Precipitation Hardened Alloys - Knight Group

Manufacturers no longer need to compromise when looking for material properties to satisfy conflicting manufacturing and end use requirements. Precipitation Hardening Stainless Steels offer the optimum combination of properties commonly found in the Austenitic and Martensitic Stainless Steel grades. Like Martensitic alloys, these grades can be strengthened through heat treatment, but have the added advantage of superior corrosion resistance that is most similar to that seen in Austenitic grades.

Available Precipitation Hardened Alloy Grades

17-4PH / 1.4542

17-7 PH / 1.4568 / S17700

What are the benefits of using Precipitation Hardened Alloys?

High work hardening rates

Very high strengths

Better corrosion resistance compared to martensitics

What are the disadvantages of using Precipitation Hardened Alloys?

Limited availability and lower corrosion resistance, formability and weldability compared to austenitics

Precipitation Hardened Alloys are one of the five groups of the Stainless Steel family. Stainless Steel Alloys within this group, offer the optimum combination of properties found in the Austenitic and Martensitic grades of Stainless Steel.

Sometimes known as Aged Hardened Alloys, these alloys possess a higher carbon content in comparison to the Ferritic Stainless Steel group. As a result of higher carbon content, these alloys can harden through air, oil or water cooling, to improve their strength. In fact, some grades can offer strength properties between three and four times higher than Austenitic Stainless Steel grades, such as 304 and 316.

Other key alloying elements include aluminium, titanium, niobium and molybdenum, either in combination or on their own. Consequently, this alloy grade offers manufacturers many superior properties, combining high work hardening rates and very high strengths, superior fatigue properties, good corrosion resistance. Equally there is minimum distortion when heat treated. In addition to these properties, this group of Stainless Steel Alloys, offer good formability.

There are three further subdivisions of Precipitation Hardened Stainless Steel, low carbon martensitic, semi-austenitic and austenitic. The most common alloy grade 17/4PH falls into the Martensitic category. Another common grade is 17-7PH, a austenitic-martensitic type alloy, which is ideal for Aerospace applications, Spring manufacturing and Surgical instruments.

Precipitation Hardening Stainless Steel Material Chemical Composition
European Designation EN 10088-2 2014Former BS Standard (Wire Only)American Designation (ASTM)TYPICAL CHEMICAL COMPOSITION %
NumberNameBS 1554 1990 nearest fitAISI nearest fitUNS nearest fitCSiMnPSCrMoNiNCuOther
1.4542X5CrNiCuNb16-4--17-4PH0. - - 5.0-3.0 - 5.0Nb: 5 x C - 0.45
1.4568X7 Cr Ni Al 17-7301S8163117-7PH0. - 18.0-6.5 - 7.8Strip: - Wire: 0.015-Al: 0.7 - 1.5
Precipitation Hardening Stainless Steel Strip Mechanical Properties Annealed Stainless Steel
European Designation EN 10088-2 2014Former BS Standard (Wire Only)American Designation (ASTM)Proof Strength 0.2% Min (N/mm2)Tensile StrengthElong. % Min. (50mm Gauge Length)Hardness Max (VPN)Surface Finish
NumberNameBS 1554 1990 nearest fitAISI nearest fitUNS nearest fit
1.4542X5CrNiCuNb16-4--17-4PH700 - 1150900 - 12703 - 63802R
1.4568X7 Cr Ni Al 17-7301S8163117-7PHAvailble on requestmax. 850Availble on request2682R
Mechanical Properties - Precipitation Hardening Stainless Steel (17/7 PH/ 1.4568 / X7 Cr Ni Al 17-7 / 301S81)
Tensile Strength in the Cold Drawn and Post Heat Treatment Condition
Nominal Diameter (mm)Min Tensile Strength Cold drawn (Condition C). (N/mm²)Expected Min Tensile for Precipitation Hardened (N/mm²)
less than 0.2019752275
0.20 – 0.3019502250
0.30 – 0.4019252225
0.40 – 0.5019002200
0.50 – 0.6518502150
0.65 – 0.8018252125
0.80 – 1.0018002100
1.00 – 1.2517502050
1.25 – 1.5017002000
1.50 – 1.7516501950
1.75 – 2.0016001900
2.00 – 2.5015501850
2.50 – 3.0015001800
3.00 – 3.5014501750
3.50 – 4.2514001700
4.25 – 5.0013501650
5.00 – 6.0013001550
6.00 – 7.0012501500
7.00 – 8.5012501500
8.50 – 10.0012501500
Note : The maximum tensile strength shall be the minimum value plus 15%.
Precipitation Hardening Material Features and Applications
European Designation EN 10088-2 2014Former BS Standard (Wire Only)American Designation (ASTM)Key FeaturesKey MarketsApplications
NumberNameBS 1554 1990 nearest fitAISI nearest fitUNS nearest fit
1.4542X5CrNiCuNb16-4--17-4PH17-4PH (1.4542) is the most commonly used Precipitation Hardening grade of Stainless Steel. This alloy offers good mechanical properties at temperatures up to 316°C (600°F), with a good combination of corrosion resistance and high strength. Its corrosion resistance is very similar to the Austenitic Stainless Steel grade 304. (1.4301), however it is significantly more resistant to stress corrosion cracking. It is susceptible to crevice corrosion in stagnant sea water.Aerospace, Marine, Sport & Leisure, Mechanical, Pulp & Paper Industry, Chemical Processing, Petrochemical, Food processingPump Components, Mechanical Parts, Golf Clubs, Seals, Surgical parts, Aerospace Components, Petrochemical Parts
1.4568X7 Cr Ni Al 17-7301S8163117-7PH17-7 PH (1.4568) is a Stainless Steel alloy which is considered austenitic in the annealed condition, but martensitic in the hardened condition. This alloy offers a combination of high strength and hardness, excellent fatigue properties and minimum distortion upon heat treatment. It has good strength and formability and is comparable to Austenitic Grade 301 (1.4310) . Corrosion resistance is generally higher than the Martensitic Stainless Steels and 17-4PH, but is lower than 304 (1.4301). This grade can be heat treated after forming to further enhance the mechanical properties.Aerospace, Medical, Springs & PressingsBellows, Honeycomb, High Temperature Fasteners, Springs, Diaphragms, Strain Gauges, Clips, Washers, Surgical Parts and Blades

All data is provided for informational purposes only. In no event will the Knight Group and its subsidiaries, be liable for in respect of any action taken by any third party arising from using the information taken from our online or printed sources. Chemical and Mechanical Properties should not be construed as maximum or minimum values for specifications, nor should information be used to assess suitability for a particular use or application. The information and data provided is deemed to be accurate to the best of our knowledge and may be revised anytime without notice and assume no duty to update

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