Process for flash welding medium control limit Mn content R350 HT steel rail with joint structure

Abstract

The invention discloses a process for flash welding a medium control limit Mn content R350 HT steel rail with a joint structure, and belongs to the technical field of steel rail flash welding. By means of the process, the technical problem that a process in the prior art easily results in a martensite structure on an R350HT steel rail flash welding joint is solved. The process comprises a weldingprocess and post-welding treatment; in the welding process, the welding heat input is controlled to be 6.5-8.0 MJ pulsation or preheating flash welding, and the welding upset forging amount is 14.0-15.0 mm; and in the process of post-welding treatment, the joint is naturally cooled to 515-545 DEG C, is subjected to heat preservation, then cooled to less than or equal to 250 DEG C, and finally naturally cooled to room temperature. By comprehensively controlling the chemical components, the hot rolling process, the welding process and the post-welding cooling of the steel rail, no abnormal structures such as the martensite structures in the steel rail flash welding joint are guaranteed, and the mechanical property of the joint is ensured at the same time.

Description

technical field

[0001] The invention belongs to the technical field of rail flash welding, and in particular relates to a process for controlling the microstructure of R350HT rail flash welding joints with a medium-limit Mn content. Background technique

[0002] With the rapid development of seamless track technology in passenger transport, freight transport, high-speed and heavy-duty railway construction worldwide, the quality of rail joints has attracted more and more attention from relevant departments. As the direct carrier of train operation, the quality and reliability of railway lines is the key to the safe operation of trains. Rail flash welding joints are the weak link of the whole line, and their quality can directly affect the safety of the railway. In the matrix of rail flash welded joints, the martensite structure belongs to the hard and brittle phase, which has high hardness and extremely low toughness. Cause rails to break on the line, drop blocks or even un...

Images