As an important component in the mechanical field, titanium castings have been widely used. Compared with traditional metal castings, titanium castings have the advantages of being light, strong, and corrosion-resistant, and therefore have important applications in aviation, aerospace, automobiles, medicine, and other fields. However, when using titanium castings, material selection and testing are very important links. These two aspects will be elaborated below.
1. Material selection for titanium castings
1)Type selection of titanium alloy
When selecting titanium casting materials, different titanium alloys need to be selected according to the actual application environment. There are currently many types of titanium alloys, such as α+β type, β type, α type, and other types. Among them, GR2, TA6V, GR5, Ti-6242, etc. are commonly used.
GR2 titanium alloy is a commonly used titanium alloy with good processability, weldability, high plasticity, good low temperature, micro-corrosion, and resistance to hot steam.
TA6V alloy is a typical α+β titanium alloy with high strength, corrosion resistance, and fatigue properties, and is widely used in aviation and aerospace fields.
GR5 alloy is a relatively uniform composition among α+β titanium alloys and has high mechanical properties and good corrosion resistance.
Ti-6242 alloy is a β-type titanium alloy with high strength, high plasticity, and good thermal expansion properties, and is widely used in the field of aviation manufacturing.
2)Purity requirements of titanium alloys
Titanium alloy is composed of titanium and other metallic elements. Purity requirements have a great impact on the mechanical properties, physical properties, and process properties of titanium alloys. The total amount of impurities corresponding to purity is usually required to be less than 0.1%.
3) Influence of other product requirements
When selecting titanium casting materials, the impact of other product requirements on the material must also be considered. Factors such as product performance requirements and usage requirements, production process status and development trends will all affect the selection of materials.
2. Inspection of titanium castings
1) Appearance inspection of titanium castings
When producing titanium castings, visual inspection must first be carried out to find corresponding defects. Appearance inspection requires naked-eye observation first, and then microscopic inspection with a magnifying glass or microscope to determine the inspection data of titanium castings.
2)X-ray detection
X-ray inspection is a non-contact inspection method that can be used to detect internal defects in titanium castings. Through X-rays entering the interior of titanium castings and recording the absorption of X-rays by titanium castings, internal defects of titanium castings can be discovered.
3)Ultrasonic testing
Ultrasonic testing is also a non-contact testing method, suitable for the detection of surface defects and internal defects. Ultrasonic testing requires the use of specialized ultrasonic probes to use the energy of sound waves to detect material defects.
4)Magnetic particle testing
Magnetic particle testing is an important method for detecting surface defects of titanium castings. It uses magnetic particle particles as a medium and sprays them on the surface of titanium castings. The magnetic particle particles are gathered on the surface of titanium castings through the action of a magnetic field, thereby discovering surface defects.
5) Coating inspection
Coating inspection is the detection of defects such as coating adhesion, surface topography, and texture. Coating inspection usually uses optical microscopes, scanning electron microscopes, and other inspection methods.
6) Routine physical performance testing
Conventional physical property testing is for mechanical property testing, chemical property testing, thermodynamic property testing, and other aspects of titanium castings. Commonly used conventional physical property tests include tensile tests, impact tests, hardness tests, chemical tests, etc.
