Hiduron® 191 is a medium-strength precipitation hardened cupronickel alloy supplied in the hot worked condition. It contains about 14.5% nickel and 4.5% manganese strengthened by additions of aluminium and iron, which may be refined by controlled small amounts of chromium.
In many critical marine applications, for example on oil platforms and naval ships, the requirement for instant service following periods of inactivity favours the anti-fouling and corrosion resistance characteristics of a cupronickel; but conventional cupronickels have the disadvantage of inherently low strength. A combination of reasonable strength with good corrosion resistance and impingement resistance is achieved with nickel aluminium bronze but the higher strength levels are only achieved at the expense of toughness with consequent limited resistance to shock.
Hiduron® 191 was developed to provide both the corrosion resistance and anti-fouling characteristics of conventional cupronickels but with superior tensile and toughness properties compared to aluminium bronzes. Its resistance to marine corrosion is comparable with that of conventional cupronickels, the combination of tensile strength and toughness is far superior to that available with aluminium bronzes and its properties are largely independent of section size. In addition, Hiduron® 191 has the relatively high modulus of elasticity of a cupronickel compared with most other bronzes.
Hiduron® 191 has the inherent good resistance to bio-fouling of a cupronickel whilst the additional elements in its composition not only improve mechanical properties but also increase resistance to localised corrosion and to impingement attack in seawater. It is virtually non-magnetic and possesses excellent sub-zero properties. Hiduron® 191 has good machineability, good weldability and can also be forged, hot upset and thread rolled without difficulty. It meets the requirements of NACE MR 0175
|Bars up to and including 5”(125mm) diameter or section||Bars greater than 5” (125mm) diameter or section|
|0.2% Proof Stress||430 N/mm2||62.4 ksi||400 N/mm2||58 ksi|
|Tensile Strength||725 N/mm2||105.1 ksi||710 N/mm2||103 ksi|
|Hardness (Brinell)||163 min.||170-280|
|Impact Strength (Room Temp)||40J min.||40J min.|
|Magnetic Permeability (20°C)||<1.01|
|Young’s Modulus (kN/mm2)||145|
|Modulus of Rigidity (kN/mm2)||52|
|Electrical Conductivity, 20°C (mΩ / mm2)||2.85 (17% of IACS)|
|Mean coefficient of thermal expansion, 20-300°C (m/m/degC)||16.0 x 10-6|
|Specific Heat, 20°C (J/kg.K)||435|
|Thermal conductivity, 20°C (W/m.K)||16.3|