Heat treatment process for G35 material penetration type shell

Abstract

The invention relates to a heat treatment technology, and discloses a heat treatment process for a G35 material penetration type shell so as to improve the qualification rate. The process comprises the following steps: S1, quenching treatment: firstly raising the temperature of the furnace to 870-920 DEG C, stabilizing, putting a workpiece into the furnace, and preserving heat for 1 hour after the workpiece is thoroughly heated; then putting the workpiece into an oil pool with the initial oil temperature of 25-30 DEG C by adopting a heat preservation device, withdrawing the heat preservation device, shaking the workpiece, starting an oil pool cooling system, and keeping the oil temperature in a range of 40-55 DEG C; after discharging from the oil pool, water-cooling for 1-2 hours; and S2, tempering treatment is conducted, specifically, the workpiece is fed into a furnace, the temperature is increased to 200-260 DEG C, heat preservation is conducted for 2-4 hours, and after the workpiece is discharged out of the furnace and air-cooled to the room temperature, water cooling is conducted for 1-2 hours.

Description

Technical Field

[0001] The present invention relates to the field of heat treatment technology, and in particular to a heat treatment process for a G35 material penetration-type shell. Background Art

[0002] During the penetration process, the shell needs to withstand large deflection moments, asymmetric loads, and high overload impacts that pose a great threat to the overall structural strength of the shell. Therefore, the shell material is required to have excellent mechanical properties such as high strength and high toughness.

[0003] Among them, G35 material is widely used in various fields with excellent comprehensive performance and good economy. G35 material adds Ni, Mo and other trace elements on the basis of 35CrMnSiA steel (GB / T3077-2015). As a high-strength material, it not only has high tensile strength and yield strength after heat treatment, but also can better ensure the impact toughness of the material, so that it has more superior plastic deformation under high overload impact conditions. Taking weight content percentage as an indicator, its chemical composition includes:

[0004] C: 0.32~0.35%; Si: 1.10~1.40%; Mn: 0.80~1.10%; S: ≤0.005%; P: ≤0.020%; Cr: 1.10~1.4%; Ni: ≤0.30%; Mo: ≤0.10%; Cu: ≤0.20%.

[0005] The shell needs to be able to resist high overload during use. Therefore, according to calculations, the mechanical properties of the shell material should meet the following requirements: tensile strength Rm ≥ 1700MPa, elongation A ≥ 9%, and impact energy KU2 ≥ 50J.

[0006] At present, G35 materials can usually be purchased from the Iron and Steel Research Institute. Traditional heat treatment methods, such as Figure 1 As shown, the heat treatment system of 35CrMnSiA steel recommended in GB / T3077-2015 is generally carried out, specifically:

[0007] 1. First quenching treatment: heat to 950℃, keep warm for 1h after heating through, and oil quench.

[0008] 2. First tempering treatment: heat to 230℃, keep warm for 2h after heating through, and air cool.

[0009] 3. Second quenching treatment: heat to 890℃, keep warm for 1h after heating through, and oil quench.

[0010] 4. Second tempering treatment: heat to 230℃, keep warm for 2h after heating through, and air cool.

[0011] However, according to the above heat treatment process, after heat treatment of multiple batches of products, the impact energy of the products is generally less than 50J, and the qualified rate is less than 40%. Obviously, the process method recommended by GB / T3077-2015 cannot be applied to the actual production situation of the factory. It is urgent to invent a heat treatment process method for G35 material penetration shells that is suitable for the factory, simple and practical, and has a high qualified rate. Summary of the invention

[0012] The present invention aims to disclose a G35 material penetration shell heat treatment process to improve the qualification rate.

[0013] To achieve the above purpose, the G35 material penetration shell heat treatment process disclosed in the present invention includes:

[0014] Step S1, quenching treatment: first raise the furnace temperature to 870℃~920℃ and stabilize it, then put the workpiece into the furnace, and keep it warm for 1 hour after it is heated through; then use a heat preservation device to put the workpiece into an oil pool with an initial oil temperature of 25℃~30℃, exit the heat preservation device, shake the workpiece and turn on the oil pool cooling system to keep the oil temperature within the range of 40℃~55℃; after leaving the oil pool, water cool for 1 hour to 2 hours.

[0015] Step S2, tempering treatment: the workpiece is put into the furnace, heated to 200°C-260°C, kept at this temperature for 2-4 hours, air-cooled to room temperature after being taken out of the furnace, and then water-cooled for 1-2 hours.

