How to Calculate Element Percentage in Weld Bead Using Dilution Formula
This tutorial explains how to calculate the percentage of a specific alloying element (e.g. C, Mn, Cr, Ni) in a weld bead based on contributions from base metal, filler metal, and other additives. This calculation is critical in welding metallurgy to predict the final chemical composition of the weld and ensure mechanical properties meet standards.
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Step 1: 📐 Formula Used:
Element Percentage in Weld Bead:
% Element in weld =
[ a × (%E in a) + b × (%E in b) + c × (%E in c) + d × (%E in d) ] ÷ (a + b + c + d) × 100
Where:
- a, b, c, d = amount (mass or weight) of each material contributing to the weld pool
- %E in a = percentage of element E in material a
- Result is the overall percentage of element E in the final weld metal
📉 Dilution Percentage Formula (Plain Text):
% Dilution = (Amount of base metal) ÷ (Total weld metal) × 100
🧪 Example 1 – Carbon Calculation:
Base metal: 60g, 0.2% Carbon
Filler metal: 30g, 0.1% Carbon
Flux: 10g, 0.05% Carbon
% Carbon = [60 × 0.2 + 30 × 0.1 + 10 × 0.05] ÷ (60 + 30 + 10) = (12 + 3 + 0.5) ÷ 100 = 0.155%
🧪 Example 2 – Chromium Calculation:
Base metal: 40g, 0.3% Chromium
Filler metal: 60g, 1.0% Chromium
% Chromium = [40 × 0.3 + 60 × 1.0] ÷ (40 + 60) = (12 + 60) ÷ 100 = 0.72%
