<P> Robotic oxy - fuel cutters sometimes use a high - speed divergent nozzle . This uses an oxygen jet that opens slightly along its passage . This allows the compressed oxygen to expand as it leaves, forming a high - velocity jet that spreads less than a parallel - bore nozzle, allowing a cleaner cut . These are not used for cutting by hand since they need very accurate positioning above the work . Their ability to produce almost any shape from large steel plates gives them a secure future in shipbuilding and in many other industries . </P> <P> Oxy - propane torches are usually used for cutting up scrap to save money, as LPG is far cheaper joule for joule than acetylene, although propane does not produce acetylene's very neat cut profile . Propane also finds a place in production, for cutting very large sections . </P> <P> Oxy - acetylene can cut only low - to medium - carbon steels and wrought iron . High - carbon steels are difficult to cut because the melting point of the slag is closer to the melting point of the parent metal, so that the slag from the cutting action does not eject as sparks but rather mixes with the clean melt near the cut . This keeps the oxygen from reaching the clean metal and burning it . In the case of cast iron, graphite between the grains and the shape of the grains themselves interfere with the cutting action of the torch . Stainless steels cannot be cut either because the material does not burn readily . </P> <P> Oxyacetylene welding / cutting is not difficult, but there are a good number of subtle safety points that should be learned such as: </P>

Can you cut cast iron with oxy acetylene