Corrosion-resistant mine grinding steel ball and production method thereof

Abstract

The present application relates to a kind of corrosion-resistant mine grinding steel ball and its production method, the mass percentage of the elemental composition of steel is, C:0.90~1.10%, Si:0.15~0.35%, Mn:0.90~1.10%, Cr:0.35~0.65%, Cu:0.20~0.40%, Ti:0.010~0.030%, Ni:0.15~0.30%, the balance is Fe and inevitable impurity elements.The production diameter of steel ball is φ25~30mm, the final metallographic structure is martensite and residual austenite, and the proportion of martensite is more than 95%, surface hardness and volume hardness are 63~66HRC, close to the hardness requirement of high-chromium cast iron ball, with higher wear resistance.24 hours standard corrosion test corrosion rate is not more than 7mg / cm 2 h, with the advantage of corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the production method of steel ball in the field of metallurgy. BACKGROUND

[0002] The grinding steel ball for mine ball mill is suitable for grinding various ores and other materials, and is the main consumable product of the ball mill, which is widely used in various mines, cement plants, power plants, building materials and chemical industries. For the mining of magnetite resources, the hardness of the raw ore is very high, higher than that of ordinary hematite. For example, the hardness coefficient F value of the magnetite ore mined by CITIC PACIFIC MINING is as high as 38, and the domestic steel plant's mine ore is generally only 10-18. The density of the ore reaches 3.5, and the density of the ordinary ore is only 3.0-3.2. For such heavy and hard ore, the ball mill needs to use very high hardness grinding steel balls after mining to meet the grinding requirements.

[0003] Patent No. CN113953426A discloses a production method of high-toughness mine wear-resistant steel ball, which comprises the following steps: making round steel, heating the round steel in a natural gas step furnace, feeding the heated round steel into the roller of a hot shearing machine by using a feeding device, uniformly distributing the round steel according to the set length by using an infrared laser intelligent ranging device, starting the hot shearing machine to segment the round steel according to the distribution information of the infrared laser intelligent ranging device, and obtaining a billet; using a mechanical hand to clamp the billet to a numerical control full hydraulic die forging hammer, and a temperature measuring device measures the temperature of the billet and transmits the measured temperature of the billet to the numerical control full hydraulic die forging hammer. The numerical control full hydraulic die forging hammer calculates the hitting energy and hitting times of the billet according to the temperature of the billet to hit the billet, so that the high-toughness mine wear-resistant steel ball is obtained. The present application precisely controls the process parameters by using the numerical control full hydraulic die forging hammer to ensure the roundness of the prepared steel ball, thereby improving the production efficiency of the steel ball. The chemical element composition and mass percentage contained in the round steel are as follows: C: 0.5-0.7wt.%, Si: 1.6-2.0wt.%, Mn: 0.65-0.95wt.%, Cr: 0.7-0.95wt.%, and the balance is Fe and unavoidable impurities. The method belongs to a heating forging process, which is suitable for the production of large-size forged steel balls. The production must use heating equipment, forging equipment and many auxiliary tools. Compared with rolled steel balls, the production cost is relatively high, and the carbon content C: 0.5-0.7wt.% belongs to medium carbon content. Theoretically, the wear resistance is relatively poor compared with high-carbon steel with C: 0.9-1.1wt.%. Moreover, the steel ball with such composition design does not have ideal corrosion resistance to corrosive solutions in the ball mill.

[0004] With the large-scale of the mine mill, the demand of wear-resistant steel ball is gradually increased, its forming process is mainly induction heating, air hammer forging or press extrusion forming, the medium frequency induction heating is used due to short time, the temperature is not uniform inside and outside the round steel in the rapid heating process, the temperature difference is large, so that the round steel organization is uneven, the product quality uniformity is poor, the quality is unstable; the air hammer forging is used, the process environment temperature is high, the labor intensity is large, the production efficiency is low, and the stability of the product quality is also difficult to guarantee; and the press extrusion does not meet the compression ratio of the steel ball forming, the steel ball density is poor, the organization grain cannot be refined, so as to affect the product quality of the steel ball.

