1. What is Heat Input in Welding?

Definition: Heat input is a calculated value representing the amount of thermal energy transferred per unit length of weld.

Purpose: It helps welders control weld quality, penetration, and mechanical properties by quantifying the energy delivered to the weld.

2. How Does the Heat Input 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 (watts), multiplied by 60 converts to joules per minute, then divided by travel speed gives energy per unit length.

3. Importance of Heat Input Calculation

Details: Proper heat input ensures adequate penetration without excessive heat-affected zone (HAZ) size, controls cooling rates, and affects mechanical properties like toughness and strength.

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 directly affects weld quality, penetration depth, microstructure, and mechanical properties of the welded joint.

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

Q3: Why multiply by 60 in the formula?
A: To convert from joules per second (watts) to joules per minute, since travel speed is in mm/min.

Q4: How does travel speed affect heat input?
A: Faster travel speed decreases heat input, while slower speed increases it (inverse relationship).

Q5: Does this calculator work for all welding processes?
A: Yes, for arc welding processes (SMAW, GMAW, GTAW, FCAW, SAW) where voltage and current can be measured.