Sanicro® 70 Tube and pipe, seamless

Datasheet updated

2022-05-10 07:46
(supersedes all previous editions)

Sanicro® 70 is an austenitic nickel-chromium-iron (NiCrFe) alloy characterized by very good resistance to carburization and nitrogen absorption and good structural stability at high temperatures. It also has good resistance to stress corrosion cracking (SCC).

Standards

  • UNS: N06600
  • W.Nr.: 2.4816
  • DIN: NiCr 15 Fe
  • BS: NA14

Product standards

  • ASTM B163, B167
  • BS 3074

Chemical composition (nominal)

Chemical composition (nominal) %
C Si Mn P S Cr Ni Cu Fe
≤0.05 0.4 0.8 ≤0.015 ≤0.015 16.5 72.5 ≤0.5 ≤10.0

Chemical composition (nominal) %

C

Si

Mn

P

S

Cr

Ni

Cu

Fe

≤0.05 0.4 0.8 ≤0.015 ≤0.015 16.5 72.5 ≤0.5 ≤10.0

Applications

Sanicro® 70 has good resistance to chlorine and hydrogen chloride at high temperatures and can therefore be used in the production of chlorinated hydrocarbons, e.g. in the oxychlorination reactor and the cracking furnace in vinylchloride plants.

Sanicro® 70 can also be used in wet corrosive conditions, where austenitic 18Cr/8Ni steels would be susceptible to stress corrosion cracking.

Corrosion resistance

General corrosion

Sanicro® 70 has approximately the same resistance to organic and inorganic acids as steel of the AISI 304 type. Its resistance to sodium hydroxide is very good even at high concentrations and temperatures.

Pitting

Resistance to pitting is equal to that of steel of the AISI 304 type.

Stress corrosion cracking

Sanicro® 70 has very good resistance to stress corrosion cracking, particularly in chloride-bearing solution.

Gas corrosion

Sanicro® 70 has very good oxidation resistance. It can be used in:

  • Air up to 1175°C (2145°F)
  • Up to 800°C (1470°F)
  • Dry chlorine and hydrogen chloride up to about 550°C (1020°F)
  • Synthesis gas (ammonia synthesis) up to 600°C (1110°F). The resistance to nitrogen absorption, e.g. cracked ammonia at high temperatures, is very good.

Due to high nickel content the material should not be used in reducing, sulphurous atmospheres (containing hydrogen sulphide) at temperatures above 550°C (1020°F).

Bending

Heat treatment after cold bending is not normally necessary, but this point must be decided with regard to the degree of bending and the operating conditions. Heat treatment, if any, should take the form of stress relieving or solution annealing.

Hot bending is carried out at 1100-850°C (2010-1560°F) and should be followed by solution annealing.

Forms of supply

Seamless tube and pipe

Tube and pipe are normally supplied in the solution annealed and white-pickled condition. Small sizes, e.g. heat exchanger tubes, can also be supplied in the bright-annealed condition. The principal size range is shown in figure 1.

Figure 1. Principal size range for seamless tube and pipe.

Heat treatment

The tubes are delivered in heat treated condition. If another heat treatment is needed after further processing the following is recommended.

Stress relieving

800-875°C (1470-1920°F), 10-15 minutes, cooling air.

Solution annealing

950-1050°C (1740-1920°F), 5-30 minutes, rapid cooling in air or water.

Mechanical properties

At 20 °C (68 °F)

Metric units
Condition Proof strength Tensile strength Elongation Hardness
Vickers
Rp0.2a) Rp1.0a) Rm Ab)
MPa MPa MPa %
approx.
Cold finished OD≤127 mm ≥241 ≥265 552-700 ≥35 160
Cold finished OD>127 mm ≥205 ≥265  552-700 ≥35 160
Hot finished ≥205 ≥230 550-700 ≥35 160
Imperial units
Condition Proof strength Tensile strength Elongation Hardness
Vickers
Rp0.2a) Rp1.0a) Rm A2"
ksi ksi ksi %
approx.
Cold finished OD ≤ 5″ ≥35 ≥38 80-101 ≥35 160
Cold finished OD > 5″ ≥30 ≥38 80-101 ≥35 160
Hot finished ≥30 ≥33 80-101 ≥35 160

1 MPa = 1 N/mm2
a) Rp0.2 and Rp1.0 correspond to 0.2% and 1.0 % offset yield strength, respectively.
b) Based on L0 = 5.65 ÖS0 where L0 is the original gauge length and S0 the original cross-section area.

At high temperatures

Metric units
Temperature Proof strength Tensile strength
°C Rp0.2 Rm
MPa MPa
min. min.
100 200 500
200 180 480
300 170 470
400 160 460
500 140 450
600
100
440
Imperial units
Temperature Proof strength Tensile strength
°F Rp0.2 Rm
ksi ksi
min. min.
200 29.6 73.2
400 26.0 69.6
600 24.4 67.9
800 22.4 66.3
1000 18.1 64.7
1100
14.9
63.9

Creep strength

Sanicro® 70 has a creep strength which is comparable to that of AISI tp 310 (UNS S31008).

Physical properties

Density: 8.4 g/cm3, 0.30 lb/in3

Scaling temperature in air: 1175 °C, 2145 °F

Thermal conductivity
Temperature, °C W/m °C Temperature, °F Btu/ft h °F
20 13 68 7.5
100 14 200 8
200 16 400 9
300 17 600 10
400 19 800 11
500 21 1000 13
600 25 1100 15
Specific heat capacity
Temperature, °C J/kg °C Temperature, °F Btu/lb °F
20 460 68 0.11
100 480 200 0.11
200 495 400 0.12
300 510 600 0.12
400 515 800 0.12
500 525 1000 0.13
600 590 1100 0.14
Thermal expansion, mean values in temperature ranges (x10-6)
Temperature, C Per °C Temperature, °F Per F
30-100 13.5 86-200 7.5
30-200 14 86-400 8
30-300 14 86-600 8
30-400 14.5 86-800 8
30-500 15 86-1000 8.5
30-600 15.5 86-1100 8.5
Modulus of elasticity (x103)
Temperature, °C MPa Temperature, °F ksi
 20  214  68  31.0
 100  206  200  30.0
 200  202  400  29.3
 300  196  600  28.3
 400  190  800  27.4
 500  185  1000  26.6
 600  180  1200  25.5
 700  171  1400  23.9
 800  161  1600  22.1
 900  149  1800  19.9
1000 135

Welding

The weldability of Sanicro® 70 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® 70, heat-input of <1.0 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 6082/AWS A5.14 ERNiCr-3 (e.g. Exaton Ni72HP)

MMA/SMAW welding

ISO 14172 E Ni 6182/AWS A5.11 ENiCrFe-3 (e.g. Exaton Ni71)

ISO 14172 E Ni 6152/AWS A5.11 ENiCrFe-7 (e.g. Exaton Ni69)

Overlay welding

ISO 18274 S Ni 6082/AWS A5.14 ERNiCr-3 (e.g. Exaton Ni72HP) wire and strip electrodes are recommended for overlay welding of tube sheets and high-pressure vessels in cases where corrosion resistance, equal to that of Sanicro® 70, is required.

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.