Method for joining steel rails with controlled weld heat input

A method for creating a welded joint between ends of two steel rails, wherein the two steel rails have a substantially pearlitic microstructure, the method comprising:

• a first heating step wherein the ends of the two steel rails are heated to obtain within the two steel rails:
• an austenitic region comprising a microstructure substantially of austenite, the austenitic region being within and/or adjacent to the ends of the two steel rails,
• a softened region adjacent to the austenitic region, the softened region comprising a microstructure substantially of softened, annealed, spheroidized, and/or degenerate pearlite, and
• an unaffected region adjacent to the softened region, the unaffected region comprising a microstructure that has not been substantially altered as compared to a starting microstructure of the two rails;
• an upsetting or forging step wherein the ends of the two steel rails are forced together to obtain:
• a weld bond between the ends of the two steel rails,
• a remaining austenitic region on both sides of the weld bond,
• a remaining softened region on both sides of the weld bond, and
• a remaining unaffected region on both sides of the weld bond;
• a cooling step wherein a temperature of the austenitic region on at least one side of the weld bond is below an A1 temperature;
• and
• a second heating step wherein
• heat is applied directly to the weld bond and to the austenitic region on at least one side of the weld bond via an external source to maintain the temperature of the weld bond and the at least said austenitic region on at least one side of the weld bond in a temperature range below said A1 temperature,
• no additional austenite is formed, and
• a hardness of the austenitic region on at least one side of the weld bond after the second heating step is less than or equal to a hardness in the austenitic region on at least one side of the weld bond without the second heating step.