The underwater oxygen-flame cutting method is usually suitable for cutting low carbon steel, low alloy steel and other easily oxidized materials, not suitable for cutting stainless steel and non-ferrous metals other than titanium, the most suitable cutting thickness range of 10 ~ 40mm. Cutting thin plates is difficult because they cool much faster in water than thick plates, making it difficult to warm up to the point of ignition. When the thickness of the plate is more than 40mm, although it can be cut, it requires high operation technology.
Although the cut quality of flux - coated electrode is poor, it is widely used. It can cut low carbon steel and low alloy steel as well as stainless steel and non-ferrous metal, especially suitable for cutting thin plates under 6mm. Cutting thick plates is more difficult and requires a jigsaw operation in which the electrode is jiggled back and forth through the cut to remove the molten metal. Molten polar water jet cutting is a pure metal melting process and can be used for cutting ferrous and non-ferrous metals.
Due to the high energy density of plasma arc, the underwater plasma arc cutting method is suitable for cutting all metal materials and some non-metal materials.