阅读说明：本技术 一种海底管线用钢X56Mo轧制方法 (Method for rolling steel X56Mo for submarine pipeline ) 是由 姚震 张坤 李新玲 李靖年 王若钢 王刚 段江涛 应传涛 于 2020-04-29 设计创作，主要内容包括：本发明涉及一种海底管线用钢X56Mo轧制方法,加热总时间限定在270～330分钟,高温段时间限制在120～180分钟,第三加热段温度限制在1230～1250℃,均热段温度限制在1210～1230℃,板坯出炉温度在1210℃以上；采用两阶段控制轧制,粗轧阶段开轧温度不小于1000℃,粗轧阶段后三道次的单道次压下量≥20mm,中间坯厚度为2.5～3倍成品厚度；精轧阶段开轧温度为820～840℃,精轧终轧温度至780～800℃,轧制完成后不停留立即入水,入水温度800～810℃；采用半自动控冷模式。本发明生产钢板各项性能指标达到理想要求,钢板性能合格率超过95％以上。钢板力学性能为：横向屈服强度值470-580MPa,抗拉强度570-620MPa,横向屈强比≤0.90；-15℃DWTT均值≥85％。(The invention relates to a method for rolling steel X56Mo for a submarine pipeline, wherein the total heating time is limited to 270-330 minutes, the time of a high-temperature section is limited to 120-180 minutes, the temperature of a third heating section is limited to 1230-1250 ℃, the temperature of a soaking section is limited to 1210-1230 ℃, and the tapping temperature of a plate blank is above 1210 ℃; rolling is controlled in two stages, the initial rolling temperature in the rough rolling stage is not less than 1000 ℃, the single-pass reduction in three passes after the rough rolling stage is not less than 20mm, and the thickness of the intermediate blank is 2.5-3 times that of the finished product; the initial rolling temperature in the finish rolling stage is 820-840 ℃, the finish rolling temperature is 780-800 ℃, water is added immediately without stopping after the finish rolling, and the water inlet temperature is 800-810 ℃; and a semi-automatic cold control mode is adopted. The steel plate produced by the invention has various performance indexes reaching ideal requirements, and the performance qualification rate of the steel plate exceeds more than 95%. The mechanical properties of the steel plate are as follows: the transverse yield strength value is 470-580MPa, the tensile strength is 570-620MPa, and the transverse yield ratio is less than or equal to 0.90; the DWTT mean value at minus 15 ℃ is more than or equal to 85 percent.)

1. A rolling method of steel X56Mo for submarine pipelines is characterized in that the steel for pipelines comprises the following chemical components in percentage by weight: 0.05 to 0.07 percent of C; 015 to 0.25 percent of Si; 1.50 to 1.60 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.003 percent; 0.03 to 0.05 percent of Nb; 0.005-0.020% of Ti; 0.12 to 0.18 percent of Cr; n is less than or equal to 0.008 percent, and the balance is Fe and inevitable impurities; the rolling method comprises the following steps:

1) heating of blanks

The total heating time is limited to 270-330 minutes, the time of the high-temperature section is limited to 120-180 minutes, the temperature of the third heating section is limited to 1230-1250 ℃, the temperature of the soaking section is limited to 1210-1230 ℃, and the tapping temperature of the plate blank is above 1210 ℃;

2) rolling is controlled in two stages, the initial rolling temperature in the rough rolling stage is not less than 1000 ℃, the single-pass reduction in three passes after the rough rolling stage is not less than 20mm, and the thickness of the intermediate blank is 2.5-3 times that of the finished product;

3) the initial rolling temperature in the finish rolling stage is 820-840 ℃, the finish rolling temperature is 780-800 ℃, water is added immediately without stopping after the finish rolling, and the water inlet temperature is 800-810 ℃;

4) in the cold control stage, a semi-automatic cold control mode is adopted, and the water feeding amount is 300-500L/(m)²Min), the water discharge amount is 1100-1400L/(m)²Min), the number of the collecting pipes is 12-15 groups, and the ratio of the total water quantity of the upper collecting pipe to the total water quantity of the lower collecting pipe is 1: 3, the roller speed is 1.1-1.5 m/s, and the temperature of red return is 460-500 ℃.

2. The rolling method of the steel X56Mo for the subsea pipeline according to claim 1, wherein the steel X56Mo for the subsea pipeline has a steel plate thickness of 25-40 mm.

Technical Field

The invention relates to the field of steel wire steel, in particular to a method for rolling steel X56Mo for submarine pipelines.

Background

In order to meet the development requirement of energy transportation, the undersea oil and gas transportation is rapidly developed, and compared with a land pipeline, the subsea pipeline has the difference that the requirements on high pressure resistance and corrosion resistance are stricter, and the performance test on a steel plate is also larger and larger.

