A production method for non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts

Abstract

The present invention provides a method for producing non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts, which comprises the following steps: blast furnace molten iron → molten iron pretreatment → converter smelting → refining → continuous casting → billet grinding → high-speed wire hot rolling → wire laying → controlled cooling in stages → off-line inspection and storage. The temperature in the converter is 1100-1220°C, the furnace time is 2-3 hours, and the temperature during the rolling process is not lower than the Ar of the steel. cm Temperature, the spinning temperature is the Ar of steel cm The wire rod is cooled at a temperature of +20-30°C in stages. The first stage is adjusted according to the wire rod specifications. The wire rod temperature is reduced to 700-720°C and immersed in a constant temperature salt solution via a roller for the second stage of controlled cooling. By controlling the cooling rate and time of the close-packed rollers in the first stage, the ferrite structure is first precipitated and distributed in a network along the original austenite boundary. The salt bath temperature in the second stage is set to the Bs point of the steel +10-30°C to decompose the remaining austenite structure into fine troostite / troostite structure.

Description

Technical Field

[0001] The present invention relates to the technical field of methods for producing 10.9-grade high-plasticity wire rods, and in particular to a method for producing non-quenched and tempered wire rods for 10.9-grade high-plasticity standard parts. Background Art

[0002] Traditional high-strength standard parts are usually produced using the tempering (quenching + tempering) process. Since the 1970s, the development of wire rod products for non-tempered standard parts has begun. By eliminating the tempering process, energy can be saved and efficiency can be increased while avoiding the decarburization and deformation of the workpiece caused by the tempering process.

[0003] Nippon Steel's NHF-S series utilizes 0.2C-1.5Mn and hot water cooling, meeting the requirements for 700-900MPa grade standard parts. Kobe Steel's KNCH8 series, featuring a carbon-manganese alloy with niobium and vanadium microalloying, allows for the production of 800MPa grade cold heading steel without quenching and tempering. Domestically, GB / T 29087-compliant products utilize niobium and vanadium microalloying and the TMCP process to produce ultrafine ferrite microstructures, enabling the development of 8.8 and 9.8 grade non-tempered steels. 10.9 grade non-tempered steel utilizes a low-carbon composition of 0.20-0.35Si and 1.9-2.3Mn, but is not yet widely adopted in the market.

[0004] The development of non-quenched and tempered wire rod typically utilizes Nb and V microalloying or a Si-high Mn composition system, combined with Stelmor blower-assisted cooling to refine the microstructure to improve the base material strength. Nb and V strengthen the steel by forming carbonitrides, while Si exists in solid solution in the steel, inhibiting cementite precipitation and exerting a solid solution strengthening effect. However, Si content also significantly increases the product's deformation resistance during drawing and forming, increasing die loss. Mn content exceeding 1.5% produces a distinct banded structure, increasing the anisotropy of the wire rod and finished product.

[0005] When developing non-quenched and tempered wire rod, in addition to considering the matrix strength, deformation resistance and die loss during processing must also be considered. Wu Bin et al. summarized three trends in the development of non-quenched and tempered steel: first, the production of ultrafine ferrite + degenerate / spheroidized pearlite structure through low-temperature, large-deformation final rolling and Nb microalloying; second, the production of ferrite + martensite or bainite dual-phase non-quenched and tempered steel through low-temperature rolling and segmented controlled cooling; and third, pearlite low-strain resistance non-quenched and tempered wire rod similar to Nippon Steel's NHF-S and Kobe Steel's KNCH8S.

[0006] The aforementioned processes and microstructure designs all require the use of low-temperature, high-deformation final rolling followed by controlled cooling after rolling, placing strict demands on post-rolling cooling speed and precision to ensure uniform and controllable microstructure and performance. Currently, the main specifications of non-quenched and tempered wire rod range from 10-15mm. The current Stelmor process can achieve a maximum cooling rate of approximately 15°C / s, making it difficult to achieve the required ultrafine ferrite or 80% ferrite + 20% martensite or bainite phase transformation. The uneven distributed cooling of loose coils after coil rolling, caused by air or water cooling, also restricts the stability of product performance and industrial application.

