PH Stainless Steels Sourced numerical data plus engineering analysis

Material / Grade

1.4568

Dura 17-7PH

1.4568 / Dura 17-7PH is a PH Stainless Steels grade centred on high strength from precipitation hardening combined with stainless corrosion resistance. This dossier separates sourced values from engineering guidance and comparison indices.

Hardness potential57 / 100Comparison index

Toughness74 / 100Comparison index

Impact resistance75 / 100Comparison index

Bending resistance94 / 100Comparison index

Abrasive wear63 / 100Comparison index

Steel Overview

Complete introduction and metallurgical analysis

1.4568 / Dura 17-7PH belongs to PH Stainless Steels and selection centres on high strength from precipitation hardening combined with stainless corrosion resistance.

The principal recorded elements are C≈0.08%, Cr≈17%, Ni≈7%. Mid-range values support engineering interpretation and do not replace purchase limits.

The expected microstructure is martensitic or semi-austenitic stainless matrix strengthened by a controlled ageing precipitate population; delivery condition, section size, melt quality and processing history can change that state.

Comparison indices are hardness 57/100, toughness 74/100, impact 75/100, wear 63/100 and bending 94/100. These are internal indices, not standard test results.

The screening temperature range is 250–500 °C; strength or hardness loss, oxidation, exposure time and creep must be assessed separately.

A representative process route is solution treatment or supplied condition followed by the specified ageing treatment. Obtain actual temperatures, times and cooling media from the grade and product data sheet.

Manufacturing indices are weldability 70/100, machinability 51/100, corrosion resistance 64/100 and fatigue resistance 72/100; use them for screening only.

The principal risk is incorrect ageing response, toughness loss, distortion or stress-corrosion cracking in an unsuitable condition. Evaluate geometry, surface condition, environment and the governing failure mechanism together.

A similar name or calculated relationship is not proof of interchangeability; match chemistry, specification, condition, heat treatment and MTC.

Engineering conclusion: 1.4568 / Dura 17-7PH is a rational candidate when high strength with better corrosion performance than conventional low-alloy steels matches the real load, environment and certified product condition.

Recorded standards:EN 1.4568ASTM/AISI 631UNS S17700

International Equivalents

International equivalents and designations

A close counterpart is not automatically interchangeable. Confirm chemistry, product standard, delivery condition, dimensions and heat treatment.

StandardOfficial designation for the same grade

Dura 17-7PH

A registered identity within the same grade record.

EN / W.NrOfficial designation for the same grade

1.4568

A registered identity within the same grade record.

OutokumpuClose counterpart requiring verification

Dura 17-7PH

Match chemistry, product standard, delivery condition, heat treatment and MTC before substitution.

EN/W.NrOfficial designation for the same grade

1.4568

A registered identity within the same grade record.

ASTM/AISI TypeClose counterpart requiring verification

631

Match chemistry, product standard, delivery condition, heat treatment and MTC before substitution.

UNSClose counterpart requiring verification

S17700

Match chemistry, product standard, delivery condition, heat treatment and MTC before substitution.

Chemical Composition

Chemical composition and the role of each element

The principal recorded elements are C≈0.08%, Cr≈17%, Ni≈7%. Mid-range values support engineering interpretation and do not replace purchase limits. Composition is shown for screening and traceability. The current purchase standard and the heat-specific MTC remain authoritative.

Element	Weight-percent range	Metallurgical role and effect
C	≈ 0.08 %	Carbon raises hardness, strength and carbide potential; excessive carbon can reduce toughness and weldability.
Cr	≈ 17 %	Chromium promotes hardenability and carbide formation and, at sufficient levels, corrosion or oxidation resistance.
Ni	≈ 7 %	Nickel generally improves toughness and through-section response and stabilises austenite in stainless systems.

Outokumpu range datasheet — typical chemical composition, % by mass Sourced with conditions

Engineering Behaviour

Engineering behaviour and selection response

Hardness potential57 / 100

Martensitic/precipitation-hardening stainless family capable of high hardness with better corrosion resistance than carbon steel. Internal comparison index: 57/100.

Engineering analysis

Toughness74 / 100

Toughness has an internal index of 74/100 (high). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Impact resistance75 / 100

Impact resistance has an internal index of 75/100 (high). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Bending resistance94 / 100

Bending resistance has an internal index of 94/100 (very high). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Abrasive wear63 / 100

Abrasive wear has an internal index of 63/100 (moderate). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Corrosion resistance64 / 100

Corrosion resistance has an internal index of 64/100 (moderate). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Weldability70 / 100

Weldability has an internal index of 70/100 (high). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Machinability51 / 100

Machinability has an internal index of 51/100 (moderate). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

High-temperature strength48 / 100

Temperature behavior is grade- and environment-specific; no single universal maximum service temperature applies. Internal comparison index: 48/100.

Engineering analysis

Creep resistance40 / 100

Creep resistance has an internal index of 40/100 (low). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Fatigue resistance72 / 100

Fatigue resistance has an internal index of 72/100 (high). Actual performance requires a documented product condition, heat treatment and test context.

