Practical nickel-titanium shape memory alloys are prepared by smelting.This alloy is composed of 53%~57% nitinol and titanium balanced.Phase transition temperature is around -50℃~160℃.
Various nickel-titanium memory alloy melting methods:
1. Vacuum induction primary melting method
First to obtain a known composition of ni-ti mother alloy,put it into the Graphite crucible,turn on the electricity and make it melted, a niti alloy molten pool is formed,
Then put the crushed material of nickel and titanium into the molten pool. The biggest advantage of this process is less smelting energy, low cost,the composition of alloy is relatively uniform.But,
In this process, the alloy is polluted by carbon, and detrimental to shape memory effect, the controllable amount of carbon is around 0.2%
2. Vacuum consumption+Vacuum induction melting
The smelting method is firstly refined into a basic alloyed nickel-titanium mother alloy by a vacuum consumable furnace,then Homogenization remelting by vacuum induction furnace.The process can effectively control the carbon content as long as the melting temperature and the melting time are properly controlled.usually,carbon content is not more than 0.1%
3. Vacuum condensing + vacuum consumable melting method and Vacuum condensing once smelting precision casting method
The vacuum consumable furnace melting method utilizes the arc discharge thermal energy release between the two electrodes to melt the self-twisting electrode to form alloy droplets, and drops the water-cooled copper crucible to form an ingot.
The vacuum condensing furnace smelting uses the positive polarity connection method to cause the high-speed electron current to collide with the molten pool to release heat energy, thereby ensuring the high temperature and electromagnetic stirring of the molten pool, and fully alloying and homogenizing the niti alloy.
We use most advanced smelting method to guarantee the quality and service time of our nitinol alloy products.
