Process for preparing high carbon martensitic stainless steel

Abstract

To provide a preparation process for obtaining a high-carbon martensitic stainless steel exhibiting characteristics such as improved wear resistance and corrosion resistance.SOLUTION: A process for preparing a high-carbon martensitic stainless steel comprises the steps of: preparing a steel composition comprising 1.7-1.9 wt.% of C, 17-18 wt.% of Cr, 1.6-2.0 wt.% of Mo, 2.9-3.5 wt.% of V, 0.40-0.60 wt.% of Nb, and Fe as a main constituent; melting the steel composition; transferring the molten steel composition to a die casting mold; demolding the steel composition at a temperature in a range of 850-950°C followed by forced air cooling; preparing the demolded steel composition for open die forging; and subjecting the steel composition to open die forging, subjecting the steel composition to anti-flaking heat treatment, followed by hardening and tempering to obtain the high carbon martensitic stainless steel.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a process for preparing high carbon martensitic stainless steel. [Background technology]

[0002] Martensitic stainless steels typically have a carbon content of 0.1% to 1.2% by weight. High-carbon martensitic stainless steels containing up to 1.2% by weight carbon are typically produced through conventional ingot casting and forging or rolling. However, to achieve higher strength levels and enhanced corrosion and wear resistance for application requirements, carbon contents of up to 1.8% by weight are required. When conventional ingot casting is used to produce this high-carbon martensitic stainless steel, the resulting steel exhibits microstructural inhomogeneities in the form of chromium carbide banding and grain boundary segregation, making the process unsuitable.

[0003] In this case, powder metallurgy is employed to produce high carbon martensitic stainless steels without the above-mentioned inhomogeneities in the microstructure, but the process is very expensive compared to traditional ingot casting, so the application of powder metallurgy is limited. Summary of the Invention

[0004] A process for preparing a high-carbon martensitic stainless steel is disclosed, comprising the steps of preparing a steel composition containing 1.7-1.9 wt% C, 17-18 wt% Cr, 1.6-2.0 wt% Mo, 2.9-3.5 wt% V, 0.40-0.60 wt% Nb, and Fe as a major component, melting the steel composition, transferring the molten steel composition to a die-casting die, demolding the steel composition at a temperature in the range of 850-950°C and then forced air cooling, preparing the steel composition for open die forging, and subjecting the steel composition to an anti-spasm heat treatment, followed by hardening and tempering to obtain the high-carbon martensitic stainless steel. [Brief explanation of the drawings]

[0005] [Figure 1A] FIG. 1 shows a 1x image of the microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 1B] FIG. 1 shows a 3x magnification image of the microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 2A] FIG. 1 illustrates the microstructure of a conventional high carbon martensitic stainless steel. [Figure 2B] FIG. 1 illustrates the microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 3A] FIG. 1 illustrates the black phase (stainless steel matrix) and white phase (carbides) in the microstructure of a conventional high carbon martensitic stainless steel. [Figure 3B] FIG. 1 illustrates the black phase (stainless steel matrix) and white phase (carbides) in the microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 4A] FIG. 1 shows primary and secondary carbides in the SEM-EDAX microstructure of a conventional high carbon martensitic stainless steel. [Figure 4B]FIG. 1 illustrates primary and secondary carbides in the SEM-EDAX microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 5A] FIG. 1 is a diagram showing a comparison of average carbide diameters (circle equivalent diameters) in conventional high-carbon martensitic stainless steels. [Figure 5B] FIG. 1 shows a comparison of average carbide diameter (circle equivalent diameter) in high carbon martensitic stainless steels prepared according to embodiments of the present disclosure. [Figure 6A] FIG. 1 is a diagram showing a comparison of nearest neighbor distances of carbides in conventional high carbon martensitic stainless steels. [Figure 6B] FIG. 1 shows a comparison of nearest neighbor distances of carbides in high carbon martensitic stainless steels prepared according to embodiments of the present disclosure. [Figure 7A] FIG. 1 is a diagram showing a comparison of the aspect ratios of carbides in conventional high-carbon martensitic stainless steels. [Figure 7B] FIG. 1 shows a comparison of carbide aspect ratios in high carbon martensitic stainless steels prepared according to embodiments of the present disclosure. [Figure 8] FIG. 1 shows a comparison of the impact strength of a conventional high carbon martensitic stainless steel and a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 9] FIG. 1 shows a comparison of the wear resistance of a conventional high carbon martensitic stainless steel and a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. [Figure 10] FIG. 1 shows a comparison of stress corrosion resistance of conventional high carbon martensitic stainless steel and high carbon martensitic stainless steel prepared according to embodiments of the present disclosure. [Figure 11] FIG. 1 illustrates the effect of demolding at various temperatures followed by forced air cooling on the microstructure of high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made herein to embodiments and specific language will be used to describe the same. Nevertheless, it will be understood that the scope of the present disclosure is not limited thereby, and that alterations and further modifications in the disclosed compositions and methods, and further applications of the principles of the present disclosure thereto, are contemplated as would normally occur to one skilled in the art to which the present disclosure pertains.

