US 2026/0275446 A1Published application

Acid-resistant pipeline steel and manufacturing method therefor

AssigneesInstitute of Research of Iron and Steel, Jiangsu Province/Sha-Steel, Co., Ltd., Jiangsu Shagang Steel Co., Ltd., Jiangsu Shagang Group Co., Ltd.

InventorsJiming ZHANG, Yanshan ZHU, Han MA, Xianjun HU

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Abstract

An acid-resistant pipeline steel includes the following chemical components in percentage by weight: 0.02-0.06% of C, 0.10-0.30% of Si, 0.80-1.10% of Mn, 0.02-0.08% of Nb, 0.06-0.12% of V, 0.20-0.30% of Ni, less than or equal to 0.08% of Mo, 0.03-0.06% of Al, 0.0005-0.0030% of Ca, less than or equal to 0.008% of P, less than or equal to 0.002% of S, 0.004-0.006% of N, less than or equal to 0.002% of O, less than or equal to 0.0015% of H, less than or equal to 0.0008% of B, and the balance of Fe and inevitable impurities.

Claims9

Dependent claims

A manufacturing method of an acid-resistant pipeline steel, comprising following steps:

performing blast furnace smelting, wherein molten steel at an end of smelting comprises following chemical components in percentage by weight:
0.30-0.60% of Si, less than or equal to 0.40% of Mn, less than or equal to 0.040% of S, and less than or equal to 0.120% of P;
performing Kambara Reactor (KR) pre-desulfurization, wherein a temperature of desulfurized molten steel is not lower than 1300° C., and a weight percentage of the chemical component S in the desulfurized molten steel does not exceed 0.002%;
performing Basic Oxygen Furnace (BOF) top-bottom combined blowing smelting, wherein a scrap steel is added to the molten steel in a smelting process to adjust the components of the molten steel;
a tapping temperature at an end of smelting is 1640° C.±30° C.;
metal manganese, ferrosilicon and aluminum ingots are added according to weight percentages during tapping to adjust the components of the molten steel, the molten steel is deoxidized, and the molten steel at the end of smelting comprises the following chemical components in percentage by weight:
less than or equal to 0.010% of P, less than or equal to 0.005% of S, and greater than or equal to 0.02% and less than or equal to 0.05% of C;
an oxygen lance position is 1.5 m-1.8 m, a bottom blowing flow is 574 m3/h-604 m3/h, and a top blowing flow is 35,000 m3/h-38,000 m3/h;
performing Ladle Furnace (LF) refining, wherein argon is blown throughout a refining process to prevent the molten steel from oxidizing, a slag melting and a slag conditioning are carried out in a heating process, a white slag making treatment is carried out, and ferroniobium is then added after standing for 10 min-20 min after the white slag making treatment to ensure a stable recovery of an Nb element;
performing Ruhrstahl Heraeus (RH) refining, wherein a vacuum degree is controlled to be less than 2 mbar and a degassing time is controlled to be greater than 15 min in a RH refining process;
ferrovanadium is added according to a weight percentage to ensure that a net circulation time is 5-10 min;
then, seamless SiCa wires are added according to a weight percentage;
after a wire feeding, a soft stirring is carried out for 12-18 min, and a slag surface fluctuates in the soft stirring, but the molten steel is not exposed to prevent the molten steel from oxidizing;
the molten steel after the RH refining comprises the following chemical components in percentage by weight:
0.02-0.06% of C, 0.10-0.30% of Si, 0.80-1.10% of Mn, 0.02-0.08% of Nb, 0.06-0.12% of V, 0.20-0.30% of Ni, less than or equal to 0.08% of Mo, 0.03-0.06% of Al, 0.0005-0.0030% of Ca, less than or equal to 0.008% of P, less than or equal to 0.002% of S, 0.004-0.006% of N, less than or equal to 0.002% of O, less than or equal to 0.0015% of H, less than or equal to 0.0008% of B, and the balance of Fe and inevitable impurities;
performing continuous casting billet stack cooling, wherein a continuous casting billet with a thickness of not less than 320 mm is obtained via an electromagnetic stirring and a soft reduction at an end of continuous casting, and the continuous casting billet is subjected to stacking and slow cooling for a hydrogen evolution treatment for at least 72 h and then unstacked;
performing furnace charging and heating, wherein the continuous casting billet is heated to 1160° C.±20° C., and a heat preservation time is 250 min-300 min;
performing single-stage rolling in a non-recrystallized zone, wherein the heated continuous casting billet is removed out of the furnace for a dephosphorization and a temperature measurement;
when a temperature of the continuous casting billet is not higher than a non-recrystallization temperature, rolling is started by using a multi-pass hot rolling process;
a high-temperature rapid rolling and a large reduction are carried out, and a finishing rolling temperature is 800° C.-840° C.;
and reduction amounts of at least three passes in a rolling process are not less than 22%;
performing Multi-Purpose Interrupted Cooling (MULPIC) rapid water cooling, wherein a rolled steel plate is subjected to a rapid water cooling at a cooling rate of 25° C./s−35° C./s, and a final cooling temperature is controlled not to exceed 300° C.;
and
performing heat treatment, wherein a water-cooled steel plate is subjected to a heat treatment, a furnace gas temperature of a heating furnace is controlled to be 450±10° C., and a heat preservation time is 30 min;
and a steel plate is removed out of the furnace and cooled to obtain the acid-resistant pipeline steel.

