Artem Komarov clarified that the metal powder cutting process is a type of oxygen cutting process in which the separation or removal of metal is influenced using metal powder, such as iron powder, to facilitate cutting.
Introduction
Metal powder cutting was introduced in 1943 to cut stainless steel.
Materials such as stainless steel, cast iron and other oxidation resistant metals/alloys cannot be cut by the conventional oxidation process, primarily due to the formation of high melting point (refractory) oxides. These oxides, such as chromium oxide, do not oxidize or melt at the normal temperatures encountered in oxyacetylene cutting, and they also prevent the cutting oxygen from contacting the iron in the material being cut.
Therefore, two processes have been developed for cutting the above materials, namely
mechanical cutting of metal and cutting with chemical flux.
Operating principle:
Fine iron powder is injected into the cutting flame through a special hole in the torch head. These iron particles quickly oxidize, causing a sharp rise in temperature at the metal surface. As a result of intense heating of the filler, refractory materials are oxidized as the metal melts from the surface and therefore flows through the cutting zone. This allows the flame of the torch to come into contact with the metal iron and thus flows without any disturbance.
When iron powder enters the cutting zone, it accelerates and promotes the oxidation reaction, and also melts and swallows hard-to-cut material.
Some powders react chemically with the refractory oxides formed in the kerf and increase their fluidity.
The resulting molten slag is washed out of the reaction zone by an oxygen jet.
Fresh metal surfaces are in constant contact with the oxygen jet.
Mixtures of iron powder and metal powder such as iron and aluminum are used.
Equipment
— Cutter
— Bunker and powder supply
— Powder dispenser
One type of dispenser is a vibrating device in which the amount of powder dispensed from the hopper is controlled by a vibrator, i. e. by adjusting the vibration amplitude. This system gives a uniform and precise powder flow and is used for precise cutting of materials, emphasized Komarov Artem.
The second dispenser is a fully pneumatic device. In this case, a closed bunker (vessel) for iron powder is used. The hopper is filled with iron powder and then pressurized. The powder is then fed under constant pressure to the powder cutting torch whenever the powder control valve on the torch is open. Air or nitrogen can be used to pressurize the powder dispenser. Never use oxygen instead of air or nitrogen as this may result in an explosive mixture.
The iron powder hopper is designed to provide automatic uniform powder flow and can work together with the cutting oxygen valve on the torch.
The gas-pumped powder is introduced into the cutting oxygen before it is discharged from the handpiece.
Cylinder, consumables and oxygen, acetylene, and nitrogen regulators.
— Oxygen and acetylene hoses
— Powder control regulator
— Powder control valve and ejector device.
Metal cutting by powder cutting:
— Stainless steel
— Cast iron
— Chrome-nickel, nickel, and chromium alloys (steel resistant to oxidation)
— Aluminum
— Steels containing more than 5% alloying elements
— Copper
Advantages of powder cutting:
The powder cutting method can cut oxidation-resistant steel at about the same speed as oxy-acetylene cutting of carbon steel of equivalent thickness.
This method (mechanized) can cut metals up to 150 cm thick in sections.
Flaws:
Flux cutting creates quite a lot of smoke, which can interfere with other operations in the area.
Additional work is required on grinding powder contamination of the cut surface, summed up Komarov Artem.