Sanicro® 625 Bar

Datasheet updated

2022-09-16 10:17
(supersedes all previous editions)

Sanicro®625 is an extremely versatile nickel-chromium-molybdenum-niobium alloy, suitable for use in severely corrosive environments requiring high strength materials. Mainly suited for wet corrosion environments. Service temperatures ranging from cryogenic to 593°C (1100°F).

This grade is characterized by:

  • Extremely good resistance to chloride-induced stress corrosion cracking
  • Excellent corrosion resistance in widely varying acidic
    and chloride containing environments
  • Excellent resistance to general corrosion, pitting, and crevice corrosion
  • Excellent resistance to corrosion in environments containing hydrogen sulfide
  • Very high and even strength the recommended service temperatures
  • Very good welding properties
  • Good machining and fabrication properties

Standards

  • ASTM: UNS N06625 Grade 1
  • UNS: N06625
  • EN Number: 2.4856

Product standards

ASTM B 446 (Grade 1), ASME SB-446 (Grade 1)
NACE MR0175/ISO15156, NACE MR0103/ISO17945

Approvals

Approved by the American Society of Mechanical Engineers (ASME) for use in accordance with ASME Boiler and Pressure Vessel Code, Section I, Section III Div. 1 classes 1 and 3, Section VIII div.1.

Certificate

EN 10204/3.1

Chemical composition (nominal)

Chemical composition (nominal) %
C Si Mn P S Cr Ni Mo Fe Nb Co Ti Al
<0.025 <0.50 <0.50 <0.015 <0.015 21 62 8.5 <5 3.5 <1.0 0.2 <0.40

Pitting Resistance Equivalent Number, (PRE) >48.

Applications

Examples of applications for Sanicro® 625

Environmental projects
Waste-to-Energy production
Pollution control equipment
Refuse-derived fuel plants

Renewable energy
Solar power plants
Geothermal power
Bio-fuel production

Oil & Gas / Refinery
Well construction and service
Gas lift equipment
Wellheads and Christmas trees

Chemical processing
Phosphoric acid production
Pickling operations

Marine applications
Drivetrain components
Offshore piping systems
Seawater coolant in industries

Corrosion resistance

General corrosion
Sanicro®625 offers excellent resistance to both reducing, oxidizing, and in mixed corrosive environments. The resistance to marine corrosion / sea water is particularly good.

Intergranular corrosion
Sanicro®625 is stabilized against intergranular attack by the niobium content,
and the extra low carbon content. The resistance to IGC is tested acc. to ASTM G-28 Method A (Streicher test). Criteria: Max. 3mm / year.

Stress Corrosion Cracking
The nickel content of Sanicro®625 is at 62 % which promotes an excellent resistance to stress corrosion cracking induced by both chlorides and alkalis.
This makes it virtually immune to chloride-induced SCC, and the resistance to cracking in the presence of H2S and chlorides is very high. According to NACE MR 0175 / ISO 15156-3 it is acceptable for use in the oil and gas industry with no environmental limits in respect of partial pressures of H2S or elemental sulfur.

Pitting and crevice corrosion
Sanicro®625 have an extraordinary resistance to pitting and crevice corrosion in seawater at a variety of temperatures. With PRE number ≥48, Sanicro®625 is one of the grades which is least susceptible to these types of corrosion.

Forms of supply

Diameters and finished condition

Sanicro®625 is stocked in imperial dimensions.
Diameter range: 76.2mm-228.6mm (3”-9”)
Delivery condition: Soft annealed, peel-turned and ground to final finish.

Lengths

Bars are delivered in random lengths of 3-6.9 m, depending on diameter.

Straightness, metric units
Height of arch, 2 mm/m

Tolerances, metric units
Diameter tolerances: -0 / +0.79 mm
Surface finish: Ra, max. 3µm

Heat treatment

The Sanicro®625 stock program bars are delivered in soft annealed and quenched condition. Annealing at min. 910°C (1670°F) followed by quenching in water.