[0005] Therefore, it is of great significance to develop a low-cost production method of the corrosion-resistant and high-wear-resistant steel ball for mine mill. SUMMARY

[0006] The present application relates to a kind of mine grinding steel ball and its manufacturing method, the grinding steel ball described in the present application, using high-carbon high-manganese and low alloy smelting, rolling process forming, on-line quenching and self tempering process, it has the production advantage of low cost easy production compared with the steel ball production process in prior art, the obtained steel ball has the characteristics of high hardness, uniform structure, good wear resistance, good corrosion resistance, is conducive to the ball mill of magnetite and other ores with high hardness is used in grinding ore.

[0007] The present application is manufactured using high-carbon low-alloy process, mainly because of the fierce market competition and the limitation of processing cost, using high-chromium wear-resistant cast ball with high chromium content of 20%, the market currently lacks corresponding low-cost high-wear-resistant alloy steel ball.

[0008] For the production method of steel ball, the present application effectively controls non-metallic inclusions, because non-metallic inclusions in steel destroy the continuity and uniformity of metal, in the process of grinding ore of steel ball, inclusions are easy to cause stress concentration, become fatigue crack source, reduce the fatigue life of steel ball, especially for hard and brittle inclusions, such as large particle point or spherical inclusions (Ds type) without deformation, because it has no plasticity, it is difficult to deform during steel ball processing and use, shorten the fatigue crack initiation period, affect the improvement of fatigue performance. In order to improve the service life of the final product, the purity of steel is very important, and the non-metallic inclusions in steel must be reduced as much as possible.

[0009] Because the surface quality of steel ball is required to be high during use, in addition to not allowing inclusions on the surface or under the skin to destroy the continuity of matrix and thus reduce the service life, if there are surface defects such as folded, scratched, pressed iron oxide skin on the surface of steel, it will also directly lead to early failure of the product. Therefore, it is necessary to ensure that the product has good surface quality.

[0010] In order to solve the above problems, through the reasonable design of the chemical composition of the steel and the targeted control of the production process, the application provides a low-cost wear-resistant steel ball steel based on low alloy element content and a manufacturing method thereof, the specification group distance of which is φ25-30mm, and the total machining compression ratio from the blank to the finished steel ball should be greater than or equal to 16. The produced steel ball has the characteristics of good surface quality, high hardness, uniform organization and low cost. The specific technical scheme of the application is as follows.

[0011] A kind of steel for grinding steel ball is designed, and the mass percentage of the element composition is as follows: C: 0.90-1.10%, Si: 0.15-0.35%, Mn: 0.90-1.10%, Cr: 0.35-0.65%, Cu: 0.20-0.40%, Ti: 0.010-0.030%, Ni: 0.15-0.30%, and the balance is Fe and inevitable impurity elements.

[0012] In the above scheme, after the chemical composition is determined, the theoretical critical quenching diameter Di is calculated by using the Caterpillar quenching coefficient and Di value calculation formula, and the quenching Di value is controlled in the range of 230-350mm.

[0013] The functions and dosage selection of the components contained in the steel ball of the application are as follows:

[0014] Carbon: C is the most economical and basic strengthening element in steel, which can significantly improve the hardness and wear resistance of steel through solid solution strengthening and precipitation strengthening, but excessive C will adversely affect the toughness and ductility of steel, and is also not conducive to atmospheric corrosion resistance. The C content range in the application is determined to be 0.90-1.10%, and the steel material involved in the application belongs to the category of high carbon steel;

[0015] Silicon: The addition of Si in steel can strengthen ferrite, improve strength, elastic limit and hardenability, and a certain content of Si can form a thin layer of silicon dioxide on the surface of the steel when heated at high temperature, which can prevent the oxidation of the steel and thus improve the corrosion resistance, but Si increases the overheating sensitivity, cracking and decarburization tendency of the steel. The Si content range in the application is determined to be 0.15-0.35%.

