阅读说明：本技术 控制含钛酸洗板表面硬度波动的方法 (Method for controlling surface hardness fluctuation of titanium-containing pickled plate ) 是由 崔凯禹 李正荣 余腾义 汪创伟 郑昊青 靳阳 于 2020-07-17 设计创作，主要内容包括：本发明属于钢铁冶金技术领域,具体涉及控制含钛酸洗板表面硬度波动的方法。本发明所要解决的技术问题在于提供一种控制含钛酸洗板表面硬度波动的方法。该方法是：控制含钛酸洗板中Ti含量的波动在0.01％以内。本发明通过将Ti含量波动优化在0.01％以内,可控制Ti造成的产品HRB波动在±2.3以内,最终有利于实现产品表面硬度HRB±6的要求。(The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for controlling surface hardness fluctuation of a titanium-containing pickled plate. The invention aims to solve the technical problem of providing a method for controlling the surface hardness fluctuation of a titanium-containing pickled plate. The method comprises the following steps: controlling the fluctuation of the Ti content in the titanium-containing acid-washing plate within 0.01 percent. According to the invention, the fluctuation of the Ti content is optimized within 0.01%, the HRB fluctuation of the product caused by Ti can be controlled within +/-2.3, and the requirement of HRB +/-6 of the surface hardness of the product is finally realized.)

1. The method for controlling the surface hardness fluctuation of the titanium-containing pickled plate is characterized by comprising the following steps: controlling the fluctuation of the Ti content in the titanium-containing acid-washing plate within 0.01 percent.

2. The method of controlling surface hardness fluctuations in titanium-containing pickled plate as claimed in claim 1, wherein: the lower limit value of the Ti content in the titanium-containing pickled plate is 0.015%.

3. The method for controlling the fluctuation in the surface hardness of titanium-containing pickled plates according to claim 1 or 2, characterized in that: the titanium-containing pickled plate comprises the following components in percentage by mass: c: 0.04-0.06%, Mn: 0.15-0.25%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Ti: 0.015 to 0.025%.

Technical Field

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for controlling surface hardness fluctuation of a titanium-containing pickled plate.

Background

The hot-rolled pickled plate is an intermediate product between a cold-rolled plate and a hot-rolled plate, and has the following advantages: (1) because the high-quality hot-rolled sheet is used as a raw material, and the surface oxide layer is removed by the pickling line, the surface quality of the hot-rolled sheet is close to that of a cold-rolled sheet, and the mechanical property of the hot-rolled sheet is kept; (2) the surface quality is high, so that the welding, oiling and painting are convenient, the dimensional precision of the product is high, and unevenness can be reduced in the leveling process; (3) compared with cold-rolled plates, the hot-rolled pickled plates can effectively reduce the raw material purchasing cost of customers.

The household appliance industry is a large application field of hot-rolled pickled plates, however, general household appliance users do not have mechanical property detection equipment, in the using process of a steel plate, the hardness is more direct to the sensory specific strength of people, and the hardness measurement is more convenient than the strength, so that the household appliance users often use the hardness as the basis for checking and accepting the mechanical property of steel, for example, a compressor manufacturing enterprise requires that the surface hardness of the pickled plate for a compressor is HRB +/-6.

In the process of manufacturing the coiled pipe of the compressor, the hardness of the hot-rolled pickled plate directly influences the opening degree of the coiled pipe, so that the welding quality is influenced, the hardness fluctuation of the hot-rolled pickled plate is accurately controlled, and the good welding quality can be ensured. At present, no relevant report of a method for controlling the surface hardness fluctuation of the titanium-containing pickled plate is found.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for controlling the surface hardness fluctuation of a titanium-containing pickled plate.

The technical scheme for solving the technical problems is to provide the method for controlling the surface hardness fluctuation of the titanium-containing pickled plate, and the method is to control the fluctuation of the Ti content in the titanium-containing pickled plate within 0.01 percent.

Further, the lower limit of the Ti content in the titanium-containing pickled plate is 0.015%.

Further, the titanium-containing pickled plate comprises the following components in percentage by mass: c: 0.04-0.06%, Mn: 0.15-0.25%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Ti: 0.015 to 0.025%.

