| 摘要 |
1370144 Heat-treating steel rails WENDELSIDELOR 21 Sept 1971 [2 Oct 1970] 44016/71 Headings C7A and C7N Rolled carbon or low alloy steel rails with high carbon and moderate manganese contents are progressively cooled by application of mixed sprays of water and pressurized air to all parts of the rail. Preferably a rail containing by weight: - is cooled from above 750‹C at a mean rate of 10‹ to 20‹ C/sec to 550‹ C or below to produce a pearlitic structure providing a hardness of VPN 380 to 430, 0À2% PS at least 75 daN/mm<SP>2</SP>, U.T.S. at least 115 daN/mm<SP>2</SP> and elongation at least 8%. When the rail after cooling is distorted it may be passed through a second cooling unit where jets of air with or without the addition of water are locally applied to bring about straightening. In a particular form of apparatus the rail is supported by rollers 2, 4, 5 and subjected to sprays 7 from symmetrically disposed distributors 6. Each nozzle 10 is secured to a universally jointed leg 10 and supplied with air and water through flow meters 17, 18 respectively. The secondary cooling unit has a simpler arrangement of sprays shown in Fig.10. |