[0016] Manganese: Mn, as a deoxidizing element in the steelmaking process, can improve the hardenability of steel, facilitate the formation of a stable corrosion layer in a weak corrosive environment, reduce the corrosion rate, and improve the corrosion resistance of steel, but excessive Mn can lead to the growth of corrosion product particles and increase the tendency of temper brittleness. The Mn content range in the application is determined to be 0.90-1.10%.

[0017] Chromium: Cr is a carbide-forming element that can improve the hardenability of steel, improve the corrosion resistance and oxidation resistance of steel, and improve the passivation ability. The Cr content range in the application is determined to be 0.35-0.65%.

[0018] Copper: Compared with conventional steel, the addition of Cu can form a rust-proof protective layer on the steel substrate, and especially when combined with chromium, it can significantly improve the atmospheric corrosion resistance. In combination with nickel elements in steel, CuNi compounds can prevent copper brittle crack phenomenon. The Cu content in the present application is controlled to be 0.20-0.40%.

[0019] Titanium: Ti is added as a grain refining element, which can form dispersed fine nanoscale titanium nitride dispersed particles on the grain boundary with N in steel, preventing grain growth and thus refining the grain. The range of Al content in the present application is determined to be 0.010-0.030%.

[0020] Nickel: Ni can improve the strength of steel while maintaining good plasticity and toughness, and also helps to improve the corrosion resistance of the alloy in a corrosive environment. At the same time, adding nickel can improve the copper brittle crack quality defect of copper-containing steel, and CuNi compounds can be produced in the intergranular region, which has a high melting point and prevents copper brittle crack phenomenon. However, since Ni is a rare and valuable resource, and in order to reduce costs, the range of Ni content in the present project steel is determined to be 0.15-0.30%.

[0021] Oxygen: A large number of tests show that excessive oxygen content will increase the content of oxide inclusions in steel, resulting in impure steel matrix and reducing the fatigue life of steel. The range of O content in the present application is determined to be ≤0.0015%.

[0022] Hydrogen: Excessive hydrogen content in steel will increase the production of white spot defects in steel, increase internal stress and cause internal cracks, resulting in early failure of steel balls. The range of H content in the present application is determined to be ≤0.00010%.

[0023] The production method of the above steel ball comprises the steps of: designing the chemical composition to smelt steel to obtain a continuous casting billet, heating and rolling the round steel to obtain round steel, segmenting and heating and rolling the round steel to form a steel ball, and quenching and self-tempering heat treatment to obtain a finished steel ball.

[0024] Molten steel smelting: the H content in the molten steel must be ≤0.0001%, and the molten steel is cast into a continuous casting billet with a cross-sectional area ≥5.76×10 4 mm 2 The continuous casting billet meets the following requirements: center segregation: equal to or better than 1.0 level, center porosity: equal to or better than 1.0 level, no center crack, corner crack and triangular zone crack; inclusion: A, B, D type coarse and fine system ≤1.5, C type coarse and fine system ≤0.5, Ds ≤1.0;

[0025] Round steel rolling: the continuous casting billet is heated to 1050-1150 DEG C, and after being kept warm for more than 3 hours, high-pressure water descaling treatment is carried out, and then rolling is carried out, the rolling temperature is 1000-1100 DEG C, and the final rolling temperature is 900-930 DEG C, and the round steel is rolled, the compression ratio of the rolling billet to the total material should be greater than or equal to 25; after rolling, controlled cooling is carried out, and after on-line slow cooling to below 400 DEG C, air cooling, cutting, packaging and collecting, and round bars with a specification of φ25-30mm are obtained;

[0026] Steel ball rolling: the round steel is segmented, heated and warmed to 800-960 DEG C, and the temperature is kept warm at 1000-1060 DEG C, and the total heating time is 40-60 minutes, and the steel ball rolling is carried out, and the wedge cross rolling mode is adopted, the rolling mill inclination angle is 3-3.3 DEG, the rolling temperature is 850-950 DEG C, and the finished product specification steel ball is rolled.

