Effect of Vanadium on Microstructure and High-Temperature Properties of Arc Cladding Layers on Semi-High-Speed Steel

Literature Overview

This paper by Zhang Yong and colleagues from Liaoning Technical University, published in 2021 in Materials Protection, investigates the influence of vanadium addition on the microstructure and high-temperature performance of argon arc cladding layers applied to semi-high-speed steel. The research was funded by the Liaoning Provincial Department of Education (project 19-1124) and focuses on the remanufacturing of semi-high-speed steel rolling mill rolls—a critical component in steel production that requires periodic restoration of surface dimensions and properties.

Core Technical Analysis

The study employs a systematic approach to evaluate the effect of vanadium content on cladding performance:

1. Process trials: Weld bead formation and wettability were assessed across different vanadium addition levels to establish the optimal range for weldability.
2. Metallographic examination and XRD phase analysis: The microstructural evolution and phase composition of the cladding layers were characterized to understand the relationship between vanadium content and microstructure.
3. High-temperature oxidation tests: The resistance of cladding layers to oxidation at elevated temperatures was evaluated, which is critical for the service conditions of rolling mill rolls.
4. Red hardness tests: The ability of the cladding material to maintain hardness at high temperatures was measured, a key property for hot-working applications.
5. Thermal fatigue tests: The resistance to cyclic thermal loading was assessed to simulate the repeated heating and cooling cycles experienced by rolling mill rolls in service.

Key Findings

The improvement in red hardness is attributed to the formation of vanadium carbides, which are known for their high hardness and excellent thermal stability. Vanadium carbides maintain their hardness at temperatures where iron carbides would soften, making them particularly valuable in hot-working applications.

Engineering Practice Implications

For engineers involved in the remanufacturing of steel mill rolls, this study provides actionable guidance on alloy design for cladding materials. The semi-high-speed steel rolling mill rolls used in finishing mills are subjected to severe thermal and mechanical loading, and the periodic remanufacturing of these rolls is a critical maintenance activity. The findings suggest that:

1. Vanadium addition should be optimized, not maximized: While vanadium improves high-temperature properties, excessive addition can compromise weldability and increase costs. The study's process trials provide the data needed to establish the optimal vanadium content range.
2. Cladding material selection should consider service temperature: The red hardness improvement from vanadium is most beneficial for rolls operating at higher temperatures, such as those used in hot band finishing mills.
3. Thermal fatigue resistance is as important as red hardness: In practice, rolling mill rolls fail through thermal fatigue cracking as much as through wear. The improvement in thermal fatigue resistance from vanadium addition addresses this failure mode directly.

The argon arc cladding process itself is well-suited to roll remanufacturing because it allows for controlled dilution and can be applied to worn surfaces without the need for complete roll replacement. The study's findings contribute to the development of cladding consumables that extend roll life and reduce maintenance costs.

Study Insights and Reflections

This study exemplifies the value of systematic alloy design in welding consumable development. The integration of process evaluation, microstructural analysis, and high-temperature property testing provides a comprehensive picture of how vanadium addition affects cladding performance. For engineers in the steel pipe and rolling mill industries, the key insight is that the selection of cladding alloy composition should be driven by the specific service conditions—temperature, load, and thermal cycling—rather than by generic property requirements. The vanadium carbide mechanism for red hardness improvement is well-established in metallurgy, but its application to argon arc cladding on semi-high-speed steel is a practical contribution that bridges fundamental metallurgy with industrial remanufacturing. The study reinforces the principle that welding consumable development must be an integrated process that considers both the welding process characteristics and the end-use performance requirements.