Forging forming method of high-manganese high-chromium high-nitrogen austenitic steel

Abstract

The invention provides a forging forming method of high-manganese, high-chromium and high-nitrogen austenitic steel, which is used for producing high-quality forgings by changing a material deformation mode and controlling a metal plastic deformation process by utilizing a press and a radial precision forging machine. The forging forming method comprises the following steps: 1) heating; (2) rolling; (3) upsetting; (4) drawing out; 5) heating; (6) precision forging forming; according to the method, the technological process is not complex, slow upsetting is carried out after full-body rounding, plastic deformation can be improved, the cracking risk can be reduced, the defects that in the upsetting process, the core of the blank is rapidly heated, the as-cast structure of the original blank is fully broken, welding air holes, looseness and other original structures are fully broken can be avoided, drawing-out is carried out through an LZ forging method, and the yield is high. And the compaction effect is guaranteed, the forge piece has good forging permeability, and material deviation is effectively prevented. In addition, a temperature control and forging control technology is adopted during precision forging forming, so that a uniform structure and fine grain size are obtained on the premise of ensuring the compaction effect, and the material performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal plastic forming and relates to a forging forming method of high-manganese, high-chromium and high-nitrogen austenitic steel. Background Art

[0002] High manganese, high chromium, and high nitrogen austenitic steel is a type of steel developed through microalloying on the basis of high manganese steel. It has good wear resistance, toughness, low temperature resistance, corrosion resistance, and non-magnetic properties, and has been widely used in shipbuilding, construction, transportation, electrical, machinery and other industries.

[0003] Because this type of steel is difficult to heat process, forging is extremely difficult and it is easy to crack during forging. At present, most high-manganese, high-chromium, high-nitrogen austenitic steels are still mainly cast. In recent years, with the continuous improvement of my country's steel manufacturing technology level and the gradual transformation and upgrading to high-end, in order to improve the internal organization, improve product quality and service life, a forging method suitable for industrial production is urgently needed. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a forging method for high manganese, high chromium, high nitrogen austenitic steel by using a press and a radial precision forging machine to change the material deformation mode and control the metal plastic deformation process to produce high-quality forgings.

[0005] The technical solution of the present invention is achieved as follows: a forging method for high manganese, high chromium and high nitrogen austenitic steel, the forging comprising the following steps: Step 1), heating: the blank is loaded into a heating furnace, and the temperature is raised to 1000℃~1200℃ through a three-stage heating method, and the holding time is not less than 8 hours to achieve plastic forging; Step 2), rolling: Roll the whole body into a round shape, pressing down 10 to 60 mm; Step 3), upsetting: Slowly upsetting with the ingot guard on the press to ensure that the height-to-diameter ratio after upsetting is between 0.68 and 0.85, and the upsetting coefficient does not exceed 2.5. In addition, pause for a few seconds during the upsetting process; Step 4) Lengthening: Square the upper and lower flat anvils, turn them into eight sides, and keep the reduction rate between 10% and 20%. Control the anvil width ratio between 0.7 and 0.95, and the material width ratio between 0.70 and 1.2. Remove the ingot guard plate and level the end surface of the ingot tail. Step 5), heating: return to the heating furnace, the furnace temperature is 950℃~1050℃, and the insulation time is 1~3 hours; Step 6), fine forging: Use a radial fine forging machine with a rectangular hammer head forging, control the hammer amount per pass to not exceed 70mm, and the finishing pass pulling speed does not exceed 3m / min. Water spraying is prohibited during the whole forging process. The last two passes are left with a width and height of 3-10mm for finishing; Step 7), air cooling: After air cooling to room temperature, the high manganese, high chromium and high nitrogen austenitic steel forging process is completed.

[0006] The blank of the high manganese, high chromium and high nitrogen austenitic steel is an electroslag ingot.

[0007] The forged product of the high manganese, high chromium and high nitrogen austenitic steel is a square piece.

[0008] The process of blanking high manganese, high chromium and high nitrogen austenitic steel press is divided into three steps: first, the whole body is rounded, then it is upset with the ingot guard plate, and finally it is stretched.

[0009] The LZ forging method is used in the drawing process of high manganese, high chromium and high nitrogen austenitic steel press. The drawing is carried out on upper and lower flat anvils. The reduction rate is 10% to 20%, the anvil width ratio is controlled in the range of 0.7 to 0.95, and the material width ratio is controlled in the range of 0.70 to 1.2.

[0010] In step 6), the initial forging temperature of the high manganese, high chromium and high nitrogen austenitic steel during the precision forging stage is 1050-900°C, and the final forging temperature is not less than 800°C.

[0011] In step 6), a special rectangular hammer is used for precision forging of high manganese, high chromium and high nitrogen austenitic steel. Water spraying is prohibited during the entire forging process. There are two finishing passes at the end of the forming. In the first finishing pass, 3 to 10 mm is left on the wide and narrow surfaces for finishing; the second pass is no finishing.

[0012] The positive effects of the present invention are as follows: the process flow of the present invention is not complicated, and by rolling the whole body and then slowly upsetting, it can not only improve plastic deformation and reduce the risk of cracking, but also avoid rapid heating of the core of the blank during the upsetting process, fully break the cast structure of the original blank, weld the original structural defects such as pores and looseness, and stretch by LZ forging method to ensure the compaction effect, so that the forging has good forging permeability and effectively prevents material deviation. In addition, by adopting temperature control and forging technology during precision forging, uniform structure and fine grain size are obtained under the premise of ensuring compaction effect, thereby improving material performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the finished forging product of high manganese, high chromium and high nitrogen austenitic steel forgings.

