A production method of high-carbon martensite 60cr13mo stainless steel wire rod

Abstract

The present application relates to a kind of high carbon martensite 60Cr13Mo stainless steel wire rod production method.Steel billet is heated at 1200~1260 ℃.Two-roll reversible breakdown mill rolling, breakdown temperature 1100~1200 ℃, wire drawing temperature 1000~1100 ℃, after being transported to coiling drum by controlled cooling roller way, it is coiled and then enters tunnel insulation furnace, insulation furnace temperature 740-780 ℃, after 2-4h, it is discharged and air cooled to below 100 ℃.Heat treatment is according to the heating rate of 50~100 ℃ / h, the coil is heated to 840-880 ℃, and is kept for 11-13h, then it is cooled to below 450 ℃ with furnace at ≤15 ℃ / h, and is discharged and air cooled to room temperature.In the process of heating, keeping and cooling, nitrogen is passed through above 500 ℃ to avoid decarburization defect of wire rod at high temperature.Acid is hydrochloric acid (10~20%) and hydrofluoric acid (3~5%), special corrosion inhibitor is added, acid temperature is 60-80 ℃, and pickling time is 50-60min.The high carbon martensite 60Cr13Mo stainless steel wire rod obtained by this method has uniform metallographic structure, and the mechanical properties and pickling surface quality meet the use requirements.

Description

Technical Field

[0001] This invention relates to a method for producing high-carbon martensitic 60Cr13Mo stainless steel wire rod. Specifically, it involves using a 60Cr13Mo stainless steel billet with a certain chemical composition, through reasonable heating, temperature-controlled rolling, and heat treatment processes, to eliminate the brittleness characteristic of martensitic stainless steel and avoid the formation of undesirable structures during hot working, thereby obtaining high-carbon martensitic 60Cr13Mo stainless steel wire rod with good structure and mechanical properties. Background Technology

[0002] 60Cr13Mo is a high-carbon, high-strength martensitic stainless steel characterized by high strength, hardness, and corrosion resistance. It is used to produce high-strength, wear-resistant, and corrosion-resistant shafts and automotive engine parts. This product is difficult to manufacture; however, by employing a reasonable heating, rolling, and heat treatment process, the plasticity of the wire rod can be improved, reducing deformation resistance and facilitating processing.

[0003] To address the above problems, this invention provides a production method for high-carbon martensitic 60Cr13Mo stainless steel wire rods, thereby solving the aforementioned problems and obtaining 60Cr13Mo stainless steel wire rod products with good microstructure and mechanical properties.

[0004] This invention discloses a method for producing high-carbon martensitic 60Cr13Mo stainless steel wire rod, applicable to the rolling, heat treatment and pickling of 60Cr13Mo stainless steel wire rod.

[0005] This invention can avoid the formation of undesirable microstructures in high-carbon martensitic 60Cr13Mo stainless steel wire rods during hot working, thereby enabling the wire rods to obtain good heat-treated microstructures and mechanical properties. Summary of the Invention

[0006] The purpose of this invention is to address the above-mentioned problems by providing a method for producing high-carbon martensitic 60Cr13Mo stainless steel wire rod.

[0007] The objective of this invention is achieved as follows: A method for producing high-carbon martensitic 60Cr13Mo stainless steel wire rod, comprising the following steps: Step 1: Using a die-cast billet or a continuously cast billet, the billet cross-sectional dimensions are (180-220) × (180-220) mm, and the billet weight is 1150-1250 kg; Step 2: Billet heating: The billet is heated in a walking beam furnace, with the first heating stage at 900-1100℃, the second heating stage at 1220-1260℃, and the soaking stage at 1200-1240℃; Step 3: Wire rod rolling: Using a two-roll reversible billet mill, rolling 9 or 11 passes at an initial rolling temperature of 1100-1200℃ to produce Φ85±2mm round bars, which are then rolled in a high-speed wire rod continuous rolling mill for 26-28 passes to produce a finished product of Φ 5.5-6.5mm wire rod, with a coiling temperature of 1000-1100℃, is transported to the coiling drum via a controlled cooling roller conveyor and then entered into a tunnel heat treatment furnace at a temperature of 740-780℃ for 2-4 hours. After heat treatment, the coil is removed from the furnace and air-cooled to below 100℃. Step 4: Wire rod heat treatment: The packaged 60Cr13Mo stainless steel wire rod is loaded into a heat treatment furnace and heated to 840-880℃ at a heating rate of 50-100℃ / h. It is held for 11-13 hours and then cooled in the furnace at a cooling rate of ≤15℃ / h to below 450℃ before being air-cooled to room temperature. Step 5: Pickling: The acid solution consists of 10-20% hydrochloric acid and 3-5% hydrofluoric acid. The acid temperature is 60-80℃, and the pickling time is 50-60 minutes. After pickling, the coil is rinsed clean, dried, and then packaged.