[0027] Further, after rolling, the steel ball is controlled at a temperature of 760-880 DEG C, and then quenched on-line, the surface temperature of the quenched steel ball is controlled at 60-100 DEG C, and then the steel ball is self-tempered in the heat preservation room, and the self-tempering temperature of the steel ball is 160-230 DEG C.

[0028] The present application uses the chemical composition of micro-alloying design, controls the purity of molten steel, directly uses the continuous casting billet as the billet, adopts large reduction ratio controlled rolling + controlled cooling method to manufacture round bars, the round bars are formed into steel balls by wedge cross rolling, and the process of on-line quenching after hot rolling + self-tempering heat treatment is adopted, so that one re-heating heat treatment process after rolling is reduced, the production cost is reduced, and the production cycle is shortened. The steel ball specification is φ25-30mm, the final metallographic structure is more than 95% of martensite and a small part of residual austenite, the surface hardness and volume hardness are 63-66HRC, close to the hardness requirement of high-chromium cast iron ball, and the steel ball has high wear resistance.

[0029] Compared with the prior art, the main advantages of the present application are that:

[0030] The steel ball manufactured according to the method has the advantages of high production efficiency, low cost and the like, and the steel ball has the characteristics of high hardness, uniform structure and good wear resistance, and due to the unique chemical composition design, the corrosion resistance is also high, which is beneficial to the use of the steel ball in a ball mill for grinding magnetite and the like, and the steel ball has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Fig. 1 is a schematic diagram (front view) of machining of a hardness sample of a steel ball according to the present application.

[0032] Figure 2 Fig. 2 is a schematic diagram (top view) of machining of a hardness sample of a steel ball according to the present application.

[0033] Figure 3 Fig. 3 is a surface microstructure diagram (400x) of a steel ball of Comparative Example 1.

[0034] Figure 4 Fig. 4 is a core microstructure diagram (400x) of a steel ball of Comparative Example 1.

[0035] Figure 5 Fig. 5 is a surface microstructure diagram (400x) of a steel ball of Comparative Example 2.

[0036] Figure 6 Fig. 6 is a core microstructure diagram (400x) of a steel ball of Comparative Example 2.

[0037] Figure 7 Fig. 7 is a surface microstructure diagram (400x) of a steel ball of Example 1.

[0038] Figure 8 Fig. 8 is a core microstructure diagram (400x) of a steel ball of Example 1. DETAILED DESCRIPTION

[0039] The present application will be further described in conjunction with the following examples, which are illustrative and are intended to explain the present application, but not to limit the present application.

[0040] The elemental composition (wt%) of the ground steel balls of Examples 1-3, the forged steel ball of Comparative Example 1, and the rolled steel ball of Comparative Example 2 is shown in Table 1, wherein P and S are unavoidable residual elements.

[0041] Table 1

[0042] C Si Mn P S Cr Cu Ni Ti Example 1 1.00 0.21 0.92 0.016 0.002 0.41 0.023 0.20 0.015 Example 2 0.99 0.23 0.95 0.015 0.002 0.42 0.021 0.19 0.016 Example 3 1.00 0.24 0.94 0.014 0.001 0.43 0.020 0.18 0.015 Comparative Example 1 0.61 1.70 0.75 0.017 0.008 0.71 0.03 0.01 0.005 Comparative Example 2 0.90 0.28 1.022 0.015 0.001 0.54 0.02 0.02 0.008

[0043] The production process and specific process of the steel ball steel of each embodiment of the present application are as follows: preparation of molten iron + scrap steel → BOF furnace initial smelting → LF furnace refining → RH furnace vacuum degassing → CCM billet continuous casting → slow cooling → continuous casting billet stripping → continuous casting billet shot blasting cleaning → heating rolling → controlled cooling → shearing / sawing → packaging and cold storage → finished product inspection → packaging.