The invention has the beneficial effects that:

according to the invention, the influence relation of each alloy element on the surface hardness of the titanium-containing pickled plate, namely HRB 45.06+38.31C +7.93Mn +453.98Ti +293.7P, is obtained through production practice and experimental research, and by optimizing the Ti content fluctuation within 0.01%, the HRB fluctuation of a product caused by Ti can be controlled within +/-2.3, and the requirement of HRB +/-6 of the surface hardness of the product is finally realized.

Detailed Description

Specifically, the invention provides a method for controlling the surface hardness fluctuation of a titanium-containing pickled plate, which is to control the fluctuation of the Ti content in the titanium-containing pickled plate within 0.01 percent.

Further, the lower limit of the Ti content in the titanium-containing pickled plate is 0.015%.

Further, the titanium-containing pickled plate comprises the following components in percentage by mass: c: 0.04-0.06%, Mn: 0.15-0.25%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Ti: 0.015 to 0.025%.

The inventors analyzed the influence of Ti element on the hardness of titanium-containing pickled plate. According to the national standard GB/T1172-1999, there is a certain relationship between hardness and strength, see Table 1.

TABLE 1 hardness to Strength correlation

The Ti has strong affinity with C, N, and TiN, TiC and Ti exist in Ti microalloyed steel₄C₂S₂And the formation of a large amount of precipitates, which exist in various stages from continuous casting to coiling, including continuous casting and cooling stages of TiN and Ti₄C₂S₂The liquid and solid phases of (1) are separated out; in the continuous rolling stage, TiC is precipitated in austenite through deformation induction; and the interphase precipitation of TiC at the layer cooling stage and the supersaturated precipitation of TiC in ferrite at the coiling stage. Wherein, the high-temperature solid precipitation TiN with the size of less than 100nm can effectively inhibit the growth of austenite grains in the heating and hot rolling processes. The austenite region deformation can induce and precipitate spherical TiC particles with the diameter of about 10 nm-30 nm, and the TiC particles are distributed in a matrix more uniformly and can play a role in refining grains. The TiC particles precipitated in the ferrite at the coiling stage are smaller and larger in size, and these particles exert a remarkable reinforcing effect. Therefore, through theoretical analysis, the strengthening effect of Ti precipitates in the titanium-containing pickled plate on the product is obvious, so that the hardness of the product is greatly influenced.

The inventor collects the chemical components of the steel product for the Panzhihua steel Ti microalloying high-quality compressor and the corresponding hardness value under each chemical component, and carries out regression analysis to research the correlation between the chemical components and the hardness, wherein the sample number is 937 volume, the hardness HRB is 52-68, and the fluctuation is +/-8. The distribution of the main chemical components is shown in table 2, the chemical components of the high-quality compressor steel are mainly C, Mn, Ti, P, etc., and Si as a residual element hardly plays a reinforcing role and can be disregarded.

TABLE 2 chemical composition distribution (number of samples: 937 vol)/%

C	Mn	P	Ti
				0.04～0.06	0.18～0.24	0.007～0.015	0.013～0.028

And (3) calculating by adopting Minitab software to obtain a regression result of the hardness and the components:

HRB＝45.06+38.31C+7.93Mn+453.98Ti+293.7P

the actual value and the fitting value of the hardness are shown in table 3, and the accuracy of the actual value and the fitting value is high and the regression effect is good as can be seen from table 3.

TABLE 3 actual values of strength, hardness and fitting values

From the influence coefficients of the respective elements in the above formula, it is found that the influence on the hardness is most significant for the Ti element, but is inferior to the P element, and the influence of the C element and the Mn element is relatively small. Since too high a P content significantly reduces the plasticity and low-temperature toughness of the steel, the P content in the pickled sheet is generally controlled to a low value, so that the influence of the P content on the hardness fluctuation of the product is reduced. Therefore, the fluctuation of the Ti content in the titanium-containing pickled plate can obviously influence the fluctuation range of the HRB (Rockwell hardness) of the product surface, and through the research, the inventor optimizes the Ti content fluctuation within 0.01 percent, can control the HRB fluctuation of the product caused by Ti element within +/-2.3, and finally is beneficial to realizing the requirement of the HRB +/-6 of the product surface.