[0007] Therefore, the organizational design and product development of wire rods with low deformation resistance, uniform and controllable performance, and high plasticity are of great significance for the industrial promotion of 10.9 grade non-quenched and tempered wire products. Summary of the Invention

[0008] The purpose of the present invention is to solve the problem that the existing technology is difficult to achieve the phase transformation requirements of ultrafine ferrite and martensite or bainite of 10.9 grade high plasticity wire rod.

[0009] In order to achieve the above object, the present invention adopts the following technical solution: a method for producing non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts, the method comprising the following steps in sequence:

[0010] blast furnace molten iron → Hot metal pretreatment → converter smelting → Refining → continuous casting → Blank grinding → High-speed wire hot rolling → Spinning silk → Staged controlled cooling → The step of offline inspection and storage, the continuous casting step is completed to obtain the continuous casting billet, the high-speed wire heating rolling step, the continuous casting billet is added to the heating furnace for heating, the furnace atmosphere temperature is controlled at 1100-1220℃, the furnace time is 2-3h, the residual oxygen content of the furnace gas is ≤3%, to avoid decarburization of the continuous casting billet surface, after heating, the billet is descaled by high-pressure water, and rolled into wire in multiple passes, and the rolling process temperature is not lower than the Ar of steel cm Temperature; after the rolling deformation is completed, the wire is formed into a loose coil by the wire laying machine and laid flat on the closely packed roller. The wire laying temperature is the Ar of the steel. cmThe temperature is +20-30°C, and the speed of the close-packed roller is adjusted according to the specifications of the wire rod to ensure that the cooling speed of the wire rod on the close-packed roller in the first stage is ≤2.5°C / s. After cooling to 700-720°C, the whole wire rod is immersed in a constant temperature salt solution through the roller for the second stage of controlled cooling. By controlling the cooling speed and time of the close-packed roller in the first stage, the ferrite structure that is first precipitated is obtained and distributed in a network along the boundary of the original austenite. In the second stage, a suitable salt solution temperature is selected to decompose the remaining austenite structure into fine troostite / troostite structure. The salt bath temperature is set to the Bs point temperature of the steel +10-30°C, and the constant temperature holding time is 2-5min.

[0011] Preferably, the chemical composition of the wire rod is as follows: C: 0.35-0.48wt.%; Si: 0.10-0.35wt.%; Mn: 1.00-1.50wt.%; Cr: 0.10-0.20wt.%; P: ≤0.020wt.%; S:

[0012] ≤0.010wt.%; V: ≤0.15wt.%; the rest are Fe and unavoidable impurities.

[0013] Preferably, the specification of the wire rod is Φ8-15mm.

[0014] Preferably, the molten iron pretreatment→converter smelting→refining is sequentially KR desulfurization pretreatment→top and bottom combined blowing converter smelting→LF refining→RH refining.

[0015] Preferably, the high-speed wire heating rolling process ensures that the temperature of the billet is uniformly and stably maintained in the austenite region of 860-900° C. throughout the entire rolling process by adjusting the cooling water flow and pressure of the high-speed wire water tank.

[0016] Preferably, the spinning temperature during the spinning process is controlled at 780-810°C.

[0017] Preferably, the salt bath temperature fluctuation during the staged controlled cooling is no more than ±2°C.

[0018] Preferably, the Bs point temperature is tested by an experimental method such as a thermal expansion instrument, or estimated according to the formula Bs (°C) = 830-270C-90Mn-70Cr, wherein the element symbols represent the key percentage values ​​of the corresponding elements.

[0019] Preferably, the volume fractions of fine troostite / troostite and ferrite in the wire rod are 85-92% and 8-15% respectively; the tensile strength is 1020-1060 MPa, the cross-sectional shrinkage is ≥50%, and the elongation after fracture is ≥15%.

