1. The WC total carbon in the cemented carbide exceeds the standard.
2. The oxygen content of the mixture (including briquette) exceeds the standard.
3. Changes in carbon content in hydrogen dewaxing and pre-burning.
4. Changes in carbon content in vacuum dewaxing and pre-burning.
5. Changes in carbon content during hydrogen sintering.
6. The change of carbon content in the vacuum sintering process of cemented carbide.
