The ductile-brittle transition temperature is an important goal to measure the brittleness transition of titanium plates. It determines the low-temperature function of titanium plates and directly affects the use of titanium plates. Among them, the chemical composition has a great impact on it, the specific impact is as follows:
1 、 C content
The carbon content has a great influence on the ductile-brittle transition temperature of the titanium plate. With the addition of the C content in the titanium plate, the plastic resistance is added, the ductile-brittle transition temperature is significantly increased, and the temperature scale of the transition is also widened. The addition of C content increases the brittleness of the titanium plate.
2. Mn content
Manganese can restrain the ferrite-pearlite transformation, promote the composition of bainite, and then improve the resistance of the titanium plate. With the addition of Mn content, the ductile-brittle transition temperature drops.
2. Mo content
Molybdenum can refine the grains and form the second phase particles, so as to advance the resistance of the titanium plate and affect the ductile-brittle transition temperature.
3, S, P content
Impurities such as sulfur and phosphorus tend to segregate at the grain boundary, reduce the surface energy of the grain boundary, cause intergranular cracking, reduce brittle cracking stress, and affect the ductile-brittle transition temperature.
4, Si content
Silicon has an adverse effect on resistance, and the determination of the Si content also has a certain effect on the reduction of the ductile-brittle transition temperature.
5, Nb content
Niobium has the effect of deposition strengthening in the process of hot rolling, which increases the strength and resistance of the titanium plate, but Nb can refine the grains, and then improve the strength and resistance of the titanium plate.
6, Ti content
Because of its strong affinity with nitrogen, titanium forms TiN, which can fix the nitrogen element in the titanium plate. TiN is dispersed in the titanium plate as finely dispersed particles, which can lower the slab heating austenitizing temperature and control austenite. The grain grows and then reaches the intention of refining the grain, which is useful for improving the data tolerance.
7, V, Al content
Vanadium and aluminum have the effects of deposition strengthening, fine grain strengthening and grain boundary strengthening in the titanium plate, and then it is conducive to the decrease of the ductile-brittle transition temperature.