Materials Joining And Technology

Emerging challenges

A survey conducted in July 2010 by the Edison Welding Institute set out to identify emerging materials joining business challenges and technology needs among several manufacturing sectors. Those sectors include automotive, oil and gas, defense, aerospace, heavy manufacturing and advanced energy, among others. Several themes were identified from the results of the survey.

Advanced Materials
The increased use of new materials and material combinations was identified to be the number one materials joining challenge (Table 1). This was the highest ranked challenge for both the automotive and advanced energy sectors (yellow highlights), and was ranked in the top four challenges across all sectors.

The technology needs rankings (Table 2) also reveal a need for technologies to join advanced materials (ranked first overall) and dissimilar materials (ranked fourth overall). This finding is consistent with a 2007 survey in which joining of high-performance and dissimilar materials were ranked second and third, respectively. These results reflect the fact that product designers are incorporating new materials and material combinations to meet performance and cost targets. For example, the need to reduce weight in automotive structures is necessitating increased use of high-strength steels, aluminum, magnesium and composites. Introduction of new materials can have a dramatic impact on many manufacturing operations, including joining, inspection and forming.

Friction Stir Weld in ¾-inch-thick high-strength steel

Friction Stir Weld in ¾-inch-thick high-strength steel

To meet the challenge, a focus will be placed on friction stir welding methods for joining high-strength steel (Figure 1) and titanium alloys in thicknesses up to one inch. Dissimilar metal joining, including inertia friction welding of aluminum to steel (Figure 2), is another focus area, as is non-destructive evaluation (NDE) methods for welds in advanced materials. For example, EWI has developed and field tested a matrix phased array ultrasonic testing system for more efficient and accurate characterization of automotive spot weld quality in advanced high-strength steels. Forming of advanced materials is another, including modeling of forming processes to predict spring-back and microstructure.

Workforce
Another theme is the ongoing concern about the availability of knowledgeable workforce in some sectors. For example, in the oil and gas sector, the shortage of engineers and designers with materials joining expertise ranked as the highest challenge (Table 1). The desire to improve workforce knowledge is also reflected in the challenge of keeping staff current on the latest materials joining processes and methods (ranked fourth overall in Table 1), and in the need to educate engineers and designers on joining alternatives (ranked second in Table 2). Providing online access to materials joining data and expertise (ranked fifth in Table 2) is one means to help expand the workforce knowledge base.

Aluminum to steel friction weld in 4.75-inch pipe

Aluminum to steel friction weld in 4.75-inch pipe

 The availability of skilled trades is also a workforce concern. For heavy manufacturing, the highest ranked challenge (Table 1) is the shortage of skilled welders and other skilled trades. This corresponds to the technology need (Table 2) for improved welder training methods.

Technology Advancement and Deployment
The survey brought to light the need to more effectively mature and introduce advanced manufacturing technologies. This theme is evident in several of the identified challenges (Table 1), including qualifying new processes (ranked second overall), maturing and transitioning technologies (ranked third) and the cost to introduce new technologies (ranked eighth). This theme is also reflected in the need for a validation strategy for new processes (Table 2).

Some solutions being considered include advanced hybrid laser-arc welding processes, a high-deposition rate narrow groove arc welding process for joining thick sections, improved resistance welding control strategies and a high-power ultrasonic metal deposition technology for additive manufacturing of metal components.

Technology Acceleration
The pace of manufacturing technology change continues to accelerate. It is necessary to understand the emerging needs of industry in order to identify those technologies that will have the greatest impact across various manufacturing sectors.

Gases and Welding Distributors Association
Chris Conrardy Meet the Author
Chris Conrardy is chief technology officer at EWI located in Columbus, Ohio, and on the Web at www.ewi.org.