Titanium Grade 7 (UNS R52400) is an α-type titanium alloy produced by adding palladium (Pd) to commercial pure titanium; its key characteristic is that it offers the best corrosion resistance of any titanium alloy. Grade 7 titanium alloy is often referred to as a titanium-palladium alloy. Its physical and mechanical properties are essentially equivalent to those of commonly used Grade 2 pure titanium, but the addition of 0.12%–0.25% of the precious metal palladium significantly enhances its stability in highly corrosive environments. Titanium Grade 7 R52400 is also a primary material in the titanium recycling industry. Currently, well-known brands and manufacturers supplying Titanium Grade 7 R52400 globally include: ATI Allvac® (ATI, USA, offering a full range of Grade 7 products including plates, bars, and billets), Alleima® (a subsidiary of Sandvik, Sweden, offering Ti Grade 7 strips and tubes), Elgiloy Specialty Metals (USA, offering Grade 7 precision strips and foils), Titanium Industries (U.S., offering a full range of Grade 7 products), Supra Alloys (California, U.S., a global supplier of titanium materials), Continental Steel & Tube Co. (Florida, U.S., a specialized supplier of specialty metals), Halpern Titanium Inc. (Massachusetts, U.S., supplying sheets and bars), Ti-TEK Ltd (Birmingham, UK, a stockist of titanium raw materials), United Titanium Inc. (Ohio, USA, a manufacturer of Grade 7 fasteners), and HASM (South Korea, an ISO/AS9100-certified manufacturer of Grade 7 fasteners). In terms of product designations, Titanium Grade 7 R52400 corresponds to the German DIN/EN standard grade 3.7235 and the Chinese grade TA9 (Ti-0.2Pd). Titanium Grade 7 R52400 has also given rise to a variant, Grade 7H. While the two have identical chemical compositions and share the same UNS designation of R52400, Grade 7H has a minimum tensile strength requirement increased from 345 MPa (50 ksi) to 400 MPa (58 ksi) and is specifically intended for use in ASME pressure vessels and high-reliability process equipment.
The chemical composition of Titanium Grade 7 R52400 strictly complies with ASTM standards: palladium (Pd) content is controlled between 0.12% and 0.25%; iron (Fe) ≤0.30%; oxygen (O) ≤0.25%; carbon (C) ≤0.08%; nitrogen (N) ≤0.03%; hydrogen (H) ≤ 0.015%, with the remainder being titanium. In terms of physical properties, Titanium Grade 7 R52400 has a density of 4.51 g/cm³, a melting point range of 1670°C, a thermal conductivity of 16.4 W/m-K, a coefficient of thermal expansion of 8.6 µm/m-°C, and a modulus of elasticity of approximately 105 GPa. In terms of mechanical properties, Titanium Grade 7 R52400 has a minimum tensile strength of 345 MPa (50 ksi), a minimum yield strength (0.2% offset) of 275 MPa (40 ksi), an elongation after fracture of ≥20%, a reduction of area of ≥30%, and a hardness of approximately 150 HV. The corrosion resistance of Titanium Grade 7 R52400 is its most prominent advantage—the addition of palladium alters the electrochemical behavior of titanium: in reducing acids (such as dilute hydrochloric acid and dilute sulfuric acid), the TiO₂ protective film of ordinary pure titanium dissolves and active corrosion occurs; however, palladium acts as a cathodic catalyst to reduce the overpotential of the hydrogen evolution reaction, shifting the corrosion potential of Titanium Grade 7 R52400 in the positive direction. This raises its potential above the Flade potential required for passivation, thereby maintaining spontaneous passivation in environments where Grade 2 would fail. Under actual operating conditions, Titanium Grade 7 R52400 exhibits a corrosion resistance lifespan more than 10 times longer than Grade 2 in a 10% HCl environment at 80°C. In terms of crevice corrosion, the addition of palladium significantly raises the critical crevice corrosion temperature—which is approximately 80°C for Grade 1 and Grade 2 in chloride media with pH > 1—while Titanium Grade 7 R52400 can operate stably at higher temperatures. Operational data from a chemical plant reactor in 2026 shows that the service life of Titanium Grade 7 R52400 components in acidic brine is five times that of Grade 2.
