Forging process of non-magnetic steel

Abstract

The invention discloses a forging process of non-magnetic steel, and belongs to the technical field of steel forging, the forging process comprises the following steps: S1, pre-treating the non-magnetic steel; s2, gradient segmented heating and heat preservation are conducted on the pretreated non-magnetic steel, the heating temperature of the first segment ranges from 900 DEG C to 950 DEG C, and the heating temperature of the second segment ranges from 1225 DEG C to 1235 DEG C; s3, the heated non-magnetic steel is subjected to two-pass forging; in the first-pass forging, flat forging is carried out after warm forging, and the forging temperature is controlled to be 850-900 DEG C; air cooling warm forging is adopted for second-pass forging, and the forging temperature is controlled to be 700-750 DEG C; s4, cooling; according to the forging technology, the quality problems of forging spirals, surface cracks, internal defects and the like in the non-magnetic steel forging process are effectively solved, and the subsequent machining and using performance of products is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of steel forging technology, and specifically relates to a forging process for non-magnetic steel. Background Technology

[0002] With the development of technology and the increasing demands of industry, non-magnetic steel materials are being used more and more widely in the field of pressure processing and forging. Non-magnetic steel is mainly used in coal mine drilling technology to prevent the magnetic field generated during high-speed drilling from interfering with measuring equipment. This type of steel is characterized by low carbon, high chromium, high manganese, and high nitrogen. Due to its special steel properties and applications, extremely strict requirements are placed on the material's hardness, toughness, permeability, magnetic gradient, and intergranular corrosion.

[0003] However, existing non-magnetic steel forging processes still have some problems. For example, during the forging process, quality issues such as forging spirals, surface cracks, and internal defects often occur, which seriously affect the subsequent processing and use of the product.

[0004] Furthermore, due to the poor thermoplasticity of non-magnetic steel, cracking is prone to occur during forging, leading to a decline in the mechanical properties of the forgings and making it difficult to meet the final performance requirements. These problems not only reduce production efficiency but also increase the difficulty of subsequent processing, affecting the overall quality of the product.

[0005] Therefore, there is an urgent need to develop a new forging process for non-magnetic steel to solve the problems existing in the current technology. In particular, it is necessary to improve production efficiency while ensuring product quality and to meet the application requirements of non-magnetic steel in special environments. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a forging process for non-magnetic steel, which effectively solves quality issues such as forging spirals, surface cracks, and internal defects during the forging process of non-magnetic steel, and significantly improves the subsequent processing and performance of the product.

[0007] The technical solution adopted by the present invention is as follows:

[0008] This invention provides a forging process for non-magnetic steel, the forging process comprising the following steps:

[0009] S1. Pre-treatment of non-magnetic steel;

[0010] S2. The pretreated non-magnetic steel is subjected to gradient segmented heating and heat preservation. The heating temperature of the first segment is 900-950℃, and the heating temperature of the second segment is 1225-1235℃.

[0011] S3. The heated non-magnetic steel is forged in two passes. The first pass is a flat forging after warm forging, with the forging temperature controlled at 850-900℃. The second pass is an air-cooled warm forging, with the forging temperature controlled at 700-750℃.

[0012] S4, Cooling.

[0013] The non-magnetic steel contains 15% to 21% Mn by mass and 1.5% to 3.5% Ni by mass.

[0014] In step S1, the pretreatment includes cutting, grinding, and pickling the non-magnetic steel in sequence.

[0015] In step S2, the heating rate of the first stage is 80-100℃ / h, and the holding time is 2-2.5h;

[0016] In step S2, the heating rate of the second stage is 140-160℃ / hour, and the holding time is 2-4h.

[0017] In step S3, during the first forging pass, a forging method of clockwise rotation for warm forging and counterclockwise rotation for leveling is adopted.

[0018] In step S3, the forging process uses mold forming.

[0019] In step S3, the cooling method is as follows: first, rotate the forging online and air cool it until the center temperature of the forging drops below 500°C, then stop the rotation and air cool it to room temperature.

[0020] Furthermore, the rotation speed is 10-15 r / min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention effectively solves quality problems such as forging spirals, surface cracks, and internal defects in the forging process of non-magnetic steel by optimizing forging process parameters and mold forming methods, and significantly improves the subsequent processing and performance of the product.

[0023] 2. The present invention adopts a warm forging process, which effectively improves the thermoplasticity of non-magnetic steel, reduces the occurrence of cracking during forging, improves the mechanical properties of forgings, and meets the final performance requirements.

[0024] 3. In the heating process, the present invention performs gradient segmented heating and heat preservation. The first stage heating temperature is 900-950℃ to achieve low-temperature preheating, and the second stage heating temperature is 1225-1235℃ to perform solution treatment on non-magnetic steel. By precisely controlling the temperature and time in the low-temperature preheating and solution treatment processes, the preheating and solution treatment effects are optimized, and the overall quality of the product is improved.

[0025] 4. This invention achieves high performance and high dimensional accuracy of irregular forgings by precisely controlling forging process parameters and using mold forming, thus overcoming the shortcomings of the prior art.

[0026] 5. This invention employs precise cooling process control, combined with warm forging process, to achieve higher product quality and performance levels, effectively improving the overall performance of non-magnetic steel forgings. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the embodiments.

