High-phosphorus deoxidized copper DHPC12200 (ASTM C12200, Chinese brand TP2) is a special pure copper produced by adding trace amounts of phosphorus (P) as a deoxidizer. Its core characteristic is the precise control of the residual phosphorus content within a range of 0.015% to 0.040%. During the smelting process, phosphorus reacts violently with oxygen in the copper melt, producing phosphorus pentoxide (P₂O₅) gas, which is then expelled. This achieves deep deoxidation (oxygen content is typically ≤0.01%), completely eliminating the risk of hydrogen disease associated with conventional electrolytic copper (ETP). DHPC12200 offers excellent brazing and weldability (especially suitable for gas welding and brazing), excellent cold bend formability (in a soft state), extremely high air and water tightness, and good corrosion resistance (especially in aqueous environments). It is the material of choice for manufacturing critical components such as refrigeration piping, heat exchangers, and water supply systems, which require leak-tight seals, excellent processability, and reliable corrosion resistance.
Production Process
The core of ASTM B111 DHPC12200 lies in phosphorus deoxidation. The process:
Raw Materials and Melting: High-purity cathode copper is used. Melting is performed in an induction furnace or reverberatory furnace.
Deoxidation: The most critical step! A phosphorus-copper master alloy (such as Cu-15%P) is added to the molten copper. Phosphorus (P) reacts with dissolved oxygen (O): 4P + 5O₂ → 2P₂O₅ (g) or 4[P] + 5[O] → 2P₂O₅ (g). This process achieves deep deoxidation and precisely controls residual phosphorus to 0.015%-0.040%.
Casting:
Semi-continuous casting (DC Casting): Casting into large ingots (square or round). Horizontal continuous casting (Continuous Casting): Directly produces tubes, bars, or slabs, offering high efficiency and relatively uniform microstructure.
Upcasting: Produces bright copper rods and bars.
Hot working: After heating the ingot, hot extrusion (for tubes and bars) or hot rolling (for plates and strip) is performed.
Cold working: Multiple passes of cold rolling (for plates and strip) and cold drawing (for tubes, bars, and wire) are used to achieve the desired size, shape, and condition (e.g., hard, semi-hard). The amount of deformation is strictly controlled to achieve the target properties.
Annealing (Soft Products): For soft (O) products or intermediate annealing during cold working, annealing is performed in a protective atmosphere (e.g., nitrogen, decomposed ammonia) or in a vacuum to eliminate work hardening and restore plasticity and conductivity. Finishing and Testing: Straightening, cutting, cleaning, eddy current testing/hydrostatic testing (for pipes), surface inspection, and rigorous testing for chemical composition, mechanical properties, flaring/flattening testing (for pipes), and airtightness/watertightness.
Material Characteristics
No Risk of Hydrogen Failure: Deep deoxidation (oxygen ≤ 0.01%) completely eliminates the possibility of embrittlement and cracking (hydrogen failure) during high-temperature use in reducing atmospheres (such as those containing hydrogen), ensuring long-term use and welding reliability.
Excellent Brazeability and Weldability: Ideally suited for flame brazing (brazing), soft soldering (tin soldering), and gas welding, resulting in dense, strong welds with excellent sealing. Also suitable for TIG and MIG welding.
Excellent Airtightness and Watertightness: With its dense structure and absence of internal oxidation defects, it is the preferred material for manufacturing pipes and containers (such as refrigeration systems) where absolute leak-proof properties are essential. Excellent Cold Formability (Soft State): The annealed soft state exhibits excellent plasticity (elongation ≥40%), making it easy to perform cold working operations such as bending, flaring, flanging, and tube expansion, and is resistant to cracking.
Good Corrosion Resistance: Particularly resistant to freshwater, seawater, and steam, its erosion corrosion resistance surpasses that of standard pure copper (ETP). Residual phosphorus contributes to the formation of a more stable and protective surface film.
High Electrical and Thermal Conductivity: Soft state electrical conductivity is ≥90% IACS (International Annealed Copper Standard), providing excellent thermal conductivity.
Good Hot Workability: The addition of phosphorus improves hot working properties and reduces the tendency to hot brittleness.
Material Applications
DHPC12200, with its hydrogen-free properties, high sealing properties, excellent weldability, and corrosion resistance, is primarily used in:
1. Refrigeration and Air Conditioning Industry:
Condenser and evaporator tubes for refrigerators and air conditioners. Refrigerant transport copper pipes (for R22, R410A, R134a, etc.), pipe fittings (elbows, tees), valve bodies, and receiver dryers.
Compressor housings, intake and exhaust pipes.
2. Heat Exchangers:
Building Heating: Radiator (radiator) water pipes.
Industrial and Marine: Condensers, coolers, oil coolers, and heater tubes.
Solar Water Heater: Collector tubes, tank liners, and connecting pipes.
3. Water Supply Systems:
Building hot and cold water supply pipes and fittings (especially for high-rise buildings and direct drinking water systems).
Medical gas pipelines (oxygen, vacuum suction).
4. Pipeline Connectors:
Joints, flanges, and valve assemblies requiring highly reliable brazing seals.
5. Marine and Offshore Engineering:
Ship seawater cooling pipes, heat exchanger tubes, fire water pipes, and domestic water pipes.
Other:
Waveguide tubes and vacuum device pipes requiring high airtightness.
Electrical equipment housings and conductive components requiring hydrogen-free and excellent formability (for applications requiring less stringent conductivity).
High-phosphorus deoxidized copper DHPC12200 (C12200/TP2) is a copper alloy produced through a deep phosphorus deoxidation process (residual P: 0.015%-0.040%). Its core advantage lies in its complete elimination of the "hydrogen-free" risk (oxygen content ≤ 0.01%). It also offers excellent airtightness and watertightness, superior brazing and weldability, excellent cold bend formability (soft state A ≥ 40%), and outstanding corrosion resistance in aqueous environments. These properties make it an ideal material for refrigeration and air conditioning system piping and heat exchanger tubes, building water supply/heating pipes, marine piping systems, and various fluid transport components requiring high-reliability sealing and corrosion resistance. It plays an indispensable role in ensuring safe, reliable, and leak-free operation of these systems.
why choose us
Professional copper pipe supplier
As a professional enterprise dedicated to global copper product trade since 2008, GNEE Metal Group deeply recognizes the quality and responsibility embodied in the ASTM B111 standard. This standard not only specifies chemical composition and mechanical properties but also represents a comprehensive quality commitment spanning manufacturing processes to testing and verification. GNEE solemnly assures global customers that every ASTM B111-standard condenser tube and copper alloy tubing we supply will strictly adhere to its requirements for seamless manufacturing, annealing treatment, eddy current testing, and various mechanical performance tests.
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