Назовите формы и функции инфинитива

1. Some metals have to be melted at very high temperatures. 2. To make non-ferrous castings, such metals as zinc, lead, aluminium and others are melted together. 3. To line pipes and electrical cables such metal as lead is used. 4. One must add some tin to make brasses stronger. 5. Very few objects are made of pure tin, but it used to make bronze, babbit, and other alloy metals. 6. Nickel is used for covering iron and brasses to make them look better. 7. Nickel does not rust and can be polished to a very bright, silvery finish. 8. To increase hardness and strength of cast copper some cold-working operations are performed.