ASTM B88 UNS C12200 Copper Tubes

ASTM B88 UNS C12200 copper tubes are seamless copper water tubes made from copper alloy UNS C12200, which is a commercially pure copper that has been deoxidized with phosphorus, leaving a relatively high residual phosphorus content. It is not susceptible to hydrogen embrittlement, but is of relatively low electrical conductivity due to the amount of phosphorus present. UNS C12200 is the most commonly used copper grade for plumbing and water service. As specified by ASTM B88, UNS C12200 copper tubes can be classified as Type K, Type L, and Type M depending on the wall thickness of the tubing. Metalin Tech supplies a wide variety of ASTM B88 C12200 copper tubes that can be used with solder, flared, or compression-type fittings in various tempers.

Chemical Composition Requirements

ASTM B88 C12200 Type L seamless copper tubes for plumbing in straight lengths.

ASTM B88 UNS C12200 shall have the copper content no less than 99.90% and the phosphorus content between 0.015% and 0.040%. Phosphorus is added primarily for its deoxidizing properties, which effectively remove oxygen, reducing the risk of hydrogen embrittlement and enhancing durability. It also improves the alloy’s workability, making it easier to bend, form, and weld, while maintaining good electrical conductivity and enhancing soldering and brazing characteristics.

International Equivalent

There are several international equivalent grades for ASTM B88 UNS C12200 copper tubes: GB/T 18033 grade TP2; DIN/EN 1057 grade CW024A; ISO/Italy/France/UK: Cu-DHP; JIS H3300 grade C1220; India Standard grade C1220; BS EN 12449 grade CW024A; AS 1432 C12200; NZS 3501 C12200.

Manufacture Processes

The cold drawing of ASTM B88 C12200 copper tubes.

ASTM B88 C12200 copper tubes for plumbing shall be manufactured by the seamless process involving hot working and cold working. They may be furnished in soft (annealed) or hard (drawn) condition with temper designation O50, O60, or H58.

• The high-purity electrolytic copper plates are used as the raw material. The copper plates are melted and cast into cylindrical hollow billets of suitable size, which will be used in the subsequent extrusion process.
• Before extrusion, the copper billets are reheated above the recrystallization temperature to ensure sufficient plasticity and flowability during the extrusion process.
• The preheated copper hollow billet is loaded into the extrusion container. In extrusion, the die is located at one end of the container section of an extrusion press; the hollow billet to be extruded is driven through the die by a ram, which enters the container from the end opposite the die. The shape of the die determines the final cross-section of the copper tube shell. The extrusion process is typically carried out under pressures ranging from 1,000 to 6,000 tons.
• Multiple passes of cold drawing of the extruded tube shell shall be done to get smaller diameter and thinner wall thickness, in which the tube shell is pulled through a die that reduces the diameter and wall thickness concurrently.
• The drawn copper tubes may be annealed. They are subsequently cut into straight lengths or wound onto a spool.

Physical Properties

UNS C12200 coiled copper water tubes in the workshop.

The main physical properties of ASTM B88 UNS C12200 include: Density: 8.94 g/cm³; Melting point: 1083℃[1981℉]; Coefficient of thermal expansion (10^-6/°C at 20-300°C): 17.7; Thermal conductivity (W/m*K, at 20 °C): 339; Electrical conductivity (%IACS, at 20 °C): 85; Specific heat (cal/g*°C, at 20°C): 0.092.