阅读说明：本技术 一种提高含镍钢板除鳞质量的方法 (Method for improving descaling quality of nickel-containing steel plate ) 是由 王成 易勋 熊艳 杨波 欧阳坤 余宏伟 梁宝珠 田慧芳 刘丰恺 于 2020-08-12 设计创作，主要内容包括：本发明公开了一种提高含镍钢板除鳞质量的方法,包括下述步骤：(1)板坯装入加热炉后,控制加热炉均热段温度较三加段低20-30℃,板坯均热时间0.1×H+10min≤T≤0.2×H+10min,保持炉膛微正压状态,炉压控制在20-30Pa,降低坯料氧化烧损；(2)设置除鳞箱程序自动控制系统,板坯出炉后采用除鳞箱自动连续除鳞两次,第一次除鳞速度为1.4-1.6m/s,第二次除鳞速度为1.1-1.4m/s,两次除鳞初始压力均保证≥19.5MPa,结束压力均保证≥18MPa；(3)在一阶段开轧时使用机身除鳞水一次；本发明通过工艺设计,在未使用保护涂料、扒皮、包铁皮保护等措施前提下,利用现有工艺装备实现了除鳞效果提升,基本杜绝了铁皮压入导致的废品,极大降低了企业成本,显著提高了含Ni品种钢的合同兑现率。(The invention discloses a method for improving the descaling quality of a nickel-containing steel plate, which comprises the following steps: (1) after the slab is loaded into the heating furnace, the temperature of the soaking section of the heating furnace is controlled to be 20-30 ℃ lower than that of the third soaking section, the soaking time of the slab is not less than 0.1 XH +10min and not more than T and not more than 0.2 XH +10min, the micro-positive pressure state of a hearth is maintained, the furnace pressure is controlled to be 20-30Pa, and the oxidation burning loss of the slab is reduced; (2) arranging a descaling box program automatic control system, automatically and continuously descaling twice by using a descaling box after the slab is discharged, wherein the first descaling speed is 1.4-1.6m/s, the second descaling speed is 1.1-1.4m/s, the initial pressure of the two-time descaling is more than or equal to 19.5MPa, and the final pressure is more than or equal to 18 MPa; (3) descaling water is used once when rolling is carried out at one stage; according to the invention, through process design, on the premise of not using measures such as protective coating, peeling, iron sheet wrapping protection and the like, the scale removing effect is improved by using the existing process equipment, waste products caused by pressing in of the iron sheet are basically eliminated, the enterprise cost is greatly reduced, and the contract cashing rate of the Ni-containing variety steel is obviously improved.)

1. A method for improving the descaling quality of a nickel-containing steel plate is characterized by comprising the following steps:

(1) after the slab raw material is loaded into the heating furnace, controlling the temperature of the soaking section of the heating furnace to be 20-30 ℃ lower than that of the third heating section, wherein the soaking time of the slab is not less than 0.1 XH +10min and not more than T and not more than 0.2 XH +10min, and H is the thickness of the slab raw material; keeping the micro-positive pressure state of the hearth, controlling the furnace pressure to be 20-30Pa, and slightly controlling the furnace pressure to be 2-5 Pa higher than that in normal production if the temperature is kept for a short time within 1h, so that the cold air suction is reduced, and the oxidation burning loss of the blank is reduced;

(2) setting a descaling box program automatic control system, automatically and continuously descaling twice by adopting a descaling box after the plate blank is discharged, namely automatically returning to an inlet of the descaling box after primary descaling is finished, and carrying out secondary descaling; setting the roller way speed of a descaling box, wherein the first descaling speed is 1.4-1.6m/s, the second descaling speed is 1.1-1.4m/s, the initial pressure of two-time descaling is guaranteed to be more than or equal to 19.5MPa, and the final pressure is guaranteed to be more than or equal to 18 MPa;

(3) when the first-stage rolling is carried out, the machine body is used for descaling water once, and after a small amount of residual iron oxide scales and secondary iron oxide scales are fully removed, the first-stage rolling is carried out.

