Blast Furnace Receiving Hopper and Distributor Lining Plate Surfacing and Insert Block Technology

Literature Overview and Background

The paper authored by Wang Lichuan and colleagues from Shandong Metallurgical Research Institute and Jinan Iron and Steel Group Corporation, published in Shandong Metallurgy in 2003, addresses a critical wear-resistant engineering challenge in blast furnace operations. The receiving hopper and distributor in a blast furnace are subjected to continuous impact and abrasion from burden materials such as iron ore, coke, and flux. The conventional Mn13 high-manganese steel lining plates, while possessing good toughness, suffer from insufficient hardness under non-impact loading conditions, leading to rapid wear and short service life. This paper presents a novel composite lining plate technology that combines a structural base plate with surfacing-welded wear-resistant alloy layers and TiC-steel insert blocks, achieving a five to eight-fold improvement in service life compared to traditional Mn13 steel.

Core Technical Approach

The fundamental design philosophy of this technology is a layered composite approach, separating the structural support function from the wear-resistant surface function. The base plate is fabricated from cast steel or Q235 carbon steel, which provides adequate structural integrity and weldability at reasonable cost. The wear resistance is then achieved through two complementary mechanisms: surfacing welding of a hardfacing alloy and mechanical insertion of TiC-steel composite blocks.

Base Plate Selection and Preparation

The choice between cast steel and Q235 steel as the base material depends on the specific loading conditions and fabrication constraints. Cast steel offers better conformability for complex hopper geometries, while Q235 steel provides superior weldability and is more readily available in plate form. The base plate thickness is typically selected to withstand the combined thermal and mechanical loads without excessive deformation. Surface preparation prior to surfacing is critical and includes grinding to remove mill scale, degreasing, and preheating to 200-300 degrees Celsius to prevent cold cracking in the subsequent welding operations.

Surfacing Welding Alloy Design

The surfacing alloy is designed to achieve a hardness of 50-60 HRC while maintaining adequate toughness to resist spalling under impact loading. The alloy typically contains a high proportion of chromium, with additions of molybdenum and vanadium to form fine, uniformly distributed carbides. The surfacing is applied using flux-cored arc welding (FCAW) or submerged arc welding (SAW) in multiple passes, with interpass temperature controlled below 250 degrees Celsius to prevent grain coarsening in the weld metal.

TiC-Steel Insert Block Integration

The TiC-steel insert blocks represent the most innovative aspect of this technology. Titanium carbide possesses an extremely high hardness (2500 HV) and excellent thermal stability, making it ideal for abrasive wear environments. The insert blocks are fabricated by embedding TiC particles in a steel matrix and are mechanically pressed or welded into pre-formed grooves on the base plate surface. The key to successful integration lies in ensuring metallurgical bonding between the insert blocks and the surrounding surfacing layer, which requires careful control of welding parameters to avoid excessive thermal input that could degrade the TiC particles.

Performance Data and Engineering Evaluation

The field application results demonstrate that the new lining plate technology extends service intervals by a factor of five to eight, translating into substantial reductions in maintenance downtime and replacement costs. The composite structure also provides a degree of self-repair capability, as the softer steel matrix around the TiC insert blocks can deform plastically to accommodate minor misalignments and thermal cycling.

Engineering Practice Insights and Recommendations

From a practical standpoint, several considerations merit emphasis. First, the transition zone between the base plate and the surfacing layer is the most vulnerable region for crack initiation, particularly under thermal cycling conditions. It is recommended to apply a transition layer of low-carbon, high-toughness alloy between the base plate and the hardfacing alloy to mitigate residual stress concentration. Second, the TiC insert blocks require precise dimensional control during fabrication to ensure uniform contact pressure with the base plate surface. Third, the surfacing welding process should incorporate a multi-pass strategy with careful interpass temperature management to achieve a homogeneous microstructure in the weld overlay.

A potential area for further development is the application of this composite lining concept to other high-wear components in the blast furnace system, such as the tuyere raceway and the furnace throat. The layered approach of combining a ductile substrate with a hard surface layer is a well-established principle in tribology, and its successful implementation in this context validates the concept for broader industrial adoption. The technology represents a practical and cost-effective solution to a persistent engineering problem, demonstrating how composite material design can significantly extend component life without requiring exotic base materials.

Study Reflections

This paper exemplifies the engineering pragmatism that characterizes effective materials selection and process design. Rather than seeking a single material that excels in all properties, the authors adopted a composite strategy that leverages the strengths of different materials in their optimal roles. The base plate handles structural loads, the surfacing alloy provides baseline wear resistance, and the TiC insert blocks deliver peak hardness where abrasion is most severe. This philosophy is directly transferable to pipe fitting and pipeline engineering, where similar composite approaches—such as overlaying carbon steel pipe with corrosion-resistant alloy cladding—have proven equally effective in extending service life and reducing lifecycle costs.