{"id":4092,"date":"2025-06-11T22:10:31","date_gmt":"2025-06-11T19:10:31","guid":{"rendered":"https:\/\/www.defencemetal.com\/?p=4092"},"modified":"2026-09-17T23:08:04","modified_gmt":"2026-09-17T20:08:04","slug":"15-5-ph-1-4545-uns-s15500-ams-5622-ams-5643-ams-5659-stainless-steel","status":"publish","type":"post","link":"https:\/\/www.defencemetal.com\/index.php\/2025\/06\/11\/15-5-ph-1-4545-uns-s15500-ams-5622-ams-5643-ams-5659-stainless-steel\/","title":{"rendered":"15-5 PH (1.4545 \/ UNS S15500) \u2014 AMS 5622 \/ AMS 5643 \/ AMS 5659 Stainless Steel"},"content":{"rendered":"

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We supply 15-5 PH.<\/strong> For sizes, standard equivalents, stock and quotations, take a look at the 15-5 PH product page<\/strong><\/a>.<\/div>\n

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15-5 PH<\/b><\/h3>\n

15-5 PH Stainless Steel: The Balance of Engineering Strength and Manufacturing Flexibility<\/b><\/b><\/h3>\n

15-5 PH (Precipitation Hardening \u2013 precipitation hardened<\/a>) stainless steel is a martensitic stainless steel that offers high strength, good toughness and corrosion resistance together. Combining the forming and weldability advantages of the austenitic steels with the strength level of the martensitic steels, this alloy is widely used in the aerospace sector above all, as well as in the automotive, energy and defence sectors. A version of 17-4 PH<\/a> developed to show more homogeneous properties, 15-5 PH provides high quality and machinability with its low carbon content and rearranged chemical structure.<\/p>\n

15-5 PH Chemical Structure and Microstructural Properties<\/b><\/b><\/h3>\n

Since 15-5 PH contains roughly 15% chromium and 5% nickel, it takes its name from those proportions. In addition, with the copper content (2\u20135%) that provides precipitation hardening, it delivers high hardness and strength after the ageing treatment. The carbon content is kept quite low (generally below 0.07%); this improves its weldability and its microstructural stability after welding. During the ageing heat treatment, copper causes intermetallic phases (particularly copper-rich phases) to precipitate, markedly improving the mechanical properties of the alloy.<\/p>\n

The alloy acquires a martensitic structure after solution annealing. The ageing treatment (at heat treatment grades such as H900, H1025, H1100 and H1150) allows the mechanical properties to be adjusted. H900 ageing, for example, gives a tensile strength of more than 1200 MPa with a hardness of around 40\u201345 HRC. In that respect, 15-5 PH is an ideal solution for fields requiring high strength while also demanding toughness, weldability and machinability.<\/p>\n

15-5 PH Standardisation and Supply<\/b><\/h3>\n

This steel is included in the precipitation hardening stainless steel class under the ASTM A564\/A564M<\/b><\/span> standard. For products used in the aerospace sector, standards with special requirements such as AMS 5659<\/b><\/span> (bar and forged products) and AMS 5862<\/b><\/span> (plate products) apply. These norms guarantee consistency of mechanical values, grain size control and microstructural homogeneity. That makes the 15-5 PH alloy usable in critical safety items such as aircraft landing gear, fasteners and engine parts.<\/p>\n

Commercially, this alloy is identified by the code \u201cUNS S15500<\/b><\/span>\u201d. One of its best-known trade names is Armco 15-5PH\u00ae<\/b><\/span>, and it may be marketed by other manufacturers under different names such as Alloy 15-5<\/b><\/span>, Custom 15-5<\/b><\/span> and 15Cr-5Ni<\/b><\/span>. In Europe, equivalents such as DIN 1.4545 or X5CrNiCuNb16-5 are available. This variety of names makes it easier for the product to find a place in different supply chains and to be integrated into international projects.<\/p>\n

Fields of Application and Engineering Advantages<\/b><\/b><\/h3>\n

15-5 PH stainless steel is preferred particularly for applications requiring good corrosion resistance and toughness alongside high strength. Thanks to these properties it is widely used in aircraft structural parts, rotor shafts, propeller shafts and fuselage fasteners. It is an ideal solution for parts in the fuselage and landing systems of aircraft that both carry mechanical load and are exposed to the corrosive effects of the outside environment.<\/p>\n

The defence industry uses the 15-5 PH alloy in missile systems, gun mountings, armour fasteners and fighter aircraft parts. In the energy sector it serves in applications exposed to abrasive and dynamic loads such as turbine shafts, pump shaft bearings and valve components. In the petrochemical industry it is suitable for parts such as pump and seal components used in environments with moderate chlorine content. In automotive it is preferred in high-performance engine parts and connection systems.<\/p>\n

Manufacturing Advantages and Machinability<\/b><\/b><\/h3>\n

Another important advantage of 15-5 PH stainless steel is that it is both weldable and machinable. In the quality levels produced by vacuum melting (ESR or VAR) in particular, microstructural change after welding is minimal thanks to the homogeneity of the internal structure. Parts are brought to the required hardness and strength by the ageing treatment applied after solution annealing. The dimensional stability of parts after this heat treatment is quite high, which supports production processes with tight tolerances.<\/p>\n

In terms of machinability, 15-5 PH shows quite good machining performance before ageing. For that reason solution annealing is generally applied first, then machining, and finally ageing. This sequence makes it possible to obtain high surface quality and dimensional accuracy, particularly with ageing grades such as H1025 or H1100.<\/p>\n

Corrosion Resistance and Environmental Stability<\/b><\/b><\/h3>\n

Thanks to its chromium content of around 15%, 15-5 PH retains its stainless character and is resistant to corrosion in many industrial environments. It provides long-term performance in environments such as fresh water, damp atmospheres, mildly acidic environments and industrial steam. Compared with 17-4 PH it shows lower delta ferrite formation in the weld zones and therefore better corrosion resistance after welding. In aggressive marine environments and chemical environments with a high chlorine content, however, it may have limitations compared with super austenitic or duplex stainless steels. Material selection should therefore be made with the environmental conditions in mind.<\/p>\n

Advantages:<\/b><\/p>\n