Method for controlling the depth of the induction hardened layer of a crankshaft

Abstract

The application provides a control method for the depth of a hardened layer of a crankshaft inductive quenching, and three measures are implemented: measure one, checking and cleaning the appearance quality defects of the journal before inductive quenching; measure two, calibrating and adjusting the size of the quenching inductor; and measure three, energy monitoring during quenching. The three measures are implemented in cooperation, so that the consistency and stability of the depth of the hardened layer of the journal after quenching using the same inductor can be effectively ensured.

Description

Technical Field

[0001] This invention belongs to the technical field of surface hardening layers of metallic materials, and in particular relates to a method for controlling the depth of the induction hardening layer of a crankshaft. Background Technology

[0002] High-power, high-load crankshafts endure complex alternating loads during operation. The entire shaft undergoes induction hardening of the journal surfaces to achieve excellent fatigue resistance and high wear resistance. Existing technical solutions involve adjusting process parameters such as heating voltage, heating time, and liquid cooling time for induction hardening of the main journal and connecting rod journals according to the journal hardening layer requirements. The hardened layer results are then verified through destructive dissection, followed by further adjustments based on the dissected hardened layer results. This iterative process of adjusting process parameters and dissecting to test the hardened layer results is used to finally determine the induction hardening process parameters that meet the technical requirements for the hardened layer of the crankshaft's main journal and connecting rod journals. This method is cumbersome and fails to consider the deformation that occurs during crankshaft induction hardening, causing changes in the dimensions of the effective heating area of ​​the crankshaft inductor. Even with the same electrical parameters, the induction hardening depth of the journals can vary significantly. The journal requires a hardened layer depth of [missing information]. However, after batch quenching of journals using the above method, the depth of the hardened layer of the journals will vary, with depths of 2.8mm, 3mm, and 3.5mm. In addition, iron filings remaining after machining on the crankshaft journals can also cause arcing during the induction heating process, resulting in unstable induction heating current and thus affecting the stability of the depth of the induction hardened layer of the journals. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention provides the following technical solution:

[0004] A method for controlling the depth of the induction hardened layer in a crankshaft includes the following measures:

[0005] Measure 1: Before induction hardening, inspect and clean the journal to eliminate any surface quality defects.

[0006] Measure 2: Calibrate and adjust the dimensions of the quenching inductor:

[0007] First, establish the standard quenching inductors corresponding to the main journal and connecting rod journal respectively: After induction quenching the crankshaft main journal and connecting rod journal with multiple quenching inductors of different sizes, determine the standard quenching inductor corresponding to the qualified hardened layer depth of the main journal and connecting rod journal after induction quenching by dissecting the journal sample.

[0008] Then, the corresponding standard distances of each effective heating coil of the standard hardening inductor corresponding to the main journal and connecting rod journal are determined, including:

[0009] The standard distance of the first distance (L1); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference is defined as the first distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference is the standard distance of the first distance.

[0010] The standard distance of the second distance (L2); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is defined as the second distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is established as the standard distance of the second distance.

[0011] The standard distance of the third distance (L3); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the journal is defined as the third distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the journal is defined as the standard distance of the third distance.

[0012] Furthermore, the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are calibrated and adjusted based on the corresponding standard distances, so that the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are equal to the corresponding standard distances.

[0013] Measure 3: Energy monitoring during the quenching process:

[0014] First, establish the standard energy curve S1 for the quenching process of the standard quenching inductor of the main journal and the standard energy curve S2 for the quenching process of the standard quenching inductor of the connecting rod journal. The horizontal axis of the energy curve is time in seconds, and the vertical axis is power in kW.

[0015] Then, multiply the power values ​​at each point of the standard energy curve of the standard quenching inductor of the main journal by the tolerance upper limit scaling factor X of the acceptable hardened layer depth. + The standard upper limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. +Multiply the power values ​​at each point of the standard energy curve S1 of the standard quenching inductor of the main journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. - ;

[0016] Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the standard quenching inductor of the connecting rod journal by the tolerance upper limit ratio factor X for the acceptable hardened layer depth. + The standard upper limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. + Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the connecting rod journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. - ;

[0017] The tolerance limit ratio coefficient X for the qualified hardened layer depth + We obtain the following using Equation 1:

[0018] X + =U + / U type 1

[0019] In Equation 1, U is the basic value of the acceptable hardened layer depth. + This represents the upper limit of the acceptable hardened layer depth.

