The future in metal

Corus Engineering Steels

Durehete 950

1% CrMoV Steel for bolting applications up to 510OC

Benefits

• Lower design and operating risks

• Simplified design for bolting configuration compared with martensitic steels or high nickel alloys.

Applications

• Power generation – turbine fasteners– boiler support rods

• Process plant – fasteners

Features

• Proven performance in long term service.

• Extensive database of long term, high temperature test results.

• High room and elevated temperature strength.

• Good creep and relaxation resistance to 510OC

• High notch tolerance.

• Thermal expansion coefficients compatible with low alloysteel turbine casing materials.

Supply Condition & Availability

• Readily available from bar stock.

• Supplied as oil quenched, tempered and cooled in air.

Chemical Composition (wt%)

* The Cr range is compatible with the compositional requirements of ASTM A193 B16.

Related Standards and Specifications

Unless stated otherwise all data are in accordance withBSEN 10269: 1999 , 40CrMoV4-6 , Steel No. 1.7711

BSEN 1515-1: 1999BS1506 671-850CEGB GDCD STD1 ISS1BS4882ASTM A193 B16

min max

C 0.36 0.44

Si - 0.40

Mn 0.45 0.85

P - 0.030

S - 0.030

Al - 0.015

Cr* 1.00 1.15

Mo 0.50 0.65

V 0.25 0.35

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Heat treatment (OC)

Test Piece Position

Room Temperature Mechanical Properties

* Charpy V notch: mean of 3 test pieces.

Mechanical Properties at ElevatedTemperatures

* Position is at greater distance below surface thanspecified in BS EN 10269: 1999 to coincide with the most highly stressed area of fasteners in service.

Durehete 950

Mechanical Properties

Test Piece Position

Bar Diameter (mm) Position

d≤25 centre

25<d≤100 12.5mm below surface

100<d≤200 25mm below surface*

Diameter (mm) 0.2% Proof Stress UTS (N/mm2) Elongation Reduction of Impact Energy (J)*

(N/mm2) (%) area (%)

d 100 Min 700 850 14 45 30

Max - 1000 - - -

100<d 200 Min 640 850 14 45 25

Max - 1000 - - -

Minimum 0.2% Proof Stress (N/mm2) at Temperature (OC)

Te m p e r a t u r e(OC ) 50 100 150 200 250 300 350 400 450 500 550 600

d 100mm 687 670 647 631 608 593 577 554 523 470 400 293

100<d 200mm 631 612 591 577 556 542 528 507 479 429 366 268

Diameter (mm) Quench temperature (OC) Coolant Temper Temperature (OC)

d 100 Min 880 oil 670

Max 950 720

100<d 200 Min 940 oil 600

Max 970 700

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Mean Stress Rupture Strength (Plain Specimens)

Mean Stress Rupture Strength (Notched Specimens)

Mean Stress Relaxation Properties

Oxidation

The oxidation resistance is similar to that obtained withDurehete 900

Durehete 950

Mechanical, Oxidation & Embrittlement Properties

Temperature (OC) Stress to Produce Rupture (N/mm2)

10,000 h 100,000 h 200,000 h

450 513 463 446

500 321 210 187

550 137 - -

Temperature (OC) Stress to Produce Rupture (N/mm2)

1,000 h 10,000 h 100,000 h

450 - 578 452

500 510 360 221

550 295 143 -

Strain = 0.15%

Temperature (OC) Residual Stress (N/mm2)

1,000 h 10,000 h 30,000 h

400 234 215 192

450 188 157 141

500 136 83 47

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Corus Engineering Steels

Published References

1 H Everson, J. Orr, D. Dulieu: “Low Alloy Ferritic Bolting Steels for Steam Turbine Applications – The Evolution of the Durehete Steels”, ASM/EPRI Conference “Advances in Material Technology for Fossil Power Plant”, September 1987, Chicago, pp 375-383.

Durehete 950

Physical Properties

Temperature (OC)

20 100 200 300 400 500 600 700

Density (kg/m3) 7810 - - - - - - -

Electrical Resistivity (n m) 273 320 390 465 560 660 785 955

Thermal Expansion (K -1x10-6) - 11.1 12.1 12.9 13.5 13.9 14.1 -

Thermal Conductivity (W/mK) 42 41 40 39 36 34 33 -

Specific Heat (J/kgK) 420 449 487 525 546 567 621 651

Heat Content (kJ/kg) 0 33.6 86.1 147 107 273 349 441

Modulus of Elasticity (kN/mm2) 211 207 198 190 183 174 165 -

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Corus Engineering Steels

w w w. c o r u s g ro u p . c o m

Corus Engineering SteelsPO Box 50Aldwarke LaneR o t h e r h a mS60 1DWUnited KingdomTe l e p h o n e +44 (0) 1709 371234F a c s i m i l e +44 (0) 1709 826233

C a re has been taken toe n s u re that the informationh e rein is accurate, butCorus Engineering Steels Limited does not acceptresponsibility for errors orfor information which isfound to be misleading.

C E S 0 2 : 6 0 0 0 : U K : 0 3 / 2 0 0 0