Sub-zero treatment is carried out in order to complete the transformation of retained austenite to martensite after hardening and before tempering. It is usually applied to high carbon, high alloy steels such as tool steels but is more-widely applied by aerospace companies to guarantee complete transformation.
Full Answer
Why would you want a zero fret?
You might be wondering why anyone would want to do this. The truth is, there are advantages and disadvantages to a Zero Fret. What is probably the biggest advantage is the ability to change string gauge as often and as dramatically as you’d like without having to resize or replace the nut.
What is sub-zero treatment?
Sub-zero treatment is carried out in order to complete the transformation of retained austenite to martensite after hardening and before tempering. It is usually applied to high carbon, high alloy steels such as tool steels but is more-widely applied by aerospace companies to guarantee complete transformation.
What are the benefits of Sub Zero treatment for hardened steel?
All hardened steels are improved by a proper Sub-Zero treatment to the extent that there will be less tendency to develop grinding cracks and therefore they will grind much more easily after the elimination of the retained austenite and the untempered martensite.
Why choose cryogenic freezers for Sub-Zero treatment?
Cryogenic freezers for sub-zero treatment of metal parts and components come in many sizes and configurations to meet varying production requirements. Also, equipment is available to accommodate batch or continuous processing.
How does sub zero treatment affect steel?
The sub-zero treatment processes can be grouped into three broad categories and they affect steel in the following ways: Shrink fitting reduces the diameter of a steel shaft so it can be readily assembled with other components.
Where is sub zero steel used?
Sub-zero treatment of steels is a relatively new process that is gaining acceptance in the United States and is becoming increasingly popular in Europe, Latin America and Asia.
Why do we need cold and cryogenic treatments?
Following heat treating cycles, many industries are now requiring Cold and Cryogenic (Deep Freezing) treatments be done in order to increase hardness and wear resistance and to further reduce metal fatigue.
Does cryogenic treatment increase wear resistance?
Cryogenic treatments are usually done immediately following quenching and before any tempering is done. It does increase the hardness and wear resistance and reduces metal fatigue, but it may also increase the chances of cracking during the process.
What Makes Cryogenic Treatment Effective?
General heat treating of steels is essential for proper usage of those materials to the maximum of their technical capabilities. Steel properties such as hardness, tensile and yield strength, as well as ductility and fracture toughness can be formed as desired for various applications when proper heat treating is used.
Cold Treatment
Cold treating of steel is widely accepted as an additional treatment for enhancing the transformation of austenite to martensite and to improve stress relief of castings and machined parts [2]. In common practice, -84 °C (-120 °F) is used as the optimal temperature for cold treatment.
Deep Cryogenic Treatment (DCT)
Deep Cryogenic Treatment (DCT), also known as cryogenic processing, is a process which uses temperatures below -150 °C (-238 °F). The most common temperature used is the temperature of liquid nitrogen, -185 ° C (-300° F) [2].
Why is sub zero used?
Sub-zero treatment also can be used to improve the strength and life of non-ferrous metal parts and components, including age-hardened aluminum alloys.
How does a freezer control the cold treatment process?
The freezer can be programmed to control the cold treatment process by adjustable gas injection and conveyor speed. Prev. Sub-zero treatment of steel can alter the phase structure to help achieve improvements in quality and finished parts performance.
What is cryogenic freezer?
Cryogenic freezers for sub-zero treatment of metal parts and components come in many sizes and configurations to meet varying production requirements. Also, equipment is available to accommodate batch or continuous processing.
Can austenite be transformed into martensite?
Sub-zero treatment can transform virtually any retained austenite present in the microstructure to martensite. Depending on the alloy, cold-processing conditions and desired design goals, repeated tempering may not be necessary to produce a fully stable structure ready for machining.
What is the advantage of using zero nut on guitar?
What is probably the biggest advantage is the ability to change string gauge as often and as dramatically as you’d like without having to resize or replace the nut. This really comes in handy for players who find themselves changing tunings a lot. For this advantage, I actually have a custom guitar by Skervesen with a Zero Nut for studio use. This way, I can pretty much record in any tuning I want to without worrying about damaging the nut.
Is zero fret bad?
There is one massive disadvantage to a Zero Fret, which is why many manufacturers stick with the classic nut. Over time, the Zero Fret will wear down, just like a nut will, except that when a Zero Nut wears down, it makes string bending a nightmare, in the same fashion that a very worn down fret will. Not only that, it’s much more difficult and expensive to replace a fret than it is to change a nut.
