The Thermic Lance
A Thermic Lance is a steel pipe packed with mixed metal wires. Pure oxygen gas is passed through the pipe from an oxygen cylinder and regulator. The end of the pipe is lit with a high temperature source, e.g. an oxy-acetylene torch. The iron in the steel burns in the oxygen coming down the pipe to produce enormous heat. Read More
4 Responses to “The Thermic Lance”
HalfWay Says:
What is a Thermic Lance?
The Thermic Lance is a consumable steel tube, packed with low carbon steel wires. They are usually supplied in three metre lengths with varying diameters. The lance is attached to a ‘lance holder ‘, which is connected to a suitable oxygen hose fitted to a high-pressure oxygen supply.
Thermic lancing is the process of cutting and removing stubborn materials by thermo-chemical reaction. When ignited the lance will burn at intense temperatures and is capable of cutting or boring through almost any material.
Thermic lance boring is a method of boring and severing concrete, steel, cast iron and hard to clean materials without noise or vibration in a fraction of the time taken by conventional methods. It is ideal for demolition work, where noise and vibration are unacceptable, or where speed is essential particularly on reinforced concrete. The equipment is extremely simple and easy to operate, and the capital cost in comparison to drills etc. is negligible. A list of applications is available by clicking on the ‘applications’ button at the top of this page.
The process was developed in France following the Second World War, as a means of assisting the break-up of gun emplacements, submarine pens, and other large concrete structures. Thermic lancing depends on the fact that red-hot steel will oxidize very rapidly in an atmosphere of pure oxygen. When the steel is at red heat, it has reached ignition (oxidation) temperature. A stream of pure oxygen directed at the red-hot area will immediately form a film of iron oxide. The melting point of iron oxide (approx. 800-900 degrees C.) is well below the melting point of steel
(1,400 – 1,500 degrees C.) The velocity of the high-pressure oxygen blows the oxide film away and another film of oxide is instantly formed and blown away. This reaction is exothermic (gives off self generated heat) and will continue as long as red heat and the oxygen stream are present. The intense heat generated at the end of the thermic lance, when applied to a material will quickly burn through it and will also consume the lance. The burning action can be stopped anytime by turning off the oxygen supply.
twistedsteel Says:
Operating Instructions* and Performance Examples
Safety Gear
The operator should wear heat protective safety apparel, gloves, and a welder’s mask (preferably with the 4 1/2″ x 5 1/4″ No. 5 or No. 6 shade). When piercing concrete, rock, or refractory material, wear protective coat and pants. Safety rules must be followed and precautions taken at all times.
Set Up
Connect our Thermolance/Oxygen Lance Holder to a proper hose (3/8″ minimum) that is connected to an oxygen supply. It is important that there are no leaks anywhere. Insert the plain end of the lance into the holder and hand tighten the cap. Depending on conditions, the experienced operator may adjust his pressure setting from 75 P.S.I.
Use
Before ignition, be properly positioned for maximum utilization and safety.
To ignite the Thermolance/Oxygen Lance, open the holder control valve just enough to allow a slight flow of oxygen through the lance. Heat 3/4″ of the end to a red hot temperature. After it ignites, immediately turn the oxygen supply on fully. The lance will then burn vigorously. The lance can be extinguished by closing the valve and can be used again when required (an oxygen acetylene torch is often the most expedient method to start ignition).
When using Thermolance to pierce concrete, rock, or refractory, apply slight pressure with the Thermolance against the material. When the thickness exceeds 8″, keep the Thermolance moving in a circular motion in order to prevent jamming. When cutting metals, keep the end of the Thermolance very close to or against the material. Where possible, start at the top and wash the molten metal downward. Maintain a kerf wide enough to prevent the Thermolance from binding on the sides.
Thermolance Performance Examples
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One 3/8″ x 10′ 6″ bar consumes an average of 60 cubic feet of oxygen.
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A temperature in excess of 5000° Fahrenheit can be reached.
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Average burn time is approximately 4 minutes per bar during which it should penetrate at least 2 feet of reinforced concrete.
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Will cut through 4 inches of steel plate in approximately 6 seconds.
twistedsteel Says:
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.
Sean Wheels Says:
March 12th, 2009 at 10:40 pm
When I was in Highschool, a bunch of us decided to build one of these.
We wound up doing it several times, due to the extreme Fun Factor.
Basically, we got a 10 foot piece of black iron pipe (no galvanizing,
no zinc fumes, eh?), and plumbed it to a tank of oxygen from Dad’s
welding rig.
Getting it lit is the trick – we used magnesium shavings packed around the
business end of the pipe (a sometimes thing), or thermite (the preferred
method).
Once it is lit, the iron pipe begins to burn in the pure oxygen
coming from inside the pipe. White hot flame, and lots of it, with
accompanying roar.
We used it to burn through:
several automobile engine blocks (too easy)
a three foot chunk of reinforced concrete (moderately difficult)
a large granite boulder (hard, had problems with crud in the hole)
Wear insulating gloves to hold the pipe, and welders goggles are reriguered.
Don’t plan on using the last three feet of the pipe, as the action
gets pretty intense that close to the burn.
You can, of course, make the pipe longer before you start.
Keep someone ready to turn off the oxygen, as this is the only control
you have – you can’t “snuff” the flame, and it will continue to burn
underwater.
The hole size you cut is very dependent on the material you are
cutting, and is very ragged.
Molten iron splatters will coat everything near the hole. Small fires
will start if you’re careless.
This technique has been used (and probably still is) to “crack” safes.
I’ve seen films of divers using this to cut up shipwrecks, too.
Kids, don’t try this at home. Do it out in a gravel pit, instead.
I’m betting the folks over in rec.pyrotechnics can give some insight,
too.