Nickel-based super alloy: hastelloy X (UNS NO6002/W.Nr 2.4665)

What is hastelloy X?

Hastelloy X, also known as “Alloy X”, is designated as UNS N06002 or W.Nr 2.4665. It is a nickel-chromium-iron-molybdenum alloy that possesses an exceptional combination of oxidation resistance, fabricability, and high-temperature strength. Hastelloy X has also been found to be exceptionally resistant to stress-corrosion cracking in petrochemical applications and resistant to carburization and nitriding. Hastelloy X (UNS N06002) is mainly made of chromium and a nickel-based superalloy with high iron content strengthened by molybdenum solid solution. It has good anti-cultivation and corrosion resistance, moderate durability and creep strength below 900℃, cold and hot working formability and welding The performance is good. Used in the manufacture of combustion chamber parts and other high-temperature parts of aero-engines, long-term use below 900 ℃, short-term working temperature up to 1080 ℃. The main products supplied are plates, strips, tubes, bars, forgings, ring parts and precision castings.

Chemical Composition Requirements of Hastelloy X

The Chemical Composition of Hastelloy X, %
Ni balance
Cr 20.5-23.0
Fe 17.0-20.0
Mo 8.0-10.0
Co 0.5-2.5
W 0.20-1.00
C 0.05-0.15
Mn ≤1.00
Si ≤1.00
P ≤0.040
S ≤0.030

Typical Physical Properties of Hastelloy X

Density

Melting Range

Specific Heat

Thermal Conductivity

Electrical Resistivity

g/cm3

°C

J/kg.k

W/m.k

µΩ·m

8.22

1260-1355

486

9.1

1180

Product Forms and Standards of Hastelloy X

Product Form Standard
Bar ASTM B572
Plate, sheet and strip ASTM B435, B906
Seamless pipe and tube ASTM B622
Welded pipe ASTM B619, B775
Welded tube ASTM B626, B751
Welding fitting ASTM B366
Billet and bar for reforging ASTM B472

*The mechanical properties of Hastelloy X materials vary according to different forms and heat treatment conditions.

The physical and chemical properties of Hastelloy X (N06002)

The melting temperature range of Hastelloy X (N06002): 1295~1381℃. 

  • Hastelloy X (N06002) alloy thermal conductivity: see Table 2-1.
  • Hastelloy X (N06002) alloy specific heat capacity: Table 2-2. 
  • Hastelloy X (N06002) alloy linear expansion coefficient: see Table 2-3. 
  • Thermal diffusivity of Hastelloy X (N06002) alloy castings: see Table 2-4. 
  • Density of Hastelloy X (N06002): ρ=8.28g/cm [1] . 
  • Hastelloy X (N06002) electrical properties: the resistivity is shown in Table 2-5. 
  • Hastelloy X (N06002) magnetic properties: the alloy is non-magnetic. 
  • Hastelloy X (N06002) chemical properties: see Table 3-1.
  • Hastelloy X (N06002) oxidation resistance: the oxidation rate of the alloy after 100h test in air medium is shown in Table 2-6. 
  • Hastelloy X (N06002) mechanical properties: The mechanical properties of different varieties specified in HastelloyX technical standards are shown in Table 3-1. 

Table 2-1 [1] 

θ/℃ 100 200 300 400 500 600 700 800 900

λ/(W/(m·℃))

13.38 17.97 20.27 22.40 24.62 26.79 29.05 31.14 33.44

Table 2 – 2 

θ/℃ 17 100 200 280 408 500 700 800 900
c/(J(kg·℃)) 372.6 372.6 389.4 456.4 427.1 452.2 515.0 535.9 561.0

Table 2- [1]

θ/℃ 20~100 20~200 20~300 20~400 20~500 20~600 20~800 20~900
α/10 -6 ℃ -1 12.1 12.5 13.4 14.0 14.3 14.8 15.8 16.1

Table 2-4

θ/℃ twenty four 100 300 400 500 600 700 800 900
Q/(10 -6 m 2 /S)) 2.78 3.06 3.68 3.64 4.36 4.32 4.38 4.91 5.23

Table 2-5[1]

θ/℃ 100 200 300 400 500 600 700 800 900
p/(10-6Ω.M)) 1.18 1.20 1.21 1.22 1.24 1.25 1.26 1.27 1.29

Table 2-6[1]

θ/℃ 700 800 900 1000 1100
Oxidation rate/(g/(m 2 ·h)) 0.0023 0.060 0.117 0.200 0.611

Table 3-1

Variety Tensile performance at room temperature 815℃ lasting performance Other properties
σ P0.2 /MPa σ b /MPa δ 5 /% σ/MPa t/h δ 5 /%  Rockwell hardness
not less than            
Cold-rolled sheet, 

cold-rolled strip, 

bar, 

ring, 

precision casting

310 

310 

310 

275 

275 

200

725 

760 

690 

690 

690 

380

35 

30 

25 

30 

30 

10

110 

– 

– 

105 

105 

24- 

– 

– 

24- 

24- 

8.