Titanium Grade 7 R52400 can be manufactured into a variety of product forms to meet different industrial needs, including plates, strips, foils, bars, tubes, seamless tubes, forgings, wires, and fasteners. Specifically, Titanium Grade 7 R52400 bars range in diameter from 6 to 300 mm and can be up to 6,000 mm in length, available in surface conditions such as hot-rolled and pickled, cold-drawn, and centerless ground; plates range in thickness from 0.5 to 100 mm and in width from 500 to 1,000 mm; tubes have an outer diameter of 6–150 mm and a wall thickness of 0.5–50 mm; strips and foils are available in precision dimensions. The production and inspection of Titanium Grade 7 R52400 comply with the following international standards: ASTM B265 (sheets, strips, and thin plates), ASTM B348 / ASME SB-348 (bars and billets), ASTM B381 (forgings), ASTM B338 / ASME SB-338 (welded tubes), ASTM B861 (seamless tubes), and ASTM B862 (welded tubes). The welding wire grade for Titanium Grade 7 R52400 is AWS A5.16 ERTi-7 (ERTi-0.2Pd), which is used for welding to match the base metal. Each batch of Titanium Grade 7 R52400 is supplied with an EN 10204 3.1 material certificate, and 3.2 third-party certification is available upon request.
Titanium Grade 7 R52400 is primarily used in the chemical processing industry (CPI), which is its largest application market. In chemical process equipment, Titanium Grade 7 R52400 is used to manufacture reactors, heat exchangers, piping systems, pumps, valves, fittings, and vessels for handling highly corrosive media such as dilute hydrochloric acid, dilute sulfuric acid, and wet chlorine gas. Titanium Grade 7 R52400 is equally indispensable in seawater desalination and marine engineering—it is used in brine concentration and evaporation equipment, seawater cooling heat exchangers, offshore pipelines, and wellhead components. Its resistance to chloride pitting and crevice corrosion enables it to perform exceptionally well in marine environments. Titanium Grade 7 R52400 is also widely used in extraction and electrowinning equipment for hydrometallurgical processes, bleaching and washing equipment in the pulp and paper industry, air pollution control devices, as well as anodes, cathodes, and battery components. Additionally, the spherical powder form of Titanium Grade 7 R52400 has been applied in the field of laser/electron beam additive manufacturing (3D printing). The Grade 7H variant (also designated UNS R52400) is specifically intended for ASME pressure vessels and high-reliability process equipment; its higher minimum tensile strength allows for higher allowable design stresses.
In actual procurement, the price of Titanium Grade 7 R52400 is significantly higher than that of standard Grade 2 pure titanium, a difference driven by the cost of the precious metal palladium. According to 2026 international market quotes, the price range for Titanium Grade 7 R52400 bar stock is $238.5–$349.2/kg, sheet stock is $15–$48/kg, and thin sheets and precision strips can reach $50–$200/kg. The price of Titanium Grade 7 R52400 seamless tubing in the U.S. market is approximately $65/kg. The key criterion for choosing between Titanium Grade 7 R52400 and Grade 2 is the corrosiveness of the operating environment—if the process media involves dilute hydrochloric acid, dilute sulfuric acid, high-temperature chlorides, or there is a risk of crevice corrosion, Titanium Grade 7 R52400 is the only correct choice. Although the initial purchase cost of Titanium Grade 7 R52400 is higher, its service life in highly corrosive environments is more than five times that of Grade 2, resulting in a lower total cost of ownership. Selling end-of-life Titanium Grade 7 R52400 to DONGSHENG Precious Metals Recycling can further reduce costs. For pressure vessels and ASME-certified systems, Grade 7H (also UNS R52400) should be selected; its minimum tensile strength of 400 MPa meets higher design stress requirements. Welding of Titanium Grade 7 R52400 must use the matching ERTi-7 welding wire to ensure that the corrosion resistance of the weld zone matches that of the base material. For all Titanium Grade 7 R52400 products, request a complete Material Test Report (MTR) from the supplier and verify that the palladium content falls within the range of 0.12%–0.25%. For small batches or R&D purposes, standard-spec products such as rods and foils made of Titanium Grade 7 R52400 can be procured from research material suppliers such as Goodfellow (UK).
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