BORON NITRIDE (BN) BREAK RINGS AND CASTING NOZZLES
Continuous casting is one of the most common metal manufacturing technologies. The liquid metal flows from a tundish into the mold, in which the strand shell is formed. The metal strand is then taken off continuously or intermittently, at a speed and solidification rate appropriate to the particular alloy.
The ceramic break ring or the nozzle comes into contact with both the melt and the solidified alloy, and must satisfy correspondingly strict requirements:
- Chemical resistance to the solidified metal, i.e. no contamination of the alloy
- Good sliding properties, i.e. does not stick to the alloy
- High thermal shock resistance
- Defined thermal conductivity
- High wear resistance
- Easy to machine
Product Solutions and Applications
With MYCROSINT® we offer a group of different boron nitride materials and boron nitride composites that are matched to different metal alloys. From these materials, we manufacture nozzles or break rings that increase the lifetimes for the following metals:
- Steels of all kinds
- Copper alloys
- Nickel alloys
- Superalloys
- Precious metals, particularly gold alloys
We will be glad to support you in choosing the appropriate material.
| Boron Nitride | |||||||
| Material properties | Norm | Symbol / Unit | MYCROSINT® HD |
MYCROSINT® S |
MYCROSINT® CD |
||
| Crystalline phases | hex. BN | hex. BN | hex. BN | ||||
| Binder phase / Binder type | <1%B2O3 | 4%B2O3 | B2O3 + CaO | ||||
| Orientation dependency | Isotropic | Anisotropic | Anisotropic | ||||
| ⊥ | II | ⊥ | II | ||||
| Density (typical) | DIN EN 623-2 | ρ [g/cm3] | 1.96 | 2.07 | 2.07 | 1.97 | 1.97 |
| Total porosity (calculated using theoretical density) | DIN EN 623-2 | P [%] | <13 | <7 | <7 | <12 | <12 |
| Brinell hardness | DIN EN ISO 6506-1 |
HBW 2.5/31.25 |
10 | 30 | 30 | 13 | 13 |
| Young’s modulus | DIN EN 843-2 | E [GPa] | 23 | 35 | 30 | 30 | 25 |
| Flexural strength | DIN EN 843-1 | σB [MPa] | 19 | 95 | 85 | 40 | 35 |
| Weibull modulus | DIN EN 843-1 | ||||||
| Compressive strength | AAW/ AC-R-302-03 |
σD [MPa] | 36 | 105 | 125 | 50 | 55 |
| Coefficient of thermal expansion | DIN EN 821-1 | Thermal expansion behavior: nonlinear, residual elonation after cooling; CTE given indication only | |||||
| 20°C - 500°C | α [10-6/K] | -1 | 1 | 2 | -1 | -1 | |
| 500°C - 1000°C | α [10-6/K] | 0.5 | 1 | 2 | 1.5 | 2 | |
| 1000°C - 1500°C | α [10-6/K] | 2.5 | 1 | 5 | 3 | 4 | |
| Specific heat at 20°C | DIN EN 821-3 | Cp [J/gK] | 0.61 | 0.6 | 0.6 | 0.58 | 0.58 |
| Thermal conductivity at 20°C | DIN EN 821-2 | λ [W/mK] | 25 | 40 | 25 | 35 | 35 |
| Maximum temperature of use (oxidizing/inert atmosphere) | [°C] | 900/1800 | 1000/ 1500 |
1000/ 1500 |
1100/ 1500 |
1100/ 1500 |
|
| Specific electrical resistance at 20°C | DIN EN 50359 | ρ [Ωcm] | >1012 | >1012 | >1012 | >1012 | >1012 |
| Boron Nitride | ||||||||
| Material properties | Norm | Symbol / Unit | MYCROSINT® SO20 |
MYCROSINT® SO43 |
MYCROSINT® O40 |
|||
| Crystalline phases | BN+ZrO2+SiC | BN+ZrO2+SiC | BN+ZrO2 | |||||
| Binder phase / Binder type | 2%B2O3 | |||||||
| Orientation dependency | Anisotropic | Anisotropic | Anisotropic | |||||
| ⊥ | II | ⊥ | II | ⊥ | II | |||
| Density (typical) | DIN EN 623-2 | ρ [g/cm3] | 2.3 | 2.3 | 2.92 | 2.92 | 2.82 | 2.82 |
| Total porosity (calculated using theoretical density) | DIN EN 623-2 | P [%] | 10 | 10 | <6 | <6 | <6 | <6 |
| Brinell hardness | DIN EN ISO 6506-1 |
HBW 2.5/31.25 |
30 | 30 | 85 | 85 | 63 | 63 |
| Young’s modulus | DIN EN 843-2 | E [GPa] | 35 | 20 | 45 | 30 | 45 | 25 |
| Flexural strength | DIN EN 843-1 | σB [MPa] | 70 | 40 | 120 | 80 | 120 | 80 |
| Weibull modulus | DIN EN 843-1 | |||||||
| Compressive strength | AAW/ AC-R-302-03 |
σD [MPa] | 85 | 100 | 175 | 175 | 185 | 185 |
| Coefficient of thermal expansion | DIN EN 821-1 | Thermal expansion behavior: nonlinear, residual elonation after cooling; CTE given indication only | ||||||
| 20°C - 500°C | α [10-6/K] | 0.5 | 4.6 | 2 | 8 | 2 | 6 | |
| 500°C - 1000°C | α [10-6/K] | 1.9 | 6.6 | 4 | 9 | 3.5 | 9 | |
| 1000°C - 1500°C | α [10-6/K] | 0.5 | 2.2 | 1.4 | 4.5 | 1.5 | 8 | |
| Specific heat at 20°C | DIN EN 821-3 | Cp [J/gK] | 0.6 | 0.6 | 0.5 | 0.5 | 0.5 | 0.5 |
| Thermal conductivity at 20°C | DIN EN 821-2 | λ [W/mK] | 45 | 25 | 40 | 30 | 30 | 20 |
| Maximum temperature of use (oxidizing/inert atmosphere) | [°C] | 1100/ 1800 |
1100/ 1800 |
1100/ 1800 |
1100/ 1800 |
1100/ 1800 |
1100/ 1800 |
|
| Specific electrical resistance at 20°C | DIN EN 50359 | ρ [Ωcm] | >1012 | >1012 | >1012 | >1012 | >1012 | >1012 |
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