Before you choose
- An alloy name alone leaves important powder requirements undefined.
- Evaluate test methods and representative sampling.
- Match the powder to a qualified machine/process route.
Separate alloy identity from feedstock qualification
316L, 17-4PH, titanium and nickel-alloy names identify broad chemistry families or designations. Particle distribution, morphology, contamination and process history add feedstock-specific questions. LPBF, DED and binder-based systems should be specified separately.
Define the evidence you need
Choose the chemistry and physical tests relevant to the machine and application. State acceptance limits and the basis of the report. A flow value is meaningful with its method; a size distribution needs its measurement and reporting basis. A powder micrograph gives a view of a sample field, not a complete batch analysis.
Keep receiving and recovery traceable
Identify the manufacturing lot, supplied condition and container. Prevent cross-mixing between materials and retain the required handling instructions. Recovered powder needs its own controlled identity and approval route. Use the equipment procedure and specific SDS for handling decisions.
| Order item | Example of what to define |
|---|---|
| Chemistry | Alloy specification and relevant element limits |
| Particle distribution | Required range/quantiles, method and reporting basis |
| Physical properties | Morphology, density or flow tests relevant to the process |
| Condition | Virgin / recovered / approved blend |
| Batch evidence | Lot identifier, measured report or defined conformity declaration |
Investigate with a controlled comparison
If a later batch performs differently, compare powder records, machine condition and process parameters against a retained reference. Keep observations, sample identity and test methods together. An isolated print failure does not identify the cause by itself.
Questions buyers ask
Can a supplier CoC replace every requested test result?
A conformity declaration and a report of measured values can have different scopes. Specify the evidence needed for acceptance.
Can a different particle cut of the same alloy use the same process settings?
Confirm the feedstock and parameter qualification. A shared alloy designation does not establish interchangeability.
Sources
- NIST — variation in metal-AM powder feedstock
Measurement and sampling affect reported powder size distribution.
- Carpenter Additive — powder-quality investigation
An investigation example using powder characterization and retained comparison material.
- EOS — metal-powder handling
Powder integrity, receiving, storage and recovery considerations.