Oxyfuel Cutting Module 32104-07 / 40104-07

1. Identify and explain the use of oxyfuel cutting equipment. Transparency 1 Objectives Upon completion of this module, the trainee will be able to do the following: 1. Identify and explain the use of oxyfuel cutting equipment. 2. State the safety precautions for using oxyfuel equipment. 3. Set up oxyfuel cutting equipment. 4. Light and adjust an oxyfuel torch. 5. Shut down oxyfuel cutting equipment. 6. Disassemble oxyfuel equipment. 7. Change empty cylinders. 8. Perform oxyfuel cutting: • Straight line and square shapes • Piercing and slot cutting • Bevels • Washing 9. Apply a rosebud flame to remove frozen components (also for preheat and expanding larger fittings). 10. Operate a motorized, portable oxyfuel gas cutting machine.

1. Set up oxyfuel equipment. 2. Light and adjust an oxyfuel torch. Transparency 2 Performance Tasks 1. Set up oxyfuel equipment. 2. Light and adjust an oxyfuel torch. 3. Shut down and disassemble oxyfuel cutting equipment. 4. Perform oxyfuel cutting: • Straight line and square shapes • Piercing and slot cutting • Bevels • Washing 5. Operate a track burner.

Introduction Also called flame cutting or burning – uses the flame and oxygen from a cutting torch to cut ferrous metals(metals containing iron) The flame is from a fuel gas mixed with pure oxygen The flame heats the metal to the kindling temperature, then a stream of high pressure pure oxygen is directed from the torch at the metals surface – this causes the metal to instantaneously oxidize or burn Oxides mix with molten iron to produce dross(the material that is expelled from the kerf when cutting using a thermal process)

Introduction Oxyfuel cutting is used on ferrous metals because they oxidize rapidly Oxyfuel cutting can also be used for certain metal alloys, like stainless steel – this requires higher preheat temperatures and more oxygen for cutting

Safety Clothing and equipment – always use safety goggles or glasses with a full face shield or helmet – the shield or helmet must have the proper light reducing tint for the type of welding or cutting to be performed Never look directly or indirectly at an electric arc without using a proper lens Wear leather or flame retardant clothing Wear leather welding gloves Wear 8-inch or taller safety shoes or boots covered by a pant leg

Safety For overhead cutting or welding wear a solid material hat or a full leather hood with a welding face plate Use earmuffs to block noise and to prevent burns to the ears – you can use earplugs to filter out the noise as well The heat and light produced by cutting or welding can damage the skin and eyes(permanent loss of vision) Oxyfuel cutting and welding can cause mild burns to the skin because of infrared heat Welding or cutting involving an electric arc can produce UV radiation – can cause severe burns to the eyes and exposed skin and permanent damage to the retina

Safety Never directly or indirectly view an electric arc without wearing properly tinted lens designed for electric arc use For oxyfuel cutting or welding wear welding goggles (shades 4 to 6) OVER safety glasses For electric arc operations a leather hood or welding helmet with a tinted lens (shades 9 to 14) must be worn over safety glasses Some may require other safety glasses or goggles based on the MSDS

Ventilation You must have adequate ventilation to remove fumes produced by welding or cutting processes The gases, dust, and fumes can be hazardous The welding area must contain at least 10,000 cubic feet of air for each welded There must be air circulation Partitions, structural barriers, or equipment must not block air circulation Avoid inhaling welding or cutting fumes The fumes and smoke generally rise straight up

Respirators Special metals require the use of respirators to protect from harmful fumes Three main types of respirators – air-purifying respirators, supplied-air respirators, self-contained breathing apparatus Make sure they are clean, put together properly, no missing parts

Air-purifying respirators Lowest level of protection Use filters to remove specific gases, vapors, and particles from the air 4 groups – no maintenance, low maintenance, reusable, powered air-purifying respirators(PAPRs) No and low maintenance – half mask respirators not for constant use – non replaceable filters Reusable – half or full face – replaceable cartridges PAPRs – half, full, or hood style – battery operated blowers pull air through the filters

Supplied-Air Respirators Supply air for extended period of time Typically used in toxic atmospheres Some can be used in atmospheres that are IDLH Two types – continuous-flow and pressure demand Continuous flow – air provided at a constant stream – one or two hoses deliver air to the face piece – unless designed to filter the pump must be located where there is breathable air Pressure demand – supply air when the user inhales

SCBA Highest level of protection Provide air from 30 to 60 minutes from a compressed-air cylinder Select the proper type of respirator for the job, make sure you are properly trained on use of the respirator Do a positive and negative fit check before use

Figure 13 – Use the right respirator for the job Transparency 3 Figure 13 – Use the right respirator for the job

Table 1 – Effects of an increase or decrease in oxygen levels Transparency 4 Table 1 – Effects of an increase or decrease in oxygen levels

