AWS A5.10 ER4043

Aluminum-Silicon Alloy, Welding Wire -- ER4043

Alloy 4043

Alloy 4043 is one of the oldest and most widely used welding and brazing alloys. Almigweld and Altigweld 4043 can be classed as a general purpose type filler alloy. The silicon additions result in improved fluidity (wet-ting action) to make the alloy a preferred choice by welders. The alloy is less sensitive to weld cracking and produces brighter, almost smut free welds.

General Information:

  • Trade designation: Almigweld and Altigweld
  • Non-Heat treatable
  • Similar to AISi5 (Germany), BS N21 (United Kingdom)
  • ISO designation: AISi5
  • Principle alloying elements: Silicon.


  • ANSI/AWS A5.10(ER&R)
  • AMS 4190
  • UNS A 9 4043
Nominal Chemical Composition (%)
Si Fe Cu Mn Mg Cr Zn V Ti Zr Al Be OE OT
4.5-6.0 0.8 max 0.30 max 0.05 max 0.05 max - 0.10 max - 0.20 max - BAL 0.0003 max 0.05 max 0.015 max