Linear Arc Welding Process

Linear arc welding is a commonly used welding process in which an electric arc is used to join two metal pieces together. The heat generated by the electric arc melts the metal, creating a weld pool that cools and solidifies to form a strong joint.

Heat Input

Heat input is an important parameter in the welding process as it determines the efficiency and quality of the weld. It is defined as the amount of heat energy supplied to the weld per unit length. Heat input is influenced by various factors, including welding current, welding voltage, welding speed, and duty cycle of the power source.

Inverse Proportionality

The question states that the heat input per unit length is inversely proportional to the welding speed. This means that as the welding speed increases, the heat input per unit length decreases, and vice versa.

Explanation

- Welding current: The welding current is the amount of electric current flowing through the welding circuit. It directly affects the heat generated by the electric arc. Higher welding current results in a higher heat input per unit length, as more heat is generated. Therefore, it is not inversely proportional to the heat input.

- Welding voltage: The welding voltage is the electrical potential difference between the electrode and the workpiece. It determines the intensity of the electric arc and affects the heat generated. However, it does not directly affect the heat input per unit length. Therefore, it is not inversely proportional to the heat input.

- Duty cycle of the power source: The duty cycle is the ratio of the welding time to the total cycle time. It represents the percentage of time that the welding machine can be operated continuously at a given current without overheating. While the duty cycle affects the overall efficiency of the welding process, it does not directly influence the heat input per unit length. Therefore, it is not inversely proportional to the heat input.

- Welding speed: The welding speed is the rate at which the welding torch moves along the joint. It determines the time available for heat transfer and solidification of the weld pool. As the welding speed increases, the heat input per unit length decreases because the weld pool has less time to absorb the heat. On the other hand, at lower welding speeds, the weld pool has more time to absorb the heat, resulting in a higher heat input per unit length. Therefore, the heat input per unit length is inversely proportional to the welding speed.

Conclusion

In a linear arc welding process, the heat input per unit length is inversely proportional to the welding speed. As the welding speed increases, the heat input per unit length decreases, resulting in a more efficient and controlled welding process.