Zr702 and Zr705 are both excellent materials in terms of corrosion resistance. Zr702 is unalloyed zirconium, with the lowest hafnium-based impurity profile of the commercial grades, while Zr705 is a zirconium-niobium alloy. Both form the tightly adherent, self-repairing oxide film that gives zirconium its outstanding performance in aggressive chemical environments.
Zr702 has excellent corrosion resistance in nuclear reactor environments and generally better corrosion resistance than Zr705 in sulfuric acid. Zr705 has a high℃of corrosion resistance in harsh chemical environments and is the preferred grade for many chemical processing applications because of its higher strength at the same corrosion resistance level. The selection depends on the specific acid, concentration, temperature, and mechanical requirements of the service.
Zr705, with about 2.5 percent niobium, has significantly higher strength than Zr702, allowing thinner-walled equipment for the same pressure rating. Zr702 has lower strength but superior ductility and formability. Both grades retain good strength at elevated temperatures, and the higher strength of Zr705 often reduces material weight and fabrication cost in pressure vessels and heat exchangers.
Zr702 is generally cheaper than Zr705 because of its simpler composition. However, the cost of these alloys can vary depending on factors such as the size and complexity of the part being produced and the quantity ordered. Lifecycle cost comparison must also consider the strength advantage of Zr705, which can reduce wall thickness and total material weight.
Zr702 is used in nuclear reactor components where low neutron absorption and corrosion resistance are critical, and in chemical equipment where its ductility supports forming. Zr705 is widely used for chemical processing equipment including heat exchangers, reactors, and piping handling hydrochloric and sulfuric acids, and in applications requiring higher strength. Both are available as plates, sheets, rods, pipes, and custom fabrications.
Q: What is the difference between Zr702 and Zr705?
A: Zr702 is unalloyed zirconium; Zr705 is a zirconium-niobium alloy with higher strength.
A: Zr702 generally shows better corrosion resistance in sulfuric acid.
A: Zr705, with about 2.5 percent niobium providing significantly higher strength.
A: Zr702, because of its simpler composition.
Q: Where is Zr702 used?
A> Nuclear reactor components and chemical equipment requiring ductility.
Q: Where is Zr705 preferred?
A: Chemical processing equipment requiring high strength and corrosion resistance.
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