Cladding Materials Research and Application for Steel Rolling Guide Plates

Literature Overview

This 2009 publication by Wang Fengping, Li Gang, and Li Guoping, published in Powder Metallurgy Industry, addresses the practical engineering challenge of extending the service life of steel rolling guide plates through appropriate cladding material selection and application. The collaboration between Laiwu Vocational and Technical College and the Laiwu City Laicheng District Science and Technology Bureau reflects the applied nature of this research, which was driven by the specific wear problems encountered in steel rolling mills in the Laiwu region of Shandong Province. The authors provide a comprehensive evaluation of cladding materials and processes suitable for the demanding conditions of hot strip rolling guide applications.

Service Environment and Wear Mechanisms

Steel rolling guide plates operate under extreme conditions characterized by high temperatures (up to 1100 degrees Celsius for hot rolling), high mechanical loads, and continuous abrasive contact with moving steel strips. The primary wear mechanisms are abrasive wear from the steel strip surface, adhesive wear from metal-to-metal contact, and thermal fatigue from cyclic heating and cooling. The guide plate surface must maintain dimensional accuracy while resisting material loss, and the cladding layer must withstand these combined mechanical and thermal loads without cracking or spalling.

The following table summarizes the service conditions and the corresponding material requirements for steel rolling guide plate cladding.

Cladding Material Selection and Comparison

The authors evaluated several cladding material systems for guide plate applications. The primary candidates include high-speed steel based hardfacing alloys, cobalt-based hardfacing alloys, and cemented carbide composite overlays. Each material system offers distinct advantages and disadvantages for this application.

High-speed steel based alloys, such as those containing 4 to 6 percent vanadium and 1 to 2 percent tungsten, produce overlays with hardness of 60 to 65 HRC and good hot hardness retention. These alloys are cost-effective and readily available but may exhibit reduced wear resistance above 800 degrees Celsius due to carbide softening.

Cobalt-based alloys, such as Stellite-type compositions, offer superior hot hardness and thermal shock resistance but are significantly more expensive. The hardness of cobalt-based overlays remains in the 40 to 50 HRC range even at 900 degrees Celsius, making them suitable for the hottest sections of the guide plate.

Cemented carbide composite overlays provide the highest wear resistance but are susceptible to thermal shock and require careful application to avoid cracking. These are typically applied as discrete patches rather than continuous overlays.

Application Process and Quality Control

The application process for guide plate cladding typically involves the following sequence: surface preparation by machining or grinding to remove scale and ensure a clean substrate, preheating to 200 to 300 degrees Celsius to reduce thermal stress, multi-pass overlay welding using submerged arc welding or gas metal arc welding, post-weld machining to achieve final dimensions, and inspection to verify overlay integrity.

Quality control is critical for guide plate overlays. The following non-destructive testing methods are recommended: visual inspection for surface defects, magnetic particle testing for surface and near-surface cracks, ultrasonic testing for subsurface lack of fusion and porosity, and hardness testing to verify overlay composition and microstructure. The bond strength between the overlay and substrate should be verified by tensile or shear testing of coupon specimens.

Study Insights and Engineering Practice

This work demonstrates the practical engineering approach to cladding material selection, where the decision is driven by the specific service conditions rather than by theoretical optimization. The authors' evaluation methodology, which considers cost, availability, weldability, and performance under actual service conditions, is exemplary for applied engineering research. My reflection on this work is that it highlights the importance of understanding the actual wear mechanism in the service environment. In many cases, engineers over-specify cladding materials based on hardness alone, without considering the combined effects of temperature, load, and thermal cycling that govern actual wear behavior. The recommendation to use a combination of material systems, with cobalt-based alloys for the hottest zones and high-speed steel alloys for cooler zones, represents a sophisticated and cost-effective engineering solution. This approach of matching material properties to local service conditions is a principle that should be more widely adopted in industrial cladding applications. The work serves as a valuable reference for engineers tasked with solving wear problems in steel rolling and similar high-temperature abrasive environments.