# US 10,870,165 B2 · Mobile flash butt welding method for 136RE+SS heat-treated rail

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- Number: US 10,870,165 B2
- Document ID: US10870165B2
- Status: Granted
- Kind: B2
- Application number: 16/111,821
- Filed: 2018-08-24
- Published: 2019-02-28
- Granted: 2020-12-22
- Earliest claimed: 2017-08-31
- Assignees: Pangang Group Research Institute Co., Ltd.
- Applicants: Pangang Group Research Institute Co., Ltd.
- Inventors: Xin Lu; Dadong Li; Ruoyu Wang; Wei Bai; Jian Deng; Feixiang Xu
- Web page: https://patentgrep.com/patent/US10870165B2

## CPC

- B23K 11/04: Flash butt welding
- C21D 9/50: for welded joints
- E01B 29/44: Methods for effecting joining of rails in the track, e.g. taking account of ambient temperature
- B23K 2101/26: Railway- or like rails
- C21D 9/04: for rails
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- E01B: PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS (derailing or rerailing blocks on track, track brakes or retarders B61K)

## Abstract

The invention discloses a mobile flash butt welding method for 136RE+SS heat-treated rail, and particularly a mobile flash butt welding method for 136RE+SS heat-treated rail in the technical field of rail welding. The mobile flash butt welding method for 136RE+SS heat-treated rail in the invention includes a pre-flash stage, a flash stage, a boost stage, an upset stage and a forge stage, with a total heat input of 7.1 MJ-10.0 MJ, a total duration of 110 s-135 s and an upsetting distance of 12.8 mm-16.7 mm during the welding process. By adopting the method of the invention, mobile flash butt welding can be conducted for 136RE+SS heat-treated rail successfully, and the rail joint has less internal defects but stable welding quality, and can pass fatigue test, tensile test and slow bend test to meet the requirements. Besides, the rail joint can pass the drop weight test for 15 welds continuously, demonstrating better stability.

## Claims

### Claim 1

A mobile flash butt welding method for a 136RE+SS heat-treated rail, said method comprising conducting on the 136RE+SS heat-treated rail a pre-flash stage, a flash stage, a boost stage, an upset stage and a forge stage, with a total heat input of 7.1 MJ-10.0 MJ, a total duration of 110 s-135 s and an upsetting distance of 12.8 mm-16.7 mm during the welding method; wherein, in the pre-flash stage, a pre-flash stage heat input is 1.9 MJ-2.2 MJ, a pre-flash stage distance is 0.1 mm-1.2 mm and a pre-flash stage duration is 22.5 s-25 s; in the flash stage, a flash stage heat input is 5.0 MJ-6.0 MJ, a flash stage distance is 1.0 mm-5.0 mm and a flash stage duration is 48.0 s-52.0 s; in the boost stage, a boost stage heat input is 0.3 MJ-1.2 MJ, a boost stage distance is 13.1 mm-15.2 mm and a boost stage duration is 29.5 s-32.0 s; in the upset stage, an upset stage heat input is 0.1 MJ-0.3 MJ, an upset stage distance is 13.7 mm-16.0 mm and an upset stage duration is 2.0 s-9.9 s; and in the forge stage, a forge stage duration is 12.8 s-14.5 s.

### Claim 2 (depends on 1)

The mobile flash butt welding method for 136RE+SS heat-treated rail according to claim 1, wherein a holding force is 25 t-35 t in the forge stage.

### Claim 3 (depends on 1)

The mobile flash butt welding method for 136RE+SS heat-treated rail according to claim 1, wherein heat treatment can be further carried out for welds after welding.

### Claim 4 (depends on 1)

The mobile flash butt welding method for 136RE+SS heat-treated rail according to claim 1, wherein during the heat treatment, a welded joint produced after welding is cooled down to below 400° C. in a first time, then heated to 860° C.-940° C., and then cooled until a temperature of the rail running surface of the welded joint is between 410° C.-450° C. in a second time.