[0020] The tolerance lower limit proportional coefficient X for the depth of the qualified hardened layer - We obtain the following using Equation 2:

[0021] X - =U - / U formula 2

[0022] In Equation 2, U is the basic value of the acceptable hardened layer depth. - This is the lower limit of the acceptable hardened layer depth;

[0023] Furthermore, during the batch induction hardening of crankshafts, it is crucial to monitor whether the actual energy curve S1” of the hardening inductor of the main journal falls within the standard upper limit energy curve S1 of the standard hardening inductor of the main journal. + The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal - Between; and whether the actual energy curve S2” of the quenching inductor for monitoring the connecting rod journal falls within the standard upper limit energy curve S2 of the standard quenching inductor for the quenching process of the connecting rod journal. + The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for connecting rod journals- If not, then the dimensions of the abnormal quenching inductor should be calibrated and adjusted.

[0024] After calibration and adjustment, the crankshaft journals are induction hardened again.

[0025] Furthermore, in Measure 1, the appearance quality defects of the straight section of each journal and the R-angle are visually inspected. The appearance quality defects mainly include iron filings, burrs, scratches, rust spots and the uniformity of R-angle machining on various parts of the journal surface.

[0026] Further, (1) check for iron filings in the straight oil holes of each main journal, the oblique oil holes of each connecting rod journal, and the chamfered edges of each oil hole. For any iron filings found, clean them with compressed air; (2) check for burrs on the chamfered edges of the straight oil holes of each main journal. For any burrs found, polish them with fine sandpaper; (3) check for iron filings, burrs, scratches, and rust spots at the R-angles at both ends of each main journal and each connecting rod journal. For any iron filings found, clean them with compressed air; for any burrs and rust spots found, clean them with compressed air. (3) Polish with fine sandpaper; any scratches found need to be re-machined and repaired; (4) Check whether the transition between the R-angle at both ends of each main journal and each connecting rod journal and the straight section of the journal is smooth and uniform. Any uneven transition between the R-angle and the straight section of the journal needs to be re-machined and repaired; (5) Check whether there are iron filings, burrs and rust spots on the straight sections of each main journal and connecting rod journal. For any iron filings found, blow them clean with compressed air; for any burrs and rust spots found, polish them clean with fine sandpaper.

[0027] Furthermore, the quenching inductor is a saddle-shaped quenching inductor.

[0028] Furthermore, the calibration and adjustment of the dimensions of the abnormal quenching inductor mentioned in Measure 3 refers to the calibration and adjustment of the first distance, second distance, and third distance of the abnormal quenching inductor.

[0029] This invention, through the combined implementation of three measures, can effectively ensure the consistency and stability of the induction hardening layer depth of the journal after quenching using the same inductor. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a visual inspection diagram of the straight section and radius of the main journal.

[0032] Figure 2 This is a schematic diagram showing the visual inspection of the straight section and the radius (R) of the connecting rod journal.

[0033] Figure 3 This is a schematic diagram showing the first distance L1 at three positions of the effective heating coils of the saddle-shaped quenching inductor. There are two sets of effective heating coils in the diagram. Points ② and ⑤ indicate the middle of the heating coil in the circumferential direction, and points ①, ③, ④, and ⑥ indicate the ends of the heating coil in the circumferential direction.

[0034] Figure 4 A schematic diagram of the second distance L2 between the effective heating coil and the adjacent shoulder;

[0035] Figure 5 A schematic diagram of the third distance L3 between the effective heating coil and the journal;

[0036] Figure 6 A schematic diagram showing the actual energy curve monitoring and comparison of the quenching inductor of the main journal;

[0037] Figure 7 This is a schematic diagram showing the actual energy curve monitoring and comparison of the quenching inductor for the connecting rod journal. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] In the description of the embodiments of the present invention, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. It is only for the purpose of facilitating the description of the present invention or simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0040] In this invention, "a plurality of" refers to two or more (including two). The terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0041] Unless otherwise explicitly stated and limited, the terms “set up,” “install,” and “connect” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a direct connection or an indirect connection through an intermediate medium.