[0016] Preferably, the housing of the present invention adopts a deep blind hole structure.

[0017] The present invention adds a heat preservation device during the quenching process, adds a cooling system during the oil cooling process, and adds a water cooling process after the oil cooling during the quenching process; it has the following beneficial effects:

[0018] 1) The process method of one-time quenching and tempering is adopted to simplify the process.

[0019] 2) Within the specified range of some parameters, the qualified rate of mechanical properties of this process can reach 100% (qualified standards are: tensile strength Rm ≥ 1700MPa, elongation A ≥ 9%, impact energy KU2 ≥ 50J). Therefore, during the implementation process, the temperature range and time range in the above process can be taken as the median, so as to appropriately reduce the stringency requirements for the production environment.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 It is a schematic diagram of the existing G35 material penetration shell heat treatment process.

[0023] Figure 2 It is a schematic diagram of the heat treatment process of the G35 material penetration-type shell disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0025] The present invention discloses a G35 material penetration shell heat treatment process, such as Figure 2 As shown, including:

[0026] Quenching treatment: first raise the furnace temperature to 870℃~920℃ and stabilize it, then put the workpiece into the furnace, and keep it warm for 1 hour after it is heated through; then use the insulation device to put the workpiece into the oil pool with an initial oil temperature of 25℃~30℃, exit the insulation device, shake the workpiece and turn on the oil pool cooling system to keep the oil temperature within the range of 40℃~55℃; after leaving the oil pool, water cool for 1 hour to 2 hours.

[0027] The water cooling environment can be a water pool at room temperature. The heat penetration standard varies according to the different structures and sizes of the shell. The present invention is particularly suitable for deep blind hole structures.

[0028] Tempering treatment: The workpiece is put into the furnace, heated to 200℃~260℃, kept warm for 2 hours to 4 hours, and then air-cooled to room temperature after being taken out of the furnace, and then water-cooled for 1 hour to 2 hours.

[0029] Based on the above process, the present invention conducts relevant experiments by selecting the following four G35 materials shown in label 1:

[0030] Table 1

[0031] C Si Mn S P Cr Ni Mo Cu Material 1 0.32 1.32 1.01 0.001 0.008 1.28 0.26 0.10 0.03 Material 2 0.33 1.31 1.01 0.001 0.009 1.28 0.26 0.10 0.03 Material 3 0.32 1.31 1.01 0.001 0.008 1.28 0.26 0.10 0.03 Material 4 0.32 1.33 1.03 0.001 0.008 1.28 0.26 0.09 0.02

[0032] The experimental data obtained for the shell of the same structure and size prepared by the above-mentioned material based on the same production process based on the traditional method, the method of the present invention and the process method outside the parameters of the present invention are shown in Table 2.

[0033] Table 2

[0034]

[0035]

[0036] In Table 2, the description of "taking the minimum, maximum or median value of the parameter" means uniformly taking the corresponding minimum, maximum or median value of the parameter within the time and temperature range, and the so-called median value is the mean between the minimum and maximum values.

[0037] Thus, based on the qualified standards of tensile strength Rm≥1700MPa, elongation A≥9%, and impact energy KU2≥50J; referring to Table 2, the qualified rate of mechanical properties of the prepared products after heat treatment in the embodiments of the present invention is significantly better than that of heat-treated products using the traditional method and similar processes of the present invention but with parameters not within the scope of the present invention.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A G35 material penetration shell heat treatment process, characterized in that: include: Step S1, quenching treatment: first raise the furnace temperature to 870℃~920℃ and stabilize it, then put the workpiece into the furnace, heat it thoroughly and keep it warm for 1 hour; then use the insulation device to put the workpiece into the oil pool with an initial oil temperature of 25℃~30℃, exit the insulation device, shake the workpiece and turn on the oil pool cooling system to keep the oil temperature within the range of 40℃~55℃; after leaving the oil pool, water cool it for 1 hour~2 hours; Step S2, tempering treatment: the workpiece is put into the furnace, heated to 200°C-260°C, kept at this temperature for 2-4 hours, air-cooled to room temperature after being taken out of the furnace, and then water-cooled for 1-2 hours.

2. The process according to claim 1, characterized in that Take the median value for the temperature and time parameters within the range.

3. The process according to claim 1 or 2, characterized in that The shell is a deep blind hole structure.

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