What Is The Plastic Processing Technology For Gr5 Titanium Plates?

Gr5 titanium plate  is the most widely used α-β type titanium alloy plate. Its plastic processing lies in the precise control of parameters such as temperature, deformation, and speed. By regulating the evolution of the α/β phase microstructure, it can balance the mechanical properties and dimensional accuracy.

 

 

Gr5 titanium plate contains titanium (Ti) as the base metal, alloyed with 5.5~6.75% aluminum (Al) and 3.5~4.5% vanadium (V), with trace impurity elements strictly controlled in accordance with ASTM B265 standards. It exhibits poor room-temperature plasticity, significant work hardening, and low thermal conductivity, and is prone to reactions with oxygen and nitrogen at high temperatures, with a β transformation point of approximately 995℃.

Plastic processing must be carried out in the isothermal region of the α+β dual-phase zone to prevent grain coarsening and cracking. The core objectives are to weaken the structural anisotropy, precisely control the grain size, and reduce oxidative contamination.

 

 

 

 

(1) Raw Material Pretreatment and Blank Preparation

Raw material pretreatment is very important to the process. It is necessary to verify the ingot grade, composition, appearance, and dimensional deviation in accordance with standards, grind and remove the surface gas-absorbing layer, and strictly control interstitial elements to prevent embrittlement.

The ingot is subjected to multi-pass heavy deformation forging and blooming in the α+β dual-phase zone at 850-950℃. After forging, the slab undergoes homogenization annealing to achieve fine grains, eliminate stress, and improve plasticity.

 

(2) Hot Rolling Process

Heating and Descaling

The slab is heated and insulated at a controlled temperature in a walking beam heating furnace. A low-oxygen/inert atmosphere is used to prevent oxidation, and infrared precise temperature control is adopted. After exiting the furnace, high-pressure water descaling is performed to completely remove the oxide scale.

 

Rolling Parameters

A combined rolling process of flat rolling + steckel rolling is adopted. Four-high flat rolling is combined with vertical rolling for width control, and the steckel mill provides on-line heat preservation. The rolling process is regulated through the AGC/AWC system, and the roll cooling intensity and rolling passes are controlled to ensure dimensional accuracy and uniform structure.

 

Post-Rolling Straightening

The coil is uncoiled and straightened at a constant temperature, with precise control of the reduction amount to ensure the flatness of the plate without defects such as springback and waviness.

 

(3) Cold Rolling Process: Precision Improvement and Surface Optimization

Cold rolling is used to produce thin-gauge Gr5 titanium plates with a thickness of ≤3mm. Room-temperature/low-temperature plastic deformation is employed to improve dimensional accuracy, surface quality, and strength. Due to the limited plasticity of the crystal structure at room temperature, a cyclic process of small deformation + intermediate annealing is adopted.

 

The pass reduction rate is adapted to the thickness and strictly controlled to prevent cracking and wrinkling. Work hardening is significant, so after each deformation pass, intermediate annealing is performed at 700-800℃ with air cooling to eliminate stress and restore plasticity. Cold rolling has strict requirements for rolls and lubrication. High-precision finishing rolls with Ra≤1.8μm and special lubricants must be used to avoid scratching and roll sticking.

 

The finished thin plate has a smooth surface and extremely small thickness tolerance. After cold rolling, the tensile strength reaches 1170MPa, and the strength and hardness are significantly improved. To address cold rolling springback, numerical simulation is used to predict the springback amount, optimize roll parameters and reduction paths, and perform secondary straightening if necessary to ensure dimensional accuracy.

 

(4) Heat Treatment Process: Precise Performance Regulation

Annealing Treatment

It is divided into stress relief annealing and full annealing. The former eliminates residual stress to prevent deformation, while the latter refines grains, improves plasticity and toughness, and reduces anisotropy, making it suitable for stamping and bending processes. Annealing at a specific temperature can obtain an ideal equiaxed grain structure, achieving optimal comprehensive performance.

 

Solution and Aging Treatment

The core purpose is to improve the strength of the plate. The basic process involves solution water quenching followed by aging air cooling to meet the requirements of high-strength applications. The double aging process can further optimize the strength-plasticity matching and improve the overall comprehensive performance.

 

(5) Finishing and Surface Treatment

After heat treatment, it is required to cut and stack with burr-free cuts and precise dimensions in order to meet customer needs. Surface treatment is customized according to requirements: electric polishing for medical applications, anodizing/sandblasting for marine and chemical applications, and ion implantation to improve surface hardness and wear resistance.

 

 

 

Ruihang has 13 years of professional experience in manufacturing titanium and titanium alloy products,covering titanium plates, bars, forgings, wires etc. For more detailed product information, please contact us via email: Sam.Rui@bjrh-titanium.com.