QPQ nitriding process

Process flow

QPQ nitriding is an advanced surface treatment technology. Quenching, polishing and subsequently re-quenching are all part of this process. Significant improvements to surface hardness, wear resistance and to a large extent corrosion resistance, are achievable for the piston rod itself.

Surface treatment effect

Surface hardness: Post QPQ treatment surface hardness values reach HV900-1100; traditional chrome plating being the point of comparison, this is a clear improvement.

Corrosion resistance: Passing a standard salt spray test is the more qualitative measure of this effect, over 96 hours of continuous testing being a common benchmark.

Microcrack reduction - fatigue related: Reducing surface initiated microcracks is one of the more desirable outcomes of the treatment; fatigue life of the piston rod is improved by this means.

Environmental protection

QPQ nitriding as a surface treatment falls under more 'green' technologies. Hexavalent chromium use (nearly impossible to fully remove) is eliminated altogether, so this is a primary environmental advantage.

Application

Application fields

Gas springs, various forms of hydraulic systems, automotive shock absorbers to name a few - furniture, automotive and near constant duty industrial equipment all benefit from QPQ treated piston rods.

Advantages (reiterated)

Durability (physical and chemical) is the end goal of all surface treatments, but QPQ at least partially meets it.

Customization: Size and/or specification of the piston rod can be tailored to a degree, again to modern day environmental and/or economic pressures.