A method for producing a low-cost corrosion-resistant steel

Abstract

The application discloses a production method of low-cost corrosion-resistant steel, and the mass percentage of the chemical components of the corrosion-resistant steel is as follows: C: 0.06-0.08%, Si: 0.30-0.50%, Mn: 0.45-0.55%, P: 0.060-0.080%, S: ≤0.005%, Cu: 0.25-0.35%, Cr: 0.40-0.45%, Ti: 0.025-0.035%, Alt: 0.020-0.050%, and the rest is Fe and inevitable impurities; and the main production process and parameters are also disclosed. The application is designed under the C-Mn component system, Ti, Cu and Cr are added, the content of P element is increased, and the Ni element is removed, so that the production cost of the steel is greatly reduced under the premise of guaranteeing the corrosion resistance of the steel. The low-cost corrosion-resistant steel has the characteristics of easy welding and good corrosion resistance, and is widely applied to the manufacturing of corrosion-resistant structural parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-cost corrosion-resistant steel, in particular to a production method of low-cost corrosion-resistant steel. BACKGROUND

[0002] Corrosion-resistant steel refers to low-alloy structural steel with good corrosion resistance in the atmosphere by adding a small amount of chromium, nickel, copper, phosphorus and other elements, and its atmospheric corrosion resistance is 2-8 times that of ordinary carbon steel, and the longer the use time, the more outstanding the corrosion resistance. In addition to good corrosion resistance, weathering steel also has excellent mechanical properties, welding and other use properties, and is widely used in fields such as railway vehicles, bridges and containers. At present, weathering steel has been maturely used abroad, and there are detailed provisions from the aspects of steel development, application and design construction. Compared with foreign countries, the development of weathering steel in China started late, but with the rapid development of the national economy, the development and use of corrosion-resistant steel have made great progress. SUMMARY

[0003] The purpose of the present application is to provide a production method of low-cost corrosion-resistant steel, which is designed under the C-Mn component system, adds Ti, Cu and C, removes Ni element by increasing the content of P element, and greatly reduces the production cost of steel under the premise of ensuring the corrosion resistance of steel. The low-cost corrosion-resistant steel of the present application has the characteristics of easy welding and good corrosion resistance, and is widely used in the manufacture of corrosion-resistant structural parts.

[0004] To solve the above technical problems, the present application adopts the following technical scheme:

[0005] The production method of low-cost corrosion-resistant steel of the present application, the mass percentage of the chemical composition of the corrosion-resistant steel is: C: 0.06-0.08%, Si: 0.30-0.50%, Mn: 0.45-0.55%, P: 0.060-0.080%, S: ≤0.005%, Cu: 0.25-0.35%, Cr: 0.40-0.45%, Ti: 0.025-0.035%, Al t: 0.020-0.050%, and the rest is Fe and unavoidable impurities;

[0006] The main production process and parameters are:

[0007] (1) Smelting-continuous casting production process: hot metal pretreatment-converter-LF refining-casting machine;

[0008] (2) hot rolling production process: casting blank-heating furnace-7 rack continuous rolling-laminar cooling-coiling; the casting blank discharge temperature is 1230±25℃, the 7 rack continuous variable crown rolling mill is adopted for finish rolling, the finish rolling temperature is 890±15℃, the hot rolled steel strip thickness is 2.2-2.7mm; the cooling adopts laminar cooling equipment, the front dispersion cooling mode, and the coiling temperature is 640±10℃.

[0009] Further, the mass percentage content of the chemical composition of the corrosion-resistant steel is: C: 0.078%, Si: 0.40%, Mn: 0.52%, P: 0.060%, S: 0.004%, Cu: 0.32%, Cr: 0.43%, Ti: 0.032%, Al t: 0.032%, and the rest is Fe and inevitable impurities.

[0010] Further, the mass percentage content of the chemical composition of the corrosion-resistant steel is: C: 0.074%, Si: 0.43%, Mn: 0.52%, P: 0.061%, S: 0.005%, Cu: 0.31%, Cr: 0.43%, Ti: 0.031%, Al t: 0.036%, and the rest is Fe and inevitable impurities.

