Titanium Alloy Grinding: Precision Surface Treatment

Titanium alloys play a pivotal role in high-end manufacturing fields such as aerospace, medical devices and chemical equipment due to their high strength, corrosion resistance and excellent biocompatibility. Grinding is the core surface treatment process for titanium alloys, which can improve the dimensional accuracy, surface finish and surface properties of workpieces. However, the special material properties of  titanium alloys  increase the difficulty of grinding and also drive the continuous innovation and upgrading of grinding technology.

Titanium Products in Ruihang

Titanium alloy grinding removes materials through the micro-cutting, sliding and ploughing effects of abrasive grains on the grinding wheel, realizing high-precision and high-surface-quality processing. It is a key surface process for precision titanium alloy parts such as aerospace blades and artificial joints. According to processing accuracy, it can be divided into three stages: rough grinding, semi-finish grinding and finish grinding. The processes are connected and coordinated to ensure processing quality.

Rough grinding adopts large-grit grinding wheels, and quickly removes excess materials with large grinding depth and feed rate, focusing on processing efficiency.

Semi-finish grinding uses medium-fine grit grinding wheels and lowers process parameters to repair surface defects caused by rough grinding.

Finish grinding selects fine-grit grinding wheels for low-speed and small-depth precision processing, which can stably control surface roughness. For high-end processing, the surface roughness can reach Ra ≤ 1.6μm or even nanoscale accuracy.

Titanium alloys have special physical and chemical properties, leading to high difficulty in grinding. Their thermal conductivity is far lower than that of steel and aluminum alloys, so grinding heat is difficult to dissipate, and the local maximum temperature can reach 1500℃.

At high temperatures, titanium alloys easily adsorb oxygen, nitrogen and hydrogen in the air to form brittle and hard oxide layers, causing surface hardening, burning and residual tensile stress of the workpiece, and reducing the fatigue performance and corrosion resistance of parts.

1. Key Process Pain Points Caused by Material Properties

Titanium alloys have high chemical activity and easily adhere to the grinding wheel material at high grinding temperatures, resulting in tool adhesion and wheel clogging, forming a vicious cycle, shortening the service life of the grinding wheel and increasing processing costs. Meanwhile, their low elastic modulus and high toughness lead to elastic deformation during grinding, increasing grinding force and producing defects such as scratches and chatter marks, which affect the stability of surface roughness.

The industry has made collaborative improvements in abrasives, processes and equipment to promote the upgrading of titanium alloy grinding towards high efficiency, precision and green development.

Traditional resin-bonded alumina materials are abandoned for grinding wheels, and special abrasives such as cubic boron nitride (CBN) and ceramic silicon carbide are used instead:

• CBN grinding wheels have high hardness and good thermal conductivity, with a service life 5 to 10 times that of ordinary grinding wheels;
• Ceramic grinding wheels have large pores and are not easy to clog, suitable for precision processing.
• Different abrasives have clear divisions of labor: silicon carbide is suitable for rough grinding, alumina is suitable for semi-finish and finish grinding, and diamond can meet the needs of high-end precision processing.

1. Optimization Principles and Practices of Grinding Parameters

Parameter optimization follows the principles of low-speed grinding, shallow grinding with fast feeding and staged control. By reasonably limiting the wheel linear speed, strictly controlling the grinding depth, matching the feed rate, and combining with spark-free grinding in the later stage of finish grinding, a gradient processing mode is formed, which can stably control the surface roughness of titanium alloys at Ra ≤ 1.6μm, balancing quality and efficiency.

2. Innovation and Application of Cooling Technology

Traditional cooling fluids have poor cooling effects and easily cause stress corrosion of workpieces. At present, new cooling processes such as high-pressure cooling, oil mist cooling, low-temperature cold air cooling and nanofluid cooling are adopted to reduce grinding temperature and wheel wear. Dry grinding realizes liquid-free green processing, which can efficiently grind titanium alloys, strengthen the surface, and avoid the problems of coolant pollution and recycling.

Ruihang Group mainly produces titanium products with the complete industry chain,including smelting,forging, straightening,rolling,surface treating,testing process. We are a technology and innovation enterprise that integrates R&D, production and sales into one integrated system. For any purchasing needs, feel free to contact us at email:Sam.Rui@bjrh-titanium.com