Patent 201810436793.X submarine pipeline steel and a rolling method thereof, wherein the submarine pipeline steel comprises the following chemical components in percentage by mass: 0.030-0.070% of C, 0.15-0.30% of Si, 1.35-1.65% of Mn, 0.030-0.060% of Nb0.030, 0.020-0.040% of V, 0.010-0.040% of Ti, 0.05-0.30% of Mo, less than or equal to 0.0020% of S, less than or equal to 0.015% of P, and the balance of Fe and inevitable impurity elements; the method for rolling the submarine pipeline steel comprises the following steps: the method comprises the following steps of deeply desulfurizing the iron until S is less than or equal to 0.0050%, carrying out composite blowing at the top and the bottom of a converter, finely adjusting alloy, refining in an LF furnace, carrying out RH vacuum degassing, continuously casting a plate blank, heating, carrying out 2-frame rough rolling and 7-frame finish rolling, carrying out laminar cooling and coiling, heating the plate blank, and discharging the plate blank at the temperature of 1160-1200 ℃; the laminar cooling refers to cooling to 400-500 ℃ at a cooling speed of 20-30 ℃/s; the 2-frame rough rolling means that: rolling back and forth by adopting a four-roller reversing mill with 2 frames, and controlling the thickness of the intermediate billet to be 55-60 mm; the 7-frame finish rolling means: adopting 7 four-roller CVC rolling mills for continuous rolling, controlling the starting temperature of finish rolling within the range of 960-1000 ℃, and enabling the accumulated deformation to be more than or equal to 60%; the finish rolling temperature is 820-880 ℃. This patent is applicable to rolled sheets.

201811118614.4A rolling method of submarine pipeline steel X65MO, the chemical composition of the steel is as follows by weight percentage: 0.03 to 0.08% of C, 0.10 to 0.30% of Si, 0.80 to 1.00% of Mn, 0.015% or less of P, 0.0015% or less of S, 0.01 to 0.02% of Nb, 0.02 to 0.05% of V, 0.008 to 0.015% of Ti, 0.10 to 0.30% of Cr, 0.008 to 0.020% of Al, 0.008 to 0.012% of N, 0.0005 or less of B, and the balance of Fe and inevitable impurities; the key production process of the steel plate comprises the following steps: pre-desulfurizing the molten iron, and slagging off to obtain low-sulfur molten iron; smelting low-sulfur molten iron by a converter, and tapping by adopting oxygen-remaining tapping and slag-stopping tapping to obtain non-deoxidized molten steel; performing carbon deoxidation on the undeoxidized molten steel through RH vacuum treatment, and adding aluminum particles for further diffusion deoxidation when the oxygen content is less than or equal to 100 ppm; sending the deoxidized molten steel to LF for refining, making white slag for deep desulfurization, adding ferrotitanium and ferroaluminum in sequence during the period, and performing other alloying operations, wherein the hydrogen increment is controlled to be less than or equal to 1.0 ppm; carrying out full-protection pouring on the refined molten steel to obtain a high-quality continuous casting billet; cutting a high-quality continuous casting billet by using rapid flame, and carrying out hot feeding and hot charging to a heating furnace; a controlled rolling process of low-temperature heating and high-temperature rolling is adopted, the heating temperature is 1100-1150 ℃, and the rolling temperature is more than or equal to 900 ℃; and (3) rapidly carrying out ultra-fast cooling after rolling, wherein the cooling speed is more than or equal to 30 ℃/s, the final cooling temperature is 480-560 ℃, and then slowly cooling to room temperature.

Patent 201610942619.3 discloses an acid-resistant submarine pipeline steel, which comprises the following chemical components in percentage by weight: c: 0.03-0.045%, Si: 0.15 to 0.23%, Mn: 1.2-1.35%, P is less than or equal to 0.01%, S is less than or equal to 0.001%, Alt: 0.01 to 0.04%, Nb: 0.04-0.06%, Ti: 0.01-0.018%, Ni: 0.2-0.4%, Cr: 0.2-0.3%, Cu: 0.01-0.013%, Mo: 0.15-0.17%, and the balance of Fe and inevitable impurity elements; the preparation steps and control parameters of the acid-resistant submarine pipeline steel are as follows: 1) blank selection: the compression ratio of the steel plate is more than or equal to 11, and a continuous casting billet with the thickness of 400mm is used for rolling; 2) a heating system: the heating temperature of the steel billet is 1170 +/-10 ℃, the in-furnace time is 380-460 min, the soaking time is more than or equal to 30min, and the uniformity of the temperature of the steel billet is improved; 3) the rolling process comprises the following steps: two-stage rolling control is adopted; in the rough rolling stage, forming passes are cancelled, the rolling temperature range is 1100-1160 ℃, the single-pass reduction rate of the last 3 passes of rough rolling is controlled to be 15-24%, and the maximum rolling speed is 1.2 m/s; the intermediate blank temperature-waiting thickness is 2.5-3 times of the thickness of the finished product; the initial rolling temperature of finish rolling is 820-890 ℃, the final rolling temperature is 790-820 ℃, the accumulated reduction rate of the finish rolling stage is 60-65%, and the maximum rolling speed is 3 m/s; 4) a water cooling process: cooling water after the finishing mill is closed, enabling the steel plate to quickly enter an ACC laminar cooling device, enabling the water inlet temperature of the steel plate to be 770-790 ℃, the final cooling temperature to be 200-350 ℃, and controlling the cooling speed to be 15-25 ℃/s; 5) after cooling the steel plates, stacking and slowly cooling the steel plates, wherein the stacking and cooling time is 12-48 hours; 6) the thickness of the prepared acid-resistant submarine pipeline steel plate is 34-48 mm. The Mo element is added in the design of alloy components, so that the production cost is relatively high.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for rolling the steel X56Mo for the submarine pipeline, and each performance index of the steel plate reaches the ideal requirement.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for rolling X56Mo steel for submarine pipelines comprises the following chemical components in percentage by weight: 0.05 to 0.07 percent of C; 015 to 0.25 percent of Si; 1.50 to 1.60 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.003 percent; 0.03 to 0.05 percent of Nb; 0.005-0.020% of Ti; 0.12 to 0.18 percent of Cr; n is less than or equal to 0.008 percent, and the balance is Fe and inevitable impurities; the rolling method comprises the following steps:

1) heating of blanks

The total heating time is limited to 270-330 minutes, the time of the high-temperature section is limited to 120-180 minutes, the temperature of the third heating section is limited to 1230-1250 ℃, the temperature of the soaking section is limited to 1210-1230 ℃, and the tapping temperature of the plate blank is above 1210 ℃;

2) rolling is controlled in two stages, the initial rolling temperature in the rough rolling stage is not less than 1000 ℃, the single-pass reduction in three passes after the rough rolling stage is not less than 20mm, and the thickness of the intermediate blank is 2.5-3 times that of the finished product;

3) the initial rolling temperature in the finish rolling stage is 820-840 ℃, the finish rolling temperature is 780-800 ℃, water is added immediately without stopping after the finish rolling, and the water inlet temperature is 800-810 ℃;

4) in the cold control stage, a semi-automatic cold control mode is adopted, and the water feeding amount is 300-500L/(m)²Min), the water discharge amount is 1100-1400L/(m)²Min), the number of the collecting pipes is 12-15 groups, and the ratio of the total water quantity of the upper collecting pipe to the total water quantity of the lower collecting pipe is 1: 3, the roller way speed is 1.1-1.5 m/s, and the temperature of red return is 460-500 ℃;

5) and in the straightening stage, 1-pass straightening is adopted.

The thickness of the steel plate X56Mo for the submarine pipeline is 25-40 mm.

Compared with the prior art, the invention has the beneficial effects that:

the steel plate produced by the invention has various performance indexes reaching ideal requirements, and the performance qualification rate of the steel plate exceeds more than 95%. The mechanical properties of the steel plate are as follows: the transverse yield strength value is 470-580MPa, the tensile strength is 570-620MPa, and the transverse yield ratio is less than or equal to 0.90; the DWTT mean value at minus 15 ℃ is more than or equal to 85 percent.

The invention controls the production and rolling process of the medium plate and improves the performance of the steel plate. The steel has the advantages of excellent performance and no addition of an alloy element Mo.

Detailed Description

The invention is further illustrated by the following examples:

the following examples describe the invention in detail. These examples are merely illustrative of the best embodiments of the present invention and do not limit the scope of the invention.

A method for rolling X56Mo steel for submarine pipelines comprises the following chemical components in percentage by weight: 0.05 to 0.07 percent of C; 015 to 0.25 percent of Si; 1.50 to 1.60 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.003 percent; 0.03 to 0.05 percent of Nb; 0.005-0.020% of Ti; 0.12 to 0.18 percent of Cr; n is less than or equal to 0.008 percent, and the balance is Fe and inevitable impurities; the rolling method comprises the following steps:

1) heating of blanks

The total heating time is limited to 270-330 minutes, the time of the high-temperature section is limited to 120-180 minutes, the temperature of the third heating section is limited to 1230-1250 ℃, the temperature of the soaking section is limited to 1210-1230 ℃, and the tapping temperature of the plate blank is above 1210 ℃;

2) rolling is controlled in two stages, the initial rolling temperature in the rough rolling stage is not less than 1000 ℃, the single-pass reduction in three passes after the rough rolling stage is not less than 20mm, and the thickness of the intermediate blank is 2.5-3 times that of the finished product;

3) the initial rolling temperature in the finish rolling stage is 820-840 ℃, the finish rolling temperature is 780-800 ℃, water is added immediately without stopping after the finish rolling, and the water inlet temperature is 800-810 ℃;

4) in the cold control stage, a semi-automatic cold control mode is adopted, and the water feeding amount is 300-500L/(m)²Min), the water discharge amount is 1100-1400L/(m)²Min), the number of the collecting pipes is 12-15 groups, and the ratio of the total water amount of the upper collecting pipe to the total water amount of the lower collecting pipe is 1: 3, the roller way speed is 1.1-1.5 m/s, and the temperature of red return is 460-500 ℃;

5) and in the straightening stage, 1-pass straightening is adopted.