[0011] Further, the mass percentage content of the chemical composition of the corrosion-resistant steel is: C: 0.070%, Si: 0.39%, Mn: 0.52%, P: 0.073%, S: 0.003%, Cu: 0.35%, Cr: 0.44%, Ti: 0.031%, Al t: 0.031%, and the rest is Fe and inevitable impurities.

[0012] Further, the performance meets: the yield strength is greater than 500MPa, the tensile strength is greater than 570MPa, and the elongation is greater than 23%.

[0013] Compared with the prior art, the beneficial technical effects of the present application are:

[0014] The beneficial effect of the present application is to provide a low-cost corrosion-resistant steel production method, the metallographic microstructure of the steel grade is ferrite+pearlite, and the corrosion-resistant steel produced by the method provided by the present application is tested in the laboratory, the surface quality and performance indicators all meet the technical agreement requirements, and meet the relevant use requirements. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the drawings.

[0016] Figure 1 The microstructure diagram of embodiment 1 of the present application. DETAILED DESCRIPTION

[0017] The application will be described in more detail by specific examples. The examples are only a description of the best mode of the application and do not have any limitation on the scope of the application.

[0018] Example 1

[0019] The hot metal was pretreated by desulphurization, and the hot metal was dephosphorized and decarburized by top and bottom combined blowing converter smelting to obtain molten steel. The converter smelting was blown with argon all the time, and the scrap steel was added into the converter. The converter tapping temperature was 1620℃. Then the molten steel after the converter smelting was subjected to LF external refining, and the on-site temperature of the refining was ≥1560℃. The temperature measurement and composition fine adjustment were carried out in the LF external refining. The chemical composition supplied to the caster in the LF external refining was shown in Table 1. The slab continuous casting superheat was 25℃, and then the slab cleaning, slow cooling and continuous casting blank quality inspection were carried out. The slab heating temperature was 1256℃, the heating time was 223min, and the rolling was carried out by using 7-stand continuous rolling mill. The finish rolling temperature was 892℃, and the finished product thickness was 2.5mm. The laminar cooling was carried out by using front dispersion cooling, the cooling speed was 20℃ / S, the steel strip temperature was reduced to 640℃ for coiling. Finally, the product performance detection was carried out.

[0020] Example 2

[0021] The hot metal was pretreated by desulphurization, and the hot metal was dephosphorized and decarburized by top and bottom combined blowing converter smelting to obtain molten steel. The converter smelting was blown with argon all the time, and the scrap steel was added into the converter. The converter tapping temperature was 1630℃. Then the molten steel after the converter smelting was subjected to LF external refining, and the on-site temperature of the refining was ≥1560℃. The temperature measurement and composition fine adjustment were carried out in the LF external refining. The chemical composition supplied to the caster in the LF external refining was shown in Table 1. The slab continuous casting superheat was 25℃, and then the slab cleaning, slow cooling and continuous casting blank quality inspection were carried out. The slab heating temperature was 1256℃, the heating time was 223min, and the rolling was carried out by using 7-stand continuous rolling mill. The finish rolling temperature was 888℃, and the finished product thickness was 2.5mm. The laminar cooling was carried out by using front dispersion cooling, the cooling speed was 19℃ / S, the steel strip temperature was reduced to 638℃ for coiling. Finally, the product performance detection was carried out.

[0022] Example 3

[0023] The molten iron is pretreated by desulphurization, and the molten iron is dephosphorized and decarburized by top and bottom combined blowing converter smelting to obtain the molten steel, the converter smelting is blown with argon all the time, the scrap steel is added into the converter, and the converter tapping temperature is 1628℃. Then the molten steel after the converter smelting is subjected to LF external refining, the refining in-place temperature is ≥1560℃, the temperature measurement and the composition fine adjustment are carried out in the LF external refining, and the chemical composition supplied to the caster in the LF external refining is shown in Table 1. The slab continuous casting superheat is 25℃, and then the slab cleaning, slow cooling and continuous casting blank quality inspection are carried out. The slab heating temperature is 1249℃, the heating time is 203min, and the rolling is carried out by using a 7-stand continuous rolling mill. The finish rolling temperature is 890℃, and the finished product thickness is 2.5mm. The laminar flow cooling is carried out by using front dispersion cooling, the cooling speed is 19℃ / S, the steel strip temperature is reduced to 643℃ for coiling. Finally, the product performance detection is carried out.

