IS 6921 FNB is commonly referred to as a Naval Brass and issued typically in a wide range of marine and subsea applications. This brass alloy offers superior strength, corrosion resistance and offers good property retention at cryogenic temperatures with excellent hot formability and very good corrosion resistance.
CHEMICAL COMPOSITION
| Elements | Min (%) | Max (%) |
| Cu | 61.00 | 64.00 |
| Pb | – | 0.20 |
| Sn | 1.00 | 1.50 |
| Fe | – | 0.10 |
| Total | – | 0.50 |
| Zn | Remainder |
Mechanical Properties According To IS 6921 (As Per Temper HB)
| Range (mm) | From | To | UTS Min (MPa) | PS Min (MPa) | Elongation Min (%) | Hardness Min | Hardness Max |
| Round (Dia) | 1.5 | 75 | 340 | – | 15 | – | – |
| Hex (A/F) | 3 | 70 | 340 | – | 15 | – | – |
| Square (A/F) | 3 | 60 | 340 | – | 15 | – | – |
| Rectangle (Thickness) | 3 | 50 | 340 | – | 15 | – | – |
| PHYSICAL PROPERTIES |
| Melting Points – Liquidus 0F | 1650 |
| Melting Points – Solidus 0F | 1630 |
| Density lb/cu in. at 68 0F | 0.304 |
| Specific Gravity | 8.41 |
| Electrical Conductivity % IACS at 68 0F | 26 |
| Thermal conductivityBtu/ Sq ft / ft hr / 0F at 680F | 67 |
| Coefficient of Thermal Expansion 68-57210 -6 Per 0F (68-5720F) | 11.8 |
| Specific Heat capacity Btu/ lb /0F at 680F | 0.09 |
| Modulus of Elasticity in Tension ksi | 15000 |
| Modulus of Rigidity ksi | 5600 |
| FABRICATION PROPERTIES |
| Technique | Suitability |
| Capacity for being cold Worked | Fair |
| Hot Worked | Excellent |
| Machinability Rating | 30% |
| Forge ability Rating | 90% |
| Silver Alloy Brazing | Excellent |
| Soft Soldering | Excellent |
| Oxyacetylene Welding | Good |
Typical uses
- Fasteners
- Industrial
- Marine
