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UNIT 4: OXYACETYLENE WELDING AND CUTTING IN AGRICULTURE.

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Presentation on theme: "UNIT 4: OXYACETYLENE WELDING AND CUTTING IN AGRICULTURE."— Presentation transcript:

1 UNIT 4: OXYACETYLENE WELDING AND CUTTING IN AGRICULTURE

2 Objectives 4.1 Define terminology 4.2 Describe the oxyacetylene welding and cutting processes in agriculture 4.3 Distinguish parts and functions of oxyacetylene welding and cutting equipment and supplies 4.4 Describe safe practices in oxyacetylene welding and cutting 4.5 Describe the process of using oxyacetylene welding and cutting equipment

3 4.1 Define terminology  1. Bleeding the lines – moving gas pressure from all lines and equipment, as with oxyacetylene welding systems  2. Brazing – the process of joining metal with a filler rod that melts at a temperature below the metal being joined  3. Carbonizing flame – a flame with excess acetylene; adjustment is needed to achieve a neutral flame  4. Cutting tip – a special tip used in cutting metal with gas systems such as oxyacetylene  5. Filler rod – a long, thin metal rod used in welding to add to or fill joints when welding or brazing

4 4.1 Terms Cont.  6. Flammable – the quality of a substance that is capable of burning  7. Fusion – the process of joining by melting, as in fusion welding  8. Gauge – a device used to measure certain substances such as pressure in an oxyacetylene welding/cutting system  9. Neutral flame – an oxyacetylene flame with a balance of oxygen and acetylene  10. Oxidizing flame – an oxyacetylene flame with an excess of oxygen; adjustment is needed to achieve a neutral flame

5 4.1 Terms Cont.  11. Regulator – a device that controls the flow amount of a liquid or gas; with oxyacetylene welding systems, regulators control the flow of oxygen and acetylene  12. Tip – the part of a welding or cutting torch with holes to release fuel for combustion  13. Tip cleaner – small, round rod-like devices that remove dirt from the holes in welding and cutting torch tips  14. Torch – the assembly in an oxyacetylene system that mixes oxygen and acetylene to provide the desired flame  15. Valve – a device that controls the flow of gas in an oxyacetylene system

6 4.2 Describe the oxyacetylene welding and cutting processes in agriculture

7 Uses of Oxy-fuel Cutting and Welding  What are some examples of cutting torch uses on the farm?  Have you ever used a gas welder at home?

8 Relate welding and cutting processes to different kinds of metal

9 4.3 Distinguish parts and functions of oxyacetylene welding and cutting equipment and supplies

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12 Regulators  Gauges - High and Low pressure  Bonnet - weakest point  Adjusting screw - Clockwise = On

13 Protector Cap  Protects valve from being knocked off  Must be in place when Regulators are off

14 Backflash Arrestor  Torch / Manifold  Regulator / torch

15 Hoses  Acetylene = Red  Notch around nut means LH thread  Oxygen = Green  RH Thread  New Hoses have talc inside - Blow out before connecting to torch

16 Needle valves  What each does  Preheat / Cutting hole pressures  Tightening

17 Torch Body  single stage / dual stage

18 Distinguish between welding and cutting components of oxy-acetylene equipment

19 Cutting Head  Preheat oxygen needle valve  Seat type / Graphite type - tightening  Body to head connection - tightening  Oxygen lever - regulator setting, #1 needle valve setting

20 Welding Tip

21 Identify, compare, and select filler rods by type and by metal to be welded

22 4.4 Describe safe practices in oxyacetylene welding and cutting

23 Objective 4: Describe fire prevention and personal protection in welding and Identify and properly use personal protection equipment in oxy-fuel cutting and welding  Identify fire protection equipment

24 List the practices to follow to prevent accidents  Make sure you have all PPE on at all times!!  This includes your shade 4 glasses at all times while looking at the flame.  Make sure that you always shut off the acetylene valve first then the oxygen.  Do not point the torch directly into the lighter. Never use a match or cigarette lighter to light the torch.

25 Identify proper ways of handling hot metal  Once you have made a weld that you want looked at use a pair of pliers to carry the hot metal. Take the metal to the sink and cool it off. Then you can bring it to me for a grade. Using this method will save our gloves in the long run!!

