4J32

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• Material:	4J32
  Other Brands:	4J32, Super-Invar, 32HКД, 32HК-BИ, Invar, Superieur
  Source Stock:	Customized
  Supplier:	Shanghai Hite Special Alloy Co., Ltd.
  Contacts:	Mr.KayDuan
  Email:	sales02@hitealloy.com

• 4J32 Details

  
  
  

  4J32 alloy, also known as Super Invar alloy. In the temperature range of -60~80 ℃, its expansion coefficient is lower than that of 4J36 alloy, but its low-temperature microstructure stability is worse than that of 4J36 alloy. This alloy is mainly used for manufacturing high-precision instrument parts that require high dimensional accuracy within the range of environmental temperature changes.

  
  

  4J32 Heat Treatment System:

  The performance inspection samples for the expansion coefficient and low-temperature structural stability specified in the standard are processed and heat treated as follows: the semi-finished samples are heated to 840 ℃± 10 ℃, kept for 1 hour, quenched with water, and then processed into finished samples, kept for 1 hour at 315 ℃± 10 ℃, and cooled in the furnace or air.

  
  

  4J32 Application Overview and Special Requirements:

  This alloy is a typical low expansion alloy that has been used in aviation factories for a long time and exhibits stable performance. Mainly used for manufacturing precision components with high dimensional accuracy within the range of environmental temperature changes. During use, the heat treatment process and processing technology should be strictly controlled, and the organizational stability should be strictly tested according to the use temperature.

  
  

  Chemical composition under YB/T5241-2005 standard:

  Grade 4J32	chemical composition,%
  	C	P	S	Si
  	≤0.05	≤0.02	≤0.02	≤0.2
  Cu	Mn	Ni	Co	Fe
  0.4~0.8	0.2~0.6	31.5~33	3.2~4.2	Remainder

  
  

  Typical average linear expansion coefficient value α,10-6/℃:

  Grade	20℃~50℃	20℃~100℃	20℃~200℃	20℃~300℃	20℃~400℃	20℃~500℃
  4J32	0.7	0.8	1.4	4.3	7.2	9.3

  
  

  Structure of 4J32 alloy:

  After the alloy is treated according to the heat treatment system specified in 1.5, and then cooled at -60 ℃ for 2 hours, there should be no martensitic structure. But when the alloy composition is not appropriate, different degrees of austenite will occur at room temperature or low temperature（ γ) Acicular martensite（ α) The transformation is accompanied by a volume expansion effect. The expansion coefficient of the alloy correspondingly increases. The main factor affecting the low-temperature structural stability of alloys is their chemical composition. From the Fe Ni Co ternary phase diagram, it can be seen that nickel is stable γ The main elements of phase. High nickel content is beneficial for γ Phase stability. Copper is also an important element for stabilizing alloy structures. As the total deformation rate of the alloy increases, its microstructure tends to become more stable. Alloy composition segregation may also cause localized γ → α Phase transition. In addition, coarse grains can also promote γ → α Phase transition.