Oxy Fuel Cutting: The Ultimate Guide
In this article, we’ll go over the definition of oxy-fuel cutting, its advantages, benefits, and the materials that can withstand it. Additionally, oxy-fuel cutting dangers and guidelines, its method, plasma cutting vs. oxy-fuel cutting comparisons, applications, and uses.
What Is Oxy Fuel Cutting?
Metals are often combined using a cutting process that primarily employs fuel gases or liquid fuels like gasoline or oxygen. Before cutting can start, the steel must be heated with the cutting torch until it reaches ignition temperature.
Advantages Of Oxy Fuel Cutting
For cutting oxy-fuel, no primary power nor compressed air are often required. Due to its portability, it is cutting metal practically simpler.
By far, this is the key strength of using oxy-fuel cutting services. In most cases, it allows cutting plates up to 150mm thick.
When using oxy-fuel cutting, steel metal plates with a thickness of over 30mm may typically be cut quickly and precisely.
Oxy-fuel cutting is typically not just the best option for cutting processes; it is also excellent for other methods that can be executed, such as heat treating and brazing.
Benefits Of Automated Oxy Fuel Cutting Machine
Some of the main benefits include:
- It can typically cut materials ranging from 1 mm to over 100 mm.
- Automated ox fuel cutting machines need less labor, which increases productivity.
- The automated oxy-fuel machine often features inexpensive equipment.
- Due to the fast cutting speed of this machine, you can weld more metal parts in a shorter amount of time.
- Automated oxy-fuel machines are portable and are used anywhere metal needs to be cut.
- It is typically simple to maintain a machine.
- The machine can also be used in other applications like heat treatment and shaping.
Thickness Of Metal To Cut With Oxy Fuel Cutting
According to tests, oxy-fuel cutting can cut steel plates up to 13 mm thick just as effectively as oxyacetylene torches. The cutting rate was superior when oxyacetylene was three times faster at plate thicknesses more significant than 13 mm. Additionally, the density of the liquid fuel vapor is nearly four times greater than that of a gaseous fuel, giving it significantly more “punch.”
The massive volume expansion during the liquid’s transformation to a vapor creates a high-velocity cutting flame that can quickly cut through spaces. Cuts through the corrosive surface elements coating old steel, including paint, grime, and rust.
Oxy Acetylene Cutting Torch
It is a cutting method that uses two gases; typically, the equipment includes one tube for acetylene supply and another for oxygen delivery to the torch. The front end of the tube that supplies oxygen is equipped with a cutting tip, and a central hole usually exists in this tip through which a jet of pure oxygen is released.
Additionally, the mixing head creates the mixture of the two gases, which is then used to cut the metal by first preheating it. The number of orifices used for oxyacetylene cutting typically ranges from 6 to 2, depending on the type and thickness of the metal cut.
Materials Oxy Fuel Cutter Can Handle
Low Carbon Steel: It is a form of steel with negligibly small carbon content, often between 0.03 and 0.05 percent. Typically more ductile and malleable than other varieties of steel due to its lower carbon content.
Mild steel: A ferrous metal consisting of iron and carbon is known as mild steel. It is a cheap material with qualities that make it appropriate for most general engineering applications.
Medium steel carbon: Besides having a manganese content between 0.60 and 1.65 percent and carbon content between 0.30 and 0.60 percent, these steels are often comparable to low-carbon steels. By raising the carbon content to about 0.5 percent while concurrently raising the manganese content, medium-carbon steels can be used in the quenched and tempered form.
Titanium: With an ultimate tensile strength of 434 MPa or 63,000 psi, titanium is a strong metal. This value is roughly equivalent to the power of a low-grade steel alloy. Because titanium is 45 percent lighter than steel, it can be used as a substitute for steel, which is a significant advantage.
Oxy Fuel Cutting Precautions
When using oxy fuel cutting technique, you should consider the following:
- Before beginning the cutting operation, at least relocate the combustible material 35 feet away from the working area. Flammable materials should, whenever feasible, be covered or guarded with flameproof material.