[0042] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] As shown in the figure, the method of the present invention includes the following measures:

[0044] Measure 1: Before induction hardening, inspect and clean the journal to eliminate any surface quality defects.

[0045] Specifically, through visual inspection, such as Figure 1 , Figure 2 The appearance quality defects of the journal straight section (or "journal surface") and the R-angle of each journal (main journal, connecting rod journal) shown are mainly iron filings, burrs, scratches, rust spots and R-angle machining uniformity present on the journal surface.

[0046] More specifically: (1) Check for iron filings in the straight oil holes of each main journal, the oblique oil holes of each connecting rod journal, and the chamfered edges of each oil hole. If any iron filings are found, clean them with compressed air; (2) Check for burrs on the chamfered edges of the straight oil holes of each main journal. If any burrs are found, polish them with fine sandpaper; (3) Check for iron filings, burrs, scratches, and rust spots at the R-angles at both ends of each main journal and each connecting rod journal. If any iron filings are found, clean them with compressed air; if any burrs and rust spots are found, clean them with compressed air. Use fine sandpaper to polish it clean; any scratches found need to be re-machined and repaired; (4) Check whether the transition between the R-angle at both ends of each main journal and each connecting rod journal and the straight section of the journal is smooth and uniform. Any uneven transition between the R-angle and the straight section of the journal needs to be re-machined and repaired; (5) Check whether there are iron filings, burrs and rust spots on the straight sections of each main journal and connecting rod journal. For any iron filings found, use compressed air to blow them clean; for any burrs and rust spots found, use fine sandpaper to polish them clean.

[0047] By performing the above-mentioned journal appearance inspection and cleaning, we can prevent various appearance defects from affecting the stability of the journal hardened layer depth.

[0048] Measure 2: Calibrate and adjust the dimensions of the quenching inductor:

[0049] If the effective heating coil of the quenching inductor and the crankshaft journal have a clearance smaller than the standard clearance (i.e., the clearance is too small), discharge is likely to occur between the effective heating coil of the inductor and the crankshaft journal, affecting the depth of the induction hardened layer of the journal and burning the journal. If the effective heating coil of the inductor and the crankshaft journal have a clearance larger than the standard clearance (i.e., the clearance is too large), it will result in greater magnetic loss, lower heating efficiency, and will also affect the depth of the induction hardened layer of the journal.

[0050] Therefore, in this measure, the standard quenching inductors corresponding to the main journal and connecting rod journal are first established: the quenching inductor used in this invention is a saddle-shaped quenching inductor. After the main journal and connecting rod journal of the crankshaft are induction quenched by using multiple saddle-shaped quenching inductors of different sizes, the standard quenching inductor corresponding to the qualified hardened layer depth of the main journal and connecting rod journal after induction quenching is determined by dissecting the journal sample.

[0051] Then, the corresponding standard distances of each effective heating coil of the standard hardening inductor corresponding to the main journal and connecting rod journal are determined, including:

[0052] The first distance L1 is the standard distance; wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference is defined as the first distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference is the standard distance of the first distance.

[0053] The standard distance of the second distance L2; wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is defined as the second distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is established as the standard distance of the second distance.

[0054] The standard distance of the third distance L3; wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the journal is defined as the third distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the journal is defined as the standard distance of the third distance.

[0055] Furthermore, the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are calibrated and adjusted based on the corresponding standard distances, so that the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are equal to the corresponding standard distances.

[0056] There are various methods for calibration and adjustment. For example, vernier calipers can be used to measure the three distances mentioned above. If the first distance of the effective heating coil does not conform to the corresponding standard distance L1, the coil can be widened or narrowed using tools to make the first distance of the effective coil equal to the corresponding standard distance. Similarly, the second and third distances of the effective heating coil can be calibrated and adjusted using the same method.

[0057] Measure 3: Energy monitoring during the quenching process:

[0058] First, establish the standard energy curve S1 for the quenching process of the standard quenching inductor of the main journal and the standard energy curve S2 for the quenching process of the standard quenching inductor of the connecting rod journal. The method for establishing the standard quenching inductor is the same as that of Measure 2, or in other words, the standard quenching inductor established in Measure 2 is the standard quenching inductor of this measure. Therefore, the method for establishing the standard quenching inductor will not be repeated here.