– 

– 

10.0 

10.0 

Bending 180° 

Bending 180° 

Hydraulic, flaring 

HBS≤241 

HBS≤241 

HBS≤96

① Room temperature tensile strength of strip with δ<0.25mm σ b ≥725MPa, δ 5 ≥25%. 
The σ b ≥240MPa and δ 5 ≥12 % of the precision casting at 815℃ . After 800℃, 50h, air cooling, (Rockwell hardness) HRC≤24. 

Alloy structure of Hastelloy X (N06002)

  • (1) The structure of the alloy in the solid solution state is an austenite matrix with a small amount of TiN and M6C carbides. After long-term aging at 700-900°C, the main precipitated phases are M12C and M3B2 , along with trace μ phase and L phase. A small amount of σ phase appeared after aging at 700°C for 200 hours, but there was no σ phase after aging at 800°C, and a trace amount of M23C6 was precipitated , sometimes a trace amount of L phase appeared. Therefore, the alloy shows a certain degree of age hardening after long-term aging, which reduces the plasticity and the high-temperature strength. 
  •  (2) The technical standard of cold-rolled sheet stipulates that the grain size of cold-rolled sheet in the supply state should be in the range of 4-8. 

Alloy process performance and requirements of Hastelloy X (N06002)

1. HastelloyX alloy forming properties:

The alloy has good cold and hot forming properties. The forging heating temperature is 1170℃±10℃, and the final forging temperature is not lower than 950℃; the slab hot rolling heating temperature is 1150℃±10℃, and the final rolling temperature is not lower than 850℃; the ring hot rolling heating temperature is 1170℃±10℃ . The high temperature tensile ductility of the alloy is shown in Figure 5-1.Figure 5-2 shows the recrystallization curve of high temperature upsetting sample after solution treatment at 1180℃ for 45min. 

2. HastelloyX welding performance:

This alloy has good welding process performance and can be welded by argon arc welding, seam welding and spot welding. HHastelloyX or HGH3113 welding wire is recommended for argon arc welding. 

(1) For HastelloyX manual argon arc welding butt specifications, see Table 5-1. 

20200729230407 38340 - Nickel-based super alloy: hastelloy X (UNS NO6002/W.Nr 2.4665) 20200729230435 47716 - Nickel-based super alloy: hastelloy X (UNS NO6002/W.Nr 2.4665)
Fig.5-1 High temperature tensile plasticity diagram of alloy Fig.5-2 Recrystallization curve of upsetting sample

Table 5-1 [5]

Material to be welded Thickness/mm State before welding Welding wire
Joint 

form

Welding current/A Argon flow/(L/min) Tungsten electrode diameter/mm
Power supply 

and polarity

Grade Diameter/mm
HastelloyX+HastelloyX 1.0 + 1.0 Supply state or solid solution state
HHastelloyX 

HGH3113

1.2~1.6 Docking 40~60 10~13 1.6~2.0
DC 

positive polarity

1.5 + 1.5
HHastelloyX 

HGH3113

1.2~1.6 50~70 12~15 1.8~2.2

(2) For HastelloyX automatic tungsten pulse argon arc welding butt specification, see Table 5-2. 
Table 5-2

Thickness/mm State before welding Welding wire Arc voltage/V Pulse current/A Arc current/A Pulse amplitude ratio Pulse width ratio Pulse frequency Welding speed/(m/min) Wire feeding speed/(m/min)
Grade Diameter/mm
1.0 

1.2 

1.5

Solid solution
– 

HGH-1 

HGH-1

– 

1.0 

1.0

8.5 

8.5 

9.0

60 

65 

100

20 

22 

28

3.5

2

3

0.25 

0.2 

0.23

– 

0.20 

0.25

(3) For HastelloyX seam welding specifications, see Table 5-3. 
Table 5-3 [5]

Material to be welded Thickness/mm State before welding Roller width/mm Welding time/s Rest time/s Welding speed/(m/min) Electrode pressure/kN
on under
HastelloyX+HastelloyX 1.0 + 1.0 Solid solution or supply state 5.5 7.0 0.14-0.18 0.14-0.22 0.34-0.40 0.25
1.5 + 1.5 5.5 7.0 0.16-0.20 0.14-0.22 0.22-0.34 0.25