[0044] Further, the above steelmaking and continuous casting process is as follows: first, smelting by converter, then LF refining, strengthening deoxidation during LF refining, and maintaining good deoxidation slag for more than 15 minutes and good fluidity. After refining, the ladle is transferred to the VD furnace for high vacuum degassing treatment, and the high vacuum pressure is maintained at 1.33 mbar for more than 15 minutes. After VD breaking, first feed aluminum wire, titanium wire and silicon calcium wire, etc. to adjust, adjust titanium and other components into the control range. After all the alloy is added, the ladle is soft argon blowing for more than 10 minutes to ensure the degassing effect and the inclusions can fully float up. The target superheat of the molten steel during continuous casting is controlled at 20-35℃, and the residence time of the casting blank in the high temperature zone is shortened as much as possible. The whole process of continuous casting is protected from oxidation to reduce the number of inclusions in the steel, and appropriate drawing speed and secondary cooling intensity are provided, and at the same time, the continuous casting adopts the measures of crystallizer M-EMS and terminal F-EMS electromagnetic stirring double linkage to effectively improve and reduce the composition segregation of the continuous casting blank. The prepared rectangular continuous casting blank with a cross-sectional size of 300mm x 340mm. The continuous casting blank satisfies: center segregation, ingot type segregation: 0.5 level, center porosity: 0.5 level, no center crack, corner crack and triangular zone crack, inclusions: A, B class coarse system ≤1.0, C class, D class coarse system ≤0.5 level; A, B class fine system ≤1.5 level, C, D class fine system, Ds class ≤1.0.

[0045] Further, after the surface of the casting blank is inspected and cleaned, the round steel manufacturing stage is carried out. The specific process of the casting blank heating and rolling stage is as follows: the continuous casting blank is slowly heated to 1050-1150℃ in a neutral atmosphere heating furnace and kept for 3 hours, and the high temperature holding time should be no less than 30 minutes, so that the alloy elements in the steel can be fully solid-solved. After the furnace is discharged and the scale is removed by high pressure water, it is directly sent to the multi-stand continuous rolling mill for rolling, and the opening rolling temperature is 1000-1100℃ and the final rolling temperature is 900-930℃. By reasonably designing the rolling deformation process, the rough rolling adopts diamond square pass series, the medium and finishing rolling are arranged alternately by flat and vertical rolling mills, and the round steel is rolled to finished product. In the rolling process, large reduction is adopted in rough rolling, the single pass reduction of the first two rough rolling is 50-60%, the single pass reduction of the next two rough rolling is 30-40%, and the total rolling reduction is more than 25. After rolling, the rolled material is cooled slowly under the cold bed heat preservation cover, the rolled material temperature is ≤400℃, then air cooling is carried out, and then the rolled material is cut and packed to obtain round bars with a specification of φ25-30mm.

[0046] Further, the round steel is segmented and heated in a natural gas walking beam furnace, the heating temperature is 800-960℃, the uniform temperature holding temperature is 1000-1060℃, and the total heating time is 40-60 minutes.

[0047] Further, after the heated steel rod is pushed out of the heating furnace, it is rolled by using the wedge cross rolling process, the rolling mill inclination angle is 3-3.3°, the opening rolling temperature is 850-950℃, and the rolled finished steel ball specification is φ25-30mm.

[0048] Further, the steel ball is quenched by entering water on line after rolling according to the residual heat control temperature of 760-880 DEG C, the water flow and water temperature are controlled according to the process, the surface temperature of the water outlet steel ball is controlled at 60-100 DEG C, then the steel ball is put into the holding room for self tempering heat treatment, the tempering holding temperature is 160-230 DEG C, the high temperature of the steel ball core is conducted to the surface to reach the required temperature of the tempering process, and the steel ball is not easy to stress crack, and the high hardness finished product wear-resistant steel ball is finally obtained.

