Cutting and welding TA2 titanium plate are common processes in titanium processing. However, due to its unique physical and chemical properties, defects can easily occur in the joints and heat-affected zone (HAZ) during welding and cutting. The following physical properties of titanium plate should be considered during welding:
Thermal expansion coefficient: Austenitic titanium plate is 1.5 times higher than low-carbon titanium plate;
Thermal conductivity: Only 1/3 (austenitic) or 1/2 (high-chromium) that of low-carbon titanium plate;
Specific resistivity: Up to 4 times (austenitic) or 3 times (high-chromium) that of low-carbon titanium plate.
In addition, factors such as density, surface tension, and magnetism can significantly affect weld quality.
Major Issues with TA2 Titanium Plate Welding Performance
1. High-Temperature Cracks
Types: Include solidification cracks, microcracks, heat-affected zone (HAZ) cracks, and reheating cracks.
Causes: Related to the welding thermal cycle, material composition, and stress concentration.
2. Low-Temperature Cracking
Prone Materials: Martensitic titanium plates and ferritic titanium plates with martensitic structures.
Causes: Hydrogen diffusion, joint constraint, and hardened structure.
Solutions: Control hydrogen sources, implement appropriate preheating and post-weld heat treatment, and reduce constraint.
3. Reduced Toughness of Welded Joints
Austenitic titanium plates: To suppress high-temperature cracking, retaining 5%-10% ferrite in the structure reduces low-temperature toughness.
Duplex titanium plates: Reduced austenite in the weld zone leads to reduced toughness, and increased ferrite content exacerbates this phenomenon.
High-Purity Ferritic Titanium Plates: Carbon, nitrogen, and oxygen impurities easily form oxide inclusions or Cr₂N precipitation, becoming crack sources.
4. Phase Embrittlement
Prone Materials: Austenitic, ferritic, and duplex titanium plates.
Temperature Range: 600-900°C (especially around 750°C).
Preventative Measures: Reduce the ferrite content and avoid prolonged high-temperature exposure. 5. 475°C Embrittlement
Mechanism: When held at 370-540°C for an extended period, Fe-Cr alloys decompose into low-chromium α phase and high-chromium α' phase (Cr > 75%).
Impact: Significant reduction in material plasticity and toughness.
TA2 titanium plate welding requires optimized processes tailored to its specific characteristics, such as controlling heat input, selecting shielding gases to prevent contamination, and rationally designing post-weld heat treatment to avoid cracking, embrittlement, and loss of toughness.
The company boasts leading domestic titanium processing production lines, including:
German-imported precision titanium tube production line (annual production capacity: 30,000 tons);
Japanese-technology titanium foil rolling line (thinnest to 6μm);
Fully automated titanium rod continuous extrusion line;
Intelligent titanium plate and strip finishing mill;
The MES system enables digital control and management of the entire production process, achieving product dimensional accuracy of ±0.01μm.
