I. Definition and Classification
C12200 phosphorus deoxidation copper bar is a kind of copper alloy bar through the phosphorus (P) deoxidation treatment, belongs to the high-purity processing of copper, mainly used in the field of corrosion resistance, weldability and processability of the requirements of high. Its naming follows the American ASTM standard system:
C: represents copper and copper alloys;
12: identifies a specific alloy group;
200: subdivided grade code.
In the Chinese standard, C12200 corresponds to the grade TP2 phosphorus deoxidized copper (GB/T 5231-2012). Characterized by residual trace phosphorus, this material combines the electrical conductivity of pure copper with the corrosion resistance of deoxidized copper, and is widely used in the refrigeration, construction and marine industries.
Second, chemical composition and physical properties
Typical chemical composition (ASTM B152/B152M)
Copper (Cu): ≥99.9% (to ensure high purity)
Phosphorus (P): 0.015%-0.040% (deoxidizer, inhibit hydrogen embrittlement and oxidation);
Total impurities (Fe, Pb, S, etc.): ≤0.1% (strictly controlled to ensure performance).
Physical properties
Density: 8.94 g/cm³ (close to pure copper);
Melting point: 1083°C (consistent with pure copper);
Conductivity: ≥85% IACS (slightly lower than oxygen-free copper C10200);
Thermal conductivity: 380 W/(m-K) (excellent heat dissipation).
Mechanical properties (soft state/hard state)
Tensile strength: 200-360 MPa (increases with cold work hardening)
Yield strength: 60-330 MPa;
Elongation: ≥45% (soft state) or ≥10% (hard state);
Hardness: HV 40-100 (can be machined to higher hardness).
III. Production process
Melting and deoxidizing
Electrolytic copper raw material is melted by medium frequency furnace, add phosphorus copper intermediate alloy to deoxidize (reaction formula: 5Cu₂O + 2P → 10Cu + P₂O₅↑);
Strictly control the phosphorus content to avoid excess leading to a decrease in electrical conductivity.
Casting and molding
Continuous casting: the melt is cast into ingots, which are homogenized and annealed to eliminate segregation;
Extrusion/hot rolling: extruded or rolled into bar billets after heating to 800-900°C;
Cold working: adjust the size by cold drawing or cold rolling, with intermediate annealing (450-650 ℃) to restore plasticity.
Surface treatment
Pickling (sulfuric acid-nitric acid mixture) to remove oxidized layer;
Polishing or plating (e.g. tin plating, nickel plating) to enhance corrosion resistance.
IV. Core Characteristics and Advantages
Corrosion resistance
Phosphorus inhibits dezincification corrosion, suitable for fresh water, steam and non-oxidizing acid environments;
Stress Corrosion Cracking (SCC) resistance is superior to ordinary pure copper.
Solderability and processability
Excellent welding performance (brazing, TIG welding, gas welding are available);
Soft state bars can be cold bent and stamped, hard state is suitable for precision turning processing.
Hygienic safety
Lead-free, non-toxic, meets drinking water pipe standards (e.g. NSF/ANSI 61);
Smooth surface, inhibit bacterial growth.
V. Application Areas
Refrigeration and HVAC
Air conditioner/refrigerator refrigeration lines, condenser U-tubes;
Heat exchanger heat transfer tubes, valve spools.
Building and Municipal
Building water supply and drainage pipes, gas transmission pipes;
Floor heating manifolds, bathroom hardware.
Ship and Marine Engineering
Seawater piping system fittings, ship condenser tube;
Fresh water transportation pipes for marine platforms.
Electrical and Electronic
Conductive terminals, connectors;
High precision instrumentation components.
VI. Precautions
Processing and use
Timely annealing is required after cold working to avoid cracking caused by residual stress;
Avoid long-term use in a strong corrosive environment containing ammonia and hydrogen sulfide.
Storage and protection
The bars should be sealed and packed to prevent oxidation and discoloration;
It is recommended that the surface be tinned or coated with a protective layer when exposed to humidity for a long period of time.
Alternative Material Selection
For higher conductivity: Oxygen-free copper C10200 (but at a higher cost);
If higher strength is needed: choose aluminum bronze C95400 (but slightly lower corrosion resistance).
VII. Relevant standards (reference)
International: ASTM B152/B152M "copper and copper alloy sheet, strip, plate and rolled bar standard;
China: GB/T 5231-2012 "Processing copper and copper alloy grades and chemical composition";
Industry norms: EN 1057 "Copper and copper alloys - Seamless round copper tubes for medical gas systems".
