Steel displaces aluminium wherever cylinder pressure keeps rising
Peak cylinder pressures in heavy-duty diesel passed 200 bar as emissions regulation pushed manufacturers toward higher injection pressures and later combustion phasing. Aluminium reaches a fatigue limit at those loads that no alloy or reinforcement development has meaningfully moved, and crown cracking follows. Steel pistons carry the load, run hotter without losing strength and allow a shorter compression height that offsets some of the weight penalty. That displacement now covers roughly 62% of heavy on-highway diesel and it is working its way down into medium commercial applications where pressures are climbing toward the same threshold.
Market Impact: Holds 34% of unit volume








