Knowledge Of Titanium Containers

1,Industrial pure titanium under the action of static challenge load, its main deformation mechanism is what?
The main deformation mechanism is slip. As plastic deformation proceeds, a large number of slip bands continue to appear, the grain and Li crystal is drawn and twisted, when the plastic deformation exceeds a certain limit, cracking occurs. When in a complex stress state, shear slip predominates, i.e., slip occurs mainly along the two sets of planes that are 45° from the tensile force. As the slip proceeds, the crack spreads, and its end remains sharply notched. The grains close to the cracked end are pulled apart by the severe deformation, and each grain seems to be a single crystal constrained by its surroundings, which are successively disconnected by the slip.
2, titanium in the static load strength characteristics and pressure vessels commonly used steel what are the differences?
Titanium in the static load strength characteristics and pressure vessels commonly used steel is different, it has no obvious physical yielding, and produce saw yield, acoustic emission phenomena, thermoplasticity, cold creep, pseudo-elasticity and shape memory effect and other special behavior.

3, industrial pure titanium why in a 196 ° C temperature still has a high toughness? What are the factors affecting its low temperature toughness?
Industrial titanium strength with the reduction of temperature and increase, but the plasticity is not reduced much, and still have good ductility and toughness, so it is suitable for use as a low-temperature pressure vessel structural materials. Titanium has high plasticity at low temperatures due to the fact that its main deformation at low temperatures is the generation of twinned crystals. In the same degree of deformation, with the lowering of the temperature, so that the generation of Li crystal density within the grain and the number of grains increased, while changing the shape of the twinned interlayer. With the increase in the degree of deformation, will make the polycrystalline aggregate completely ⻓ into Li crystals, to achieve the strengthening of the grain itself, and then start the intergranular deformation.
The main factor affecting the low-temperature performance of titanium is the content of interstitial elements, low interstitial elements (N, 0, H, C) and iron content of industrial pure titanium, better resistance to cold embrittlement. Secondly, the manufacturing process of titanium equipment also has an impact on low temperature performance. In addition to poor control of process conditions, invasive gas impurities affect the performance, stamping and molding of the cold deformation of the low-temperature performance also has an impact. When the cold deformation exceeds a certain limit, it will lead to low temperature embrittlement.
4,Why is anisotropic titanium material according to isotropic steel pressure vessel design guidelines will lead to greater waste?
Industrial pure titanium and a-type titanium alloy at room temperature for the dense row of hexagonal crystals, the metal lattice has a clear phenomenon of preferential orientation, resulting in the anisotropy of titanium single crystal. This anisotropy is further strengthened in the rolling process of titanium, so that the rolled titanium has a significant anisotropy, so titanium pressure vessels have a better two-way strengthening benefits, that is, titanium in the two-way stress under the action of the strength of the unidirectional strength than a great increase in any two-way stress ratio of the case are strengthened. For spherical titanium pressure vessels, the strengthening effect, theoretical and experimental results reached 50 % and 40 %, respectively. For round simple shape titanium pressure vessel, when the circumference and plate rolling direction overlap, the strengthening effect of the theoretical and experimental value of 42% and 3 6%; when the circumference and plate rolling direction perpendicular to the theoretical and experimental value of 48% and 37%, respectively. So the titanium pressure vessel wall thickness calculation method according to GB 150-2011 "pressure vessel" provisions, to consume 20% ~ 40% more titanium.
5, why the rolled titanium heat pipe ring bearing capacity is significantly higher than the axial direction?
Due to the industrial pure titanium and the "type of titanium alloy character of preferential orientation, resulting in the anisotropy of titanium single crystal. The degree of this anisotropy is further enhanced with the rolling process. In particular, the rolled titanium tube is usually orthogonal anisotropy, that is, axial, circumferential and radial respectively for the three anisotropic spindle direction; and has been rolled in one direction, so the degree of anisotropy of rolled titanium heat exchanger tubes is higher than the plate. According to the titanium tube in the axial and annular bearing test results, its ring yield limit and strength limit are higher than the axial direction, in which the yield limit of the difference of 33%, so the rolled titanium tube ring bearing capacity is significantly higher than the axial direction, and in the bi-directional stress of titanium tubes under the yield strength and ultimate strength than in the unidirectional stress has increased significantly.