Low Expansion Alloy

Super Invar

Super Invar has a certain coefficient of linear thermal expansion in the range of 20-100 degrees Celsius. It mainly produces various instruments and instrument parts requiring stable size, or thermal bimetallic passive layer.

Equivalent Grades

GBГОСТASTMUNSDINW.Nr.NFBSJISSS
4J3232НКДSuper Invar

Chemical Composition, %

AlloyCMnSiPSNiCuCoFe
4J32≤0.050.2-0.6≤0.2≤0.02≤0.0231.5-33.00.4-0.83.2-4.2Rest
4J36≤0.050.2-0.6≤0.3≤0.02≤0.0235-37Rest
Nb-Invar≤0.05≤0.6≤0.3≤0.02≤0.0230-35Nb≤0.53-5Rest

Average Linear Expansion Coefficient

AlloyHeat treatment for sampleAverage linear expansion coefficient a/10-6.K-1
20~100℃-40~20℃-20~20℃
4J32Heating to temperature between 840℃±10℃ in a protective or vacuum atmosphere. Holding for 1hour then water cooling. Machining the sample to the finial dimensions, reheating them to 315℃±10℃ holding for 1 hour, then furnace/air cooling≤1.0
4J36≤1.5
Nb-Invar≤0.5≤0.6≤0.5

Available Products and Specifications

Rod, Bar, Wire and ForgingsYB/T5241-2014, Q/SYY 7-1999, ГОСТ 10994-1974, ГОСТ 14080-78
Plate, Sheet and StripYB/T5241-2014, Q/SYY 7-1999, ГОСТ 10994-1974, ГОСТ 14080-78
Pipe and TubeYB/T5241-2014, Q/SYY 7-1999, ГОСТ 10994-1974, ГОСТ 14080-78
Welding Product
OthersYB/T5241-2014, Q/SYY 7-1999, ГОСТ 10994-1974, ГОСТ 14080-78

Features

Fairly low linear expansion coefficient at the temperature between -60℃ and 100℃.

Applications

They are usually applied for making dimension stable components in various instruments.