Its never a great idea to introduce a residual stress and then heat treat and expect the part not to move.
The most significant residual stress will probably due to the quenching process involved in solution treatment and if this is the cause of distortion you may struggle.
What are they like...
If you have the engineering stress/strain curves for these materials you can easily estimate the true/stress stain data between yield and maximum tensile stress.
True Strain = ln(1+ engineering strain (At very low strain there is little difference)
True Stress = Engineering Stress * (1 +...
I am planning to make a small batch of close tolerance shafts from a 4340 VAR steel.
The shafts will need significant machining on their ends and we plan to stress relieve at 630degC prior to grinding.
Once ground we would like to Plasma Nitride the shafts (400 degC) and use them without...
Once you have reached the quenching rate needed to produce a complete transformation to martensite it is unlikely that faster cooling rates will have any impact on hardness.
The thermal capacity of the part will impact on the cooling rate needed for complete transformation as will the...
A 'zincate solution' in normally an alkali solution made from dissolving zinc, zinc oxide or zinc hydroxide and contain Zn(OH)42− anions which are known as tetrahydroxozincate.
Gumm's Bondal for example contains this material and is commonly used as a preparation for chrome plating aluminium...
Frederick,
I just don't believe you comments concerning the movement if voids and other crystal structure changes due to DCT and I have never seen a paper which was based on good science to explain these phenomena.
Most diffusion processes are thermally activated so how can very low...
It would seem obvious that it is not sensible to try to lubricate the grip to testpiece interface.
Your use of the term 'gall' indicates that adhesive wear was taking place and this is typical of the damage that occurs in wedge grips when the grip body to insert interface in not adequately...
What kind of vehicle?
Motorcycles and bicycles commonly use a stainless steel but they don't need the same heat capacity as those required for automobiles.
I would also think that ferritic stainless steels may be more suitable than Austenitic grades which also work harden significantly.
The...
I don't really agree that the coefficient of friction between the grip body and the wedge insert has any impact on gripping in the 'ideal' condition.
Ideal would be a coefficient of 'zero' and the relationship between wedge angle and clamping force would correlate perfectly.
Th greater the...
I don't quite understand why galling alone will make the test piece slip.
Assuming you are using conventional wedge grips it is customary to lubricate the sliding faces with a Moly type grease to prevent this type of wear.
If you do have damage to the back of the insert then re-grinding to...
I think 'ductility' testing is a relatively complex subject.
12% Elongation of a 4d gauge length is not a very impressive amount of ductility but would be useful to ensure that relatively high strength bolts were not brittle.
A gauge length of 4 x Diameter would be considered relatively short...
In another life I was the Chief Metallurgist at Thompson Friction Welding from 1972 until 1979 when I left to take a research post with regard to Elasto-Plastic Fracture Mechanics.
We used Friction welding to replace many flash butt welding machines used to make tubular components including...
Welding to any cast iron would a risky process and unlikely to provide very good results.
Forgings would be much better and if you used Friction Welding steels of slightly different composition would not present any real issues.
Even with Friction Welding you will need to consider joint design...
Very interesting paper and a colleague of mine carried out some work years ago using X-70 Pipeline Steels.
He was reporting 4ppm as having an influence on ductility.
The measurement of hydrogen were made using a Balzers Thermo-Balance and the value reported was around or just below the limits...
I did some work some years ago on a very tough Reactor Steel and we looked in some detail at the influence of the notch in terms of angle, acuity and depth.
In these very tough steels there was very little variation in CVN.
We deliberately used notches produced by grinding, broaching, milling...
The first question you really need to answer is what tensile strength are you trying to obtain.
For example I would think that for a tensile strength of around 850/1000 MPa the Limited Ruling Section would be around 10" diameter.
For lower strength levels you would be able to use a larger...
Your comments make little sense in any real terms.
If the Chemistry is OK and the heat treatment is OK why is it not strong enough.
What is the precise chemistry?
Have you done a hardness test as a basic check?
What can you learn from the fracture surface and nature of the tensile failure...