[0028] Example 1

[0029] A forging process for non-magnetic steel, the specific steps of which are as follows:

[0030] S1. Pretreatment of non-magnetic steel: P530 non-magnetic steel with a mass percentage of 18% Mn and 1.6% Ni is cut and ground to a diameter of 250mm and a length of 500mm, which meets the forging requirements; then pickling is performed at room temperature using a 5% hydrochloric acid solution to remove oxide scale.

[0031] S2. The pretreated non-magnetic steel is subjected to gradient segmented heating and heat preservation. The first segment is heated to 920℃ at a heating rate of 80℃ / hour and held for 2 hours; then the temperature is increased to 1230℃ at a heating rate of 150℃ / hour and held for 3 hours.

[0032] S3. The heated non-magnetic steel is forged in two passes. The first pass is a flat forging after warm forging, with the forging temperature controlled at 870℃. The second pass is an air-cooled warm forging, with the forging temperature controlled at 730℃.

[0033] S4. Cooling: An online rotary air cooling process is adopted, with a rotation speed of 10r / min. The temperature of the forging is monitored in real time by a platinum resistance temperature sensor. When the center temperature of the forging drops below 500℃, the rotation is stopped and the forging is air cooled to room temperature.

[0034] Example 2

[0035] A forging process for non-magnetic steel, the specific steps of which are as follows:

[0036] S1. Pretreatment of non-magnetic steel: P550 non-magnetic steel with a mass percentage of 20% Mn and 2% Ni is cut and ground to a diameter of 300mm and a length of 600mm, which meets the forging requirements; then pickling is performed at room temperature using a 10% mass concentration sulfuric acid solution to remove oxide scale.

[0037] S2. The pretreated non-magnetic steel is subjected to gradient segmented heating and heat preservation. The first segment is heated to 930℃ at a heating rate of 80℃ / hour and held for 2 hours; then the temperature is increased to 1225℃ at a heating rate of 150℃ / hour and held for 4 hours.

[0038] S3. The heated non-magnetic steel is forged in two passes. The first pass is a flat forging after warm forging, with the forging temperature controlled at 890℃. The second pass is an air-cooled warm forging, with the forging temperature controlled at 740℃.

[0039] S4. Cooling: An online rotary air cooling process is adopted, with a rotation speed of 10r / min. The temperature of the forging is monitored in real time by a platinum resistance temperature sensor. When the center temperature of the forging drops below 500℃, the rotation is stopped and the forging is air cooled to room temperature.

[0040] Comparative Example 1

[0041] The rest is the same as in Example 1, except that the temperature of the second forging in step S3 is controlled at 800°C.

[0042] Comparative Example 2

[0043] The rest is the same as in Example 2, except that the temperature of the second forging in step S3 is controlled at 800°C.

[0044] The properties of the non-magnetic steels forged in the above embodiments and comparative examples are shown in Table 1.

[0045] Table 1

[0046] Hardness 1 (HBW) Yield strength (MPa) Tensile strength (MPa) Elongation (%) Example 1 360 880 1080 32 Example 2 405 920 1160 31 Comparative Example 1 280 830 980 38 Comparative Example 2 320 850 1050 36

[0047] As can be seen from Table 1, the non-magnetic steel parts forged using the forging process provided by this invention have good performance.

[0048] No cracking occurred during the forging process of the above embodiments, and there were no quality problems such as forging spirals, surface cracks and internal defects. This achieved high performance and high dimensional accuracy of the irregular forgings and improved the overall quality of the products.

[0049] In Comparative Example 1, the high temperature of the final molding pass resulted in lower surface hardness, lower strength, and higher plasticity compared to Example 1. In Comparative Example 2, the high temperature of the final molding pass resulted in lower surface hardness, lower strength, and higher plasticity in the finished product compared to Example 1.

[0050] The above detailed description of a forging process for non-magnetic steel with reference to the embodiments is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications that do not depart from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A forging process for non-magnetic steel, characterized in that, The forging process includes the following steps: S1. Pre-treatment of non-magnetic steel; S2. The pretreated non-magnetic steel is subjected to gradient segmented heating and heat preservation. The heating temperature of the first segment is 900-950℃, and the heating temperature of the second segment is 1225-1235℃. S3. The heated non-magnetic steel is forged in two passes. The first pass is a flat forging after warm forging, with the forging temperature controlled at 850-900℃. The second pass is an air-cooled warm forging, with the forging temperature controlled at 700-750℃. S4, Cooling.

2. The forging process for non-magnetic steel according to claim 1, characterized in that, The non-magnetic steel contains 15% to 21% Mn by mass and 1.5% to 3.5% Ni by mass.

3. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S1, the pretreatment includes cutting, grinding, and pickling the non-magnetic steel in sequence.

4. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S2, the first stage heating rate is 80-100℃ / h, and the holding time is 2-2.5h.

5. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S2, the second stage heating rate is 140-160℃ / h, and the holding time is 2-4h.

6. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S3, during the first forging pass, a forging method of clockwise rotation for warm forging and counterclockwise rotation for leveling is adopted.

7. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S3, the forging process uses mold forming.

8. The forging process for non-magnetic steel according to claim 1 or 2, characterized in that, In step S3, the cooling method is as follows: first, rotate the forging online and air cool it until the center temperature of the forging drops below 500°C, then stop the rotation and air cool it to room temperature.

9. The forging process for non-magnetic steel according to claim 8, characterized in that, The rotation speed is 10-15 r / min.