[0007] Those skilled in the art will understand that the foregoing general description and the following detailed description are exemplary and explanatory of the present disclosure and are not restrictive of the present disclosure.

[0008] References throughout this specification to "one embodiment," "an embodiment," or similar language mean that the particular configuration, structure, or feature described in connection with that embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0009] The terms "comprise," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion and are not to be construed as "consisting only of," such that a process or method that comprises a list of steps may not include only those steps, but may also include other steps not expressly listed in or inherent in the process or method.

[0010] Similarly, the terms "having" and "including" and their grammatical variations are intended to be open-ended, such that the recitation of an item in a list does not exclude other items that may be substituted for or added to the listed item.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, the preferred methods and materials are described herein. All publications mentioned herein are incorporated by reference.

[0012] The term "primary carbides" refers to M7C3 carbides composed mainly of liquid metals, such as carbon (C) and metals (M), such as iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), and molybdenum (Mo), in the martensitic matrix of the steel, with a mole fraction of 40-70% Cr and a mole fraction of 0.5-20% of other elements, such as V, Mo, and Fe, in the martensitic matrix of the steel.

[0013] The term "secondary carbides" refers mainly to the precipitates of M from austenite due to C in the martensitic matrix of steel and M such as Fe, Cr, V, Nb, and Mo. 23 C6 carbide, which contains 50-90% Cr mole fraction and 0.5-20% other elements such as V, Mo, and Fe mole fraction in the martensitic matrix of the steel.

[0014] The term "specific metal carbide" refers to a carbide composed mainly of liquid metals such as C and M, such as Fe, Cr, V, Nb, and Mo, in the martensitic matrix of the steel, and contains either 40 to 70% Nb mole fraction (referred to as "niobium-rich carbide") or 40 to 90% V mole fraction (referred to as "vanadium-rich carbide") and trace amounts of other metals, such as Cr and Fe, in a molar fraction of up to 10% in the martensitic matrix of the steel.

[0015] In its broadest scope, the present disclosure relates to a process for preparing a high-carbon martensitic stainless steel, the process comprising the steps of preparing a steel composition containing 1.7-1.9 wt.% C, 17-18 wt.% Cr, 1.6-2.0 wt.% Mo, 2.9-3.5 wt.% V, 0.40-0.60 wt.% Nb, and Fe as a major component, melting the steel composition, transferring the molten steel composition to a die-casting die, demolding the steel composition at a temperature in the range of 850-950°C and then forced air cooling, preparing the steel composition for open die forging, and subjecting the steel composition to an anti-scaling heat treatment, followed by hardening and tempering to obtain the high-carbon martensitic stainless steel.

[0016] The present inventors have found that both the disclosed composition and process are important to achieving high carbon martensitic stainless steels with improved malleability, corrosion resistance, and wear resistance.

[0017] Melting of the steel composition can be carried out using any known equipment. In an embodiment, melting is carried out in an induction furnace at a temperature in the range of 1470-1520°C for a time in the range of 60-90 minutes.

[0018] After melting, the molten composition is transferred into the die casting mold using any known method. In an embodiment, transfer is performed using a pouring ladle at a uniform pouring rate.

