Q: What is Black Nitriding?
A: The thermochemical process known as Salt Bath Ferritic Nitrocarburizing simultaneously diffuses nitrogen and carbon into the surface of ferrous metals. Such properties increase wear-resistance, fatigue strength, corrosion resistance, lubricity and cosmetic appeal.
Q: What is QPQ?
A: The QPQ process is an advanced Black Nitriding process, which augments the standard Nu-Tride process. Enhancing corrosion resistance involves a secondary polishing operation, followed by re-oxidation to produce a lustrous black finish. Lustrous black finishes increase the consumer product applications’ cosmetic appeal, making products appear modern and attractive.
Q: What is the compound zone?
A: A catalytic reaction at the surface occurs when ferrous components are immersed into the molted bath where cyanate breaks down, releasing nitrogen and carbon. Iron nitride compounds form from these elements, diffusing in the ferrous surface leading to a change in element concentration.
Q: What hardness can I expect?
A: Unalloyed carbon steel's compound zone hardness equals approximately HRC 55. Nitride-forming elements, such as chrome, increase the compound zone hardness in the base material. An increase in hardness, up to HRC 70 minimum, results in corresponding progressive increases in chromium from 0% (carbon steel) to 17% (stainless steel).
Q: What is the effect on metal-to-metal applications?
A: Tests show significant reduction in wear to components subjected to BLACKNITRIDE™.
Q: What is the effect on surface finish?
A: Surfaces will be slightly rough after Black Nitriding; however, the original surface finish can be restored through polishing (QPQ).
Q: What is the effect on the core hardness?
A: If the core region's depth is not influenced by diffused nitrogen, the degree of tempering associated with time and temperature during the Black Nitriding cycle determines change in core hardness as follows:
1. Additional tempering occurs during Black Nitriding if the pre-hardened component has been pre-tempered below the subsequent Black Nitriding temperature. Reduction in core hardness depends primarily on the steel grade used and attendant-tempering characteristics.
2. If the pre-hardened component is pre-tempered, or non-pre-hardened above subsequent temperature, core hardness will not change significantly as a result of the Black Nitriding process.
Q: How long does it take to get parts processed?
A: Please allow for 3-5 days production time after receipt of order.