The Production Process And Welding Quality Of Titanium Plates Determine The Quality Of Titanium Plates
Grade 5 Titanium Sheet has high corrosion resistance and specific strength, and is widely used in electric power, chemical industry, aviation components, building materials, sports equipment, medical treatment and other fields and is still expanding. From the point of view of usage and manufacturing technology, titanium plate is low in price, high in performance, multi-functional, and easy to produce. From the point of view of application expansion, titanium alloys represented by Ti-1Fe-0.35O, Ti-5Al-1Fe, Ti-5Al-2Fe-3Mo (mass%) make full use of cheap Fe, O, N and other elements. Pure titanium plate for various surface finishing and improved discoloration resistance. A notable feature of titanium plate is its strong corrosion resistance. This is because it has a particularly high affinity for oxygen and can form a dense oxide film on its surface, which can protect titanium from medium corrosion. , Neutral salt solution and oxidizing medium have good stability, and the corrosion resistance is better than the existing stainless steel and other commonly used non-ferrous metals.
So how does the corrosion resistance of titanium come about? In the mysterious titanium world, let us unravel its mysteries one by one. Titanium is extremely corrosion-resistant, so people usually think it is an inert metal, but on the contrary, titanium is actually a very active metal, its equilibrium potential is very low, and its thermodynamic corrosion tendency in the medium is large, but in fact it is Titanium is very stable in many media, such as titanium is corrosion-resistant in oxidizing, neutral and weakly reducing media. This is because the titanium rod has a great affinity with oxygen. In air or in an oxygen-containing medium, a dense, strong adhesion, and high inert oxide film will be formed on the titanium surface, which protects the titanium substrate from corrosion. Even due to mechanical wear, it will quickly self-heal or regenerate the oxide film. This shows that titanium is a metal with strong passivation tendency, and the oxide film of titanium always maintains this characteristic when the medium temperature is below 315 °C.
Corrosion resistance of titanium and titanium plates Titanium materials are highly stable in neutral or weakly acidic oxide solutions, for example, titanium and titanium plates are in CuC12 at 100 °C FeCl100 °C, HgC1 at 100 °C: (all concentrations ), 60% AlCl2 and all concentrations of NaCl at 100°C are stable, and many other metal oxides of titanium are also stable in 100% monooxyacetic acid and 100% dioxyacetic acid, thus making titanium and Titanium plates have been widely used in the above solutions.
Titanium and Grade 5 Titanium Sheet have high corrosion resistance in gasoline, toluene, phenol, formaldehyde, trichloroethane, acetic acid, citric acid, monochloroben, etc., but at the boiling point and without gas, titanium is in Formic acid with a mass fraction of less than 25% will be severely corroded. In a solution containing acetic anhydride, titanium will not only be severely corroded, but also pitted. For complex organic media that are in contact with many organic synthesis processes, such as in In the production of propylene oxide, phenol, acetone, chloroacetic acid and other chemical media, the corrosion resistance of titanium and titanium plates is better than that of stainless steel and other structural materials.
Titanium and Grade 5 Titanium Sheet are also highly stable to ion-containing oxidant solutions, such as 100qC sodium hypochlorite solution, oxygen water, gas (up to 75°C), sodium oxide solution containing hydrogen peroxide, etc. The corrosion resistance of titanium and titanium plates in wet chlorine gas exceeds that of other commonly used metals. This is because chlorine has a strong oxidation effect. Titanium and titanium plates can be in a stable passive state in wet chlorine. In order to maintain the passivation of titanium in chlorine gas Sexuality requires a certain water content. The critical water content is related to factors such as oxygen pressure, flow rate, temperature, etc., and is also related to the shape and size of titanium equipment or parts and the degree of mechanical damage on the titanium surface. Therefore, the critical water content of titanium passivation in oxygen is inconsistent in the literature , it is generally believed that a mass fraction of 0.01% to 0.05% can be used as the critical water content of titanium in oxygen, but practical experience points out that in order to ensure the safe use of titanium equipment in oxygen, sometimes a water mass fraction of 0.6% is not enough and needs to be as high as 1.5%. The critical water content also increases with the increase of chlorine gas temperature and the decrease of air velocity.
The quality of titanium plate depends to a large extent on the smelting process of the titanium plate manufacturer, including the chemical composition of titanium, the cleanliness of titanium water (gas, harmful elements, inclusions) and the quality of the billet (composition segregation, decarburization and Its surface condition), these aspects are the key control points of the smelting operation.
In addition, industrial titanium plates also require sufficient hardenability to ensure uniform microstructure and mechanical properties throughout the spring section. The main cause of fatigue cracks is the oxide inclusions in titanium, and the damage of D-type inclusions to fatigue life is greater than that of B-type inclusions. Therefore, foreign titanium factories and automobile factories put forward higher requirements for oxide inclusions in industrial titanium plates. For example, the Swedish SKF standard requires that the oxygen content in titanium is lower than 15×10-6, and the D-type inclusions are lower than the B-type inclusions. things. Especially Al2O3 and TiN inclusions are extremely harmful to the fatigue life of titanium springs. In order to produce high-quality industrial titanium plates, special smelting methods such as electric furnace-electroslag remelting or vacuum arc remelting were usually used in the past.
Due to the special physical and chemical properties of titanium plates and rods, their welding process is very different from other metals. Titanium welding is a TiG welding process that uses inert argon to effectively protect the welding area. Before using argon, check the factory certificate on the bottle body to verify the purity index of argon, and then check whether the bottle valve is leaking. or malfunction.
When welding titanium plates and rods, it must be ensured that:
The metal in the welding zone will not be polluted by active gas N0H and harmful impurity elements such as CFeMn above 250 °C. The purity shall not be lower than 99.98%, and the water content shall be less than 50Mg/m32. Argon: industrial grade pure argon.
Coarse-grained structure cannot be formed. The welding process must follow the predetermined construction sequence, and no large welding residual stress and residual deformation can be generated. so. In strict accordance with the process quality management standards, the implementation of the whole process of quality control. Make the factors of man, machine, material and method in a well-controlled state, so as to ensure the welding quality of titanium tubes within a reasonable construction period.