[0019] In an embodiment, the steel composition is cooled in the die casting die to a temperature in the range of 850-950°C within 5 minutes. Demolding is performed at a temperature in the range of 850-950°C. After demolding, the resulting steel composition is subjected to forced air cooling using any known means, such as direct or indirect forced air cooling. The inventors have found that demolding at a temperature in the range of 850-950°C prior to forced air cooling inhibits the formation of secondary carbides.

[0020] After forced air cooling, the material is prepared for free-die forging using known means. In an embodiment, the material is forged at a minimum forging temperature of 950°C for a time of 30-50 minutes per inch. soaking For example, the material is prepared by heating the material to a temperature in the range of 1100-1200°C. In some embodiments, the material is forged at a minimum forging temperature of 950°C for a time of 30-50 minutes per inch. soaking It is prepared by heating the material to a temperature of 1120-1150°C.

[0021] In the next step, an anti-scaling treatment is carried out to allow hydrogen to diffuse out of the steel. The anti-scaling treatment is carried out by heating the steel composition to a lower critical temperature (AC1) less than This is accomplished by well-known means by heating at a temperature sufficient to allow hydrogen to diffuse out of the steel. soaking In embodiments, the anti-strip heat treatment is carried out at a temperature of 760-800°C for a time period ranging from 15-25 hours. In some embodiments, the anti-strip heat treatment is carried out at a temperature of 760-780°C for a time period ranging from 18-20 hours.

[0022] In an embodiment, the curing is performed at a rate of 30 to 60 minutes per inch. soaking In some embodiments, curing is carried out at temperatures ranging from 1080 to 1130°C using known means. In some embodiments, curing is carried out at temperatures ranging from 30 to 60 minutes per inch. soaking For hardening, the hardening is carried out at a temperature in the range of 1110-1130°C. In an embodiment, after hardening, the steel composition is quenched in oil. Any oil known for quenching steels can be used.

[0023] In embodiments, the quenched steel composition is tempered using known means at a temperature of 320-370°C for a time period of 60-90 minutes per inch. In some embodiments, the quenched steel composition is tempered at a temperature of 350-370°C for a time period of 60-90 minutes per inch. The tempered steel composition is then formed into a final product.

[0024] The present disclosure also relates to a high-carbon martensitic stainless steel obtained using the disclosed process, which contains 1.7-1.9 wt% C, 17-18 wt% Cr, 1.6-2.0 wt% Mo, 2.9-3.5 wt% V, 0.40-0.60 wt% Nb, and Fe as the major component, and has a microstructure consisting of 15-30 vol% primary carbides and less than 2 vol% secondary carbides.

[0025] In an embodiment, the microstructure of the high carbon martensitic stainless steel is predominantly martensitic.

[0026] The high carbon martensitic stainless steel of the present disclosure comprises primary carbides that are uniformly sized and uniformly distributed within the microstructure of the steel. Figures 1A and 1B show the distribution of primary carbides within the microstructure of a high carbon martensitic stainless steel prepared according to an embodiment of the present disclosure.

[0027] In embodiments, the microstructure comprises primary carbides having an average carbide diameter (equivalent circle diameter) in the range of 10 to 30 microns with a distance between successive (or nearest neighbor) primary carbides in the range of 0.4 to 0.6 microns. In some embodiments, the microstructure comprises primary carbides having an average carbide diameter of about 17.19 microns with a distance between successive primary carbides of 0.51 microns. In embodiments, the carbides in the disclosed high carbon martensitic stainless steels have an average aspect ratio in the range of 1 to 2. In some embodiments, the carbides have an average aspect ratio of 1.9.

[0028] In embodiments, the microstructure of the high carbon martensitic stainless steel comprises primary carbides in the range of 20-30% by volume. In embodiments, the microstructure of the high carbon martensitic stainless steel comprises secondary carbides in an amount less than 1% by volume. In embodiments, the microstructure of the high carbon martensitic stainless steel comprises selected metal carbides in the range of 1-5% by volume. In some embodiments, the microstructure of the steel comprises selected metal carbides in the range of 2-4% by volume. The selected metal carbides improve the wear resistance of the disclosed high carbon martensitic stainless steel.

[0029] In embodiments, the high carbon martensitic stainless steel comprises an amount in the range of 1.80 to 1.90 wt% C. In some embodiments, the high carbon martensitic stainless steel comprises an amount of 1.8 wt% C.

