In the field of metal composite materials, titanium-steel composite plates, with their unique performance advantages, have broad application prospects in a wide range of industries, including aerospace, marine engineering, and the chemical industry. As one of the key methods for producing titanium-steel composite plates, hot rolling, with its process characteristics, key technical points, and challenges, has attracted considerable attention not only within the industry but also from the titanium industry itself, undoubtedly fueling further excitement and anticipation for the development of this field.
Basic Process of Hot Rolling Production
Hot rolling production of titanium-steel composite plates begins with a critical assembly step: forming a composite of an iron-based material and a titanium cladding material, with the coating covering at least one edge of the cladding surface. The cladding of the base material is crucial in this process, and 20 to 30 g/m² of Mo (molybdenum) or V (vanadium) is required. After assembly, the material is heated to its melting point and then oxidized at temperatures between 50°C and 1050°C. This oxidation step reduces titanium oxides, creating favorable conditions for the subsequent hot rolling process. The oxidized material is then ready for hot rolling.
Oxide Addition and Temperature Control
Among the process parameters of hot rolling, oxide addition and heating temperature control are two key elements.
Oxide Addition
To optimize the hot rolling process and improve the quality of composite plates, specific oxides need to be added. MoO₃ (molybdenum trioxide) and V₂O₅ (vanadium pentoxide) are commonly used additives. These oxides play a vital role in the hot rolling process. They participate in chemical reactions, improve the interfacial bonding between the materials, and strengthen the bond between titanium and steel, thereby enhancing the overall performance of the composite plate.
Temperature Control
The heating temperature has a direct impact on the hot rolling results. Different process stages and material combinations have different heating temperature requirements. When adding MoO₃, the heating temperature should be controlled between 845°C and 1050°C; when adding V₂O₅, the heating temperature range is 740°C to 1050°C. Precise temperature control ensures the material maintains optimal plasticity during the hot rolling process, allowing titanium and steel to fully fuse, while also preventing degradation of material properties or defects caused by excessively high or low temperatures.
Advantages and Applicability of Hot Rolling Technology
Hot rolling for producing titanium-steel clad plates offers remarkable cladding properties and is relatively cost-effective. In the production of stainless steel clad plates, hot rolling is a popular process due to its efficiency, continuity, and suitability for large-scale production. However, applying hot rolling to the production of titanium-steel clad plates presents numerous challenges.
Challenges in Hot Rolling Production of Titanium-Steel Clad Plates
Titanium is a highly reactive metal. At high temperatures, it readily reacts with oxygen in the air to form titanium oxide, which also chemically reacts with other metals. This characteristic predisposes the titanium surface to an oxide layer during hot rolling, impairing its bonding with steel. Furthermore, achieving a satisfactory cladding effect is challenging because the reactivity of titanium at high temperatures leads to complex interactions between the cladding material and the titanium, making it difficult to maintain a stable cladding state.
Countermeasures and Cost Issues
To address the problem of titanium reacting with iron during hot rolling and forming compounds at the boundary, a barrier material must be added between the titanium and base material to form a barrier. These materials are preferably metallic, as they are more compatible with both titanium and iron, effectively preventing direct contact and reaction between them. However, these barrier metals are often precious metals, such as the aforementioned Mo and V, which are relatively expensive. This significantly increases the production cost of titanium-steel composite plates, making them relatively expensive in the market and limiting their large-scale application in cost-sensitive applications.
To address the problem of titanium reacting with iron during hot rolling and forming compounds at the boundary, a barrier material must be added between the titanium and base material to form a barrier. These materials are preferably metallic, as they are more compatible with both titanium and iron, effectively preventing direct contact and reaction between them. However, these barrier metals are often precious metals, such as the aforementioned Mo and V, which are relatively expensive. This has led to a significant increase in the production cost of titanium-steel composite plates, making them relatively expensive in the market, limiting their large-scale application in some cost-sensitive fields.