- Oxy-fuel cutting should not be done in a crowded environment to prevent potential dangers during the process.
- The fire extinguisher should be accessible, functional, and positioned strategically within the vicinity of the oxy-fuel cutting.
- During the oxy-fuel cutting area, always use the authorized friction sticker; never use matches or a cigarette lighter.
- The flame must not be directed at the regulator or any other individual.
- Always maintain a tight connection between the regulator and the cylinder.
- If the gauge does not reset to zero after the pressure is released, have it fixed right away.
- Close the main valve after completing the oxy-fuel cutting procedure, bleed the lines, and loosen the regulator using the adjusting screws.
- Always wind up the hoses after turning off everything.
- The cylinder needs to be kept somewhere with good ventilation, preferably outside.
- Grease, oil, or other coatings shouldn’t be applied to the hoses because they will hide any damage.
- Make sure the cylinder joints are clean and free of sealant before mounting the regulator.
Oxy-acetylene Cutting Tips
Side stand – As you carefully open the cylinder valve, situate yourself to the regulator side. The regulator will probably malfunction if the gain force is applied to the direction bonnet and pressure adjustment knob. At that time, leave the acetylene valve partially or fully open, but entirely open the oxygen valve cylinder.
Leak test – Properly tighten metal-to-metal connectors with a wrench, including those between the gas torch and gas hoses. Then, by saturating the connections with the leak test solution and looking for glowing bubbles, leak test the links. Use only the certified leak test products.
Good size tip – If you want the best cut quality, use the correct size tip for the metal thickness. Also, regulate gas pressure in line with the tip chart for your specific brand of cutting equipment. Consult the tip chart if unsure because each brand has a unique size tip.
Pressure drop – Consider that the gas pressure will decrease when it reaches the torch using a long or narrow hose. To ensure the torch pressure’s back meets the cutting requirement tip, you can adjust for the pressure loss by raising the regulator supply pounds per square inch gauge.
Gauges on the handle – Check the exact pressure drops for your rig if you frequently move a long way from your cylinder. First, attach the pressure gauge to determine the gap between the pressure at the cylinder output and the torch. Increase the PSIG at the regulator until the indicator on the torch reaches the desired pressure.
Brace yourself – In any way you can, use your free hand to support your cutting hand. It is done by a worker in a scrap yard bracing their free hand on some scrap.
Ready to pierce – Before you puncture the steel with the cutting flame, be sure it has reached the igniting point. The temperature can also be measured by lightly depressing the cutting oxygen lever in addition to the reliable reddish-yellow tint.
The lever can be fully depressed if the steel develops slag quickly. If not, release the cutting oxygen lever and continue to burn the preheat flame for a short while.
Spiral out – Start in the middle of the target and work toward the cutting path.
The torch height – The acetylene torch’s inner cones should typically be held off the cutting surface. Nevertheless, torch height is more tolerant with alternative fuels.
Light alternative fuel – If you’re having trouble starting the flame, hold it at a 45-degree angle to the plate so the plate “traps” the gas. Once lit, the flame can be extinguished by providing more oxygen.
Relight the torch if it goes out, position the tip at a 45-degree angle to the plate, and preheat oxygen gradually until the flame catches.
Oxy Fuel Cutting Process
Step One: Preheat
The steel must be heated to the igniting temperature, or roughly 1800°F before you can begin cutting. The steel quickly reacts with oxygen at this temperature.
The preheat flames from an oxy-fuel torch are what generates the heat. A fuel gas and oxygen mixture is combined inside the torch to produce a highly combustible mix.
Step Two: Piercing
A stream of pure oxygen is activated to start piercing through the plate whenever the surface or edge reaches the igniting temperature. The single bore in the nozzle’s center creates the jet known as the “cutting oxygen” jet.
Besides, the quick oxidation process starts when the cutting oxygen stream contacts the previously heated steel. The real fun begins at this point.