Mechanical properties

Tensile strength

Min. values at room temperature:

Dimension Proof strength Rp0.2 Tensile strength Rm Elongation A5
D≤101.9mm  415 MPa / 60 ksi 830 / 120 ksi 30%
D>101.9mm 345 MPa / 50 ksi 760 / 110 ksi 30%

Impact strength

-60°C Min. values Longitudinal Transversal (D>60mm)
Average 68J 47J
Single 61J 41J

Hardness
Hardness in the delivery condition is max. 35 HRC.

Physical properties

Density, at 20°C: 8.4 g/cm3, 0.31 lb/in3

Thermal conductivity

Temperature, °CW/(m °C)Temperature, °FBtu/(ft h°F)
20 9.8 68 5.7
100 10.8 200 6.2
200 12.5 400 7.2
300 14.1 600 8.2
400 15.7 800 9.1
500 17.5 1000 10.1
600 19 1200 11
700 20 1400 12
800 22.8 1600 13.2
900 25.2 1800 14.6

Specific heat capacity

Temperature, °CJ/(kg °C)Temperature, °FBtu/(lb °F)
20 410 68 0.10
100 427 200 0.10
200 455 400 0.11
300 475 600 0.12
400 505 800 0.12
500 525 1000 0.13
600 550 1200 0.14
700 575 1400 0.14
800 600 1600 0.15
900 625 1800 0.15

Thermal expansion, mean values in temperature ranges (x10-6)

Temperature, CPer °CTemperature, °FPer °F
30-100 12.5 86-200 7
30-200 13 86-400 7.5
30-300 13.5 86-600 7.5
30-400 13.5 86-800 7.5
30-500 14 86-1000 8
30-600 14 86-1200 8
30-700 15 86-1400 8.5
30-800 15.5 86-1600 9
30-900 16 86-1800 9

Resistivity

Temperature, °CµΩmTemperature, °FµΩin.
20 1.30 68 51.2
100 1.32 200 52.0
200 1.34 400 52.8
300 1.35 600 53.2
400 1.36 800 53.5
500 1.37 1000 54.3
600 1.38  1200 54.3 
700 1.38 1400  54.0 
800 1.38 1600  53.5
900 1.38 1800  53.1 

Modulus of elasticity (x103) (annealed condition)

Temperature, °CMPaTemperature, °Fksi
 20  208  68  30
 100  203  200  29.5
 200  198  400  28.5
 300  193  600  28
 400  187  800  27
 500  181  1000  26
 600  174  1200  24.5
 700  166  1400  23.5
 800  156  1600  21.5

Modulus of elasticity (x103) (solution annealed condition)

Temperature, °CMPaTemperature, °Fksi
 20  205  68  29.5
 100  200  200  29
 200  194  400  28
 300  188  600  27
 400  182  800  26
 500  176  1000  25
 600  169  1200  24
 700  162  1400  23
 800  154  1600  21.5

Welding

The weldability of Sanicro® 625 is good. Suitable methods of fusion welding are manual metal-arc welding (MMA/SMAW) and gas-shielded arc welding, with the TIG/GTAW method as first choice.

For Sanicro® 625, heat-input of <1.2 kJ/mm and interpass temperature of <100°C (210°F) are recommended. A string bead welding technique should be used.

Recommended filler metals

TIG/GTAW or MIG/GMAW welding:
ISO 18274 S Ni 6625/AWS A5.14 ERNiCrMo-3 (e.g. Exaton Ni60)

MMA/SMAW welding:
ISO 14172 E Ni 6625/AWS A5.11 ENiCrMo-3 (e.g. Exaton Ni60)

Machining

Materials in this group of alloys (N06625) are challenging to machine.
This is due to a number of properties, leading to high cutting forces,
severe wear and poor chip control.Dedicated cutting tools and strategies to be used.For details on tool geometries, tool grades and cutting data, the tool supplier should be able to support.

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.