Engineering analysis

Numerical scores are internal comparison indices. They are not standard test results, allowable design stresses or a manufacturer guarantee. Data Method

Hardness & Hardenability

Hardness and hardenability

Martensitic/precipitation-hardening stainless family capable of high hardness with better corrosion resistance than carbon steel. Internal screening index: 57/100 (moderate).

57/100

moderate

Comparison index

Governing factors

Chemistry and section size
Austenitising and quench severity
Tempering temperature and time
Test method and surface preparation

Data limits

Final acceptance requires the current standard, product form, dimensions, delivery condition and heat-specific MTC.

Impact & Toughness

Toughness, impact and fracture behaviour

Impact resistance is indexed at 75/100 and toughness at 74/100. These are not Charpy or Izod energy values; temperature, orientation, geometry and actual microstructure govern component behaviour.

75/100highComparison index

Microstructure, hardness and grain size influence impact tolerance.
Sharp radii, notches and surface defects reduce fracture resistance.
Test temperature, specimen direction and section must be identified.
For critical parts, accept impact energy only from a documented test of the same condition.

Temperature & Creep

Service temperature, thermal stability and creep

Temperature behavior is grade- and environment-specific; no single universal maximum service temperature applies. 250–500 °C is a screening range or sourced limit according to its evidence label. Check strength loss, oxidation, creep, exposure time and environment.

Continuous service

250–500 °CEngineering guidance

Review the limit against strength or hardness loss and exposure time.

Intermittent service

Do not assign an intermittent limit without product-specific source data.

Tempering and phase stability

Working and coating temperatures must remain compatible with the tempering condition and required microstructure.

Oxidation and environment

Oxidation or corrosion may become limiting before the strength criterion.

Relative creep resistance40/100Comparison index

The relative creep index is 40/100 (low). It is not an allowable creep stress or rupture-life value.

Do not select this grade for long-term static high-temperature loading from the internal index alone.

Wear & Surface Behaviour

Wear resistance and surface behaviour

Abrasive wear

The abrasive-wear index is 63/100; final hardness, carbides, microstructure, contact mode and lubrication govern actual resistance.

Comparison index

Adhesive wear

Assess adhesive wear with the counterface material, lubrication, roughness, pressure and temperature.

Engineering analysis

Surface improvement

Evaluate surface treatment or coating only after confirming compatibility with chemistry, substrate and process temperature.

Engineering guidance

Mechanical & Physical Properties

Mechanical and physical properties

The record contains 1 sourced mechanical-property rows; each applies only to its stated condition, dimensions and test temperature.

Property	Value	Condition	Dimension	Test temperature
Achievable hardness	38–41 HRC	After final heat treatment	According to the product data sheet	20 °C

Sourced with conditions

Physical properties

Density≈ 7.8 g/cm³Sourced with conditions

Elastic modulus≈ 200 GPaSourced with conditions

Thermal expansion 20–100°C≈ 13 ×10⁻⁶/KSourced with conditions

Thermal conductivity≈ 16 W/m·KSourced with conditions

Heat capacity≈ 500 J/kg·KSourced with conditions

Electrical resistivity≈ 0.8 Ω·mm²/mSourced with conditions

Heat Treatment

Heat-treatment stages and process controls

The representative family route is solution treatment or supplied condition followed by the specified ageing treatment. Numerical temperatures are shown only when supported by the record.

Preheating and austenitising

Engineering guidance

Set preheat steps and austenitising parameters from the grade/product data sheet and actual section size.

Cooling: Grade- and process-specific cooling

Annealing / stress relief

Engineering guidance

Assess the supply condition, residual stress, section size and prior machining before selecting time and temperature.

Cooling: Grade- and process-specific cooling

Preheating and austenitising

Engineering guidance

Set preheat steps and austenitising parameters from the grade/product data sheet and actual section size.

Cooling: Grade- and process-specific cooling

Quenching / controlled cooling

Engineering guidance

Choose the quench medium and cooling severity against hardenability, geometry, distortion and crack risk.

Cooling: Grade- and process-specific cooling

Tempering / property adjustment

Engineering guidance

Set tempering or ageing to the required hardness, toughness and service-temperature balance.

Cooling: Grade- and process-specific cooling

Process control: Review delivery condition, actual section, equipment capability, crack and distortion risk and target hardness before approving the cycle.

Engineering Charts

Hardness, toughness, impact, temperature and process charts

Chemistry data retain their evidence label; 0–100 charts are internal indices and stages without temperature are process sequences.

Multi-axis engineering profile

Comparison index

Chemical composition

Derived from source data

Hardness–toughness balance

Comparison index

Toughness, impact and fatigue

Comparison index

Wear and surface response

Comparison index

Mechanical properties or comparison indices

Sourced with conditions

Service temperature

Engineering guidance

Heat treatment

Engineering guidance

Related-grade similarity

Comparison index

All comparison indices

Comparison index

Failure Modes & Selection

Potential failure modes and selection guidance

Potential failure mechanisms

incorrect ageing response, toughness loss, distortion or stress-corrosion cracking in an unsuitable condition.
Fatigue initiation from surface defects, section transitions or stress concentration.
Property loss after unsuitable heat treatment, cooling or finishing.
Corrosion, oxidation or environmental attack when protection is inadequate.

