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    Zirconium + Zirconium Alloy

Zirconium and Zirconium Alloy In 1789 has been discovered by  the chemist Martin Heinrich Klaproth.

Zirconium is mainly obtained from zirconium sands (ZrSiO4) and Baddelites (ZrO2), which are most common in Australia.

Zirconium and zirconium alloys are among the reactive metals.
Zirconium is very corrosion resistant. Zirconium has a passivating oxide layer (ZrO2), which renews itself again and again when in contact with water-containing media.
Among other things, zirconium Zr702 offers resistance to almost all organic acids, mineral acids and alkaline solutions.

It is used in the construction of chemical plants, for example for valves, pumps or agitators. In electronics, it is used for the production of vacuum tubes for X-ray technology.

Zirconium semi-finished products and zirconium alloys

Today, semi-finished products made of zirconium are mainly used in the nuclear and chemical industries, with the materials used mainly differing by the remaining hafnium content.

Zr alloys chemical composition

Grade UNS Number Zr+Hf(min) Hf(max) Fe+Cr Sn Hmax Cmax Nb Omax
Zr700 R60700 99.2 <2,5 <0.20 0.005 0.05 0.10
Zr702 R60702 99.2 <4,5 <0.20 0.005 0.05 0.16
Zr704 R60704 97.5 <4,5 0.2-0.4 0.005 0.05 0.18
Zr705 R60705 95.5 <4,5 <0.20 1.0-2.0 0.005 0.05 2.0-3.0 0.18
Zr706 R60706 95.5 <4,5 <0.20 0.005 0.05 2.0-3.0 0.16
Zircaloy 2 R60802 98.5 <100ppm 0.07-0.20 1.2-1.7
Zircaloy 4 R60804 98 <100ppm 0.28-0.37 1.2-1.7
ZrNb2,5 R60901 96.8-97.5 <100ppm 0.28-0.37 1.2-1.7 2.4-2.8 0.14

Zr alloys mechanical properties

Grade UNS Number Tensile strength min(Mpa) Yield strength min(Mpa) Elongation min % Bending radius *
Zr700 R60700 380 305 2 5T
Zr702 R60702 380 205 16 5T
Zr704 R60704 415 240 14 5T
Zr705 R60705 550 380 16 3T
Zr706 R60706 510 345 20 2.5T
Zircaloy 2 R60802 413 241 20
Zircaloy 4 R60804 413 241 20
ZrNb2,5 R60901 448 310 20

Due to a stable zirconium oxide layer, zirconium Zr 702 (Zr 700) has excellent corrosion properties, which are highly appreciated by the chemical industry. The hafnium content plays a minor role here.

In contrast, the nuclear industry requires zirconium alloys with the lowest possible amount of hafnium. Here, the material Zirkaloy with a hafnium content of 0.1% serves as a fuel element sleeve tube, in which a low neutron capture cross-section is required in order to achieve a maximum yield at the desired chain reaction of the fuel uranium.
Hafnium is a so-called neutron poison.

The separation of hafnium from zirconium is difficult and complex. This is reflected in material prices. Zirconium Zr 700, Zr 702 and Zr 705 as well as Zircaloy 2 and Zircaloy 4 are generally available in all semi-finished products.

The mechanical properties of Zr 700 and Zr 702 are determined by the dissolved residual gases in the metal, wherein oxygen plays an essential role.
In the other alloys, desired properties are adjusted by targeted alloying of other elements, such as niobium.

Zirconium semi-finished products

Zr Semi finished products ASTM Zr702 Zr 705
Zr Sheets, Strips B551
Zr forged parts B493
Zr round bar B550
Zr tubing seamless and welded B523
Zr Tubes over 50mm OD, seamless and welded B658