Langley Alloys: How does Nitronic® 50 compare with other alloys?

Nitronic 50 is an austenitic stainless steel, produced with an increased nitrogen content which improves its strength and corrosion resistance. This alloy is also widely referred to as XM19, which is the designation of the generic alloy caption in ASTM A276 and ASTM A479, as well as UNS S20910 or DIN 1.3964. Nitrogen, along with chromium and molybdenum all increase the Pitting Resistance Equivalent Number (PREN) to >34, which is a similar value as S32205 duplex stainless steel and way above low-alloyed grades.

Nitronic 50 is available in two conditions; annealed and hot-rolled, which is also known as high-strength. Whilst the annealed condition has a minimum yield strength of 55ksi / 380N/mm2, when supplied in the hot-rolled condition it achieves a minimum yield strength of 105ksi / 725N/mm2.

A common question from customers is how Nitronic 50 vs Nitronic 60 compare? Although both were originally developed by Armco (now AK Steel Corporation) and benefit from increased nitrogen contents, their overall composition, properties and typical applications are quite different. Nitronic 60 (Fermonic 60, UNS21800) contains increased alloying additions of silicon and manganese, which are less commonly used in stainless steels. Consequently, it has excellent galling and wear resistance, meaning that is mostly used for items such as connectors and couplings despite lower corrosion resistance and strength compared with Nitronic 50.

The other common comparison requested by customers is how Nitronic 50 vs. 17/4PH compare? 17/4 PH is a martensitic stainless steel named for its nominal 17% chromium and 4% nickel content, with increased strengths induced by heat treatment to give precipitation hardening, hence the PH. The ‘double-aged’ H1150D condition is perhaps the most widely specified, giving a minimum yield strength of 105ksi / 725N/mm2. Therefore, it’s the same strength of Nitronic 50HS, although the corrosion resistance is substantially less with a PREN >16 only.

In terms of Nitronic 50 price, it is more expensive than duplex and super duplex stainless steels, standard austenitic stainless steels such as Alloys 304L and 316L, and also the likes of 17/4PH. This is related to its higher content of more expensive alloying elements, particularly nickel. Therefore, it is used only where its properties are more desirable than lower cost alternatives. This can include improved impact toughness versus duplex alloys particularly at lower temperatures, or ease of fabrication.

Langley Alloys carries a comprehensive stock of XM19 / S20910 in both annealed and hot-rolled condition as round bar, in diameters from 1” (25.4mm) to 102 (254mm).

Common applications for Nitronic 50 include:

• Valves fittings, particular stems due to the excellent alloy toughness
• Marine applications, include rod rigging using cold drawn lengths, tie-downs and fittings
• Pump shafts
• Sucker rods for oil rigs
• Fasteners

If you have any questions about Nitronic 50, please get in touch today.

Nitronic® is a trademark of AK Steel Corporation.

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