
Sources
- Brass - Definition as a Cu-Zn substitutional alloy; melting range and density; uses; leaded-brass leaching and California plumbing limits; DZR, naval and red brasses; season cracking; α/α+β/β classification and named commercial alloys; historical brass/bronze naming confusion.
- List of copper alloys - UNS family ranges for brasses versus bronzes, cupronickel and nickel silver; wrought cartridge, yellow and naval brass compositions; dezincification as selective leaching of zinc.
- Copper-zinc alloys (brass) - Usable zinc window of about 5-45%; EN/DIN grouping of wrought brasses (binary, leaded, multi-alloy) under CEN/TS 13388 and EN 1412; German trade name MS58 as an obsolete leaded-brass grade.
- Composition of Common Brass Alloys - Crosswalk of common names to UNS/ISO/EN/JIS designations and Cu/Zn/Pb ranges (gilding metal through free-cutting brass); red-brass Zn ≲ 15% rule of thumb; tin in naval brass against dezincification.
- Preventing and Treating the Dezincification of Brass - CCI Notes 9/13 - α versus duplex microstructure by zinc content; susceptibility above ~15 wt% Zn; porous copper remnant and plumbing leaks; admiralty brass as tin-bearing cartridge brass.
- Dezincification: Breaking the 15-Percent Zinc Wall - European DZR alloy CZ132/CW602N; US lead-free plumbing shift after 2014; As/Sb/P inhibitors and thermal processing as DZR tools.
- Wrought Copper-zinc and Copper-tin Binary Alloys - Compositions, Properties, Standards and Uses - EN symbols CW500L-CW503L (CuZn5-CuZn20), old BS CZ equivalents, tensile/proof ranges, %IACS conductivity and typical uses of binary brasses.
- ISO Recommendation R 426: Classification of brasses, leaded brasses, special brasses and high tensile brasses (1965) - ISO chemical designations CuZn10-CuZn40 and leaded/special grades with composition windows for wrought products.
What the second pass must settle
- Does this registry entry own brass material only, or also brass stock and scrap categories that need explicit links to neighbouring models?
- Which designation systems and composition boundaries should resolve commercial names and complex copper-zinc alloys consistently?
- What identification and sampling evidence is sufficient for each decision when plating, surface zinc depletion or mixed scrap may misrepresent bulk composition?
- Which grade- and condition-specific sources establish fabrication limits and corrosion suitability for the intended applications?
- Which inspection criteria and jurisdiction-specific contact requirements must be researched before accepting damaged or compositionally uncertain brass for service?