Abstract: A method for hardening the grooves of steel pistons of steel piston heads whereby hardening of the bottom of the grooves is avoided. The laser beam is directed onto the sides of the groove in an approximately tangential direction in relation to the outer diameter of the piston.

Abstract: A cold applied joint sealant usable for both portland cement and asphaltic concrete pavements, which comprises an asphalt/urethane formulation resulting from the mixture of a liquid butadiene polymer, containing predominantly primary terminal hydroxyl groups, with a urethane reactant of di- or polyisocyanate. The sealant has low urethane content and cures to provide a low modulus, high penetration, with 85%-95% resilience and zero flow. An initial set time of less than about 120 minutes is achieved, which permits vehicular traffic to be accommodated thereover soon after application.