Dura 17-7PH
EN 1.4568, ASTM TYPE 631

General characteristics

Precipitation hardening grade with high strength and hardness, good corrosion resistance and satisfactory formability (depending on heat treatment/”Condition”). For e.g. retaining rings, springs, valves and gears, aircraft parts.

Typical applications

  • Retaining rings
  • Springs
  • Valves and gears
  • Aircraft parts


Product forms, available sizes and finishes


Product typeFinishesThicknessWidth
Cold rolled coil2BB, 2C, 2D, 2E, 2G, 2H, 2J, 2R0,05-2,003-1250
Cold rolled sheet2BB, 2D, 2E, 2G, 2J, 2R0,80-2,00350-1250
Hot rolled coil, pickled1C, 1U3,50-4,001000-1030
Precision strip2H, 2R0,05-1,503-649


Product typeFinishesThicknessWidth
Cast billet127,00-180,00127-180
Wire rod (Rod coil) hex9,00-27,009-27
Wire rod (Rod coil) round5,00-27,005-27
Wire rod (Rod coil) square9,00-24,009-24
Chemical composition


The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by mass.

Typical 0.0817.07.0Al:1.0
EN 10088-2 ≤0.09≤1.016.0-18.06.5-7.8Al:0.7-1.5
EN 10088-3 ≤0.09≤1.016.0-18.06.5-7.8Al:0.7-1.5
EN 10088-4 ≤0.09≤1.016.0-18.06.5-7.8Al:0.7-1.5
Mechanical properties



StandardRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
Product type: Cold rolled coil and sheet
Typical (thickness 1 mm)
EN 10088-2 ≤ 1030 ≥ 19
Product type: Hot rolled coil and sheet
Typical (thickness 4 mm)3303608503794
Product type: Hot rolled quarto plate
Typical (thickness 15 mm)21024070050
Product type: Wire rod

1)Elongation according to EN standard:
A80 for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A2” or A50.

Corrosion resistance


Pitting corrosion resistanceCrevice corrosion resistance

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F



Physical properties



DensityModulus of elasticityThermal exp. at 100 °CThermal conductivityThermal capacityElectrical resistanceMagnetizable


More detailed information concerning welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.

Standards & approvals



EN 10088-21.4568
EN 10088-31.4568
EN 10088-41.4568

17-7-PH is a registered trademark of AK Steel Corporation.