Cutting metal with a cutter for beginners

Safety engineering

The equipment is classified as explosive, therefore, the work site must be equipped with the following accessories:

  • fire extinguisher,
  • sand box,
  • fire stand with appropriate tools.

Each performer must have a set of protective clothing.

It is not allowed to wear under the protection clothing made of flammable material, for example, synthetic materials, and the edges of the sleeves should fit tightly around the body so that sparks do not get inside.

How much gas is consumed

Gas consumption when cutting metal with a propane-oxygen cutter depends on the thickness of the structure and the configuration of the cut. For clarity, we present the table below:

Workpiece size (thickness), mm Time per hole, sec Cut size (width), mm Consumption, per cut m3
propane oxygen
4.0 5-8 2.5 0.035 0.289
10.0 8-13 3.0 0.041 0.415
20.0 13-18 4.0 0.051 0.623
40.0 22-28 4.5 0.071 1,037
60.0 25-30 5.0 0.087 1,461

Gas consumption is significantly reduced when surfacing or brazing is performed.

Application features

To understand how to properly cut metal with a cutter, you need to study the design and know that such equipment is not used for cutting steels with high carbon, since there is no way to create a temperature that can ensure stable melting. When cutting cast iron workpieces or structures, there is a concentration of graphite between the metal grains, which complicates the work.

The cutter cannot be used to cut products consisting of aluminum, copper and alloys based on it.

Terms of use

They are similar to safety precautions for welding, but have specific additions:

  • It is not recommended to neglect protective equipment, since this leads to injuries in the form of skin burns or damage to the cornea of ​​the eyes by flying sparks, therefore glasses and gloves with long sockets to the elbow are required.
  • The performer’s clothes and footwear are made of non-combustible material.
  • Gas cylinders are located at least five meters from the cutting site.
  • The torch flame is directed only in the opposite direction from the hoses.
  • Cutting is carried out in rooms equipped with strong ventilation or in open areas.

When the equipment is idle for a long time, it is necessary to carry out preventive work before using the torch for its intended purpose.

Pros and cons

Gas cutting and metal welding has many advantages, but we are only interested in cutting, which has the following advantages:

  • It is in demand when a thick metal is cut or a stencil cut is needed, and an angle grinder cannot cope with curved sections.
  • The gas analogue is much more convenient for work, has a low weight, operates twice as fast as equipment with a gasoline engine.
  • Propane is cheaper than acetylene and gasoline, so its use is more cost-effective.
  • The cut edge is much narrower and the structure is cleaner than from an angle grinder or gasoline equipment.

Disadvantages. a narrow range of metals subject to similar processing.

Propane to oxygen ratio

To properly cut metals with an oxy-propane torch, you need to adjust the flow of gases to the nozzle. Such adjustment is carried out according to the recommendations of reference books, where there are tables and diagrams; in the absence of the necessary literature, one must check the technology specified in the product documents. In the absence of regulatory documents, the ratio of one part of propane to ten parts of oxygen is used.

Danger of kickback

If the jet burns incorrectly, cotton occurs and the flame is drawn into the inside of the product, which leads to an explosion, since the fire spreads through the hoses and reaches the containers with gases. To prevent a hazardous situation, the torch is equipped with a check valve that cuts off the flame and prevents it from spreading.

Equipment set

Before starting flame cutting or welding, the equipment should be carefully prepared:

  • Containers with gases.
  • Connection hoses.
  • Cutter.
  • A mouthpiece with specific dimensions.
  • Volume control and control reducers.

The equipment does not depend on the manufacturer, the valve marking is standard.

How much gas is consumed

Gas consumption when cutting metal with a propane-oxygen cutter depends on the thickness of the structure and the configuration of the cut. For clarity, we present the table below:

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Workpiece size (thickness), mm Time per hole, sec Cut size (width), mm Consumption, per m 3 cut
propane oxygen
4.0 5-8 2.5 0.035 0.289
10.0 8-13 3.0 0.041 0.415
20.0 13-18 4.0 0.051 0.623
40.0 22-28 4.5 0.071 1,037
60.0 25-30 5.0 0.087 1,461

Gas consumption is significantly reduced when surfacing or brazing is performed.

Equipment

The main equipment for flame cutting is a torch. The kit includes: nozzle for welding and melting.

Thanks to the cutter, the dosage of the gas mixture and oxygen can be controlled. Also, with the help of this equipment, the ignition of the combustible mixture is carried out, the flame is supplied to the place of processing.

The cutter consists of two blocks: cutting and heating. The first is represented by an oxygen stream outlet tube, a valve and an internal mouthpiece.

The heating unit includes valves that are designed to regulate the pressure of the gas mixture and oxygen. There is also a feed tube, an outside mouthpiece, a mixing chamber and an injection cell.

Cutters are hand and machine. The latter are stationary, therefore, for repair work, it is preferable to use manual.

Additionally, the following gas-cutting equipment is used:

  • reducer. designed to reduce pressure;
  • device for changing pressure;
  • steel cylinder with gas and oxygen;
  • connecting hoses.

