Kallings 2Kalling's Reagent
Kalling's No. 2
Material Specific
Composition
Ethyl alcohol 85–95%, Copper (II) chloride 0.5–5%, Hydrogen chloride 2–7%, Methyl alcohol 1–5%
PACE product, by weight
Method
Swab
Time
5–60 s
Alternative Names
Tags
Reveals
Grain boundaries in austenitic stainless steels; delta-ferrite in duplex; sigma phase (preferential boundary attack); carbides at boundaries
Typical Results
The standard etchant for austenitic stainless steels (304, 316, 321, 347), duplex (2205, 2507), and many nickel-base alloys. Reveals grain boundaries cleanly without attacking ferrite or matrix. Mild, and a good first-try etchant on austenitic SS.
Application Method
Method:Swab
Typical Time:5–60 s
Preparation Notes
PACE Kalling's No. 2 is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Ethyl alcohol | 64-17-5 | 85–95% | Yes |
| Copper (II) chloride | 7447-39-4 | 0.5–5% | Yes |
| Hydrogen chloride | 7647-01-0 | 2–7% | Yes |
| Methyl alcohol | 67-56-1 | 1–5% | Yes |
| Isopropyl alcohol | 67-63-0 | 1–5% | Yes |
Application Notes
Swab the freshly polished surface 5–60 s at room temperature. Rinse with water then ethanol; air-dry.
Troubleshooting
Sensitized 304/316 etches preferentially at boundaries; distinguish step vs ditch by morphology and confirm with 10% oxalic A262 Practice A. Cold-worked SS under-etches: extend to 60 s.
Storage Notes
Amber glass at room temperature. Stable several months.
Alternative Etchants
- Adler's Etchant
- Glyceregia
- Vilella's Reagent (martensitic only)
Similar Etchants
- Adler's Etchant