[0030] In embodiments, the high carbon martensitic stainless steel comprises Cr in an amount ranging from 17.0 to 17.5 wt %. In some embodiments, the high carbon martensitic stainless steel comprises Cr in an amount of 17 wt %.

[0031] In embodiments, the high carbon martensitic stainless steel includes an amount in the range of 1.90-2.0 wt.% Mo. In some embodiments, the high carbon martensitic stainless steel includes an amount of 2 wt.% Mo. Alloying Nb and Mo in the disclosed percentages reduces the formation of primary carbides by half and contributes to increasing the malleability of the disclosed high carbon martensitic stainless steel.

[0032] In an embodiment, the high carbon martensitic stainless steel includes an amount in the range of 3.1 to 3.20 wt. % V. In some embodiments, the high carbon martensitic stainless steel includes V in an amount of 3.2 wt. %.

[0033] In embodiments, the high carbon martensitic stainless steel comprises Nb in an amount ranging from 0.45 to 0.50 wt %. In some embodiments, the high carbon martensitic stainless steel comprises Nb in an amount of 0.5 wt %.

[0034] High carbon martensitic stainless steels contain trace amounts of nickel (Ni). In embodiments, the high carbon martensitic stainless steels contain Ni in an amount up to 0.50 wt. %. In some embodiments, the high carbon martensitic stainless steels contain Ni in an amount up to 0.20 wt. %.

[0035] In embodiments, the high carbon martensitic stainless steel comprises silicon (Si) in an amount ranging from 0.30 to 0.60 wt %. In some embodiments, the high carbon martensitic stainless steel comprises Si in an amount of 0.36 wt %.

[0036] High carbon martensitic stainless steel contains trace amounts of tungsten (W). In embodiments, the high carbon martensitic stainless steel contains up to 0.07 wt. % W. In some embodiments, the high carbon martensitic stainless steel contains 0.01 wt. % W.

[0037] In embodiments, the high carbon martensitic stainless steel comprises manganese (Mn) in an amount ranging from 0.40 to 0.60 wt %. In some embodiments, the high carbon martensitic stainless steel comprises Mn in an amount of 0.45 wt %.

[0038] In embodiments, the disclosed high carbon martensitic stainless steel has a hardness in the range of 53 to 57 HRC. In some embodiments, the high carbon martensitic stainless steel has a hardness of 55 to 57 HRC. In some embodiments, the high carbon martensitic stainless steel has a hardness of 55 HRC.

[0039] In an embodiment, the high carbon martensitic stainless steel has a strength of 18 to 24 J / mm 2 In some embodiments, the high carbon martensitic stainless steel has a Charpy impact strength in the range of 20 to 21 J / mm 2 In some embodiments, the high carbon martensitic stainless steel has a Charpy impact strength of 20 J / mm 2 It has a Charpy impact strength of

[0040] In embodiments, the high carbon martensitic stainless steel exhibits corrosion resistance to failure in a range of 200 to 300 hours under 350 MPa tensile loading in an H2S atmosphere in accordance with NACE 0177-201. In some embodiments, the high carbon martensitic stainless steel exhibits corrosion resistance to failure in a range of 220 to 280 hours under 350 MPa tensile loading in an H2S atmosphere in accordance with NACE 0177-201. In some embodiments, the high carbon martensitic stainless steel exhibits corrosion resistance to failure in a range of 220 hours under 350 MPa tensile loading in an H2S atmosphere in accordance with NACE 0177-201.

[0041] In an embodiment, the high carbon martensitic stainless steel has a hardness of 200-280 mm when measured under a load of 45 N with an alumina abrasive for 30 minutes. 3 In some embodiments, high carbon martensitic stainless steel has a wear mass loss in the range of 260-280 mm when measured under a load of 45 N with an alumina abrasive for 30 minutes. 3 In some embodiments, the high carbon martensitic stainless steel has a wear mass loss of 260 mm when measured under a load of 45 N with an alumina abrasive for 30 minutes. 3 has a wear mass loss of [Example]

[0042] In order that the present invention may be better understood, the following examples are set forth, which are intended for illustrative purposes only, and the exact compositions, preparation methods, and embodiments described are not intended to limit the invention, and any obvious variations will be apparent to those skilled in the art.