[0020] Beneficial effects of the present invention:

[0021] Through the composition design and staged controlled cooling process of the present invention, a fine troostite / troostite+net ferrite dual-phase structure is obtained, wherein the volume fractions of the fine troostite / troostite and the ferrite are 85-92% and 8-15% respectively; the tensile strength is 1020-1060MPa, the cross-sectional shrinkage rate is ≥50%, and the elongation after fracture is ≥15%.

[0022] After the wire rod is descaled and surface saponified, it is drawn or rounded to a diameter reduction of no more than 1mm. Under existing equipment conditions, the production of standard parts meets the 10.9 level performance requirements, and there is no significant increase in mold loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a metallographic image of the wire rod prepared in Example 1 of the present invention;

[0024] Figure 2 This is a metallographic image of the wire rod prepared in Example 2 of the present invention;

[0025] Figure 3 This is a metallographic image of the wire rod prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Example 1, as Figure 1 The present invention provides a method for producing non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts. The chemical composition of the wire rod used in this embodiment is shown in Table 1.

[0029] Table 1 Chemical composition of the wire rod of the embodiment / wt.%

[0030] C Si Mn P S Cr V 0.41 0.15 1.20 0.015 0.005 0.15 0.08

[0031] The production process is as follows: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting → billet grinding → high-speed hot rolling → spinning → controlled cooling in stages → off-line inspection and storage. The 180 x 240 mm rectangular billets are produced through the following steps: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting. After KR desulfurization, the molten iron entering the converter has a sulfur content of ≤0.005%. The converter uses a double slag blowing process to reduce impurity levels in the steel, achieving a final converter P content of ≤0.015% and a S content of ≤0.010%. Protective casting is implemented throughout the continuous casting process to prevent secondary oxidation of the steel. The superheat of the steel is controlled between 15 and 30°C during continuous casting, and electromagnetic stirring and casting speed regulation are used to control centerline segregation of the continuously cast billets.

[0032] Billet grinding steps: To ensure product quality, after the continuous casting billet cools to room temperature, it is subjected to shot blasting or peeling treatment to ensure that there are no defects on the billet surface that affect the surface quality of the finished product.

[0033] After shot blasting, flaw detection, and grinding, the continuous casting billets are then hot-rolled. The furnace atmosphere is controlled at approximately 1200°C, with a residual oxygen content of ≤3% to prevent surface decarburization. The billets are held at this temperature for 135 minutes before rolling begins. After heating, the billets are descaled with high-pressure water and rolled in multiple passes into Φ11mm wire. The rolling process temperature is controlled between 900°C and 920°C, ensuring a uniform and stable austenitic temperature of 860°C to 900°C throughout the rolling process. The wire drawing temperature is controlled between 780°C and 810°C.

[0034] Controlled cooling in stages: After the billet is rolled and deformed, it is formed into a loose coil on the laying machine and laid flat on the close-packed roller. The speed of the close-packed roller is adjusted according to the specifications of the wire rod to ensure that the cooling rate of the wire rod on the close-packed roller in the first stage is ≤2.5℃ / s. After the wire rod is controlled to 710℃ on the close-packed roller, the whole wire rod is immersed in a constant temperature salt solution through the roller for the second stage of controlled cooling. By controlling the cooling rate and time of the close-packed roller in the first stage, the ferrite structure is first precipitated and distributed in a network along the boundary of the original austenite. In the second stage, a suitable salt solution temperature is selected to decompose the remaining austenite structure into fine troostite / troostite structure. The salt bath temperature is set to the Bs point temperature of the steel + 15℃ = 556℃, and the constant temperature is maintained for 3 minutes. The salt bath temperature fluctuation during the heat treatment is not more than ±2℃.

[0035] The Bs point temperature of this embodiment is obtained by testing using a thermal expansion instrument test method. Since this test method belongs to the existing technology, it will not be described in detail.

[0036] The microstructure of the wire rod obtained by the production method of this embodiment is shown in FIG. Figure 1 , which is 89% fine troostite / troostite + 11% reticular ferrite.

[0037] Mechanical properties are shown in Table 2.