2. A method of improving the descaling quality of a nickel-containing steel sheet according to claim 1, wherein: the thickness of the plate blank raw material is 200-300mm, and the thickness of the finished steel plate is 10-120 mm.

Technical Field

The invention relates to the technical field of production of nickel-containing steel plates, in particular to a method for improving the descaling quality of a nickel-containing steel plate.

Background

Surface quality is the user to the directly perceived embodiment of wide and thick board product quality requirement, because scale that the descaling quality is unstable leads to impresses, the steel sheet surface pit that forms, pitted surface, defects such as mottle can directly influence the pleasing to the eye degree of wide and thick board product, reduce user' S use and experience, especially contain the Ni steel, compare in ordinary steel, its steel billet is at the S emergence reaction in the heating process and the burner gas, the extension of oxygen in the steel has been aggravated, the oxidation aggravation, the iron sheet stickness increases, high pressurized-water descaling is difficult to get rid of, final defect leads to the coping to increase, delivery cycle extension, some steel sheets can only do and scrap the processing, manufacturing cost is showing and is increasing. Before the invention, the produced steel for the tank body containing Ni, the steel for the engineering machinery and the like generally have the defect of scale pressing in surface caused by incomplete descaling, part of the steel plate is polished and then barely meets the delivery requirement of a user, only waste judgment can be carried out seriously, the delivery cycle of the steel plate is severely limited, the cost is increased, and huge waste is caused.

Disclosure of Invention

The invention aims to solve the problems that the scale removal effect of the existing nickel-containing steel plate is not ideal due to the limitation of the existing process, so that various surface defects of the finished steel plate are caused due to incomplete scale removal, even the steel plate cannot be delivered and can only be judged to be useless, and the production cost is obviously increased, and provides a method for improving the scale removal quality of the nickel-containing steel plate; the method can obviously improve the descaling quality of the heated billet, reduce/eliminate the press-in of the primary scale and ensure that the surface quality of the Ni-containing steel plate meets the requirements of delivery technical conditions.

The invention discloses a method for improving the descaling quality of a nickel-containing steel plate, which comprises the following steps:

(1) after the slab raw material is loaded into the heating furnace, controlling the temperature of the soaking section of the heating furnace to be 20-30 ℃ lower than that of the third heating section, controlling the soaking time of the slab to be 0.1 XH +10min or less and T to be less than or equal to 0.2 XH +10min, and controlling the thickness of the H slab raw material; keeping the micro-positive pressure state of the hearth, controlling the furnace pressure to be 20-30Pa, and slightly controlling the furnace pressure to be 2-5 Pa higher than that in normal production if the temperature is kept for a short time within 1h, so that the cold air suction is reduced, and the oxidation burning loss of the blank is reduced;

(2) setting a descaling box program automatic control system, automatically and continuously descaling twice by adopting a descaling box after the plate blank is discharged, namely automatically returning to an inlet of the descaling box after primary descaling is finished, and carrying out secondary descaling; setting the roller way speed of a descaling box, wherein the first descaling speed is 1.4-1.6m/s, the second descaling speed is 1.1-1.4m/s, the initial pressure of two-time descaling is guaranteed to be more than or equal to 19.5MPa, and the final pressure is guaranteed to be more than or equal to 18 MPa;

(3) the descaling water of the machine body is used once during the first-stage rolling, and a first-stage rolling and subsequent rolling processes are carried out after a small amount of residual iron oxide scales and secondary iron oxide scales are sufficiently removed; after descaling according to the process, the rolled finished product Ni-containing steel plate is inspected by a turning plate, and no iron scale is pressed into the upper and lower surfaces of the rolled finished product Ni-containing steel plate, so that the quality standard requirement is met.

