Got some fact to it, Not bad.
I doubt they know what we care about. Their interest is in manufacturing brass, not optimizing the hardness for benchrest grade accuracy. I'm sure they've got a grip on process and how to get it where *they* want it, though.If any case manufacturing engineers/metallurgists are following these annealing threads, they are no doubt laughing! They obviously understand their final anneal process and its effect. However, there is no reason for them to share the information with their customers and/or competitors!
If any case manufacturing engineers/metallurgists are following these annealing threads, they are no doubt laughing! They obviously understand their final anneal process and its effect. However, there is no reason for them to share the information with their customers and/or competitors!
Read the Report 1231/1A on the AMPS website. It explains eveything you need to know. If you cannot understand it it's your problem.
Or maybe they know what a can of worms they would open.If any case manufacturing engineers/metallurgists are following these annealing threads, they are no doubt laughing! They obviously understand their final anneal process and its effect. However, there is no reason for them to share the information with their customers and/or competitors!
That's the problem, by definition the process we use isn't annealing, it's stress relieving. We may have come to using the word "annealing" incorrectly by abusing it for decades but the word doesn't describe the process any more than it describes what we accomplish.
Found this as I was doing some light research...
Annealing
Metals are cold worked in order to change their shape. A material loses ductility when it is cold worked or moreover, cold rolled. If one wishes to partially or fully restore a cold worked material to its original properties, one can anneal the material. Annealing is performed by heating a material; in this instance, the material is a metal. There are three stages of annealing and each stage produces different results. The three stages of annealing are recovery, recrystallization, and grain growth.
Recovery
The recovery stage is the first stage of annealing. This stage occurs when the metal is first subjected to heat. The dislocation density and grain distortion in the material is little affected by this stage of annealing. However, the recovery stage eliminates most of the residual stresses in the material. One can think of this as the heat relaxing the built up tension in the material. Much electrical conductivity is restored in the material as well. The recovery stage permits the dislocations to move slightly and form what is known as the polygonized subgrain structure.
Recrystallization
As a cold worked material is subjected to a temperature at or above its recrystallization temperature, new grains begin to nucleate from the cell boundaries created by the polygonized subgrain structure. This nucleation eliminates most of the dislocations in the worked material.
Grain Growth
As the subjected temperature is raised higher, the grains grow and a fine recrystallized grain structure is produced. The larger, faster growing grains consume the smaller grains in the process. All of the effects of cold working are eliminated at this point. Grain growth can be detrimental to the properties of the material and can typically produce a rough surface appearance on components formed from sheet metal.
Time and Temperature
It is found that temperature variations have a much stronger influence on the annealing of metals than time variations. The standard annealing time is one hour; only temperature is varied. The annealing temperature is dependent on the component’s thickness, composition, and geometry.
Annealing Temperature and Activation Energy
The minimum annealing temperature for an actual effect to be had from annealing is approximately one-third to one-half the melting point of the material specimen. Because there is a minimum temperature, the annealing process is governed by an Arrhenius Rate Equation. Because it is difficult to measure recrystallization, the 50% recrystallization time is measured as the time at which the metal reaches half its original hardness.
Even that is for manufacturing, not the tea leaves of trying to shrink a group by 1" at 1000 yards.Oh I think cartridge case manufacturers know exactly what's desirable as do manufacturers of machines for exactly this purpose. https://radyne.com/products/small-caliber-ammunition-annealing/. You can't optimize a process for benchrest when you don't even understand fully what's going on.
Our annealing has recrystallization and grain growth can be seen if annealing a really worked piece of brass if annealed correctly. AMP goes into recrystallization in their “Annealing under the microscope” articles.What we're doing is most definitely annealing. There's three phases to annealing, recovery, recrystalization, and grain growth. What we're doing (attempting to do), is recovery annealing. That is, applying enough heat energy for sufficient time to allow the rows of dislocated atoms to rearrange themselves into a lower energy state without applying so much heat as to change the grain structure of the material. "Full annealing" refers to heating the material beyond the recovery phase into recrystalization and grain growth where the grain structure is changed. In school the textbooks we used referred to it as Partial and Full annealing but I think Recovery annealing is a better term because it matches the recovery phase of annealing.
Even that is for manufacturing, not the tea leaves of trying to shrink a group by 1" at 1000 yards.
My point is simply that if you don’t understand the metallurgy etc in even basic detail - let alone intricate detail - you aren’t in a position to refine anything for a narrower, more precise purpose. I’ve read many threads here on annealing. What is clear is that the general level of knowledge is actually rather low. I’ve yet to read a clear description with a precise understanding of what is done at manufacturing and the impact on the brass then let alone refining that further. There’s a lot of guessing. I built a fairly sophisticated version of the GinaErick induction annealer. Painting brass cases with Tempilaq is still guessing at required times let alone providing an understanding of whether the brass has been changed appropriately, over the appropriate area, at a molecular level.
Our annealing has recrystallization and grain growth can be seen if annealing a really worked piece of brass if annealed to the correctly. AMP goes into recrystallization in their “Annealing under the microscope” articles.![]()