[0038] Table 2 Mechanical properties of wire rods in the examples

[0039] Specification microstructure tensile strength Sectional shrinkage Elongation at break Φ11mm Fine troostite / troostite+reticular ferrite 1042MPa 54％ 17％

[0040] The wire rod was pickled for descaling and phosphorus saponification, and then drawn to reduce the diameter by 0.35 mm to produce 10.65 mm fine wire. After straightening and blanking, the end was tapped and cold-bent to produce U-bolts. After forming, the bolts were Dacromet-treated at 380°C for 50 min. The mechanical properties of the finished products are shown in Table 3.

[0041] Table 3 Specifications and mechanical properties of finished product of Example 1

[0042]

[0043] Example 2, as Figure 2 This embodiment provides a method for producing non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts. The chemical composition of the wire rod used in this embodiment is shown in Table 4.

[0044] Table 4 Chemical composition of wire rod of Example 2 (wt.%)

[0045] C Si Mn P S Cr V 0.48 0.10 1.00 0.015 0.005 0.20 0.08

[0046] The production process is as follows: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting → billet grinding → high-speed hot rolling → wire drawing → staged controlled cooling → off-line inspection and storage. The 180 x 240 mm rectangular billets are produced through the following steps: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting. After KR desulfurization, the molten iron entering the converter has a sulfur content of ≤0.005%. The converter uses a double slag blowing process to reduce impurity levels in the steel, achieving a final converter P content of ≤0.015% and a S content of ≤0.010%. Protective casting is implemented throughout the continuous casting process to prevent secondary oxidation of the steel. The superheat of the steel is controlled at 18-25°C during continuous casting, and electromagnetic stirring and casting speed regulation are used to control centerline segregation of the continuously cast billets.

[0047] Billet grinding steps: To ensure product quality, after the continuous casting billet cools to room temperature, it is subjected to shot blasting or peeling treatment to ensure that there are no defects on the billet surface that affect the surface quality of the finished product.

[0048] After shot blasting, flaw detection, and grinding, the continuous casting billets are then hot-rolled. The furnace atmosphere is controlled at 1100-1220°C, with a residual oxygen content of ≤3% to prevent surface decarburization. The billets are held at this temperature for 180 minutes before rolling begins. After heating, the billets undergo high-pressure water descaling and multi-pass rolling to produce Φ15mm wire rod. The rolling process temperature is controlled at 890-910°C, ensuring a uniform and stable austenitic temperature of 860-900°C throughout the rolling process. The wire drawing temperature is controlled at 780-810°C.

[0049] Controlled cooling in stages: After the billet is rolled and deformed, it is formed into a loose coil on the laying machine and laid flat on the close-packed roller. The speed of the close-packed roller is adjusted according to the specifications of the wire rod to ensure that the cooling rate of the wire rod on the close-packed roller in the first stage is ≤2.5℃ / s. After the wire rod is controlled to 700℃ on the close-packed roller, the whole wire rod is immersed in a constant temperature salt solution through the roller for the second stage of controlled cooling. By controlling the cooling rate and time of the close-packed roller in the first stage, the ferrite structure is first precipitated and distributed in a network along the boundary of the original austenite. In the second stage, a suitable salt solution temperature is selected to decompose the remaining austenite structure into fine troostite / troostite structure. The salt bath temperature is set to the Bs point temperature of the steel + 10 = 606℃, and the constant temperature is maintained for 5 minutes. The salt bath temperature fluctuation during the heat treatment is not more than ±2℃.

[0050] The Bs point temperature of this embodiment is calculated using the following formula.

[0051] Bs(℃)=830-270C-90Mn-70Cr, where the element symbols represent the key percentage values ​​of the corresponding elements.

[0052] The microstructure of the wire rod obtained by the production method of this embodiment is shown in FIG. Figure 2 , which is 85% fine troostite / troostite + 15% reticular ferrite.

[0053] Mechanical properties are shown in Table 5.

