Application of ESAB Strip Cladding Technology in Industrial Practice

Literature Overview and Technical Background

Strip cladding, particularly the electrode strip welding technology developed and commercialized by ESAB, represents one of the most widely adopted methods for producing bimetallic plates and clad components in heavy industry. The literature reviewed here focuses on the practical application of ESAB's electrode strip welding system, which employs a submerged arc welding (SAW) process using a continuously fed stainless steel or alloy strip as the facing material and a consumable carbon steel electrode as the backing material. The resulting weld overlay achieves a metallurgical bond between the corrosion-resistant facing layer and the structural base plate, combining economic strength with superior corrosion resistance.

The fundamental principle relies on the simultaneous melting of a solid alloy strip and a consumable electrode, with the molten metal pool cooled in a flux layer to produce a dense, low-porosity weld deposit. Typical deposit thicknesses range from 3 to 12 mm per pass, with overall cladding thicknesses of 3 to 25 mm achievable through single or multi-pass configurations. The literature emphasizes that the strip cladding process achieves deposition rates significantly higher than conventional multi-pass submerged arc welding, with productivity improvements of 50 to 80 percent compared to conventional SAW overlay methods.

Core Technical Parameters and Process Windows

The following table summarizes the key process parameters discussed in the literature for ESAB strip cladding applications:

The literature highlights that proper synchronization between strip feed rate and travel speed is the single most critical parameter for achieving sound weld quality. When the strip feed rate exceeds the travel speed, excessive dilution occurs, reducing the corrosion resistance of the overlay layer. Conversely, when the travel speed exceeds the strip feed rate, the weld pool becomes unstable, leading to incomplete fusion, undercuts, and porosity defects.

Metallurgical Bonding Mechanism and Dilution Control

A central theme in the literature is the metallurgical bonding mechanism between the cladding layer and the base plate. During the strip cladding process, the first layer of the overlay weld undergoes significant dilution from the base material, typically ranging from 20 to 40 percent. This dilution layer, often called the "transition zone," may exhibit reduced corrosion resistance compared to the pure overlay material. The literature recommends that for critical applications requiring high corrosion resistance, a minimum of two overlay passes should be applied, with the second pass achieving dilution below 10 percent.

Microstructural analysis of the cladding weld reveals a columnar grain structure growing from the fusion boundary into the weld metal. The columnar grains are characteristic of directional solidification and are influenced by the thermal gradient and growth rate. In stainless steel overlay cladding using 309L or 316L strips on carbon steel base plates, the transition zone typically exhibits a ferrite-austenite microstructure with increased ferrite content due to dilution. The literature notes that excessive ferrite content in the transition zone can lead to reduced ductility and increased susceptibility to intergranular corrosion, particularly in the 304 and 316 stainless steel systems.

The following table presents typical dilution levels and corresponding corrosion performance:

Common Defects and Countermeasures

The literature identifies several common defects encountered in strip cladding operations and provides systematic countermeasures:

Cracking is particularly problematic in strip cladding of low-alloy steel base materials with higher carbon equivalent values (CE > 0.45). The literature emphasizes that hydrogen-induced cracking can be effectively controlled by maintaining preheat temperatures above 150 °C for steels with CE between 0.40 and 0.55, and above 250 °C for steels with CE above 0.55. Post-weld heat treatment (PWHT) is recommended for critical applications to relieve residual stresses and further reduce hydrogen content.

Engineering Practice and Quality Control

In practical engineering applications, the literature describes quality control procedures that include visual inspection (VT) of the entire overlay surface, magnetic particle testing (MT) for surface and near-surface defects, and ultrasonic testing (UT) for bond integrity verification. For nuclear and pressure vessel applications, full radiographic testing (RT) of the overlay weld is typically required per applicable codes such as ASME Section VIII Division 2 or GB/T 150.

The literature also discusses the importance of mechanical property verification, including hardness testing across the weld cross-section to confirm proper dilution gradients, tensile testing of the overlay weld to verify adequate strength, and impact testing at service temperatures to ensure sufficient toughness. For corrosion-critical applications, intergranular corrosion testing per ASTM A262 Practice E or acid number testing per ASTM A923 may be required to verify the metallurgical quality of the overlay layer.

Study Insights and Engineering Implications

The most valuable insight from this literature is the emphasis on process synchronization and parameter control as the foundation of successful strip cladding operations. The literature demonstrates that even small deviations in strip feed rate relative to travel speed can lead to significant quality variations, underscoring the importance of automated feed systems with precise speed matching capabilities. Furthermore, the literature reinforces that strip cladding is not merely a welding operation but a specialized metallurgical process requiring careful consideration of base material chemistry, overlay material selection, thermal management, and quality verification protocols.

From a cost-benefit perspective, the literature confirms that strip cladding offers significant economic advantages over alternative cladding methods such as explosive cladding or roll bonding for moderate thickness requirements, while providing superior metallurgical bonding compared to mechanical bonding methods. The technology is particularly well-suited for large plate dimensions and production environments where consistent quality and high deposition rates are required. Engineers working in bimetal product manufacturing should prioritize investment in well-maintained strip cladding equipment and comprehensive welder qualification programs to maximize the benefits of this versatile technology.