[0008] During the heating, holding, and cooling processes in step four, nitrogen gas is introduced throughout the process above 500℃ to protect the wire rod from decarburization defects at high temperatures.

[0009] The chemical composition (mass fraction) of the high-carbon martensitic 60Cr13Mo stainless steel wire rod applicable to this method is as follows: C: 0.56-0.65%, Si: 0.25-0.50%, Mn: 0.25-0.50%, P≤0.035%, S≤0.015%, Cr: 13.0-14.0%, Ni≤0.60%, Mo: 0.25-0.60%, Cu≤0.25%.

[0010] The beneficial effects of this invention are: this method can avoid the formation of undesirable structures in high-carbon martensitic 60Cr13Mo stainless steel wire rods during hot working, enabling the wire rods to obtain good structure and mechanical properties, meeting the requirements for use in high-strength, wear-resistant, and corrosion-resistant shafts and automotive engine parts. Detailed Implementation

[0011] The technical solution of this invention is as follows: 1. The chemical composition range of the high-carbon martensitic 60Cr13Mo stainless steel wire rod to which this invention is applicable is shown in the table below.

[0012]

[0013] The billet has a cross-sectional size of (180~220)×(180~220)mm, a weight of 1150~1250kg, and no defects on its surface that would affect its use in wire rod processing.

[0014] 3. Walking beam furnace: Heating stage 1 temperature 900~1100℃, heating stage 2 temperature 1220~1260℃, soaking stage temperature 1200~1240℃.

[0015] 4. Wire rod rolling: Using a two-roll reversible billet mill, 9 or 11 passes are rolled at an initial rolling temperature of 1100-1200℃ to produce Φ85±2mm round steel. Then, it enters a high-speed wire rod mill for 26-28 passes to produce Φ5.5-6.5mm wire rod at a wire drawing temperature of 1000-1100℃. After being transported to the coiling drum via a controlled cooling roller conveyor, it enters a tunnel holding furnace at a holding temperature of 740-780℃ for 2-4 hours before being air-cooled to below 100℃.

[0016] 5. Wire Rod Heat Treatment: The packaged 60Cr13Mo stainless steel wire rods are loaded into a heat treatment furnace and heated to 840-880℃ at a heating rate of 50-100℃ / h. The temperature is held for 11-13 hours, then cooled in the furnace to below 450℃ at a cooling rate of ≤15℃ / h before being air-cooled to room temperature. During the heating, holding, and cooling processes, nitrogen gas is used for protection above 500℃ to prevent decarburization defects in the wire rods at high temperatures.

[0017] 6. Prepare the acid solution with hydrochloric acid (10-20%) and hydrofluoric acid (3-5%), add a special corrosion inhibitor, the acid temperature is 60-80℃, the pickling time is 50-60 minutes, rinse thoroughly after pickling, and package after drying. Example 1

[0018] This embodiment describes a method for producing 60Cr13Mo stainless steel wire rod with a diameter of 5.5mm.

[0019] The chemical composition is shown in the table below.

[0020]

[0021] 2. Billet preparation: Continuous casting billet, billet cross-section size 220×220mm, billet weight 1200kg.

[0022] 3. Billet heating: Walking beam furnace, heating stage 1 temperature 1050℃, heating stage 2 temperature 1248℃, soaking stage temperature 1235℃.

[0023] 4. Wire rod rolling: Using a two-roll reversible billet mill, 11 passes are rolled at an initial rolling temperature of 1185℃ to produce Φ85.4mm round steel. Then, it enters a high-speed wire rod mill for 28 passes to produce Φ5.5mm wire rod at a wire drawing temperature of 1088℃. After being transported to the coiling drum via a controlled cooling roller conveyor, it is placed in a tunnel holding furnace at a temperature of 760℃ for 3 hours. After holding at this temperature, it is air-cooled to 80℃.

[0024] 5. Wire Rod Heat Treatment: The packaged 60Cr13Mo stainless steel wire rods are loaded into a heat treatment furnace and heated to 850℃ at a heating rate of 75℃ / h. The temperature is held for 12 hours, then cooled in the furnace to 405℃ at a cooling rate of 10℃ / h before being air-cooled to room temperature. During the heating, holding, and cooling processes, nitrogen gas is used for protection above 500℃ to prevent decarburization defects in the wire rods at high temperatures.

[0025] 6. The acid solution is made of hydrochloric acid (15%) and hydrofluoric acid (4%). Add a special corrosion inhibitor. The acid temperature is 70℃ and the pickling time is 55 minutes. After pickling, rinse thoroughly, air dry, and then package.

