QPQ (Quench-Polish-Quench)
Quench polish quench (QPQ) is a specialized type of nitrocarburizing case hardening that increases corrosion resistance, Three steps involved: nitrocarburizing, polishing, and post-oxidizing. This process is usually used when two or more of the following properties are required in a workpiece: wear resistance, corrosion resistance, lubricity, or fatigue strength. And also superior corrosion resistance is required. Common applications are piston rods for shock absorbers, cylinders and rods for hydraulic systems, pumps, axles, spindles, and valves.
QPQ Coating Applications：
Transportation and automobile industries
The Defense Industry and Firearms
Power transmission components such as gears and bearings
Hydraulic and pneumatic components
Petroleum and gas industry
Medical and dental supplies