The thickness of the plate blank raw material is 200-300mm, and the thickness of the finished steel plate is 10-120 mm.

The invention achieves the aim of the invention by improving the prior art, and the specific process improvement reason is as follows:

(1) the heating process sets the temperature of the soaking section 20-30 ℃ lower than that of the third heating section, and simultaneously ensures that the soaking time is more than or equal to 0.2 XH +10min and more than or equal to T more than or equal to 0.1 XH +10 min: the method aims to ensure that the soaking time and temperature of the plate blank can meet the requirements of tapping temperature and section uniformity, and can avoid the aggravation of blank oxidation caused by long-time soaking and the disadvantage of descaling. The Ni-containing steel is different from other common steel types, Ni is easy to react with S in furnace gas of a heating furnace at the high temperature of more than 1000 ℃ to form an NiS network structure with a lower melting point, a protective film formed by a billet at the lower temperature is damaged after the Ni is melted, S ferrite in the billet is increased in the heating process, the diffusion of oxygen in the steel is accelerated, the oxidation is intensified, the iron sheet viscosity is increased, the iron oxide layer is thicker and the viscosity is larger along with the increase of the heating temperature and the extension of the heat preservation time, so the soaking time of the Ni-containing steel is not too long, and the soaking temperature is slightly lower than the heating section to be beneficial to the improvement of the descaling effect through experimental investigation; the micro-positive pressure state of the hearth is kept to reduce the cold air suction and reduce the oxidation burning loss of the steel plate;

(2) the reason for designing continuous automatic two-time descaling in the descaling process is as follows: for Ni-containing steel, because part of iron sheet is still not removed in one-time descaling, two continuous automatic descaling procedures are designed, a descaling box is utilized to carry out full descaling, and the primary oxide scale formed by heating a plate blank in a furnace is removed; the continuous twice pressure maintaining and the descaling of more than 18MPa by utilizing the descaling box are designed by fully considering the characteristics of pressure change and speed rise of a descaling system in the descaling process and a descaling gap: the method comprises the steps of firstly, removing scale at medium and high speed, wherein the scale is removed at about 1.5m/s, the pressure of the system is reduced to be slightly lower than the set scale removing pump speed-raising pressure (the speed-raising pressure is supplemented at 19.5-20.8 MPa), the speed-raising pressure is supplemented to be set initial pressure (about 23 MPa) by utilizing the clearance time of automatic slab rewinding, and the continuous two-time scale removing pressure guarantee is realized on the premise of not changing the system hardware condition of a scale removing box by adopting the medium and low speed scale removing at about 1.3m/s during the second scale removing;

(3) the reason for using the descaling water once during the first-stage rolling is as follows: in order to fully remove a small amount of residual iron scales and secondary iron scales, the primary iron scales are ensured to be finally and completely removed, and the user requirements are met.

According to the invention, through process design, on the premise of not using measures such as protective coating, peeling, iron sheet wrapping protection and the like, the scale removing effect is improved by using the existing process equipment, waste products caused by pressing in of the iron sheet are basically eliminated, the enterprise cost is greatly reduced, and the contract cashing rate of the Ni-containing variety steel is obviously improved.

Drawings

FIG. 1 is a schematic view of a process for heating a fractured slab in example 1 of the present invention;

FIG. 2 is a state diagram of the discharging timing of a Ni-containing slab in example 1 of the present invention;

FIG. 3 is a view showing a state after first descaling of a Ni-containing slab in example 1 of the present invention;

FIG. 4 is a view showing a state after continuously performing second descaling on a Ni-containing slab according to example 1 of the present invention;

FIG. 5 shows the surface condition of a rolled steel sheet according to example 1 of the present invention.

Detailed Description

In order to better explain the technical solution of the present invention, the technical solution of the present invention is further described below with reference to specific examples, which are only exemplary to illustrate the technical solution of the present invention and do not limit the present invention in any way.