Presentation on theme: "Oxyfuel Fusion Welding. 2 Definition A welding process that uses an oxyfuel flame to melt the steel piece(s) forming a pool (puddle) that when cooled,"— Presentation transcript:
Oxyfuel Fusion Welding
2 Definition A welding process that uses an oxyfuel flame to melt the steel piece(s) forming a pool (puddle) that when cooled, solidifies to form the joint. Oxyfuel fusion welding: How popular is the process today?
3 Preparing To Weld What safety preparations should be completed before attempting an oxyacetylene steel fusion weld? How does oxyfuel welding meet the three requirements of fusion welding 1.Heat 2.Shielding 3.Filler material
4 Five (5) Factors Which Control The Quality of Oxyfuel Fusion Welds. 1. Heat 2. Filler rod 3. Torch position 4. Travel Speed 5. Manipulation
5 1. Heat List the eight (8) ways that are used when oxyfuel fusion welding to control the heat of the weld. Heat is provided by a flame utilizing oxygen and acetylene gas. Based on the laws of physics, what two methods can be used to control the flow of a gas?
6 Heat #1.1 - Tip Size What determines the best tip size to use? Notice from the chart that tip sizes are not standardized.
7 Heat #1.2 - Fuel gas working pressure What determine the ideal working pressures? What is a possible problem with excessive working pressure? What is a possible problem with insufficient working pressure?
8 Heat #1.3 - Torch settings Torch setting refers to the position of the oxygen and acetylene torch valves. Which one of the torch valves controls the amount of heat? Which one of the torch valves controls the type of flame?
9 Oxyfuel Welding Tips On the system that we use what is normally called a welding tip is actually a welding tip and a mixing chamber. The welding tip can be purchased separately—reduces cost.
10 Using Tip Cleaner Start with the smallest size that will enter the orifice without excessive force and work up to orifice size. Be careful, a broken tip cleaner usually means a destroyed tip. Clean the face of the tip with the included file.
11 Heat #1.4 - Torch Angles Two welding angles are important in OxyFuel welding. –Work –Travel Will increasing the travel angle change the heat at the weld? Explain!
12 Heat # Travel Speed Why does changing the speed of travel change the temperature of the weld?
13 Heat #1.6 - Welding Rod Manipulation Manipulating the torch produces a wider bead. The heat of the flame is applied to a larger area--lower weld temperature.
14 Heat #1.7 - Size of welding rod Standard rods are 36 inches long and are available in a range of sizes from 1/16 to 1/4 inch diameter. A slightly larger or smaller rod than what is recommended can be used to manipulate the heat of the weld. –Explain!
15 Heat #1.8 - Distance from the torch to the metal The distance between the torch and the metal influences the temperature of the weld in two ways. 1.As the distance is increased the heat is spread over a wider area. This reduces the temperature of the weld. 2. The temperature of the flame is not uniform.
16 Heat #1.8 - cont. What is the distance? What is the critical distance when oxyfuel fusion welding called?
17 2. Filler Rod What are the desirable characteristics of the filler rod? How will use a rod larger or smaller than recommended affect the welding process?
18 3. Torch Position Critical torch positions are angle and height. Explain the effect of having incorrect angle and/or height.
19 4. Welding Speed Travel speed should be adjusted so that as the edges of the puddle melt they form a collapsed key hole at the front edge of the puddle each time the rod is dipped into the weld puddle. What factors determine the ideal speed of travel?
20 5. Manipulation Three common manipulation patterns: 1Circular/spiral 2C or crescent 3Dipping
21 Oxyfuel Welding Process
22 Seven (7) steps to Oxyfuel Welding 1.Prepare metal 2.Attach the correct welding tip 3.Turn on system 4.Set regulators to correct working pressure 5.Light the torch and adjust the flame 6.Form a puddle 7.Manipulate torch and filler rod (if used) to complete the weld
Prepare Metal You need to complete an oxyacetylene fusion weld on this piece of sheet metal. Should anything be done to the metal before you start? If so what?
2 – Attach the correct tip What determines the correct tip? 24 How should it be attached?
Turn On System What are the step for preparing an oxyacetylene system for use?
4 – Set Regulators How do you set the regulators to the correct working pressure? 26 What do you do if you set the pressure to high?
Lighting Torch & Adjusting Flame Should the acetylene or the oxygen torch valve be opened first? How far should you open the torch valve when starting the torch? Why?
5 – Lighting Torch and Adjusting Flame – cont. 28 Fusion welding requires a neutral flame. Describe a neutral flame.
29 6 – Form Puddle Hold torch stationary, or 1/8 circle, at the beginning of the weld until the molten puddle is formed. Note: The puddle should form in 3 to 4 seconds.
30 7 – Manipulate Torch and Rod Requirements; 1The torch must be moved to the back of the puddle before the rod is dipped in. 2The rod must be dipped into the molten puddle and withdrawn when the desired amount is melted off. 3The rod must stay within the outer flame. 4The rod a torch advance 1/8 – 3/16 inch each time the rod is withdrawn. Note: To produce a good weld the welder must practice until they can maintain a constant rhythm.
31 Joints & Spacing Use the correct joint preparation. Describe each one of these joints.
32 Acceptable Welds An acceptable weld has the designed strength and meets appearance standards. Strength –Bending –Tensile Appearance evaluation 1.Uniformity 2.Appropriate weld size 3.Penetration 4.Reinforcement 5.Undercutting 6.Starved joint
33 Unacceptable Welds 1.The weld doesn’t completely fill the joint. 2.Surface reinforcement is greater than 1/8 inch. 3.Undercutting is greater than 1/32 inch. 4.The weld breaks during a bend test. 5.The weld metal was not fused to the base metal. Five unacceptable fusion weld conditions: