1. What is Heat Input in Welding?

Definition: Heat input is the amount of energy transferred per unit length of weld, measured in kilojoules per millimeter (kJ/mm).

Purpose: It helps welders control the thermal effects on the material being welded, affecting mechanical properties and microstructure.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HI \) — Heat Input (kJ/mm)
• \( V \) — Voltage (V)
• \( I \) — Current (A)
• \( S \) — Travel Speed (mm/min)

Explanation: The product of voltage and current gives power (in watts), which is multiplied by 60 to convert to joules per minute, then divided by travel speed to get energy per unit length.

3. Importance of Heat Input Calculation

Details: Proper heat input control ensures weld quality, prevents defects, and maintains material properties. Different materials have specific heat input requirements.

4. Using the Calculator

Tips: Enter the welding voltage in volts, current in amperes, and travel speed in mm/min. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is heat input important in welding?
A: It affects weld penetration, microstructure, and mechanical properties. Too much heat can cause distortion, while too little may cause lack of fusion.

Q2: What's a typical heat input range?
A: It varies by material and process, but common ranges are 0.5-2.5 kJ/mm for most steels.

Q3: Why multiply by 60 in the formula?
A: It converts seconds to minutes (since watts are joules/second) and kilojoules to joules (1 kJ = 1000 J).

Q4: How does travel speed affect heat input?
A: Faster travel speed decreases heat input, while slower speed increases it, for the same voltage and current.

Q5: Does this formula work for all welding processes?
A: It works for most arc welding processes (SMAW, GMAW, GTAW, etc.), but efficiency factors may need to be considered for some processes.