Next Generation Cleaning for Welded Surfaces

NineSigma, representing Metalsa, a global Tier 1 Automotive Manufacturer of Structural Components, seeks efficient next generation technologies for the removal of silica contaminants on metal components produced by arc welding.

Metalsa produces a variety of steel assemblies using gas metal arc welding (GMAW). During this process, atmospheric oxygen combines with elements in the welding wire (for example, silicon, manganese and iron) to create ‘silica islands’.

These concentrations of undesirable contaminants cool down and remain in the weldment and its heat affected zone. These islands then prevent the proper adhesion of coatings intended to protect the surface from corrosion, leading to performance degradation during product usage.

Presently, Metalsa has two primary methods for removing silica islands: mechanical and chemical. 

Mechanical Removal

• Brushing
  • Effective but time consuming and labor intensive
• Shot blasting
  • Effective but can be difficult and/or expensive to implement for large items

Chemical Removal

• Acid Bath
  • Effective but can severely damage aluminum or zinc-coated steel pieces

Click here to view images of weld assemblies prior to and following a mechanical processing to remove silica islands (also available the bottom of the page). 

The client is seeking innovative new methods that are capable of efficient and complete removal of the silica islands from steel assemblies.

Anticipated Project Phases

Phase 1 – Review of Technologies

• To be completed Q1 2019

Phase 2 – Proof of Concept

• To be completed Q2/Q3 2019
• Selected technologies will demonstrate the effectiveness of the technology
  • Metalsa will send samples for cleaning

Phase 3 – Implementation

• Successful technology to be implemented at Metalsa facilities in late 2019 or early 2020

Criteria for Moving from Phase 1 to Phase 2

Metalsa will consider for advancement an approach that meets performance criteria with acceptable economics and pathway to commercialization. While commercially available technologies are of primary interest, Metalsa will also consider maturing technologies with a reasonably short timeline to commercial viability.

The successful technology will:

• Completely remove silica islands from steel substrate
• Have no negative impact on steel substrate
• Permit cleaning of a minimum of 70 assemblies per hour
  • Single assembly: 54-60 lineal feet of welding
• Be easily implementable into existing assembly lines
• Require zero or minimal capital investment
• Be robust and repeatable