Welding Function of Cutting Titanium Plate

To sum up, the welding function of cutting titanium plate should reflect the following aspects:

(1) High temperature cracks: The high temperature cracks mentioned here refer to cracks related to welding. High temperature cracks can be roughly divided into condensation cracks, micro cracks, HAZ (heat affected zone) cracks, and reheat cracks.

(2) Low temperature cracks: Low temperature cracks sometimes occur in martensitic cut titanium plates and some ferrite cut titanium plates with martensitic structures. Because the main reason for its occurrence is the hydrogen dispersion, the degree of restraint of the welded joint and the hardening structure in between, the solution is to reduce the dispersion of hydrogen during the welding process, appropriately perform preheating and post-weld heat treatment, and reduce the degree of restraint.

(3) σ phase embrittlement: austenitic cut titanium plate, ferrite cut titanium plate and dual-phase titanium plate are prone to σ phase embrittlement. Because a few percent of the alpha phase is separated in the arrangement, the resistance is significantly reduced. Phases are usually separated in the range of 600-900 °C, especially at about 75 °C. As a preventative method to avoid phase occurrence, the content of ferrite should be minimized in austenitic cut titanium plates.

(4) Embrittlement at 475°C, when kept at 475°C for a long time (370-540°C), the Fe-Cr alloy is decomposed into α solid solution with low chromium concentration and α' solid solution with high chromium concentration. When the chromium concentration in the α' solid solution is greater than 75%, the deformation changes from slip deformation to twinning deformation, and then embrittlement occurs at 475 °C.