[0054] Table 5 Mechanical properties of wire rod in Example 2

[0055] Specification microstructure tensile strength Sectional shrinkage Elongation at break Φ15mm Fine troostite / troostite+reticular ferrite 1080MPa 54.8％ 17.5％

[0056] After pickling, descaling, phosphorus saponification, and micro-drawing and rounding, the wire rod is produced into 14.85mm fine wire. After straightening and blanking, the end is tapped and cold-bent to produce U-bolts. After forming, the bolts are treated with Dacromet at 380℃*50min. The mechanical properties of the finished products are shown in Table 6.

[0057] Table 6 Specifications and mechanical properties of finished product of Example 2

[0058]

[0059] Example 3, as Figure 3This embodiment provides a method for producing non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts. The chemical composition of the wire rod used in this embodiment is shown in Table 7.

[0060] Table 7 Chemical composition of wire rod of Example 3 (wt.%)

[0061] C Si Mn P S Cr V 0.35 0.35 1.50 0.02 0.001 0.10 0.15

[0062] The production process is as follows: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting → billet grinding → high-speed hot rolling → wire drawing → staged controlled cooling → off-line inspection and storage. The 180 x 240 mm rectangular billets are produced through the following steps: blast furnace hot metal → KR desulfurization → top-bottom combined blowing converter steelmaking → LF furnace refining → RH furnace refining → continuous casting. After KR desulfurization, the molten iron entering the converter has a sulfur content of ≤0.005%. The converter uses a double slag blowing process to reduce impurity levels in the steel, achieving a final converter P content of ≤0.015% and a S content of ≤0.010%. Protective casting is implemented throughout the continuous casting process to prevent secondary oxidation of the steel. The superheat of the steel is controlled at 18-25°C during continuous casting, and electromagnetic stirring and casting speed regulation are used to control centerline segregation of the continuously cast billets.

[0063] Billet grinding steps: To ensure product quality, after the continuous casting billet cools to room temperature, it is subjected to shot blasting or peeling treatment to ensure that there are no defects on the billet surface that affect the surface quality of the finished product.

[0064] After shot blasting, flaw detection, and grinding, the continuous casting billets are then hot-rolled. The furnace atmosphere is controlled at 1100-1220°C, with a residual oxygen content of ≤3% to prevent surface decarburization. The billets are held at this temperature for 120 minutes before rolling begins. After heating, the billets are descaled with high-pressure water and rolled in multiple passes into Φ8mm wire. The rolling process temperature is controlled at 880-900°C, ensuring a uniform and stable austenitic temperature of 860-900°C throughout the rolling process. The wire drawing temperature is controlled at 780-810°C.

[0065] Controlled cooling in stages: After the billet is rolled and deformed, it is formed into a loose coil on the laying machine and laid flat on the close-packed roller. The speed of the close-packed roller is adjusted according to the specifications of the wire rod to ensure that the cooling rate of the wire rod on the close-packed roller in the first stage is ≤2.5℃ / s. After the wire rod is controlled to 720℃ on the close-packed roller, the whole wire rod is immersed in a constant temperature salt solution through the roller for the second stage of controlled cooling. By controlling the cooling rate and time of the close-packed roller in the first stage, the ferrite structure is first precipitated and distributed in a network along the boundary of the original austenite. In the second stage, a suitable salt solution temperature is selected to decompose the remaining austenite structure into fine troostite / troostite structure. The salt bath temperature is set to the Bs point temperature of the steel + 15℃ = 545℃, and the constant temperature is maintained for 2 minutes. The salt bath temperature fluctuation during the heat treatment is not more than ±2℃.

[0066] The Bs point temperature of this embodiment is obtained by testing using a thermal expansion instrument test method. Since this test method belongs to the existing technology, it will not be described in detail.

[0067] The microstructure of the wire rod obtained by the production method of this embodiment is shown in FIG. Figure 3 , which is 92% fine troostite / troostite + 8% reticular ferrite.

[0068] Mechanical properties are shown in Table 8.