[0014] 1. M2 manipulator; 2. Square forgings; 3. Rectangular special hammer head for radial precision forging machine; 4. M1 manipulator. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is described below with specific embodiments: Example 1: The weight of the electroslag ingot used in this example is 2.6 tons, the material is 70Mn18Cr7N, and the forging operation process of high manganese, high chromium and high nitrogen austenitic steel is as follows: Step 1) Heating: Load the electroslag ingot into a heating furnace, and heat it to 1180°C through a three-stage heating method, and keep it warm for 10 hours to achieve plastic forging; Step 2), rolling: Roll the whole body into a round shape, pressing down 10 to 60 mm; Step 3), upsetting: Upsetting: Slowly upsetting with the ingot guard on the press, upsetting to a height of 650mm (diameter Φ810mm), pausing for 6 seconds during the upsetting process; Step 4) Lengthening: Lengthen the steel to 380mm on the upper and lower flat anvils by LZ forging method, control the reduction rate at 10% to 20%, the anvil width ratio at 0.7 to 0.95, the material width ratio at 0.70 to 1.2, and heat the steel to 400mm; remove the ingot guard plate and level the end face of the ingot tail; Step 5), heating: return to the heating furnace, furnace temperature 1000 ℃, insulation time 3 hours; Step 6), precision forging: water spraying is prohibited throughout the process, and the rectangular special hammer head 3 of the radial precision forging machine is used to forge the finished product into a square forging 2 213×315mm. During the forging process of the precision forging machine, the hammer amount per pass is controlled to be no more than 70mm, and the pulling speed of the finishing pass is no more than 3m / min; 1 is the M2 manipulator, and 4 is the M1 manipulator; the initial forging temperature of the precision forging stage of high manganese, high chromium, and high nitrogen austenitic steel is 1050~900℃, and the final forging temperature is not less than 800℃; A rectangular special hammer is used for precision forging of high manganese, high chromium and high nitrogen austenitic steel. Water spraying is prohibited during the entire forging process. There are two finishing passes at the end of the forming process. In the first finishing pass, 3 to 10 mm is left on the wide and narrow sides for finishing; the second pass is no amount of finishing. Step 7), air cooling: After air cooling to room temperature, the high manganese, high chromium and high nitrogen austenitic steel forging process is completed.

Claims

1. A forging method for high manganese, high chromium and high nitrogen austenitic steel, characterized in that: Forging includes the following steps: Step 1), heating: the blank is loaded into a heating furnace, and the temperature is raised to 1000℃~1200℃ through a three-stage heating method, and the holding time is not less than 8 hours to achieve plastic forging; Step 2), rolling: Roll the whole body into a round shape, pressing down 10 to 60 mm; Step 3), upsetting: slowly upsetting with the ingot guard plate on the press, ensuring that the height-to-diameter ratio after upsetting is between 0.68 and 0.85, and the upsetting coefficient does not exceed 2.5, and pausing in the middle of the upsetting process; Step 4) Lengthening: Square the upper and lower flat anvils, turn them into eight sides, and keep the reduction rate between 10% and 20%. Control the anvil width ratio between 0.7 and 0.95, and the material width ratio between 0.70 and 1.

2. Remove the ingot guard plate and level the end surface of the ingot tail. Step 5), heating: return to the heating furnace, the furnace temperature is 950℃~1050℃, and the insulation time is 1~3 hours; Step 6), fine forging: Use a radial fine forging machine with a rectangular hammer head forging. When forging with the fine forging machine, control the hammer drop per pass to not exceed 70mm, and the finishing pass pulling speed to not exceed 3m / min. Water spraying is prohibited during the whole forging process. The last two passes are left with a width and height of 3-10mm for finishing; Step 7), air cooling: After air cooling to room temperature, the high manganese, high chromium and high nitrogen austenitic steel forging process is completed.

2. The forging method of a high manganese, high chromium, high nitrogen austenitic steel according to claim 1, characterized in that: The blank of the high manganese, high chromium and high nitrogen austenitic steel is an electroslag ingot.

3. The forging method of a high manganese, high chromium and high nitrogen austenitic steel according to claim 1, characterized in that: The forged product of the high manganese, high chromium and high nitrogen austenitic steel is a square piece.

4. The forging method of a high manganese, high chromium and high nitrogen austenitic steel according to claim 1, characterized in that: The process of blanking high manganese, high chromium and high nitrogen austenitic steel press is divided into three steps: first, the whole body is rounded, then it is upset with the ingot guard plate, and finally it is stretched.

5. The forging method of high manganese, high chromium and high nitrogen austenitic steel according to claim 1, characterized in that: The LZ forging method is used in the drawing process of high manganese, high chromium and high nitrogen austenitic steel press. The drawing is carried out on upper and lower flat anvils. The reduction rate is 10% to 20%, the anvil width ratio is controlled in the range of 0.7 to 0.95, and the material width ratio is controlled in the range of 0.70 to 1.

2.

6. The forging method of high manganese, high chromium and high nitrogen austenitic steel according to claim 1, characterized in that: In step 6), the initial forging temperature of the high manganese, high chromium and high nitrogen austenitic steel during the precision forging stage is 1050-900°C, and the final forging temperature is not less than 800°C.

7. The forging method of high manganese, high chromium and high nitrogen austenitic steel according to claim 1, characterized in that: In step 6), a special rectangular hammer is used for precision forging of high manganese, high chromium and high nitrogen austenitic steel. Water spraying is prohibited during the entire forging process. There are two finishing passes at the end of the forming. In the first finishing pass, 3 to 10 mm is left on the wide and narrow surfaces for finishing; the second pass is no finishing.

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