Work Areas You must be aware of your work space – is it a confined space – does it have the potential to ignite – can you get out if needed Keep area clean – things you can trip over – things that can catch on fire If you are finished working use soapstone to write the word HOT on it before you leave Make sure you have proper ventilation

You may have to get a hot work permit to perform work that may pose a fire hazard If working in an area that may pose a fire hazard, you need to have a fire watch person Containers must be steam cleaned, flushed with water, or washed with a detergent until all traces of the material have been removed After cleaning, fill it with water or an inert gas (argon or CO2) to prevent ignition

Figure 16 – Hot work permit Transparency 5 Figure 16 – Hot work permit

Cylinder storage and handling Oxygen and fuel gas cylinders or other flammable materials must be stored separately All cylinders must be stored vertically and have protective caps screwed on firmly Secure with a chain or other device so it cannot be knocked over accidentally Store away from halls, stairwells, or exits so they will not block an escape route Store away from heat, radiators, furnaces, and welding sparks

Store where they cannot be tampered with If cylinders are not in use they must have a valve protection cap to prevent the valve from breaking off In gaseous form, acetylene is extremely unstable and explodes easily – its pressure must remain below 15 psi If tipped over, stand the tank upright and wait at least 30 minutes before use When using, open the cylinders no more than one and a half turns – preferably no more than three-fourths

Equipment The equipment used for oxyfuel cutting – oxygen and fuel gas cylinders, oxygen and fuel gas regulators, hoses, and a cutting torch, and possibly a torch cart Oxygen – colorless, odorless, tasteless gas that supports combustion – combined with burning material, pure O2 allows a fire to flare and burn out of control – when mixed with fuel gases O2 produces high temperature flames required to cut metals O2 cylinders come in different sizes – have a bronze control valve with a safety valve in case the pressure gets too high

Acetylene – a compound of carbon and hydrogen formed when calcium carbide is dissolved in water – strong garlic like odor In gaseous form it is extremely unstable and explodes easily – it cannot be compressed more than 15 psi When combined with O2, it creates a flame that burns hotter than 5,500 F Cylinders are specially constructed to hold acetylene – they are filled with a porous material soaked with acetone to absorb the acetylene and help it stay stable

Acetylene tanks must be stored upright – if turned over wait at least 30 minutes before using Do not withdraw the gas at a rate higher than 15psig and at an hourly rate more than one-tenth of the cylinder capacity They have a safety plug that will melt if the temperature gets too hot (220 F) so the cylinder will not explode

Figure 21 – High-pressure oxygen cylinder markings and sizes Transparency 6 Figure 21 – High-pressure oxygen cylinder markings and sizes

Figure 25 – Acetylene cylinder markings and sizes Transparency 7 Figure 25 – Acetylene cylinder markings and sizes

Table 2 – Flame temperatures of oxygen with various fuel gases Transparency 8 Table 2 – Flame temperatures of oxygen with various fuel gases

Figure 27 – Liquefied fuel gas cylinder Transparency 9 Figure 27 – Liquefied fuel gas cylinder

Regulators/hoses Regulators reduce the cylinder pressures to the required working pressures and maintain a steady flow of gas Most have two gauges –a high pressure and a low pressure Oxygen regulators are often green and have right hand threads and fuel gas are painted red and have left hand threads Oxygen hoses are green or black Fuel gas hoses are red

Transparency 10 Figure 30 – Heavy-duty three-tube one-piece positive-pressure hand cutting torch

Figure 32 – One- and two-piece cutting tips Transparency 11 Figure 32 – One- and two-piece cutting tips

Table 3 – Sample acetylene cutting tip chart Transparency 12 Table 3 – Sample acetylene cutting tip chart

Figure 33 – Typical acetylene torch cutting tips Transparency 13 Figure 33 – Typical acetylene torch cutting tips

Figure 34 – Typical cutting tips for liquefied fuel gases Transparency 14 Figure 34 – Typical cutting tips for liquefied fuel gases

Figure 35 – Special-purpose torch cutting tips Transparency 15 Figure 35 – Special-purpose torch cutting tips

Always use a friction lighter to light the torch You can use soapstone to mark your cuts because it can be seen through the tinted lens

Figure 66 – Typical empty cylinder marking Transparency 16 Figure 66 – Typical empty cylinder marking

Figure 68 – Cutting thin steel Transparency 17 Figure 68 – Cutting thin steel

Figure 69 – Cutting thick steel Transparency 18 Figure 69 – Cutting thick steel

Figure 70 – Steps for piercing steel Transparency 19 Figure 70 – Steps for piercing steel

Figure 71 – Cutting a bevel Transparency 20 Figure 71 – Cutting a bevel

Transparency 21 Figure 72 - Washing

Figure 74 – Victor track burner controls Transparency 22 Figure 74 – Victor track burner controls