[0026] 7. Wire Rod Quality: The 60Cr13Mo stainless steel wire rod treated with the above heat treatment process has a uniform metallographic structure and a grain size of grade 9. The tensile strength meets the requirement of 650-760 MPa, the reduction of area meets the requirement of ≥45%, and the decarburized layer depth meets the requirement of ≤0.05 mm.

[0027]

[0028] Example 2 This embodiment describes a method for producing 60Cr13Mo stainless steel wire rod with a diameter of 6.5mm.

[0029] 1. The chemical composition is shown in the table below.

[0030]

[0031] 2. Billet preparation: Continuous casting billet, billet cross-section size 220×220mm, billet weight 1190kg.

[0032] 3. Billet heating: Walking beam furnace, heating stage 1 temperature 1045℃, heating stage 2 temperature 1252℃, soaking stage temperature 1233℃.

[0033] 4. Wire rod rolling: A two-roll reversible billet mill is used to roll 9 passes at an initial rolling temperature of 1180℃ to produce Φ85.7mm round steel. Then, it enters a high-speed wire rod mill for 26 passes to produce Φ6.5mm wire rod at a wire drawing temperature of 1085℃. After being transported to the coiling drum via a controlled cooling roller conveyor, it is placed in a tunnel holding furnace at 765℃ for 2.5 hours before being air-cooled to 85℃.

[0034] 5. Wire Rod Heat Treatment: The packaged 60Cr13Mo stainless steel wire rods are loaded into a heat treatment furnace and heated to 855℃ at a heating rate of 70℃ / h. The temperature is held for 13 hours, then cooled in the furnace to 398℃ at a cooling rate of 12℃ / h before being air-cooled to room temperature. During the heating, holding, and cooling processes, nitrogen gas is used for protection above 500℃ to prevent decarburization defects in the wire rods at high temperatures.

[0035] 6. The acid solution is prepared with sulfuric acid and hydrochloric acid (16%) and hydrofluoric acid (3.5%), with the addition of a special corrosion inhibitor. The acid temperature is 70℃, the pickling time is 50 minutes, and after pickling, rinse thoroughly, air dry, and then package.

[0036] 7. Wire Rod Quality: The 60Cr13Mo stainless steel wire rod treated with the above heat treatment process has a uniform metallographic structure and a grain size of grade 9. The tensile strength meets the requirement of 650-760 MPa, the reduction of area meets the requirement of ≥45%, and the decarburized layer depth meets the requirement of ≤0.05 mm.

[0037]

[0038] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for producing high-carbon martensitic 60Cr13Mo stainless steel wire rod, characterized in that: Includes the following steps: Step 1: Use ingot casting billets or continuous casting billets. The cross-sectional dimensions of the billets are (180-220) × (180-220) mm, and the weight of the billets is 1150-1250 kg. Step 2: Billet heating: The steel billet is heated in a walking beam furnace. The first heating stage is 900-1100℃, the second heating stage is 1220-1260℃, and the soaking stage is 1200-1240℃. Step 3: Wire rod rolling: Using a two-roll reversible billet mill, roll 9 or 11 passes at an initial rolling temperature of 1100-1200℃ to produce Φ85±2mm round steel. Then, it enters a high-speed wire rod mill for 26-28 passes to produce Φ5.5-6.5mm wire rod at a wire drawing temperature of 1000-1100℃. After being transported to the coiling drum via a controlled cooling roller conveyor, it enters a tunnel holding furnace at a temperature of 740-780℃ and is held for 2-4 hours before being air-cooled to below 100℃. Step 4: Wire rod heat treatment: The packaged 60Cr13Mo stainless steel wire rods are loaded into the heat treatment furnace and heated to 840-880℃ at a heating rate of 50-100℃ / h. The temperature is held for 11-13h, and then cooled to below 450℃ with the furnace at a cooling rate of ≤15℃ / h. The wire rods are then removed from the furnace and air-cooled to room temperature. Step 5: Pickling: Prepare the acid solution with 10-20% hydrochloric acid and 3-5% hydrofluoric acid. The acid temperature should be 60-80℃, and the pickling time should be 50-60 minutes. After pickling, rinse thoroughly, air dry, and then package. During the heating, holding, and cooling processes in step four, nitrogen gas is introduced throughout the process above 500℃ to protect the wire rod from decarburization defects at high temperatures. The chemical composition (mass fraction) of the high-carbon martensitic 60Cr13Mo stainless steel wire rod applicable to this method is as follows: C: 0.56-0.65%, Si: 0.25-0.50%, Mn: 0.25-0.50%, P≤0.035%, S≤0.015%, Cr: 13.0-14.0%, Ni≤0.60%, Mo: 0.25-0.60%, Cu≤0.25%.

Images