Step Three: Cutting
The torch can begin operating at a consistent pace to create a continuous cut once the cutting oxygen stream has completely penetrated the plate.
The bottom of the plate is blown out with the molten slag generated during this stage. Just before the cut, the plate is warmed up by the heat produced by the chemical interaction between the oxygen and the steel, but not reliably enough to cut without preheated flames.
Plasma Cutting Vs. Oxy-Fuel Cutting
Due to the production of an oxide that hinders complete oxidization, oxy-fuel can only cut ferrous steels up to a thickness of 24 inches. It cannot cut metals like stainless steel, aluminum, or copper. While any electrically conductive metal, including aluminum, copper, and stainless steel, can be cut by plasma.
Unlike plasma cutting, which requires no preheating, oxy-fuel cutting requires a preheating operation before the cutting can begin.
Technology, the power source’s size, and the air tanks’ size all affect portability due to primary power management methods provided in some plasma cutters.
Many units may operate successfully in the field using engine-driven generators and a range of primary power sources, as opposed to being extremely portable, independent of a primary power source, and able to cut through any material with torches and gas tanks.
Depending on the power output of the power source, plasma cutting typically performs remarkably well on thinner materials. In addition, it works well with expanding materials and can cut stack material.
It requires very little preparation time and yields a small, precise cut. On the other hand, oxy-fuel does not require a primary power source and can cut metals up to 24 inches thick with efficiency.
Oxy Fuel Cutting Safety Practices
When possible, use local exhaust ventilation. Fume generation through safe work practices, engineering controls, and personal protective equipment if good ventilation is available (PPE).
Eye protection is necessary to avoid exposure to flying debris, hot metal slag burns, fume, gas, and vapor. Wear full-face-piece safety glasses with tinted lenses that have received ANSI approval.
Wearing heavy quality leather gloves, helmets, aprons, long-sleeved coats, and leggings over cotton clothing will protect the entire body from flying molten metal/sparks.
Characteristics Of Quality Oxy-fuel Cut Parts
For proper metal-oxygen welding, fuel cut components must have a square top corner with the smallest radius.
Oxygen fuel cuts should have a cut face that is flat from top to bottom with no undercuts.
The oxy-fuel cut component also requires a characteristic that makes the dragline almost vertical and a smooth surface to function as intended.
The machine must also leave little to no slag on the bottom edge to make it easier to remove the scraping.
Gases To Use In Oxy Fuel Cutting
Acetylene is the gas type we’re looking for if we’re looking for one with the maximum flame temperature. Of all the gas types, Acetylene has one of the fastest cutting speeds since it has the highest peak temperature. Additionally, it has a far quicker burn than something like propane.
In terms of how much it is used for flame cutting, propylene quickly catches up to Acetylene. There are several causes for that. First, it uses gasoline five times more quickly than Acetylene while using the same amount of fuel. Additionally, propylene cuts more quickly and generates less slag as a result.
Alternative fuel gas with a high-temperature range, around 2800° C, is the maximum. The flame has a lower concentration than Acetylene, which causes a greater HAZ and a prolonged piercing time.
It is the fastest cutter and piercer on the list. However, due to its widespread commercial availability, LPG is an excellent alternative to the other fuel gases on this list.
Applications Of Oxy Fuel Cutting
Because the oxy-fuel cutting technology offers such good cutting precision, it is frequently employed to produce steel rotors to be used as components of a brake system for massive electrical machinery.
Using oxy-fuel cutting and machining creates a steel crankshaft counterweight for a power generation application.
It is easy for a rock crushing application to create a unique steel drive ring because of the accuracy and strength of the oxy-fuel flame cutting technique.
People Also Ask:
No, stainless steel is one of the metals that oxy-fuel cannot cut.
- It is usually sensitive to corrosion and dirt.
- Usually takes a long warm-up time before the breakthrough.
- It also requires operators’ knowledge.
- Only suitable for mild steel cutting.