[0059] The horizontal axis of the energy curve above represents time in seconds, and the vertical axis represents power in kilowatts (kW).

[0060] Then, multiply the power values ​​at each point of the standard energy curve S1 of the standard quenching inductor of the main journal by the tolerance upper limit scaling factor X of the acceptable hardened layer depth. + The standard upper limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. + Multiply the power values ​​at each point of the standard energy curve S1 of the standard quenching inductor of the main journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. - ,like Figure 6 As shown;

[0061] Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the standard quenching inductor of the connecting rod journal by the tolerance upper limit ratio factor X for the acceptable hardened layer depth. + The standard upper limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. + Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the connecting rod journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. - ,like Figure 7 As shown;

[0062] The tolerance limit ratio coefficient X for the qualified hardened layer depth + We obtain the following using Equation 1:

[0063] X + =U + / U type 1

[0064] In Equation 1, U is the basic value of the acceptable hardened layer depth. + This represents the upper limit of the acceptable hardened layer depth; for example, if the basic value U for the acceptable hardened layer depth is 3mm, then the upper limit U is... + If the thickness is 3.1 mm, then the upper limit of the tolerance for the acceptable hardened layer depth is X. + =3.1 / 3.

[0065] The tolerance lower limit proportional coefficient X for the depth of the qualified hardened layer - We obtain the following using Equation 2:

[0066] X - =U - / U formula 2

[0067] In Equation 2, U is the basic value of the acceptable hardened layer depth. - This is the lower limit of the acceptable hardened layer depth; for example, if the basic value U of the acceptable hardened layer depth is 3mm, then the lower limit U of the acceptable hardened layer depth is... - If the thickness is 2.9mm, then the lower tolerance limit proportionality coefficient X for the acceptable hardened layer depth is... - =2.9 / 3.

[0068] Furthermore, during the batch induction hardening of crankshafts, it is crucial to monitor whether the actual energy curve S1” of the hardening inductor of the main journal falls within the standard upper limit energy curve S1 of the standard hardening inductor of the main journal. + The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal - Between (e.g.) Figure 6 (as shown); and whether the actual energy curve S2” of the quenching inductor for monitoring the connecting rod journal falls on the standard upper limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal. + The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for connecting rod journals - Between (e.g.) Figure 7 If not, the dimensions of the abnormal quenching inductor are calibrated and adjusted. Specifically, the first distance, second distance, and third distance of the abnormal quenching inductor are calibrated and adjusted.

