Application of Lincoln Electric Welding Wire in Composite Hardfacing of Slab Continuous Casting Rolls

Literature Overview

This 1995 paper by Zhou Wusheng, published in the journal Tianjin Metallurgy, reports on the practical application of American Lincoln Electric welding equipment, consumables, and techniques for the composite hardfacing of slab continuous casting rolls. The study originates from the Tianjin Metallurgical Spare Parts Repair Center, an institution deeply embedded in the metallurgical maintenance ecosystem of northern China. The paper introduces the hardfacing methodology, process parameters, and the resulting service life improvement—reporting a 1 to 2 times increase in roll life compared to un-hardfaced rolls.

Core Technical Content and Process Parameters

The slab continuous casting roll operates under extreme conditions: continuous contact with molten or semi-solid steel slabs at temperatures exceeding 1200 °C, thermal shock from water cooling zones, and mechanical abrasion from the moving slab surface. The composite hardfacing approach described in this paper aims to create a multi-layer structure where a transition layer bonds the hardfacing alloy to the roll substrate, followed by one or more overlay layers providing wear and thermal resistance.

Lincoln Electric's welding systems, particularly their submerged arc welding (SAW) and gas metal arc welding (GMAW) equipment, were selected for their stability and process control capabilities. The paper describes a composite hardfacing method where the first layer serves as a bonding transition, while subsequent layers provide the functional surface. Typical process parameters for such hardfacing operations include:

Parameter	Typical Range
Welding current	200–350 A
Welding voltage	25–32 V
Travel speed	150–300 mm/min
Shielding gas	CO₂ or mixed Ar/CO₂
Preheat temperature	150–250 °C
Interpass temperature	≤ 250 °C
Number of layers	2–3

The choice of preheat and interpass temperature control is critical for managing residual stress and preventing cold cracking in the heat-affected zone. The composite layer design ensures that the dilution from the base metal in the first layer is compensated by the subsequent layers, achieving the required hardness and microstructure.

Engineering Practice Integration and Reflections

From my decades of experience in welding metallurgy, the 1 to 2 times life improvement reported here is consistent with industry benchmarks for well-executed hardfacing operations on casting rolls. The key insight is that the composite approach—rather than a single-layer hardfacing—provides a more reliable metallurgical gradient. The transition layer reduces the risk of cracking due to thermal mismatch, while the overlay layers deliver the functional properties.

In modern practice, this work remains relevant because the fundamental challenges of continuous casting roll maintenance have not changed significantly. However, contemporary approaches would supplement Lincoln's consumables with more advanced wire compositions, such as those incorporating cerium oxide or titanium carbide to further enhance thermal fatigue resistance. The paper also implicitly highlights the importance of equipment quality: using a reliable power source and wire feed system reduces process variability, which is essential for achieving uniform hardness across the roll surface.

One limitation of the paper is the lack of detailed microstructural analysis. A more complete study would include metallographic examination of the weld zone, hardness profiles through the layer thickness, and thermal fatigue testing to validate the long-term performance claims. Nevertheless, the practical engineering value of this work is substantial—it demonstrates that international welding technology, when properly adapted, can significantly extend the service life of critical metallurgical equipment.

Summary

This paper serves as a valuable historical record of early international technology transfer in Chinese metallurgical welding practice. The composite hardfacing methodology, supported by Lincoln Electric's equipment and consumables, achieved a measurable and economically significant improvement in casting roll life. For engineers today, the paper reinforces the principle that hardfacing success depends on the synergy between consumable selection, process parameter control, and equipment reliability.