|
|
Oxygen Lance Cutting - It is an oxygen cutting process where in the severing or removal of metals is effected by oxygen supplied through a consumable lance and the preheat is obtained by other means.Oxygen lance is a length of steel pipe (3 to 6 mm internal diameter) used to convey oxygen to the point of cutting.
Purpose of Lance Cutting
It is used to cut heavy thick sections which are not possible to be cut by oxy acetylene flame cutting described earlier.
Whereas an oxy acetylene torch can cut steel thickness up to 60 cm, the oxygen lance cutting can cut steel up to 240 cm.
|
|
Equipment Required
(i) Oxy acetylene welding or cutting torch, which preferably is special long to preheat deeper into the thickness of the metal to be cut.
(ii) Oxygen and acetylene cylinders.
(iii) Heavy duty pressure regulators and hoses.
(iv)Safety equipments such as goggles, gloves, apron, etc. because considerable sparking accompanies the cutting operation.
(v) A lance, i.e., a long piece of low alloy steel tubing, 3 to 6 mm internal diameter to carry oxygen to the desired depth of the metal to be cut. The tubing or pipe should have a length allowance because it consumes, as the cutting progresses, owing to very high temperatures involved in oxygen lance cutting.
|
|
|
Principle of operation
(i) Preheat the edge of the piece (to be cut) with a heavy duty welding or cutting torch to a cherry red colour.
(ii) Bring the oxygen lance against this preheated section and release oxygen (at approximately 40 to 50 psi pressure) through the pipe.
The oxygen in combination with the preheated steel results in rapid oxidation of the surface. The oxygen jet blows the reaction products there by cutting the metal section.
When cutting comparatively lighter sections, the preheating torch is removed, once the oxygen for the lance is turned on.
When cutting extremely thick sections, preheating temperature is maintained continuously using a special, long torch during cutting. The cut is generally started at an angle and brought to a vertical position by
manipulating the lance and of course the torch if used continuously.
|
During cutting, as the lance reaches the bottom of the metal in the depth direction, it is brought back (or raised) to the top and again lowered doing cutting, each time making an advance so that the job can be cut along the line of cut previously marked on the job.
Advantages
(i) Oxygen lance cutting can cut heavy thick steel sections which cannot be done so by oxy fuel gas cutting.
(ii) It economically cuts large steel and cast iron sections.
Applications
(i) Oxygen lance cutting can cut steels having thickness up to 240 cm.
(ii) It is an excellent tool for piercing holes in steel plates and castings.
(iii) It is routinely used in tapping blast and open hearth steel furnaces.
|
|
|
