Patent ID: 9358628
Filing Date: 2016-06-07
CPC Classification: B23K,E01B

Claim Text:
1. A method for repairing railhead defects in a steel rail, comprising: removing the railhead defect by forming a slot in a railhead of a steel rail, said slot removing defective material and some surrounding material, said slot being formed in a general perpendicular direction to the longitudinal direction of the rail; selecting a welding material having mechanical properties closely correlating with those of the steel rail; wherein said welding material has a lower carbon content than that of the steel rail; pre-heating the welding area using electrical strip heaters clamped on both sides of the steel rail to uniformly raise the temperature of the steel rail between approximately 150° C. to 450° C.; using said welding material to fill the slot by multi-pass gas metal arc welding (“GMAW”) at a heat input that is sufficiently high to avoid ductile fracture characteristics and sufficiently low to avoid brittle fracture characteristics, wherein a sufficient number of passes of said GMAW is performed until said slot is completely filled by a weld formed from said welding material; applying post-weld heat treatment to an area of the weld for 2-20 minutes to cause austenization; quenching of the weld; removing any excess welding material extending out of said slot so as to form a substantially continuous repaired railhead surface.