Selection and design notes

Match designation, material number, product standard and supply form before purchase.
Compare the governing failure mechanism with hardness 57, toughness 74, impact 75 and wear 63 indices out of 100.
Use mechanical values only within their cited condition, dimensions and test temperature.
Confirm the heat-treatment route and target hardness with the processor before final machining.
Review the heat number, MTC and required test results before release.

Derived calculations

Pitting-resistance equivalent PREN (indicative)17 Calculated

Calculated from recorded inputs; apply only within the stated formula scope and limitations.

Advantages & Limitations

Advantages, limitations and unsuitable applications

Advantages

high strength with better corrosion performance than conventional low-alloy steels.
A clearly labelled engineering profile supports comparison with related grades.
Grade identity, chemistry, counterparts and references remain traceable in one dossier.

Limitations and weaknesses

incorrect ageing response, toughness loss, distortion or stress-corrosion cracking in an unsuitable condition.
A 0–100 index cannot be converted into design stress, impact energy or creep life.
Hardness and toughness depend on section, delivery condition and actual processing.
Do not approve a substitute before checking the product standard and heat-specific MTC.

Cases requiring caution or an alternative material

Critical design without condition- and section-specific test dataDirect substitution based only on name or similarity scoreLong-term creep service without sourced time–stress–temperature dataincorrect ageing response, toughness loss, distortion or stress-corrosion cracking in an unsuitable condition

Applications & Processing

Industrial applications and processing

Typical applications

Gears and power-transmission components
Shafts, axles and rotating machine components
High-strength fasteners and mechanical connections
Coil, leaf and torsion springs or resilient components
Industrial blades, knives and cutting tools
Marine, chloride-bearing and desalination service
Aerospace, landing-gear and high-integrity rotating components
Wear-resistant machine and surface-contact components

Manufacture, welding and surface engineering

Weldability has an internal index of 70/100 (high). Actual performance requires a documented product condition, heat treatment and test context.

Forming and forging depend on steel family, delivery condition and the grade-specific qualified temperature range.

Clean and passivate after fabrication or welding where the specification requires it.
Electropolishing may be used where cleanliness or corrosion performance requires it.
Prevent free-iron contamination and preserve the specified surface condition.

Engineering Conclusion

Engineering conclusion and selection recommendation

1.4568 / Dura 17-7PH is worth evaluating when the principal need is high strength with better corrosion performance than conventional low-alloy steels. Internal indices of hardness 57/100, toughness 74/100, impact 75/100 and wear 63/100 must be aligned with the real failure mechanism. The leading risk is incorrect ageing response, toughness loss, distortion or stress-corrosion cracking in an unsuitable condition. Final approval requires the current standard, product form, dimensions, delivery condition, heat treatment and heat-specific MTC.

Engineering analysis

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Frequently Asked Questions

Frequently asked questions

What is 1.4568 / Dura 17-7PH steel?

What are the main applications of 1.4568 / Dura 17-7PH?

Application contexts include Gears and power-transmission components, Shafts, axles and rotating machine components, High-strength fasteners and mechanical connections and Coil, leaf and torsion springs or resilient components, subject to the product standard and actual condition.

How hard can 1.4568 / Dura 17-7PH be?

Martensitic/precipitation-hardening stainless family capable of high hardness with better corrosion resistance than carbon steel. Internal screening index: 57/100 (moderate).

Is 1.4568 / Dura 17-7PH suitable for impact loading?

Impact resistance is indexed at 75/100 and toughness at 74/100. These are not Charpy or Izod energy values; temperature, orientation, geometry and actual microstructure govern component behaviour.

What is the service-temperature limit of 1.4568 / Dura 17-7PH?

Can 1.4568 / Dura 17-7PH be replaced by a close grade?

Approve substitution only after matching chemistry, specification, product form, condition, heat treatment and MTC.

Steel Comparison

Engineering steel comparison

Compare this grade with any other dossier. Scores from 0 to 100 are internal screening indices, not laboratory values or allowable design stresses.

Close suggestions:

Search for the second steel

Current grade1.4568 / Dura 17-7PHPH Stainless Steels

Selected grade1.4310 / Core 301/4310Austenitic Stainless Steels

Current-grade chemistry

Second-grade chemistry

Current-grade heat treatment

Second-grade heat treatment

Current-grade applications

Limitations

Second-grade applications

Limitations

Select a second grade to update the comparison.

Sources & Evidence

Sources, methodology and evidence

Sources support grade identity, recorded values or the engineering method. General guidance does not replace product-specific certification.

Grade-specific sources

Outokumpu Dura rangeManufacturer Range Page · Tier A

Reference supporting grade identity or recorded values; interpret it within the cited product and condition context. Role: manufacturer range page.

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Outokumpu Dura range datasheetManufacturer data sheet · Tier A

Reference supporting grade identity or recorded values; interpret it within the cited product and condition context. Role: manufacturer datasheet.

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stahldaten.deOfficial material-number register · Tier A

Reference supporting grade identity or recorded values; interpret it within the cited product and condition context. Role: official material number register.

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