UNIT 4: OXYACETYLENE WELDING AND CUTTING IN AGRICULTURE

Objectives

4.1 Define terminology4.2 Describe the oxyacetylene welding and

cutting processes in agriculture4.3 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

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

4.1 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

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

4.2 Describe the oxyacetylene welding and cutting processes in agriculture

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?

Relate welding and cutting processes to different kinds of metal

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

Regulators

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

Protector Cap

Protects valve from being knocked off Must be in place when Regulators are off

Backflash Arrestor

Torch / Manifold Regulator / torch

Hoses

Acetylene = Red Notch around nut means LH thread

Oxygen = Green RH Thread

New Hoses have talc inside - Blow out before connecting to torch

Needle valves

What each does Preheat / Cutting hole

pressures Tightening

Torch Body

single stage / dual stage

Distinguish between welding and cutting components of oxy-acetylene equipment

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

needle valve setting

Welding Tip

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

4.4 Describe safe practices in oxyacetylene welding and cutting

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

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.

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!!

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 - 2120 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

Identify practices to follow in safely storing and using compressed gas Oxygen Cylinders

Pressure is about 2200 psi at 700 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

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

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

4.5 Describe the process of using oxyacetylene welding and cutting equipment

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.

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- 15-20 psi

Close the oxygen blowpipe valve.

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- 7-10 psiWelding- 5-7 psi

Close the acetylene blowpipe valve.

Lighting Procedure

5. Put on gloves, and lower goggles or face shield over eyes.

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.

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.

Lighting Procedure

8. Open oxygen blowpipe valve and set the desired flame type.

The correct shutting down procedure is as follows.

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.

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.

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.

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.

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.

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.

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.

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.

Flame types

Carborizing Neutral Oxidizing

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