Before using the equipment, it is important to check that it is working properly in order to avoid explosion of the cylinder or reducer. The torch is pre-purged with oxygen

The principle of operation of gas welding

Oxygen and combustible gas are supplied to the device through the nozzles, ignition occurs through the nozzle, and the flame power is regulated by valves. The flame consists of several main parts, a torch, a recovery process and a core. The highest temperature parameters are observed in the core, the process occurs as part of the flame between the core and recovery.

Exposure to high temperatures on the surface of materials entails protecting the welding area from excess air, which contains impurities of heavy gases. High performance in cutting metals allows you to perform work with high precision, to produce the necessary products. There are different types of gas welding.

Welding gas plays an important role in the density, quality of the joint, acetylene is designated as a popular gas for use.

Preparatory work

How to set up a torch for cutting metal. first of all, you need to make sure that the product is in good condition, ready for work, then the following procedure is performed:

  • The hoses from the cylinders are connected to the cutter by pre-blowing the product to remove foreign inclusions from the inside.
  • Oxygen is connected to the right hand thread and propane to the left hand thread.
  • Set the propane supply level to 0.5, and oxygen supply to 5.0 atmospheres.
  • We check the connections for leaks, as well as the operation of reducers and pressure gauges.

If gas leaks are found, then the nuts are tightened or the gaskets are changed.

The diagram shows the correct connection of the cylinders to the cutter.

Mechanized flame cutting

Mechanized and automated gas-plasma cutting systems can further improve the accuracy and utilization of metal. Their main advantages are as follows:

  • High cutting speed while maintaining precision.
  • Below are the requirements for the qualifications and experience of the gas cutter.
  • Automatic control and correction of operating parameters, including travel speed, torch tilt, gas flow, torch width and length. This allows you to reduce non-productive metal losses.
  • Incoming gas quality control. If the permissible content of impurities is exceeded, the installation blocks the operation.
  • Compatibility with computer programs for optimizing the cutting of blanks allows you to avoid the marking procedure. This increases the utilization rate of metal and reduces the cost of cutting.
  • The preheating function of the sheet helps to reduce thermal stresses in the sheet and reduce warpage. Preheating also shortens the main operation time.
  • Auxiliary devices remove slags and carbon deposits from the surface of the sheet, and without stopping the main operation.

The operating parameters of modern automatic cutting machines reach:

  • cutting speed. up to 0.6 meters per minute;
  • the width of the cut is 1-2 mm;
  • dimensional accuracy. up to 1 mm.

It has automatic oxy-fuel cutting and a number of disadvantages. These are, first of all, restrictions on the size of the sheet to be cut. The installation is strictly stationary and cannot be used in a mobile version; its installation and commissioning takes several weeks.

Terms of use

They are similar to safety precautions for welding, but have specific additions:

  • It is not recommended to neglect protective equipment, since this leads to injuries in the form of skin burns or damage to the cornea of ​​the eyes by flying sparks, therefore glasses and gloves with long sockets to the elbow are required.
  • The performer’s clothes and footwear are made of non-combustible material.
  • Gas cylinders are located at least five meters from the cutting site.
  • The torch flame is directed only in the opposite direction from the hoses.
  • Cutting is carried out in rooms equipped with strong ventilation or in open areas.
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When the equipment is idle for a long time, it is necessary to carry out preventive work before using the torch for its intended purpose.

Cutting features

Take your time when opening the valve on the propane torch. In this case, oxygen will ignite naturally as a result of interaction with a heated metal. By doing this, you will eliminate the risk of flames blowing back, during which a popping sound can be observed. It is necessary to slowly conduct the oxygen stream strictly parallel to the specified mowing line

It is important here not to be mistaken with the angle of inclination.

First, it is kept at 90 degrees, after which it is necessary to create a slight deviation of 5-6 degrees in the direction that is opposite to the movement of the torch. If you have to deal with metal, the thickness of which is more than 95 mm, then it is allowed to increase the deviation to 70 degrees. After the cut in the metal reaches 15-20 mm, the angle of inclination begins to increase to 20-30 degrees.

Negative deformation

Novice welders are concerned with the question of how to use the propane oxygen cutter correctly so that the surface of the part does not warp. First you need to figure out what factors contribute to the occurrence of these defects:

  • with uneven heating of the surface;
  • high speed cutter was selected;
  • there was a sharp cooling of the heating place.

In order to exclude the occurrence of the above factors on the workpieces, they are previously securely fixed and heated, and the speed is increased gradually. If warpage still occurs, then you can return to its original shape by firing or tempering, and the sheets can be straightened on rollers.

Metal cutting

To start cutting metal, lower the cutting valve handle in a smooth, slow motion. As a result, oxygen will begin to flow to the combustion site, which should ignite the preheated metal. If the material is hot enough, the reaction will start instantly, after which you can increase the pressure even more until the moment when the metal is completely cut through.

After that, gradually move the torch along the intended direction of the cut. The speed of the cutting movement must be selected so that the resulting slag, sparks and hot metal drops are blown down or flow away from the burner flame.

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After making the cut, the site should be carefully inspected for large pieces of molten metal. You should not step on them under any circumstances, as this can lead to burning even a thick sole. A cut sheet or piece of metal is cooled by water or naturally.

