Brasses are copper zinc alloys with a wide range of engineering uses. The addition of zinc to copper raises the strength and gives a range of properties, and the brasses are a very versatile range of materials. They are used for their strength, corrosion resistance, appearance and colour, and ease of working and joining. The single phase alpha brasses, containing up to about 37% zinc, are very ductile and easy to cold work, weld and braze. The dual phase alpha-beta brasses are usually hot worked.