(4) For HastelloyX spot welding specifications, see Table 5-4. 
Table 5-4 [5]

Material to be welded Thickness/mm State before welding Electrode diameter/mm Welding time/s Electrode pressure/kN Single point shear strength/MPa Tensile strength/MPa
on under
HastelloyX+HastelloyX 1.0 + 1.0 Solid solution or supply state 6 7 0.16~0.24 0.1~0.2 ≥9.35 ≥6.36
1.5 + 1.5 6 7 0.20~0.36 0.2~0.3 ≥12.30 ≥10.60

(5) The mechanical properties of HastelloyX welded joints are shown in Table 5-5. 
Table 5-5 [6]

Welding method
Thickness 

/mm

State before welding Post-weld treatment Welding wire grade θ/℃ Joint strength Lasting performance
σ b /MPa Strength coefficient/% σ/MPa t/h
Argon arc welding 1.5 Supply status Untreated HHastelloyX
20 

650 

815

800 

586 

337

100 

100 

100

– 

294 

110

– 

217.6 

46.4

Pulse argon arc welding 1.0 Supply status Untreated
20 

650

842 

531

100 

90

– 

– 

1.5 Supply status Untreated HSG-1
20 

650

826 

581

100 

98

– 

294

– 

296.5

Seam welding 1.5 Supply status Untreated
20 

650 

815

763 

514 

325

96 

91 

100

– 

294 

110

– 

214.2 

48.6

3. Heat treatment process of HastelloyX parts:

  • Solid solution treatment of plate parts: 1150℃±10℃, 2~15min, rapid air cooling.
  • Welding parts or flame tube treatment: 980℃±10℃, 60min, air cooling.
  • Stress relief treatment after machining: 870℃±10℃, 30~60min, air cooling.
  • Stable dimension treatment of parts: 760℃±10℃, 2h, air cooling.

Heat treatment system of hastelloy X (N06002)

Plates and tubes: 1130~1170℃, fast air cooling or water cooling; bar and ring test samples: 1175℃±15℃, air cooling or faster cooling; strip : 1065~1105℃, rapid cooling.
Specifications and supply status of hastelloy X (N06002): supply δ0.5~4.0mm plate, δ0.05~0.8mm strip, outer diameter 4~20mm, wall thickness 1.0~2.0mm pipe , Welding wire with a diameter of 0.2~10.0mm, rods with a diameter of ≤300mm, ring parts with various diameters and wall thicknesses, and precision castings with different shapes and sizes. Plates, strips and pipes are supplied after solution treatment and pickling. Strips can also be supplied in cold rolled state; welding wire is delivered in hard state, semi-hard state, solid solution plus pickling, bright solution treatment state , Can also be delivered straight; bars and ring parts are delivered without heat treatment. Precision castings are supplied in the as-cast state.

Smelting and casting process of hastelloy X (N06002)

Adopts electric arc furnace plus electroslag or non-vacuum induction furnace plus electroslag remelting process. The production of castings uses induction furnace to remelt the master alloy and then pouring it into a heated mold shell. The pouring speed is better. 

Application profile and special requirements of hastelloy X (N06002): This alloy has been widely used in foreign aero-engines and civil industries. China is mainly used to manufacture combustion chamber parts and other hot end parts and honeycomb structures. . The alloy has a certain age hardening phenomenon after long-term use at high temperature.

  • Gas turbines
  • Petrochemical industry
  • Industrial furnaces
  • Heat treating equipment
  • Nuclear engineering
  • Jet engine combustion chambers
  • Aircraft cabin heaters
  • Turbine exhaust components

hastelloy x astm b572 uns n06002 round bars - Nickel-based super alloy: hastelloy X (UNS NO6002/W.Nr 2.4665)

Hastelloy X round bars, ASTM B572 Gr. N06002, O.D=219 mm, Length=1025 mm.

Hastelloy X round bars manufactured to ASTM B572 Gr. N06002. Density: 0.297 lb/in3 [8.23 g/cm3]; Condition: hot rolled & solution annealed.

Alloy X is one of the most widely used nickel base superalloys for gas turbine engine combustion zone components such as transition ducts, combustor cans, spray bars and flame holders as well as in afterburners, tailpipes and cabin heaters. It is recommended for use in industrial furnace applications because it has unusual resistance to oxidizing, reducing and neutral atmospheres. Hastelloy X is also used in the chemical process industry for retorts, muffles, catalysts support grids, furnace baffles, tubing for pyrolysis operations and flash drier components.

Source: China Hastelloy X Flanges Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

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