The temperature of Oxidized flame in gas welding is
Gas Welding Flame Temperatures Explained
In gas welding, the type of flame used is very important for achieving a strong and proper weld. The flame is created by mixing a fuel gas, usually acetylene, with an oxidizer gas, typically oxygen. By changing the ratio of oxygen to acetylene, different types of flames can be produced, each having a different temperature and characteristic, making them suitable for welding different materials.
Types of Gas Welding Flames
There are three main types of flames produced in oxy-acetylene welding:
- Neutral Flame: This flame is produced when the ratio of oxygen to acetylene is roughly 1:1. It has a clear, well-defined inner cone, a luminous white envelope, and an outer blue envelope. It is called "neutral" because it does not add excess oxygen or carbon to the weld metal, making it the most commonly used flame for welding materials like steel, cast iron, and copper.
- Carburizing (or Reducing) Flame: This flame is produced when there is an excess of acetylene compared to oxygen. It has three distinct zones: a bright inner cone, an intermediate feathery white zone, and an outer blue envelope. The feathery zone indicates the presence of unburnt carbon particles. This flame adds carbon to the weld metal and is used for welding high-carbon steels, hard-facing, and surfacing applications.
- Oxidizing Flame: This flame is produced when there is an excess of oxygen compared to acetylene. It has a shorter, sharper, and bluish inner cone, a smaller luminous envelope, and a shorter outer envelope. The excess oxygen can react with the molten metal, causing oxidation. This flame is used for welding materials like brass and bronze.
Temperature of the Oxidized Flame in Gas Welding
Each flame type operates at a different temperature. The temperature is highest in the inner cone of the flame.
The neutral flame has a typical maximum temperature of about $3200^{\circ}\text{C}$.
The carburizing flame is slightly cooler than the neutral flame, with temperatures around $3000^{\circ}\text{C}$ to $3100^{\circ}\text{C}$.
The oxidizing flame is the hottest flame type in oxy-acetylene welding due to the excess oxygen available for combustion. Its temperature can reach higher values than the neutral flame. Based on common values associated with gas welding flames, a temperature around $3480^{\circ}\text{C}$ is considered characteristic of an oxidized flame.
Comparing Gas Welding Flame Temperatures
Here is a summary comparing the typical maximum temperatures of the different oxy-acetylene flame types:
| Flame Type | Oxygen:Acetylene Ratio | Key Characteristic | Typical Maximum Temperature |
|---|---|---|---|
| Neutral | ≈ 1:1 | Well-defined inner cone | ≈ $3200^{\circ}\text{C}$ |
| Carburizing | > 1:1 (Acetylene excess) | Feathery intermediate zone | ≈ $3000 - 3100^{\circ}\text{C}$ |
| Oxidizing | < 1:1 (Oxygen excess) | Short, sharp inner cone | ≈ $3300 - 3500^{\circ}\text{C}$ |
Therefore, the temperature of an oxidized flame in gas welding is approximately $3480^{\circ}\text{C}$, which is higher than that of the neutral or carburizing flames.
Revision Table: Gas Welding Flame Properties
| Flame Property | Neutral Flame | Carburizing Flame | Oxidizing Flame |
|---|---|---|---|
| Oxygen-Acetylene Ratio | Balanced (approx. 1:1) | Excess Acetylene | Excess Oxygen |
| Inner Cone Appearance | Sharp and distinct | Luminous, feathery edge | Short, sharp, pointed |
| Temperature (Max) | $\approx 3200^{\circ}\text{C}$ | $\approx 3000 - 3100^{\circ}\text{C}$ | $\approx 3300 - 3500^{\circ}\text{C}$ |
| Primary Use | General welding (steel, iron) | Hard-facing, surfacing | Welding brass, bronze |
Additional Information: Controlling Gas Welding Flames
Controlling the gas welding flame accurately is crucial for successful welding. The flame type is adjusted by regulating the flow rates of oxygen and acetylene using valves on the welding torch. Starting with equal pressures, the operator lights the acetylene and then gradually adds oxygen until the desired flame characteristic is achieved. The neutral flame is often the starting point, and then the oxygen or acetylene flow is adjusted to create a slightly carburizing or oxidizing flame as needed for the specific material being welded. Correct flame adjustment ensures proper heat input and avoids defects like oxidation or carbon pickup in the weld.
Important Questions from Welding
To weld metals together, high temperature is required. Such a high temperature is obtained by burning:
Which one of the following is not classified as a fusion welding process?
The material used for coating the electrode is called
When attaching a High-Speed Steel (HSS) cutting insert to a carbon steel tool holder, which joining technique is commonly used to ensure a strong bond without adversely affecting the heat treatment of the HSS?
- What is the primary action of the electrodes during resistance seam welding?
