Debugging method for surface quenching strengthening parameters of concave fillet of crankshaft of medium-high speed diesel engine

Abstract

The invention discloses a method for debugging surface quenching strengthening parameters of a medium-high speed diesel engine crankshaft concave fillet. The method comprises the following steps: manufacturing N journal process test blocks which are the same as a crankshaft to be tested in material and specification; taking a journal process test block, assembling the journal process test block with the left tool and the right tool, connecting the indent fillet surface quenching strengthening inductor with a transformer of a medium-frequency quenching machine tool, and starting the medium-frequency quenching machine tool to enable the indent fillet surface quenching strengthening inductor to be in contact with the journal process test block; the known parameters and the adjusting parameters are input into an indent fillet surface quenching strengthening inductor, and a crankshaft indent fillet surface quenching strengthening process test is started; the method comprises the following steps of: grinding, polishing, corroding, measuring the depth of a hardening layer at a shaft neck part, the depth of a hardening layer at a concave fillet part and the height of the hardening layer at the concave fillet part of a U-shaped sample after the hardening layer appears, and applying qualified surface quenching parameters to crankshaft production, so that the crankshaft is prevented from being directly debugged by using the crankshaft, the crankshaft is prevented from being damaged, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of crankshaft surface quenching, and in particular relates to a method for debugging parameters of the surface quenching strengthening of the inner concave fillet of a crankshaft of a medium- and high-speed diesel engine. Background Art

[0002] The existing crankshaft surface quenching and strengthening can only perform surface quenching and strengthening on the crankshaft journal, resulting in a relatively low fatigue life of the crankshaft; in order to further improve the fatigue life of the crankshaft, it is necessary to increase the surface quenching and strengthening of the crankshaft concave fillet. However, the conventional crankshaft surface quenching and strengthening, its heating coil cannot achieve the strengthening of the crankshaft concave fillet, due to the limitation of the width of the crankshaft main journal and the inner gear of the bend neck, the induction heating coil is too thin, and the surface strengthening of the concave fillet cannot be achieved; if the induction coil is too thick, the heating coil cannot be placed normally on the crankshaft journal, and thus the normal induction heating function cannot be achieved. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a debugging method for obtaining the surface quenching strengthening parameters of the concave fillet of the crankshaft of a medium- and high-speed diesel engine.

[0004] To achieve the above object, the present invention provides a method for debugging the surface quenching strengthening parameters of the concave fillet of a medium- and high-speed diesel engine crankshaft as follows:

[0005] 1) Make N journal process test blocks with the same material and specifications as the crankshaft to be tested;

[0006] 2) Take a journal process test block, assemble the two ends of the journal process test block with the left and right tooling respectively, and then place them together on the medium frequency quenching machine for clamping and leveling;

[0007] 3) Connect the concave fillet surface quenching strengthening sensor to the medium frequency quenching machine transformer, start the medium frequency quenching machine, and make the concave fillet surface quenching strengthening sensor contact with the journal process test block;

[0008] 4) Input known parameters and adjustment parameters into the concave fillet surface quenching strengthening sensor to start the crankshaft concave fillet surface quenching strengthening process test; the adjustment parameters include output power, frequency and heating time;

[0009] 5) After the surface quenching and strengthening is completed in step 4), the journal process test block is taken out, and a U-shaped specimen with a flange at the journal neck position is cut along the length direction on the surface of the journal process test block;

[0010] 6) grinding, polishing and etching the U-shaped specimen in step 5), and after the hardened layer appears, measuring the depth of the hardened layer at the neck portion of the U-shaped specimen, the depth of the hardened layer at the concave fillet portion, and the height of the hardened layer at the concave fillet portion;

[0011] 7) If the depth of the hardened layer at the journal part, the depth of the hardened layer at the concave fillet part and / or the height of the hardened layer at the concave fillet part do not meet the hardened layer requirements of the crankshaft main journal or connecting rod journal to be tested, optimize the adjustment parameters, take a new journal process test block, and repeat steps 2) to 6) until the test results meet the hardened layer requirements.

