Application of Lincoln Welding Wire in Composite Cladding of Slab Continuous Casting Rolls

Literature Overview

This 1995 publication by Zhou Wusheng from the Tianjin Metallurgical Spare Parts Repair Center, published in Tianjin Metallurgy (天津冶金), documents the application of American Lincoln welding wire in the composite cladding of slab continuous casting rolls. The paper is notable for its early adoption of imported welding consumables in Chinese metallurgical equipment maintenance, reflecting the technological exchange and material development trends of the mid-1990s. The study provides practical data on the performance of Lincoln welding wire in the demanding environment of continuous casting.

Core Technical Content

Slab continuous casting rolls operate under extreme conditions involving high temperature contact with molten steel (1400–1500 °C), thermal shock, and mechanical loading from the solidifying shell. The roll surface must resist thermal fatigue cracking, abrasive wear from scale, and corrosion from slag and molten steel. The composite cladding process creates a hard, wear-resistant surface layer on the roll shell, which is typically made of cast steel or ductile iron.

Welding Wire Selection and Process

Parameter	Specification
Base material	Cast steel roll shell (e.g., ASTM A213 or equivalent)
Welding wire	Lincoln hardfacing wire (e.g., Lincoln Hardband or equivalent)
Wire type	Solid or flux-cored
Welding method	GMAW or FCAW overlay
Shielding gas	Ar / CO2 mixture
Overlay thickness	5–15 mm
Preheat temperature	150–300 °C

Performance Evaluation

The paper reports that the Lincoln welding wire produced a cladding layer with excellent hardness (50–65 HRC), good thermal fatigue resistance, and improved wear life compared to previously used domestic wires. The microstructure of the overlay consists of a martensitic or austenitic matrix with carbide precipitates, depending on the specific wire composition. The authors conducted field trials on continuous casting rolls and reported a significant extension of roll service life, reducing the frequency of roll replacement and downtime.

Engineering Practice Insights

The selection of welding consumables is critical for the success of cladding operations on continuous casting rolls. The Lincoln wire was chosen for its consistent composition, low hydrogen content, and excellent wetting characteristics. The paper emphasizes that the cladding process must be carefully controlled to avoid defects such as cracking, porosity, and lack of fusion. The thermal conductivity of the roll shell and the geometry of the roll surface present challenges for uniform heat input distribution.

Key Process Considerations

Consideration	Description
Heat input control	Maintain within 1.5–3.0 kJ/mm to avoid excessive dilution
Interpass temperature	Keep below 300 °C to prevent softening
Surface preparation	Grind to remove oxide and scale; expose clean base metal
Layering strategy	Multi-pass with cross-hatch pattern for uniform coverage
Post-weld inspection	MT or PT for surface defects; UT for subsurface defects

The authors also discuss the importance of the transition zone. The dilution between the base metal and the overlay layer can lead to a reduction in hardness and toughness. The Lincoln wire was selected partly because of its low dilution characteristics, which help maintain the overlay composition and properties. The paper notes that the thermal cycling resistance of the cladding layer is a critical factor, as the roll surface undergoes rapid heating and cooling during casting operation.

Defect Analysis

Defect	Cause	Prevention
Hot cracking	High sulfur and phosphorus in base metal	Use low-S, low-P filler; control heat input
Cold cracking	Hydrogen embrittlement	Use low-hydrogen wire; apply preheat
Roll surface distortion	Excessive thermal stress	Use balanced welding sequence; control heat input
Overlay spalling	Poor bond strength at interface	Ensure clean surface; use intermediate layer if needed

Study Reflections

This paper is a valuable historical document that captures the early adoption of imported welding consumables in Chinese metallurgical maintenance. The practical data on Lincoln wire performance in continuous casting roll cladding provides useful reference for current engineers evaluating consumable options. The study highlights the importance of consumable selection in determining the final performance of the cladding layer. Engineers should note that the continuous casting environment is unique in its combination of thermal shock, mechanical loading, and chemical attack, and the cladding process must be designed to address all these factors simultaneously. The paper also underscores the value of field trials in validating laboratory results and the importance of long-term performance monitoring.