1. What is Welding Heat Input?

Definition: Welding heat input is a calculated value that represents the amount of thermal energy introduced into a material per unit length during welding.

Purpose: It helps welding professionals control the thermal effects on materials and ensure proper weld quality and mechanical properties.

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 the power, which is multiplied by 60 to convert to kJ/min, then divided by travel speed to get energy per unit length.

3. Importance of Heat Input Calculation

Details: Proper heat input control ensures adequate penetration, prevents defects, and maintains material properties within specified ranges.

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: Heat input affects the microstructure, mechanical properties, and potential for defects in the weld and heat-affected zone.

Q2: What are typical heat input ranges?
A: Typical ranges vary by process and material, but common values are 0.5-2.5 kJ/mm for most arc welding processes.

Q3: Why multiply by 60 in the formula?
A: The factor of 60 converts from joules/second (watts) to kilojoules/minute (1 W = 1 J/s × 60 s/min × 1 kJ/1000 J).

Q4: How do I measure travel speed?
A: Measure the time to complete a known length of weld, then calculate speed as length divided by time.

Q5: Does this apply to all welding processes?
A: This formula works for arc welding processes (SMAW, GMAW, GTAW, etc.) but may need adjustment for other processes.