What Is TP1 (C12000) Copper?
TP1 is a phosphorus-deoxidized copper grade defined in the Chinese standard GB/T 5231. In the Unified Numbering System it is designated UNS C12000. During melting, phosphorus is added to combine with dissolved oxygen and remove it from the liquid metal, so the solid product contains almost no copper oxide. The residual phosphorus is kept low, typically 0.004 to 0.012 percent, which places C12000 in the low-residual-phosphorus group, commonly abbreviated DLP (deoxidized low phosphorus). The designation DHP (deoxidized high phosphorus) belongs to the higher-phosphorus grade C12200, which is the UNS counterpart of the Chinese grade TP2.
Because the oxygen content is effectively removed, TP1/C12000 tubing can be welded, brazed, and soldered without the internal cracking that affects oxygen-bearing copper when it is heated in a reducing atmosphere. This makes it a first-choice material for refrigeration circuits, water tubes, and heat exchanger tubing where sound joints are required.
Chemical Composition
| Element | Content (%) |
|---|---|
| Cu + Ag, min | 99.90 |
| P (residual) | 0.004 - 0.012 |
| Pb, max | 0.005 |
| Sb, max | 0.002 |
| Bi, max | 0.001 |
| Fe, max | 0.005 |
| S, max | 0.005 |
Physical and Mechanical Properties
| Property | Typical Value |
|---|---|
| Density | 8.9 g/cm3 |
| Electrical conductivity | 90 - 95% IACS |
| Thermal conductivity | About 350 W/(m.K) |
| Melting point | About 1083 C |
| Elastic modulus | About 132 GPa |
| Tensile strength, hard drawn (Y) | 275 MPa min |
| Tensile strength, annealed (M) | 200 MPa min |
| Elongation, annealed | 40% min |
The residual phosphorus lowers conductivity slightly compared with pure oxygen-free copper, which typically reaches 100 to 101% IACS. For most tubing, welding, and heat transfer duties the conductivity difference is irrelevant, while the weldability advantage is decisive.
Designation Equivalents
| Standard | Designation |
|---|---|
| China (GB/T 5231) | TP1 |
| UNS / ASTM | C12000 |
| ISO 1337 | Cu-DLP |
| EN 1652 / EN 12449 | Cu-DLP (CW023A) |
| JIS H3300 | C1220 family (phosphorus deoxidized) |
| Germany (DIN 1787) | SF-Cu, DLP type |
A common error is to treat TP1 as equivalent to oxygen-free electronic copper. The correct map is: TP1 (GB) to C12000/DLP, and TP2 (GB) to C12200/DHP. Oxygen-free grades such as TU1/TU2 (GB) or C10100/C10200 (UNS) are a separate family produced without a deoxidizer, specified only when maximum conductivity or ultra-low oxygen is mandatory.
TP1 vs. TU2: Which One to Choose
| Feature | TP1 (C12000, DLP) | TU2 (C10200, OF) |
|---|---|---|
| Oxygen content | Removed by phosphorus deoxidation | Very low, 0.001% max |
| Weldability / brazing | Excellent, no hydrogen-embrittlement risk | Excellent |
| Electrical conductivity | About 90 - 95% IACS | 100 - 101% IACS |
| Typical use | ACR tubes, water tubes, heat exchangers, medical gas lines | Waveguides, magnet coils, vacuum and electronic components |
| Cost | Lower | Higher |
For refrigeration and plumbing tubing, TP1 is the economical and technically sufficient choice. TU2 should be reserved for applications that genuinely need maximum purity and conductivity, such as high-frequency conductors, cryogenic busbars, and vacuum-tube components.
Frequently Asked Questions
Q: Is TP1 the same as C12000?
A: Yes. TP1 is the GB/T 5231 designation and C12000 is the corresponding UNS designation for the same phosphorus-deoxidized, low-residual-phosphorus copper.
Q: Is C12000 a DHP copper?
A: No. C12000 is a DLP grade. The DHP grade is C12200, which corresponds to the Chinese grade TP2.
Q: Which tempers are commonly supplied for TP1 tubes?
A: Common tempers are annealed (soft, for bending and flaring), light drawn, and hard drawn. Annealed material offers maximum formability; drawn material provides higher strength for self-supporting lines.
Q: How does the phosphorus affect conductivity?
A: The low residual phosphorus reduces conductivity to roughly 90 to 95% IACS compared with about 100 to 101% IACS for oxygen-free copper. For tube and fitting applications the difference has negligible effect on performance.
Q: Can TP1 tubes be brazed in a hydrogen furnace?
A: Yes. Because the oxygen has been removed by deoxidation, TP1 is not subject to hydrogen embrittlement, so brazing or annealing in reducing atmospheres is safe.
Q: What standards cover TP1/C12000 tubing?
A: Common tubing standards are ASTM B75 (seamless tube), ASTM B88 (water tube), and ASTM B280 (air-conditioning and refrigeration tube); GB/T 1527 covers Chinese drawn tubes.