[0024] Comparative Example 1

[0025] The molten iron is pretreated by desulphurization, and the molten iron is dephosphorized and decarburized by top and bottom combined blowing converter smelting to obtain the molten steel, the converter smelting is blown with argon all the time, the scrap steel is added into the converter, and the converter tapping temperature is 1625℃. Then the molten steel after the converter smelting is subjected to LF external refining, the refining in-place temperature is ≥1560℃, the temperature measurement and the composition fine adjustment are carried out in the LF external refining, and the chemical composition supplied to the caster in the LF external refining is shown in Table 1. The slab continuous casting superheat is 25℃, and then the slab cleaning, slow cooling and continuous casting blank quality inspection are carried out. The slab heating temperature is 1220℃, the heating time is 203min, and the rolling is carried out by using a 7-stand continuous rolling mill. The finish rolling temperature is 871℃, and the finished product thickness is 2.5mm. The laminar flow cooling is carried out by using front dispersion cooling, the cooling speed is 20℃ / S, the steel strip temperature is reduced to 623℃ for coiling. Finally, the product performance detection is carried out.

[0026] Table 1 Chemical composition (wt%) of the steel coils of Examples 1-3 of the present application

[0027]

[0028] The steel coils of Examples 1-3 of the present application are subjected to mechanical property inspection, and the inspection results are shown in Table 2.

[0029] Table 2 Mechanical properties of the steel coils of Examples 1-3 of the present application

[0030]

[0031] From the data in Table 2, it can be seen that the mechanical properties and process properties of the low-cost corrosion-resistant steel produced according to the method provided by the present application meet the requirements of the agreement signed with the user.

[0032] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application.

Claims

1. A method of producing a low cost corrosion resistant steel, characterized by: The mass percentage of the chemical composition of the corrosion-resistant steel is: C: 0.06-0.08%, Si: 0.30-0.50%, Mn: 0.45-0.52%, P: 0.060-0.061%, S: ≤0.005%, Cu: 0.25-0.35%, Cr: 0.40-0.45%, Ti: 0.031-0.035%, Alt: 0.020-0.050%, and the rest is Fe and inevitable impurities; The main production process and parameters are: (1) smelting-continuous casting production process: hot metal pretreatment-converter-LF refining-casting machine; (2) hot rolling production process: casting blank-heating furnace-7 rack continuous rolling-laminar cooling-coiling; the casting blank discharge temperature is 1230±25℃, the 7 rack continuous variable crown rolling mill is used for finish rolling, the finish rolling temperature is 890±15℃, the hot rolled steel strip thickness is 2.2-2.7mm; the cooling uses laminar cooling equipment, the front dispersion cooling mode, and the coiling temperature is 640±10℃.

2. The method of producing a low-cost corrosion-resistant steel according to claim 1, characterized by: The mass percentage of the chemical composition of the corrosion-resistant steel is: C: 0.078%, Si: 0.40%, Mn: 0.52%, P: 0.060%, S: 0.004%, Cu: 0.32%, Cr: 0.43%, Ti: 0.032%, Alt: 0.032%, and the rest is Fe and inevitable impurities.

3. The method of producing a low-cost corrosion-resistant steel according to claim 1, characterized by: The mass percentage of the chemical composition of the corrosion-resistant steel is: C: 0.074%, Si: 0.43%, Mn: 0.52%, P: 0.061%, S: 0.005%, Cu: 0.31%, Cr: 0.43%, Ti: 0.031%, Alt: 0.036%, and the rest is Fe and inevitable impurities.

4. The method of producing a low-cost corrosion-resistant steel according to claim 1, characterized by: The performance meets: yield strength greater than 500MPa, tensile strength greater than 570MPa, and elongation greater than 23%.

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