[0043] Methods for characterizing high carbon martensitic stainless steels formed using embodiments of the claimed processes are also described herein.

[0044] Example 1: Comparison of an exemplary high carbon martensitic stainless steel with a conventional high carbon steel having a similar composition A high carbon martensitic stainless steel (INV1) prepared according to an embodiment of the present disclosure was compared to a high carbon martensitic stainless steel (CR4) prepared using a conventional ingot casting method.

[0045] INV1 and CR4 had compositions including Fe and other untested metals as well as the following elements in the amounts listed below: [Table 1]

[0046] Process used to prepare INV1: Steel compositions were prepared according to the compositions set forth in Table 1 above. The steel compositions were melted at 1520°C. After melting, the molten steel compositions were transferred to a die casting die at a temperature of 1470°C and then demolded. Demolding of the steel compositions was carried out at a temperature of 950°C followed by forced air cooling using direct forced air cooling. The demolded steel compositions were then forged at a minimum forging temperature of 950°C for a time of 50 minutes per inch. soaking The steel compositions were prepared for free forging at a temperature of 1150°C. In a next step, the steel compositions were subjected to free forging. The forged steel compositions were subjected to an anti-strip heat treatment at a temperature of 760-780°C for a time period ranging from 18 to 20 hours. The resulting steel compositions were subjected to a time period of 60 minutes per inch. soaking The steel composition was hardened at a temperature of 1120°C. After hardening, the steel composition was quenched in oil. The quenched steel was tempered at a temperature of 370°C for a time of 90 minutes per inch to obtain a high carbon martensitic stainless steel. This tempered steel composition was then formed into the final product.

[0047] Process used to prepare CR4: CR4 was prepared using conventional ingot casting methods.

[0048] Evaluation of primary, secondary and specific metal carbides in CR4 and INV1: CR4 and INV1 were evaluated to calculate the percentage of primary carbides, secondary carbides and specific metal carbides therein.

[0049] Characterization Method: Multiple microstructural images were recorded at various magnifications using a Dewinter microscope and processed by image processing software (Biowizard software) to estimate the total % of carbides (primary carbides, secondary carbides, and specific metal carbides). EDAX (Energy Dispersive X-ray) mapping was performed using a JEOL scanning electron microscope to evaluate the chemical composition of each carbide. Based on the chemical composition of each carbide, primary carbides, secondary carbides, and specific metal carbides were identified.

[0050] Figures 2A and 2B show the microstructures of CR4 and INV1, respectively. Figures 3A and 3B show the black phase (stainless steel matrix) and white phase (carbides) in the microstructures of CR4 and INV1, respectively. Figures 4A and 4B show the primary and secondary carbides in the SEM-EDAX microstructures of CR4 and INV1, respectively.

[0051] The percentages of primary, secondary and specific metal carbides within the microstructure of both CR4 and INV1 are summarized in Table 2 below. [Table 2]

[0052] Figures 5, 6 and 7 show the circle equivalent diameter, nearest neighbor distance and aspect ratio of primary carbides in the microstructures of CR4 and INV1, respectively. The characteristics of primary carbides in the microstructures of both CR4 and INV1 are summarized in Table 3 below. [Table 3]

[0053] Both INV1 and CR4 were tested to evaluate their impact strength, abrasion resistance and corrosion resistance. Characterization methods used: 1.Impact strength: A Charpy impact test, i.e., a Charpy V-notch test (IS Code 1757), was carried out under the following conditions to evaluate the impact strength of the steel material. Notch: None Temperature: 24℃ 2. Wear resistance: A rubber wheel abrasion test (ASTM G65) was carried out under a load of 45 N for 30 minutes to evaluate the abrasion resistance of the steel material. 3. Stress corrosion test: The susceptibility to stress corrosion was measured according to NACE0177-2016 under the following atmospheres: H2S 200ml / min / lit 5% NaCl + 0.5% glacial acetic acid pH: 2.7 Load: 25-45% UTS Temperature: 24℃

[0054] Results and Discussion: FIG. 8 shows a comparison of the impact strength of CR4 and INV1. It was confirmed that INV1 had an impact strength that was approximately 155% higher than that of CR4. FIG. 9 shows a comparison of the wear resistance of CR4 and INV1. It was confirmed that INV1 had an wear resistance that was approximately 47% higher than that of CR4. FIG. 10 shows a comparison of the corrosion resistance of CR4 and INV1. It was confirmed that INV1 had an stress corrosion resistance that was approximately 400% higher than that of CR4.

