Selection of Continuous Casting Billets for Steel Rails
1.Selection and Specifications of Continuous Casting Billets for Steel Rails
The selection of steel rail billets primarily requires a sufficient compression ratio to ensure the inherent quality of the finished rail, prevent excessively concentrated microscopic defects, improve the rail's fatigue life, and guarantee the safety of railway transportation. Domestic standards stipulate that the ratio of the finished rail cross-sectional area to the billet cross-sectional area should be no less than 1:8 or 1:9. In production, a compression ratio below 1:11 is generally used. If the casting blank quality is good and internal defects are minimal, a smaller compression ratio can be employed to produce high-quality rails.
The billet cross-section sizes commonly used in China for rail production are 325 mm × 280 mm, 380 mm × 280 mm, and 320 mm × 410 mm, corresponding to the 38~75 kg/m rail series.
Thyssen Steel in Germany uses billet sections of 250 mm × 320 mm, 260 mm × 300 mm, and 265 mm × 380 mm to roll various rail profiles.
Hayange in France uses a 325 mm × 225 mm billet to roll 38~75 kg/m rails.
Studies indicate that a width-to-height ratio below 1.5 for the rail billet is preferable, as it ensures stable internal quality.
2.Examples of Rail Billets
2.1 Raw Materials for Universal Rail Production Line #1
Rectangular Billet Cross-Section: 280 mm × 325 mm, 280 mm × 380 mm,
320 mm × 410 mm, 240 mm × 240 mm
Billet Length: 4.4 m ~ 8.0 m
Maximum Billet Weight: 8161 kg
2.2 Raw Materials for Universal Rail Production Line #2
Bloom Cross-Sections:
BB1: 555 mm × 440 mm × 105 mm, 969 kg/m
BB2: 730 mm × 370 mm × 90 mm, 891 kg/m
BB3: 1024 mm × 390 mm × 120 mm, 1461 kg/m
BB4: 350 mm × 290 mm × 100 mm, 543 kg/m
Rectangular Billet Cross-Section: BL1: 280 mm × 380 mm, 825 kg/m
Billet Length: 4.35 m ~ 13.6 m
Maximum Billet Weight: 19472 kg
2.3 Raw Materials for Universal Rail Production Line (2+2+2+1 Mill Configuration)
Rectangular Billet Cross-Sections: 280 mm × 325 mm, 280 mm × 380 mm, 500 mm × 200 mm
