jasent
Well-Known Member
An article I found.
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This is what I learned working with cartridge brass ( 70 Cu- 30 Zn).
Makes me think that the more you aneal the less heat is needed to achieve full aneal( less work hardening between anneals). Also makes me think temp is not as critical as some believe
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This is what I learned working with cartridge brass ( 70 Cu- 30 Zn).
- All brass of the same grade is not the same when specifying annealing temperature
- Most yellow brass is manufactured from recycled brass, aka scrap
- The use of recycled brass introduces impurities of iron, lead, tin, phosphorus . and others
- Whne brass is annealed , it recrystallizes to an initial grain size that is dependent on the cold work in the brass along with prior in process hot anneals ( grain size) and purity.
- Although brass with low imputities and sufficient cold work will recrystallize ( anneal) at 370 C. , it was common to anneal cartridge brass at 500C or higher to meet unique grain size requirments for shellcase.
- To adjust for impuity levels in the brass, the brass was reclassified after melting and casting into sub categories ( about 5 ) for t purpsoe of specifying annealing parameters
- The annealing temperature required to achieve uniform grain size varied by nearly 100 degrees C dependent on the impurity level
- In the special case of a phosphorus impuity of greater than 0.001% in the presence of iron, we would bnot use this grade for shellcase as the annealing repsonse was very unpreditcable for the shellcase grain size specifications
- There are other things we learned and applied that iI dont need to reveal - need some secrets.
Makes me think that the more you aneal the less heat is needed to achieve full aneal( less work hardening between anneals). Also makes me think temp is not as critical as some believe