Commercial titanium is graded according to the content of impurity elements. It has excellent stamping process properties and weldability, is insensitive to heat treatment and tissue type, and has a certain strength under satisfactory plastic conditions. Its strength mainly depends on the content of oxygen and nitrogen in the interstitial elements. It has high corrosion resistance in seawater, but is poor in inorganic acids. It is generally used for manufacturing various sheet metal parts or forgings that work under a temperature of -253 to 350°C, and can also produce rivet wire and pipe.
The typical grades of commercial pure titanium are: Gr-1, Gr-2, Gr-3, Gr-4 of ASTM, USA; classl, 2, 3 of Japanese JIS; 115, 125, 130, 155, 160 of British IMI; Germany DIN 3.7025, 3.7035, 3.7055, 3.7065. The commercial grades of commercial titanium in China include deformed commercially pure titanium TA1, TA2, and TA3, and commercial pure titanium ZTAl, ZTA2, and ZTA3.
Commercial pure titanium should generally be smelted through two vacuums (at least one of which is in a vacuum consumable electrode electric arc furnace), and its casting is usually produced in a vacuum shell furnace. Commercial titanium can withstand both thermal processing and cold processing. Since titanium easily absorbs oxygen, hydrogen, and nitrogen during heating, the plasticity is reduced, and the properties are deteriorated. Therefore, it is necessary to ensure that the atmosphere in the furnace is maintained in a neutral or weak oxidizing atmosphere during heating, and a reductive atmosphere is avoided as much as possible. Allows hydrogen heating. Forging, extruding, rolling and stretching can be carried out on the usual equipment. The thermal processing temperature is in the range of 800-900°C. When cold working, when the cold working rate reaches a certain value (such as 30% to 60%), intermediate annealing should be performed.
Commercial titanium is similar to austenitic stainless steel in machinability, but because titanium has high chemical activity and poor thermal conductivity, it has a high tendency to stick to the tool surface, so the specific cutting process and steel should be different. With sharp gorlg tools, high feed rates, lower cutting speeds and solvent-based coolants, and rigid tooling, smooth machining is possible. Commercial titanium is suitable for all kinds of welding, and the weld zone has excellent fluidity. There are many welding methods, and argon arc welding is the most widely used commercially.
Since commercial titanium has good comprehensive properties and excellent corrosion resistance, it becomes an indispensable structural material for many commercial parts. As a biological implant material, it has been widely used clinically since the 1960s. In all common implanted metal materials, titanium has good biocompatibility, and because its density and elasticity are close to human bones and non-magnetic, titanium is used in stainless steel, cobalt-chromium-molybdenum alloy and titanium three-metal implant materials. It is one of the most promising bioengineering materials. The application of titanium has solved many major engineering and technical difficulties, promoted the progress of science and technology and brought about obvious economic benefits, while titanium's excellent performance and great potential have demonstrated its broader application prospects.