What Is C12200
C12200 DHP copper, also written C122, is commercially pure copper that has been deoxidized with phosphorus, leaving a relatively high residual phosphorus content of 0.015 to 0.040 percent. Copper alloy 122 is not susceptible to hydrogen embrittlement, which is one of its key advantages over non-deoxidized coppers such as C11000 ETP copper, because the phosphorus ties up oxygen and prevents hydrogen from reacting with copper oxides to form steam and cause cracking.
Chemical Composition
The composition is copper 99.9 percent minimum with phosphorus 0.015 to 0.040 percent. The relatively high phosphorus content gives the alloy its excellent weldability and brazability, at the cost of a somewhat lower electrical conductivity of about 85 to 90 percent IACS.
Fabrication Properties
Soldering, brazing, and gas shielded arc welding are rated excellent for C12200, with butt welding and oxyacetylene welding rated good. Coated metal arc welding, spot welding, and seam welding are not recommended. The capacity for cold working and hot forming is excellent, with a forgeability rating of 65 and machinability rating of 20 percent of free-cutting brass.
Mechanical Properties
In the annealed condition, tensile strength is about 220 MPa with elongation of 45 to 50 percent. Half-hard temper provides about 270 MPa, and hard tempers up to 380 MPa, with corresponding reductions in elongation. Mechanical properties vary by form, temper, and section size.
Applications
C12200 is used for distiller and brewery tubes, heat exchanger shells, expansion joint tubes, kettles, condenser tubes, medical gas-oxygen lines, and gaskets. It is the standard material for plumbing water tubes, HVAC refrigerant lines, and brazed assemblies, supplied as sheet, plate, pipe, tube, and fittings under ASTM B42, B68, B75, B88, B111, B152, and B280.
Frequently Asked Questions
Q: What does DHP stand for?
A: Deoxidized high phosphorus, with 0.015 to 0.040 percent phosphorus.
Q: Is C12200 susceptible to hydrogen embrittlement?
A: No, the phosphorus ties up oxygen and prevents cracking.
Q: What is the electrical conductivity of C12200?
A: About 85 to 90 percent IACS.
Q: What welding methods are suitable?
A: Soldering, brazing, and gas shielded arc welding are excellent.
Q: What forms are available?
A: Sheet, plate, pipe, tube, and fittings.
Q: What applications use C12200?
A: Condenser tubes, medical gas lines, heat exchangers, and gaskets.
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