[0049] The element composition of the grinding steel ball of the present application is lower than 1% of the same kind of low alloy steel ball with the previously published chromium content, the corrosion resistance in the acidic and other corrosive solutions is increased, the corrosion resistance test of the steel ball of each embodiment is carried out according to the standard of JB / T7901-1999, the round piece sample is processed along the steel ball axis, the size is: φ25 (±2) mm x thick 5 (±0.1) mm, the surface original metal surface layer is polished by using the water sandpaper of 120 number particle size specified in GB / T 2481 (smoothness is better than Ra:3.2um), 24 hours of sulfuric acid corrosion test is carried out for each steel type:

[0050] The test solution is 50wt% sulfuric acid solution, the sample is weighed, the mass of the steel sample before the test is recorded in sequence, the size of the sample is accurately measured, the surface area is calculated, the sulfuric acid solution is added in the beaker according to the surface area of the sample, the amount of the test solution is required to be not less than 20mL per sample surface area, the beaker containing the sulfuric acid solution is placed in the constant temperature water bath of 70 DEG C in sequence for heating, the temperature of the solution is measured by using the thermometer, when the temperature of the sulfuric acid solution reaches 70 DEG C, the sample is put into the beaker in sequence for soaking, at this time, the timing starts, after reaching the specified time, the sample is taken out and washed in running water, then alcohol is washed, cold air is blown dry, the mass of each steel sample after the test is weighed, and the corrosion rate of each steel sample is calculated according to the following formula.

[0051] c ( W 0 - W 1 )( S * h )

[0052] In the formula, c : corrosion rate, W 0 : mass of the sample before the test mg, W 1 : mass of the sample after the test mg, S : total area of the sample cm 2 , h : test time h.

[0053] The 24-hour corrosion rates of Examples 1-3 and Comparative Examples 1, 2 are shown in Table 2.

[0054] Table 2

[0055] 24 hour corrosion rate c, (mg / cm 2 h)]]> Difference in corrosion rate from Comparative Example 1 Difference in corrosion rate from Comparative Example 2 Example 1 6.74 -16.6% -11.6% Example 2 6.69 -17.5% -12.4% Example 3 6.85 -14.7% -9.8% Comparative Example 1 7.86 / / Comparative Example 2 7.52 / /

[0056] In Table 2, the corrosion rate difference = (corrosion rate of the example - corrosion rate of the comparative example) / corrosion rate of the example x 100%.

[0057] As can be seen from Table 2, the steel ball performance of the examples is superior to that of the ordinary forged ball and rolled ball used in the market, and the corrosion rate is reduced by more than 10%, and the 24-hour corrosion rate is not more than 7 mg / cm 2 h.

[0058] For the important indicator of the wear resistance of the steel ball, the hardness (HRC) test was carried out according to the ISO 6508-1 standard requirements. When preparing the sample, linear cutting or electric spark cutting was used, and the equator and two poles of the rolled steel ball were cut along the equator and two poles Figure 1 and Figure 2 respectively, and the surface was polished smooth by sandpaper or grinding machine, and the A surface was marked 3 / 4, 1 / 2, 1 / 4, center. The surface hardness was tested along the B surface close to the surface 2-4 mm. The corrosion results of the examples and comparative examples 1, 2 are shown in Table 3.

[0059] Table 3

[0060] Surface hardness (HRC) 3 / 4 radius hardness (HRC) 1 / 2 radius hardness (HRC) 1 / 4 radius hardness (HRC) Core hardness (HRC) Average volume hardness* (HRC) Example 1 64.2 63.6 64 64.5 64 64.0 Example 2 63.7 64.5 64.5 63.7 64.2 64.3 Example 3 64.2 64.5 63.5 64 64.5 64.2 Comparative Example 1 57 61 60.8 60 58 59.8 Comparative Example 2 *Average volume hardness is calculated as follows: 60.5 62 61 61.6 62 61.4

[0061] In Table 3, the average volume hardness was calculated using the formula given in the YB / T 091-2019 standard "Forged (rolled) steel ball" industry standard.