[0069] Table 8 Mechanical properties of wire rod in Example 3

[0070] Specification microstructure tensile strength Sectional shrinkage Elongation at break Φ8mm Fine troostite / troostite+reticular ferrite 1023MPa 51％ 16％

[0071] The wire rod was pickled for descaling and phosphorus saponification, and then drawn to reduce the diameter by 0.45 mm to produce 7.55 mm fine wire. After straightening and blanking, the end was tapped and cold-bent to produce U-bolts. After forming, the bolts were Dacromet-treated at 380°C for 50 min. The mechanical properties of the finished products are shown in Table 9.

[0072] Table 9 Specifications and mechanical properties of finished product of Example 3

[0073]

[0074] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for producing non-quenched and tempered wire rod for 10.9 grade high-plasticity standard parts, comprising the following steps: blast furnace molten iron → molten iron pretreatment → converter smelting → refining → continuous casting → billet grinding → high-speed wire hot rolling → spinning → controlled cooling in stages → off-line inspection and storage, characterized in that: The continuous casting step is completed to obtain a continuous casting billet. In the high-speed wire heating rolling step, the continuous casting billet is added to a heating furnace for heating, the atmosphere temperature in the furnace is controlled at 1100-1220°C, the furnace time is 2-3 hours, the residual oxygen content of the furnace gas is ≤3%, and decarburization of the continuous casting billet surface is avoided. After heating, the billet is descaled by high-pressure water and rolled into wire in multiple passes. The rolling process temperature is not lower than the Ar of steel. cm Temperature; after the rolling deformation is completed, the wire is formed into a loose coil by the wire laying machine and laid flat on the closely packed roller. The wire laying temperature is the Ar of the steel. cm The temperature is +20~30℃, and the speed of the close-packed roller is adjusted according to the specifications of the wire rod to ensure that the cooling rate of the wire rod on the close-packed roller in the first stage is ≤2.5℃ / s. After cooling to 700-720℃, the whole wire rod is immersed in a constant temperature salt bath via a roller for the second stage of controlled cooling. By controlling the cooling rate and time of the close-packed roller in the first stage, the ferrite structure that is first precipitated is obtained, and is distributed in a network along the boundary of the original austenite. In the second stage, a suitable salt bath temperature is selected to decompose the remaining austenite structure into fine sorbite / troostite structure. The salt bath temperature is set to the Bs point temperature of the steel +10~30℃, and the constant temperature holding time is 2-5min; the volume fractions of fine sorbite / troostite and ferrite in the wire rod are 85~92% and 8~15%, respectively; the tensile strength is 1020-1060MPa, the cross-sectional shrinkage rate is ≥50%, and the elongation after fracture is ≥15%.

2. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The chemical composition and proportion of the wire rod are: C: 0.35-0.48wt.%; Si: 0.10-0.35wt.%; Mn: 1.00-1.50wt.%; Cr: 0.10-0.20wt.%; P: ≤0.020wt.%; S: ≤0.010wt.%; V: ≤0.15wt.%; the rest are Fe and unavoidable impurities.

3. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 2, characterized in that: The specification of the wire rod is Φ8-15mm.

4. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The molten iron pretreatment→converter smelting→refining sequentially adopts KR desulfurization pretreatment→top and bottom combined blowing converter smelting→LF refining→RH refining.

5. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The high-speed wire heating rolling process ensures that the temperature of the billet is uniformly and stably maintained in the austenite region of 860-900°C throughout the entire rolling process by adjusting the cooling water flow and pressure of the high-speed wire water tank.

6. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The spinning temperature during the spinning process is controlled at 780-810°C.

7. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The salt bath temperature fluctuation during the stage-by-stage controlled cooling is no more than ±2°C.

8. The method for producing a non-quenched and tempered wire rod for 10.9 grade high plasticity standard parts according to claim 1, characterized in that: The Bs point temperature is tested by a thermal expansion instrument experimental method, or estimated according to the formula Bs (°C) = 830-270C-90Mn-70Cr, wherein the element symbols represent the key percentage values ​​of the corresponding elements.

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