CNC-machined Copper C122 (DHP copper) is a phosphorus-deoxidized copper that welds and brazes well and resists hydrogen embrittlement, with lower conductivity than C110.
C122 (Cu-DHP) is at least 99.9% copper deoxidized with 0.015–0.040% phosphorus, which makes it resistant to hydrogen embrittlement and gives it excellent soldering, brazing, and gas-shielded arc welding behavior. The trade-off is lower conductivity than C110, and it machines poorly. Annealed it is soft and very ductile.
Copper C122 is well suited to plumbing and heat-exchanger components, fittings, and brazed or welded copper assemblies.