[0055] Example 2: Effect of demolding steel compositions at various temperatures on the microstructure of the steel The effect of demolding the steel composition at temperatures above 850°C on the microstructure of the steel was investigated by performing the demolding process at 900°C, 400°C and room temperature, followed by forced cooling. Three sets of experiments were carried out using the process of Example 1, varying the temperature at which the demolding was performed.

[0056] Results and Discussion: FIG. 11 shows the effect of demolding the steel composition at various temperatures on the microstructure of a high carbon martensitic stainless steel.

[0057] It was confirmed that demolding at temperatures higher than 850°C resulted in a uniform distribution of carbides from the core to the surface of the cast steel, whereas demolding at a reduced temperature of 400°C or at room temperature resulted in non-uniform and agglomerated carbide precipitation from the surface to the core. [Industrial Applicability]

[0058] The disclosed process for preparing high carbon martensitic stainless steel allows for control of the amount and distribution of carbides within the steel matrix, and can be performed using existing ingot casting equipment and systems.

[0059] The high carbon martensitic stainless steels obtained using the disclosed process exhibit properties such as the necessary toughness (impact strength) for dynamic applications, as well as improved wear and corrosion resistance compared to those obtained using known, expensive methods such as powder metallurgy. The high carbon martensitic stainless steels obtained using the disclosed process also exhibit significantly improved malleability compared to high carbon martensitic stainless steels processed by conventional ingot casting methods followed by forging or rolling operations.

Claims

1. 1. A process for preparing a high carbon martensitic stainless steel, comprising: preparing a steel composition comprising 1.7 to 1.9 wt. % C, 17 to 18 wt. % Cr, 1.6 to 2.0 wt. % Mo, 2.9 to 3.5 wt. % V, 0.40 to 0.60 wt. % Nb, and the balance being Fe and unavoidable impurities; melting the steel composition; transferring the molten steel composition to a die casting die; demolding the steel composition at a temperature in the range of 850-950°C followed by forced air cooling; preparing the demolded steel composition for open die forging by heating the demolded steel composition to an elevated temperature, and performing open die forging on the steel composition; The forged steel composition is subjected to a spallation prevention heat treatment at a temperature below the lower critical temperature (AC1) to diffuse hydrogen, and then hardened at a temperature in the range of 1080 to 1130°C, followed by quenching and tempering to obtain the high carbon martensitic stainless steel; A process comprising:

2. 10. The process of claim 1, wherein melting the steel composition is carried out at a temperature in the range of 1470 to 1520°C for a time in the range of 60 to 90 minutes.

3. 10. The process of claim 1, wherein the steel composition is cooled in the die casting mold to a temperature in the range of 850-950°C within 5 minutes prior to demolding.

4. 10. The process of claim 1, wherein the demolded steel composition is prepared for open die forging by soaking a control cross section of the steel composition for a time period of 30-50 minutes per inch and heating the material to a temperature in the range of 1100-1200°C, followed by forging at a temperature of 950°C or greater.

5. 10. The process of claim 1, wherein the anti-strip heat treatment is carried out at a temperature of 760-800° C. for a time period ranging from 15 to 25 hours.

6. 10. The process of claim 1, wherein the hardening step is carried out by soaking the control cross section of the steel composition for a time period of 30 to 60 minutes per inch.

7. 10. The process of claim 1, wherein the quenched steel composition is tempered at a temperature of 320-370°C for a time of 60-90 minutes per inch across the control section of the steel composition.

8. The process described in claim 1, wherein the rapid cooling is performed in oil.

9. The process of claim 1, wherein the steel composition contains up to 0.50 wt. % Ni.

10. The process of claim 1, wherein the steel composition contains up to 0.07 wt. % W.

11. The process of claim 1, wherein the steel composition contains Si in an amount ranging from 0.30 to 0.60 wt. %.

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