The project goal is to implement silicate-free (SF) gas metal arc welding technology mitigating need for multipass weld inter-pass cleaning. The project objectives are:

  1. Develop matrix of welding procedures for tandem gas metal arc welding (T-GMAW) process (target implementation process) at min and max heat inputs for two HSLA-65 steel plate thicknesses.
  2. Evaluate T-GMA properties using representative welding procedure qualification tests.
  3. Evaluate soundness per MIL-STD-271 and Tech Pub -248 testing requirements.
  4. Evaluate procedure qualification (Bends, Tensiles, and Charpys) properties per

Tech Pub -248 procedure test requirements and compare results to MIL-70S-6.

  1. In addition, evaluate typical deposit composition, microhardness distribution

(maps) and microstructure to correlate any microstructure changes to


  1. Determine next steps to drive transition into shipbuilding.


In gas metal arc welding (GMAW) of shipbuilding steels, silicates (small slag islands) form on the weld deposit surface and must be removed during multi-pass welding of steel joints and before structure painting. Silicate cleaning processes have a negative impact on welding productivity. New GMAW electrode technology

needs to be developed and implemented to offer silicate free deposition and acceptable properties.

Key Deliverables / Benefits:

Silicate cleaning processes have a negative impact on welding productivity. Silicate cleaning can often take as long as welding. Multi-pass butt joint welding productivity can easily increase by 50 to 100% (2X) by eliminating inter-pass silicate cleaning procedures and minimizing visual examinations. This is a high priority at Ingalls and other shipyards to maximize return on investment of automated panel lines.

Point of Contact:

Dr. Dennis Harwig | EWI | dharwig@ewi.org


Welding Technology

Project Team:

  •  EWI, HII-Ingalls Shipbuilding, NSWCCD

 April 2023 – April 2024