Ohmalloy Invar 36 Low Expansion Alloy Wire

• Customization: Available
• Product Type: Wire
• Material: Feni Alloy
• Model NO.: Invar 36
• PCD: 0~100
• ET: 0~100
• Hole: 0
• Diameter: 0.05~10mm
• Condition: Bright Surface, Soft
• Heat Treatment: Done
• Magnetic Properties: Less Than 230 Celsius Is Ferromagnetic.
• Transport Package: Spool, Wooden Case
• Specification: SGS
• Trademark: OhmAlloy-4J36
• HS Code: 722990900
• Production Capacity: 5000 Kgs Per Month

Product Description

OhmAlloy-4J36  (Expansion alloy)

(Common Name: Invar, FeNi36, Invar Standard, Vacodil36)
OhmAlloy-4J36 (Invar), also known generically as FeNi36 (64FeNi in the US), is a nickel-iron alloy notable for its uniquely low coefficient of thermal expansion (CTE or α).
 
The name Invar comes from the word invariable, referring to its relative lack of expansion or contraction with temperature changes.
 
It was invented in 1896 by Swiss physicist Charles Édouard Guillaume. He received the Nobel Prize in Physics in 1920 for this discovery, which enabled improvements in scientific instruments.
OhmAlloy-4J36 (Invar) is used where high dimensional stability is required, such as precision instruments, clocks, seismic creep gauges, television shadow-mask frames, valves in motors, and antimagnetic watches. In land surveying, when first-order (high-precision) elevation leveling is to be performed, the Level staff (leveling rod) used is made of Invar, instead of wood, fiberglass, or other metals. Invar struts were used in some pistons to limit their thermal expansion inside their cylinders.


Normal composition%

Ni	35~37.0	Fe	Bal.	Co	-	Si	≤0.3
Mo	-	Cu	-	Cr	-	Mn	0.2~0.6
C	≤0.05	P	≤0.02	S	≤0.02

 
 

Typical Physical properties

Density (g/cm3)	8.1
Electrical resistivity at 20ºC(mm2/m)	0.78
Temperature factor of resistivity(20ºC~200ºC)X10-6/ºC	3.7~3.9
Thermal conductivity, λ/ W/(m*ºC)	11
Curie point   Tc/ ºC	230
Elastic Modulus,  E/ Gpa	144

 
 
Coefficient of expansion

θ/ºC	α1/10-6ºC-1	θ/ºC	α1/10-6ºC-1
20~-60	1.8	20~250	3.6
20~-40	1.8	20~300	5.2
20~-20	1.6	20~350	6.5
20~-0	1.6	20~400	7.8
20~50	1.1	20~450	8.9
20~100	1.4	20~500	9.7
20~150	1.9	20~550	10.4
20~200	2.5	20~600	11.0

 
Temperature factor of resistivity

Temperature range, ºC	20~50	20~100	20~200	20~300	20~400
aR/ 103 *ºC	1.8	1.7	1.4	1.2	1.0

 

The heat treatment process
Annealing for stress relief	Heated to 530~550ºC and hold 1~2 h. Cold down
annealing	In order to eliminate hardening, which be bring out in cold-rolled, cold drawing process. Annealing needs heated to 830~880ºC in vacuum,hold 30 min.
The stabilization process	In protective media and heated to 830 ºC, hold 20min. ~ 1h, quench Due to the stress generated by quenching, heated to 315ºC,hold 1~4h.
Precautions	Can not be hardened by heat treatment Surface treatment can be sandblasting, polishing or pickling. Alloy can be used 25% hydrochloric acid pickling solution at 70 ºC to clear oxidized surface

 

Style of supply

Alloys Name	Type	Dimension
OhmAlloy-4J36	Wire	D= 0.1~8mm
OhmAlloy-4J36	Strip	W= 5~250mm	T= 0.1mm
OhmAlloy-4J36	Foil	W= 10~100mm	T= 0.01~0.1
OhmAlloy-4J36	Bar	Dia= 8~100mm	L= 50~1000