[0069] After calibration and adjustment, the crankshaft journals are induction hardened again.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the depth of the induction hardened layer in a crankshaft, characterized in that, This includes implementing the following measures: Measure 1: Before induction hardening, inspect and clean the journal to eliminate any surface quality defects. Measure 2: Calibrate and adjust the dimensions of the quenching inductor: First, establish the standard quenching inductors corresponding to the main journal and connecting rod journal respectively: After induction quenching the crankshaft main journal and connecting rod journal with multiple quenching inductors of different sizes, determine the standard quenching inductor corresponding to the qualified hardened layer depth of the main journal and connecting rod journal after induction quenching by dissecting the journal sample. Then, the corresponding standard distances of each effective heating coil of the standard hardening inductor corresponding to the main journal and connecting rod journal are determined, including: The standard distance of the first distance (L1); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference is defined as the first distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference is the standard distance of the first distance. The standard distance of the second distance (L2); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is defined as the second distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the adjacent shaft shoulder is established as the standard distance of the second distance. The standard distance of the third distance (L3); wherein, the distance between the left and right sides of each effective heating coil of the quenching inductor at the middle and both ends of the circumference and the journal is defined as the third distance, and the distance between the left and right sides of each effective heating coil of the standard quenching inductor at the middle and both ends of the circumference and the journal is defined as the standard distance of the third distance. Furthermore, the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are calibrated and adjusted based on the corresponding standard distances, so that the first, second, and third distances of the effective heating coils of the quenching inductors corresponding to each main journal and connecting rod journal for batch induction hardening of the crankshaft are equal to the corresponding standard distances. Measure 3: Energy monitoring during the quenching process: First, establish the standard energy curve S1 for the quenching process of the standard quenching inductor of the main journal and the standard energy curve S2 for the quenching process of the standard quenching inductor of the connecting rod journal. The horizontal axis of the energy curve is time in seconds, and the vertical axis is power in kW. Then, multiply the power values ​​at each point of the standard energy curve of the standard quenching inductor of the main journal by the tolerance upper limit scaling factor X of the acceptable hardened layer depth. + The standard upper limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. + Multiply the power values ​​at each point of the standard energy curve S1 of the standard quenching inductor of the main journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal is obtained. - ; Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the standard quenching inductor of the connecting rod journal by the tolerance upper limit ratio factor X for the acceptable hardened layer depth. + The standard upper limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. + Multiply the power values ​​at each point of the standard energy curve S2 of the standard quenching process of the connecting rod journal by the tolerance lower limit proportional coefficient X of the acceptable hardened layer depth. - The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for the connecting rod journal is obtained. - ; The tolerance limit ratio coefficient X for the qualified hardened layer depth + We obtain the following using Equation 1: X + =U + / U Form 1 In Equation 1, U is the basic value of the acceptable hardened layer depth. + This represents the upper limit of the acceptable hardened layer depth. The tolerance lower limit proportional coefficient X for the depth of the qualified hardened layer - We obtain the following using Equation 2: X - =U - / U Formula 2 In Equation 2, U is the basic value of the acceptable hardened layer depth. - This is the lower limit of the acceptable hardened layer depth; Furthermore, during the batch induction hardening of crankshafts, it is crucial to monitor whether the actual energy curve S1” of the hardening inductor of the main journal falls within the standard upper limit energy curve S1 of the standard hardening inductor of the main journal. + The standard lower limit energy curve S1 of the quenching process of the standard quenching inductor of the main journal - Between; and whether the actual energy curve S2” of the quenching inductor for monitoring the connecting rod journal falls within the standard upper limit energy curve S2 of the standard quenching inductor for the quenching process of the connecting rod journal. + The standard lower limit energy curve S2 of the quenching process of the standard quenching inductor for connecting rod journals - If not, then the dimensions of the abnormal quenching inductor should be calibrated and adjusted. After calibration and adjustment, the crankshaft journals are induction hardened again.

2. The method for controlling the depth of the induction hardened layer in a crankshaft as described in claim 1, characterized in that, In Measure 1, visual inspection is conducted on the straight sections of each journal and the appearance quality defects at the R-angle. The appearance quality defects mainly include iron filings, burrs, scratches, rust spots, and the uniformity of R-angle machining on various parts of the journal surface.

3. The method for controlling the depth of the induction hardened layer in a crankshaft as described in claim 2, characterized in that, (1) Check for iron filings in the straight oil holes of each main journal, the oblique oil holes of each connecting rod journal, and the chamfered edges of each oil hole. Clean any iron filings found with compressed air. (2) Check for burrs on the chamfered edges of the straight oil holes of each main journal. Clean any burrs found with fine sandpaper. (3) Check for iron filings, burrs, scratches, and rust spots at the R-angles at both ends of each main journal and connecting rod journal. Clean any iron filings found with compressed air; clean any burrs and rust spots found with fine sandpaper. (3) Sand the surface clean with sandpaper; any scratches found need to be re-machined and repaired; (4) Check whether the transition between the R-angle at both ends of each main journal and each connecting rod journal and the straight section of the journal is smooth and uniform. Any uneven transition between the R-angle and the straight section of the journal needs to be re-machined and repaired; (5) Check whether there are iron filings, burrs and rust spots on the straight sections of each main journal and connecting rod journal. For any iron filings found, blow them clean with compressed air; for any burrs and rust spots found, sand them clean with fine sandpaper.

4. The method for controlling the depth of the induction hardened layer in a crankshaft as described in claim 1, characterized in that, The quenching inductor is a saddle-shaped quenching inductor.

5. The method for controlling the depth of the induction hardened layer in a crankshaft as described in claim 1, characterized in that, The calibration and adjustment of the dimensions of the abnormal quenching inductor mentioned in Measure 3 refers to the calibration and adjustment of the first distance, second distance, and third distance of the abnormal quenching inductor.

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