Development Of L415 Pipeline In Jiusteel Company

Rolled coil of L415 pipe line steel (C: 0.04-0.07%, Si: 0.20-0.35%, Mm 1.30-1.45%, P: ≤0.013%, S: ≤0.008% Nb: 0.01-0.03%. V: 0.02-0.04%) was produced by Jiuquan Iron and Steel Co Ltd. through the processes of production from hot metal pre-treatment-120t converter melting-ladle furnace refining (slagging, desulphurization, argon stirring, feeding wire)- compact strip production.Catch carbon is used by converter to control converter end (C: ≤=0.02%) , FeAlMn was added to deoxidation. The volume of FeAlMn is 6.0-7.5 kg/t, and when the endpoint carbon is low, it is added accordance to the upper limit, instead when it is high, to the lower limit, low carbon FeMn FeNb and FeV alloying and feeding Al wire and CaSi wire in LF refining. Argon shielded casting is used through the whole process in continuous casting. Then the L415 pipe line steel was developed successfully.The test result indicates that, the chemical ingredient is designed reasonably, and the finally-determined smelting craft satisfies the CSP casting craft, and the quality indicators of continuous-casting slab meets the rolling requirements. The deoxidized alloy craft may reduce the content of nonmetallic inclusions which has smaller size. The content of harmful gas is few which achieve a better level among the similar product. The yield strength of this kind of steel is 470-520MPa, and the ultimate strength is 525-575MPa, which all meet the demand of the GB/T14164-1993 and have good rolled coil surface, and it can be applied to the corresponding rank pipe-line construction.