Titanium plate, with its excellent mechanical properties, corrosion resistance, and low density, has shown broad application prospects in a wide range of fields, including aerospace, chemical equipment, medical devices, and marine engineering. Its unique properties play an irreplaceable role in numerous industries. Notably, the oxide film on the surface of the titanium plate hot rolling process acts as a natural, durable separator. Using a titanium seed plate reduces separator requirements, facilitating plate separation and eliminating the need for seed plate pre-treatment, further broadening the application range of the titanium plate.
So, how do we produce a suitable titanium plate? This is the core topic we will discuss today. First, a titanium plate is a general term encompassing various types, including hot-rolled plate, cold-rolled plate, coil, strip, and foil. Today, we will focus on the production process of hot-rolled titanium plate.
The production process of hot-rolled titanium plate consists of two key steps: slab production and plate rolling.
During the slab production stage, the titanium plate hot rolling process, like other titanium products, begins as a titanium ingot. However, the ingots used here are massive, weighing over 6-10 tons. Titanium ingots undergo a forging process to form titanium billets measuring 210x1100x8000mm. After the billets are completed, the black oxide layer on the surface must be removed. This process is typically performed using a large gantry milling machine to mill away the oxide scale on all four sides of the slab.
After understanding slab production, let's first clarify what hot rolling is. Hot rolling refers to rolling performed above the recrystallization temperature of the titanium billet. To facilitate understanding, imagine a common noodle press in northern China, and imagine the titanium sheet as noodles, undergoing multiple passes of pressing and rolling. Of course, the basic principles of actual titanium sheet production are similar, but the process is more complex and precise.
Titanium sheet rolling primarily involves four processes: heating, rough rolling, finish rolling, cooling, and surface treatment.
During the heating phase, the titanium slab is placed in a suitable temperature environment. The ideal heating temperature range for titanium sheet is 900°C to 1000°C. The heating and holding time is generally required to be at least 4-4.5 hours to ensure the titanium slab reaches the ideal rolling state.
During the rough rolling stage, the heated titanium billet is descaled with high-pressure water to remove surface oxide scale before entering the roughing mill for initial shaping. Rough rolling typically utilizes a reversing rolling process, such as a two- or four-high mill, to reduce the billet to an intermediate thickness through multiple passes. This stage may also include widening or shaping rolling to adjust the width and shape in preparation for subsequent finishing rolling.
During the finishing rolling phase, the intermediate billet undergoes head and tail trimming before entering a multi-stand finishing mill, such as a seven-stand four-high mill. Finishing rolling utilizes high-speed rolling and precise reduction control to reduce the material to its final thickness. Closed-loop shape control technology is employed to ensure dimensional accuracy and maintain standard titanium plate quality.
During the cooling and coiling phase, the finished titanium coil is rapidly cooled to coiling temperature via a laminar cooling system before being coiled by the coiler. The cooling process is dynamically adjusted based on the titanium grade and final rolling temperature to optimize material properties. The final product may require subsequent processing, such as bundling and labeling, for easier storage and transportation.
The hot rolling process offers the following significant advantages:
1. Energy efficiency: During hot rolling, the titanium plate hot rolling process exhibits excellent plasticity, low deformation resistance, and minimal work hardening, making them easier to roll. This reduces the energy required for metal deformation and lowers production costs.
2. High production efficiency: Hot rolling typically utilizes large ingots and high reductions, resulting in a fast production cycle and high output. This creates favorable conditions for large-scale production and meets the high market demand for titanium plates.
3. Optimized microstructure and properties: Hot rolling transforms the as-cast microstructure into a processed microstructure, significantly improving the material's plasticity. Furthermore, precise temperature control (850-950°C) and multiple rolling passes refine the titanium alloy's microstructure and optimize its properties, enhancing the overall performance of the titanium plates.
4. Property Anisotropy: The characteristics of the rolling process determine the anisotropy of the rolled plate's properties. This means that the material exhibits significant differences in properties longitudinally, transversely, and vertically, along with deformation and recrystallization textures, resulting in distinct directional characteristics in the punching performance. This characteristic must be considered during application to fully leverage the performance advantages of the titanium plate.
The titanium plate hot rolling process is a core technology for high-end metal processing. Although current technology has overcome industry bottlenecks such as rolling force fluctuations of ±5% and plate shape tolerances of ±0.1mm, continued innovation is still necessary to further advance the titanium plate hot rolling process, given the aerospace industry's demand for higher strength-to-toughness ratios in alloys such as TA15 and TC4.