26 Identify practices to follow in safely storing and using compressed gas  Acetylene Cylinders  Acetone - absorbs acetylene under pressure  Consumption rate = 1/7 content per hour  Fusible plug F  Temperature has an extreme affect on pressure  Let stand upright at least 20 minutes before using  Protected valve or cylinder cap  Stored away from oxygen and combustibles  5’ high wall  1/2 hour fire rating

27 Identify practices to follow in safely storing and using compressed gas  Oxygen Cylinders  Pressure is about 2200 psi at 70 0 F  Hydrostatic tested to 3300 psi  Forged from a single piece of steel - no welding  Minimum of 1/4” thickness  Annealed periodically  Stored away from combustibles  5’ high wall  1/2 hour fire rating

28 Acetylene safety Precautions  Never call acetylene “gas”  Extremely explosive with air or oxygen  Leave wrench on tank

29 Oxygen Safety Precautions  Never call oxygen “Air”  Never allow oxygen to come in contact with oil, grease, or other petroleum bases  Never use oxygen for compressed air  Never move cylinders without caps  Always secure cylinders

30 4.5 Describe the process of using oxyacetylene welding and cutting equipment

31 Lighting Procedure  1. Place goggles or safety glasses and face shield on your forehead.  Must be shade 4 lenses.  2. Be sure regulator adjusting screws are turned out.  The screw should turn freely.

32 Lighting Procedure  3. Standing to one side, not directly in front of the regulator, open the oxygen cylinder valve slowly, then open it all the way.  Set the regulator at the correct working pressure.  Open the oxygen blowpipe valve and fine tune the operating pressure. Cutting- 40 psi Welding psi  Close the oxygen blowpipe valve.

33 Lighting Procedure  4. Standing to one side, not directly in front of the regulator, open the acetylene cylinder valve slowly.  Only open the tank valve ½ to ¾ of a turn.  Set the regulator at the correct working pressure.  Open the acetylene blowpipe valve and fine tune the operating pressure. Cutting psi Welding- 5-7 psi  Close the acetylene blowpipe valve.

34 Lighting Procedure  5. Put on gloves, and lower goggles or face shield over eyes.

35 Lighting Procedure  6. With the friction lighter in the left hand at the tip of the blowpipe, and the blowpipe in the right hand, open acetylene blowpipe valve with the right thumb and forefinger one-eighth to one-quarter turn.  Strike the friction lighter and adjust the acetylene level.

36 Lighting Procedure  7. Adjust the acetylene by opening the blowpipe valve until the flame leaves the tip about ¼ inch.  Close the valve very slowly until the flame is pulled back to the end of the tip.  Open the valve slowly again, stopping just before the flame leaves the tip.  This is the proper adjustment for most welding.

37 Lighting Procedure  8. Open oxygen blowpipe valve and set the desired flame type.

38 The correct shutting down procedure is as follows.

39 Shut Down Procedures  1. Close the acetylene blowpipe valve.  2. Close the oxygen blowpipe valve.  3. Close acetylene tank valve.  4. Close oxygen tank valve.

40 Shut Down Procedures  5. Open the acetylene blowpipe valve to drain the hose and release all pressure from the hose and regulator.  6. Turn out the pressure-adjusting screw on the acetylene pressure regulator by turning it counterclockwise.

41 Shut Down Procedures  7. Close the acetylene blowpipe valve.  8. Open the oxygen blowpipe valve to drain the hose and release all pressure from the hose and regulator.

42 Shut Down Procedures  9. Turn out the pressure-adjusting screw on the oxygen pressure regulator by turning it counterclockwise.  10. Close the oxygen blowpipe valve.  11. Wrap up hoses and put welding accessories in their proper place.

43 Fuel Gas Welding Techniques  setting the proper flame  preparing the pieces to be welded  knowing the common types of welds  holding and using the blowpipe and rod  completing the different types of welds.

44 Three types of oxyacetylene welding flames. 1. The neutral flame is usually used for welding. A neutral flame will produce a smooth, shiny bead of the best quality.

45 Three types of oxyacetylene welding flames. 2. The oxidizing flame is caused by an excessive amount of oxygen, which produces a short white inner cone and a short envelope flame.  An oxidizing flame will produce sparks that shower the weld area with droplets of metal and slag, leaving the weld zone weak and porous.

46 Three types of oxyacetylene welding flames. 1. The carburizing flame is caused by an excessive amount of acetylene and has a long, bluish outer flame.  A carburizing flame will cause the puddle to foam and boil, leaving a brittle, porous, and scaly weld area.  The carburizing flame is used for hard-surfacing.

47 Flame types CarborizingNeutral Oxidizing

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49 Review  Describe the oxyacetylene welding and cutting processes in agriculture  Distinguish parts and functions of oxyacetylene welding and cutting equipment and supplies  Describe safe practices in oxyacetylene welding and cutting  Describe the process of using oxyacetylene welding and cutting equipment


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