Necessary equipment

As in the case of any other work, even before starting to cut metal with gas, the necessary equipment should be prepared:

  • Propane and oxygen cylinder. 1 pc.;
  • High pressure hoses;
  • Cutter;
  • Mouthpiece that must be of a certain size.

A prerequisite is the presence of a reducer on all cylinders, with which it will be possible to adjust the gas supply. It should be remembered that the propane cylinder has a reverse thread, which makes it impossible to screw an additional reducer onto it.

13 Ways to Cut Metal

In general, gas equipment for cutting metal has a similar device, regardless of the manufacturer. Three valves can be distinguished in the design:

  • the first provides propane supply;
  • the second valve allows you to change the oxygen supply;
  • the last is the cutting oxygen valve.

Oxygen valves are usually labeled in blue, and red or yellow for propane valves.

Cutting metal is provided by a jet of hot flame that acts on the metal, which is created using a cutter. When it is turned on, propane and oxygen are mixed in a special mixing chamber, which leads to the appearance of a combustible mixture.

With a propane cutter, you can cut metal with a thickness of less than 300 mm. A detailed installation is completed with elements, which are mostly replaceable. For this reason, if a particular part fails, it will not be difficult for the operator to carry out repairs directly at the workplace.

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Care should be taken when choosing a mouthpiece. The key parameter that you need to pay attention to is the thickness of the metal. If you have to deal with an object that provides elements of different thicknesses ranging from 6 to 300 mm, then you will have to prepare mouthpieces with internal numbers from 1 to 2, and external numbers from 1 to 5.

cutting, metal, cutter

Application features

To understand how to properly cut metal with a cutter, you need to study the design and know that such equipment is not used for cutting steels with high carbon, since there is no way to create a temperature that can ensure stable melting. When cutting cast iron workpieces or structures, there is a concentration of graphite between the metal grains, which complicates the work.

cutting, metal, cutter

The cutter cannot be used to cut products consisting of aluminum, copper and alloys based on it.

Preparation for work

Before starting work, it is imperative to inspect the device to make sure that the torch is fully functional. Then follow these steps:

  • The first step is to connect the hoses to the cutting machine. Before attaching the sleeve, you need to purge it with gas to remove any debris or dirt that has got there. The oxygen hose is attached to the right-hand thread with a nipple and nut, the second (for propane) hose to the left-hand thread. Remember to check the torch passages for leaks before attaching the gas hose. To do this, connect the oxygen hose to the oxygen connection, and the gas connection must remain free. Set the oxygen supply to 5 atmospheres and open the gas and oxygen valves. Feel the free fitting with your finger to see if air is leaking. If not, clean the injector and blow out the torch passages.
  • Next, check the detachable connections for leaks. If you find a leak, tighten the nuts or change the seals.
  • Do not forget to check how tight the mountings of the gas reducers are and whether the pressure gauges are in good working order.

Safety requirements

Gas equipment that is used in the process of cutting metals, namely the oxy-acetylene torch, is classified as explosive and flammable. Therefore, before using the gas torch, you should follow all the mandatory safety recommendations.

For this, the workplace should be equipped with:

  • fire extinguisher. The use of a gas torch is accompanied by open flames and high temperatures, therefore fire extinguishing means must be present at the post;
  • protective clothing, consisting of:
  • cotton suit, if possible, impregnated with fire retardant;
  • gloves or gaiters made of tarpaulin or sufficiently thick leather;
  • boot with leather soles;
  • protective goggles with built-in light filters.

When working with the cutter, under no circumstances should you wear items of clothing made of synthetics or other easily flammable fabrics, as well as those that do not fit snugly to the body or have severely frayed edges. All this can lead to fire and, accordingly, danger to health and life.

Only various grades and types of unalloyed carbon steel can be gas cut. Stainless steel, non-ferrous metals and various alloys cannot be cut with a propane cutter.

How much gas is consumed

Gas consumption when cutting metal with a propane-oxygen cutter depends on the thickness of the structure and the configuration of the cut. For clarity, we present the table below:

Workpiece size (thickness), mm Time per hole, sec Cut size (width), mm Consumption, per cut m3
propane oxygen
4.0 5-8 2.5 0.035 0.289
10.0 8-13 3.0 0.041 0.415
20.0 13-18 4.0 0.051 0.623
40.0 22-28 4.5 0.071 1,037
60.0 25-30 5.0 0.087 1,461

Gas consumption is significantly reduced when surfacing or brazing is performed.

Terms of use

They are similar to safety precautions for welding, but have specific additions:

  • It is not recommended to neglect protective equipment, since this leads to injuries in the form of skin burns or damage to the cornea of ​​the eyes by flying sparks, therefore glasses and gloves with long sockets to the elbow are required.
  • The performer’s clothes and footwear are made of non-combustible material.
  • Gas cylinders are located at least five meters from the cutting site.
  • The torch flame is directed only in the opposite direction from the hoses.
  • Cutting is carried out in rooms equipped with strong ventilation or in open areas.

When the equipment is idle for a long time, it is necessary to carry out preventive work before using the torch for its intended purpose.