Piston Rod Assembly

A crosshead-piston rod assembly, comprising:

• a piston rod having a longitudinal axis and forming a piston rod neck and a piston rod shoulder, the piston rod comprising a first end integral or coupled with a piston head and a second end axially opposing the first end;
• a crosshead comprising
• a main body portion defining a cavity and having a first end portion and a second end portion axially opposing the first end portion, the second end portion defining an opening through which a connecting rod extends from the cavity;
• a flange having an inner surface defining a bore through which the second end of the piston rod and the piston rod neck extends, the flange coupled with the first end portion of the main body portion, and the inner surface formed from a first material having a Brinell hardness;
• and
• a cylindrical sleeve disposed circumferentially about the piston rod neck, the cylindrical sleeve formed from a second material having a lower Brinell hardness than the first material of the inner surface of the flange having a Brinell hardness.