Steel and production method thereof

Steel and production method thereof

  • CN 102,206,788 B
  • Filed: 05/13/2011
  • Issued: 04/08/2015
  • Est. Priority Date: 05/13/2011
  • Status: Active Grant
First Claim
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1. a production method for the steel of anti-lamellar tearing, it is characterized in that described steel comprise by weight 0.16% C, 0.48% Si, 1.47% Mn, 0.004% S, 0.012% P, 0.050% Nb, 0.021% Ti, 0.052% V, 0.18% Ni, 0.032% Als, be no more than 40 ×

  • 10 -6n, be no more than 40 ×

    10 -6o and be no more than 2 ×

    10 -6h, surplus is Fe and inevitable impurity, wherein Als represents dissolved aluminum, described method comprise carry out successively hot metal pretreatment, top and bottom combined blown converter smelting, LF refining, RH refining, sheet billet continuous casting, strand slow cooling, 4300mm Plate rolling, finished product slow cooling Wherein, in hot metal pretreatment, to desulfurizing iron, strict implement technological process, the sulphur in molten iron controls 0.008%, and temperature is 1250 DEG C, the complete slag scratching clean molten iron surface of desulfurization;

    Pretreated molten iron enters converter, and nickel plate adds converter with steel scrap bucket, and slag material adds in terminal for first 3 minutes, and finishing slag basicity controls at R=4.0, and the terminal pressure rifle time is 69 seconds, adopts the deoxidation of aluminium manganese titanium, adds aluminium manganese titanium 2.5kg/t steel, during tapping, add sweetening agent 2.9kg/t along steel stream steel, add and start when putting steel 1/2 opportunity to add when being added to 3/4, molten steel go out to 1/4 time, add ferromanganese, ferrosilicon, ferro-niobium and vanadium iron in batches, molten steel go out to 3/4 time add, wherein, sweetening agent is a kind of desulfurization slag charge containing CaO 83% ~ 95%;

    Molten steel after converter smelting enters LF refining furnace, adds lime carry out slag making according to practical situation, and yellowish-white slag or white slag hold-time are 13 minutes, adopt omnidistance Bottom Argon Stirring, soft blow argon gas 5 minutes, and finishing slag basicity is 3.9, and aluminum steel add-on is 0.45kg/t steel, titanium wire add-on is 0.96kg/t steel;

    Molten steel after LF refining enters RH refining furnace, and RH refining adopts present treatment pattern, avoids chemical heating, guarantee that pure degassing time is 5 minutes, soft blow argon gas 10 minutes, add CaFe line 1.10kg/t before soft blow argon during RH process steel, smelting cycle controls at 50 minutes;

    Employing whole process protection is poured into a mould, and covering slag adopts peritectic steel covering slag, and secondary cooling water adopts weak cold pattern, continuously cast bloom specification is;

    300mm ×

    1800mm, setting pulling rate stationary phase is 0.85m/min, specific water 0.40L/kg, requires that the steel billet stacking slow cooling of flaw detection is sent for 48 hours more later and rolls;

    Rolling temperature control, ensures to be rolled in the temperature range of regulation, steel billet tapping temperature 1150-1200 DEG C, roughing start rolling temperature is 1140 DEG C, finishing temperature is 1070 DEG C, roughing overall compression ratio >

    50%, and workpiece thickness is 140mm, trimmed size 68mm, finish rolling start rolling temperature is 860 DEG C, and final cooling temperature is 650 DEG C, and speed of cooling is 10 DEG C/s, roll rear steel plate slow cooling 36 hoursThe performance of described steel plate is as follows;

    lower yield strength is 475MPa, and tensile strength is 600MPa, and yield tensile ratio is 0.79, and elongation after fracture is that 23%, 180 degree of clod wash d=3a are qualified, and-40 DEG C of longitudinal AKv are 191J, and Z-direction relative reduction in area is 60%.

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