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Dependencies are inferred from the claim text.

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Abstract

A manufacturing method of an acid-resistant pipeline steel, comprising following steps:

performing blast furnace smelting, wherein molten steel at an end of smelting comprises following chemical components in percentage by weight:
0.30-0.60% of Si, less than or equal to 0.40% of Mn, less than or equal to 0.040% of S, and less than or equal to 0.120% of P;
performing Kambara Reactor (KR) pre-desulfurization, wherein a temperature of desulfurized molten steel is not lower than 1300° C., and a weight percentage of the chemical component S in the desulfurized molten steel does not exceed 0.002%;
performing Basic Oxygen Furnace (BOF) top-bottom combined blowing smelting, wherein a scrap steel is added to the molten steel in a smelting process to adjust the components of the molten steel;
a tapping temperature at an end of smelting is 1640° C.±30° C.;
metal manganese, ferrosilicon and aluminum ingots are added according to weight percentages during tapping to adjust the components of the molten steel, the molten steel is deoxidized, and the molten steel at the end of smelting comprises the following chemical components in percentage by weight:
less than or equal to 0.010% of P, less than or equal to 0.005% of S, and greater than or equal to 0.02% and less than or equal to 0.05% of C;
an oxygen lance position is 1.5 m-1.8 m, a bottom blowing flow is 574 m3/h-604 m3/h, and a top blowing flow is 35,000 m3/h-38,000 m3/h;
performing Ladle Furnace (LF) refining, wherein argon is blown throughout a refining process to prevent the molten steel from oxidizing, a slag melting and a slag conditioning are carried out in a heating process, a white slag making treatment is carried out, and ferroniobium is then added after standing for 10 min-20 min after the white slag making treatment to ensure a stable recovery of an Nb element;
performing Ruhrstahl Heraeus (RH) refining, wherein a vacuum degree is controlled to be less than 2 mbar and a degassing time is controlled to be greater than 15 min in a RH refining process;
ferrovanadium is added according to a weight percentage to ensure that a net circulation time is 5-10 min;
then, seamless SiCa wires are added according to a weight percentage;
after a wire feeding, a soft stirring is carried out for 12-18 min, and a slag surface fluctuates in the soft stirring, but the molten steel is not exposed to prevent the molten steel from oxidizing;
the molten steel after the RH refining comprises the following chemical components in percentage by weight:
0.02-0.06% of C, 0.10-0.30% of Si, 0.80-1.10% of Mn, 0.02-0.08% of Nb, 0.06-0.12% of V, 0.20-0.30% of Ni, less than or equal to 0.08% of Mo, 0.03-0.06% of Al, 0.0005-0.0030% of Ca, less than or equal to 0.008% of P, less than or equal to 0.002% of S, 0.004-0.006% of N, less than or equal to 0.002% of O, less than or equal to 0.0015% of H, less than or equal to 0.0008% of B, and the balance of Fe and inevitable impurities;
performing continuous casting billet stack cooling, wherein a continuous casting billet with a thickness of not less than 320 mm is obtained via an electromagnetic stirring and a soft reduction at an end of continuous casting, and the continuous casting billet is subjected to stacking and slow cooling for a hydrogen evolution treatment for at least 72 h and then unstacked;
performing furnace charging and heating, wherein the continuous casting billet is heated to 1160° C.±20° C., and a heat preservation time is 250 min-300 min;
performing single-stage rolling in a non-recrystallized zone, wherein the heated continuous casting billet is removed out of the furnace for a dephosphorization and a temperature measurement;
when a temperature of the continuous casting billet is not higher than a non-recrystallization temperature, rolling is started by using a multi-pass hot rolling process;
a high-temperature rapid rolling and a large reduction are carried out, and a finishing rolling temperature is 800° C.-840° C.;
and reduction amounts of at least three passes in a rolling process are not less than 22%;
performing Multi-Purpose Interrupted Cooling (MULPIC) rapid water cooling, wherein a rolled steel plate is subjected to a rapid water cooling at a cooling rate of 25° C./s−35° C./s, and a final cooling temperature is controlled not to exceed 300° C.;
and
performing heat treatment, wherein a water-cooled steel plate is subjected to a heat treatment, a furnace gas temperature of a heating furnace is controlled to be 450±10° C., and a heat preservation time is 30 min;
and a steel plate is removed out of the furnace and cooled to obtain the acid-resistant pipeline steel.

22 more elements