[0062] As can be seen from Table 3, the steel ball manufactured in the examples is superior to the ordinary forged ball and rolled ball used in the market in terms of surface hardness and core hardness, and the average volume hardness is more than 64HRC, which is 2-3HRC higher than that of the comparative examples. High hardness means that the steel ball is more wear-resistant, and the ball mill production can reduce the replacement cycle of the steel ball and improve the grinding production efficiency.

[0063] Comparing the metallographic structure of Example 1 with Comparative Examples 1 and 2, the martensite structure of the steel ball surface and core of the example is relatively uniform, and some residual austenite is distributed therein, and the proportion is not more than 5%. In addition to the martensite, there is also some pearlite structure in Comparative Example 1, and the structure is not uniform, resulting in uneven hardness.

[0064] In addition to the above embodiments, the present application also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the claims of the present application.

Claims

1. A method of producing a corrosion resistant mine grinding steel ball, characterized by: The steel has the following element content: C: 0.90-1.10%, Si: 0.15-0.35%, Mn: 0.90-1.10%, Cr: 0.35-0.65%, Cu: 0.20-0.40%, Ti: 0.010-0.030%, Ni: 0.15-0.30%, the balance being Fe and inevitable impurities, and the production method comprises, Steel smelting: the H content in molten steel must be ≤0.0001%, and the molten steel is cast into a continuous casting billet with a cross-sectional area ≥5.76×10 4 mm 2 by using a continuous casting process, and the continuous casting billet meets the following requirements: center segregation: equal to or better than 1.0 level, center porosity: equal to or better than 1.0 level, no center crack, corner crack and triangular zone crack; inclusions: A, B, D type coarse and fine system ≤1.5, C type coarse and fine system ≤0.5, Ds ≤1.0; Round steel rolling: heating the continuous casting billet to 1050-1150 DEG C, keeping for more than 3 hours after reaching the temperature, after keeping, carrying out high-pressure water descaling treatment, then carrying out rolling, opening rolling temperature: 1000-1100 DEG C, finishing rolling temperature: 900-930 DEG C, rolling into round steel, the compression ratio of the first two passes in rough rolling should be greater than 50%, the compression ratio of the next two passes should be greater than 30%, the total compression ratio of the rolled billet should be greater than 25; after rolling, carrying out controlled cooling, air cooling after on-line slow cooling to below 400 DEG C, cutting, packing and collecting, obtaining round bar with specification of φ25-30mm; Steel ball rolling: heating the round steel in sections to 800-960 DEG C, keeping at uniform temperature of 1000-1060 DEG C, total heating time being 40-60 minutes, carrying out steel ball rolling, adopting wedge cross rolling mode, rolling mill inclination angle being 3 DEG -3.3 DEG, opening rolling temperature being 850-950 DEG C, rolling into finished product specification steel ball; after rolling, carrying out residual heat temperature control, controlling temperature at 760-880 DEG C, on-line water quenching, controlling the surface temperature of the water outlet steel ball at 60-100 DEG C, then entering the temperature holding room for self tempering heat treatment, self tempering temperature holding temperature of the steel ball being 160-230 DEG C.

2. The method of producing corrosion resistant mine grinding steel balls according to claim 1, characterized by: The steel has O≤0.0015% and H≤0.00010%.

3. The method of producing corrosion resistant mining grinding steel balls as claimed in claim 1, characterized by: The diameter of the steel ball is 25-30mm, the final metallographic structure is martensite and residual austenite, the proportion of martensite is more than 95%, the surface hardness and volume hardness are 63-66HRC, the corrosion rate of 24-hour standard corrosion test is not more than 7mg / cm 2 h.

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