Surface Cladding of Side Press Modules Performance and Application

Literature Overview

This 2009 publication by Wang Guanghuan, Lin Tao, Jiang Guangbiao, and Li Xiaobing, affiliated with Shanghai Jiao Tong University, Baosteel Hot Rolling Plant, and Baosteel Research Institute, addresses the application of weld overlay cladding technology on side press modules used in hot rolling production lines. The paper was published in the journal Materials and Mechanical Engineering (机械工程材料) and represents an early systematic study on the performance evaluation and engineering deployment of cladding technology in heavy-duty hot rolling equipment. The authors combine academic research with industrial practice, which gives the paper significant engineering value.

Core Technical Content

The side press modules in hot rolling mills operate under extreme conditions involving high temperature, heavy mechanical load, and severe abrasive wear from scale and oxide debris. The base material is typically a low-alloy steel or carbon steel, which provides adequate structural strength but lacks sufficient surface hardness and wear resistance. The cladding process introduces a hardfacing alloy layer to improve the surface properties without compromising the bulk mechanical integrity.

Cladding Process Parameters

Parameter	Typical Range	Notes
Base material	Q345R / 16Mn	Structural steel for module body
Cladding alloy	High-carbon martensitic / Carbide-forming	e.g., Cr-Mo-V hardfacing
Welding method	SAW overlay / GMAW overlay	Depends on module geometry
Preheat temperature	200–300 °C	To prevent cracking
Interpass temperature	≤ 350 °C	Controlled cooling
Overlay thickness	3–8 mm	Depends on wear severity
Post-weld treatment	Stress relief 550–600 °C	To reduce residual stress

Key Performance Indicators

The study evaluates the cladding layer through several critical metrics: hardness (typically 45–60 HRC for martensitic hardfacing), wear resistance measured by pin-on-disc or block-on-ring tests, bond strength between the overlay and base metal, and impact toughness of the transition zone. The authors emphasize that the transition zone is the most critical region, as it is susceptible to microcracking and delamination under cyclic loading conditions.

Engineering Practice Insights

In hot rolling service, side press modules experience a combination of compressive loading, impact from scale ejection, and abrasive wear. The cladding layer must maintain its integrity under repeated thermal cycling between ambient and 800–1000 °C surface temperatures. The paper highlights that excessive preheat can reduce the hardness of the overlay layer due to softening, while insufficient preheat leads to cold cracking in the transition zone. This trade-off requires careful process optimization.

The study also discusses the importance of layering strategy. A single thick overlay layer tends to develop higher residual stress and is more prone to cracking. Multi-layer cladding with controlled interpass temperature is recommended. The authors note that for Baosteel's hot rolling line, the cladding life improvement was significant, extending service intervals by a factor of 2 to 3 compared to uncladded modules.

Defect Analysis and Countermeasures

Defect Type	Root Cause	Countermeasure
Cracking in transition zone	High carbon equivalent of base metal	Increase preheat to 250–300 °C; use low-hydrogen filler
Overlay delamination	Poor wetting at interface	Clean base surface; apply intermediate layer
Hardness variation	Inconsistent cooling rate	Control interpass temperature; use multi-pass strategy
Spatter-induced porosity	Gas shielding instability	Optimize gas flow rate and nozzle position

Study Reflections

This paper is valuable because it bridges academic research with industrial application in a clear and practical manner. The authors do not merely report laboratory results but also discuss field performance and maintenance considerations. One key insight is that the cladding process must be designed with the full service environment in mind, not just the wear mechanism. The thermal cycling in hot rolling is often underestimated in laboratory evaluations. Engineers should pay close attention to the transition zone design, as it is the most common failure location in practice. The work also underscores the importance of post-weld heat treatment to relieve residual stresses and stabilize the microstructure of the overlay layer.