[0012] Furthermore, after step 7), a new journal process test block is taken to perform a crankshaft concave fillet surface quenching strengthening process test according to the last adjustment parameters, and repeated 1 to 2 times. If the depth of the hardened layer at the journal neck and the depth and height of the hardened layer at the concave fillet are consistent, the adjustment parameters are solidified.

[0013] Furthermore, in step 7), the specific process of optimizing the adjustment parameters is as follows:

[0014] If the depth of the hardened layer at the neck, the depth of the hardened layer at the concave fillet, and the height of the hardened layer at the concave fillet are all too small, increase the output power, increase the heating time, and reduce the frequency;

[0015] If the depth of the hardened layer at the neck and the concave fillet are both too large, and the height of the hardened layer at the concave fillet is too small, increase the frequency and heating time;

[0016] If the depth of the hardened layer at the neck part and the depth of the hardened layer at the concave fillet are both too small, and the height of the hardened layer at the concave fillet is too high, reduce the frequency and shorten the heating time.

[0017] Furthermore, the journal process test block includes a journal, a left flange at the left end of the journal and a right flange at the right end of the journal, and the journal, the left flange and the right flange are coaxially arranged; a left boss extends outward from the middle of the outer end surface of the left flange, a right boss extends outward from the middle of the outer end surface of the right flange, a circle of left inner groove is opened on the edge of the inner end surface of the left flange, and a circle of right inner groove is opened on the edge of the inner end surface of the right flange.

[0018] Further, the left tooling includes a left flange, a left end rod extending from the outer end surface of the left flange, and a left flange groove is formed on the inner end surface of the left flange; the right tooling includes a right flange, a rod extending from the right end of the outer end surface of the right flange, and a right flange groove is formed on the inner end surface of the right flange;

[0019] Embed the left boss of the journal process test block into the left flange groove of the left tooling, and connect the left tooling and the left end of the journal process test block with bolts; embed the right boss of the journal process test block into the right flange groove of the right tooling, and connect the right tooling and the right end of the journal process test block with bolts.

[0020] Furthermore, in the step 3), the medium frequency quenching machine is started, the concave fillet surface quenching and strengthening sensor is adjusted to the middle of the journal process test block, and lowered onto the journal process test block, so that the left positioning block of the concave fillet surface quenching and strengthening sensor contacts the left outer cylindrical surface of the journal process test block, and the right positioning block contacts the right outer cylindrical surface of the journal process test block; then the left sensor and the right sensor of the concave fillet surface quenching and strengthening sensor are opened, so that the left protruding induction coil of the concave fillet surface quenching and strengthening sensor is embedded in the left inner groove of the journal process test block, and the right protruding induction coil is embedded in the right inner groove of the journal process test block.

[0021] Furthermore, the known parameters include cooling time, quenching medium concentration and medium frequency quenching machine speed.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: by debugging in the crankshaft process test block according to the present invention, surface quenching process parameters that meet the requirements of surface quenching and strengthening of the hardened layer of the concave fillet of the crankshaft can be obtained, and qualified surface quenching parameters can be applied to crankshaft production, avoiding directly using the crankshaft for debugging to damage the crankshaft and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall assembly structure of the present invention;

[0024] Figure 2 for Figure 1 Schematic diagram of the main view of the middle journal process test block;

[0025] Figure 3 for Figure 1 Schematic diagram of the side view of the middle journal process test block;

[0026] Figure 4 for Figure 1 Schematic diagram of the main view of the inductor with concave rounded corners and surface quenching and strengthening;

[0027] Figure 5 for Figure 1 Schematic side view of the inductor with concave fillet and surface hardening strengthening;

[0028] Figure 6 for Figure 1 The center left is the main view of the tooling;

[0029] Figure 7 for Figure 1 Schematic diagram of the main view of the tooling on the middle right. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] The method for debugging the surface quenching strengthening parameters of the concave fillet of a crankshaft of a medium- and high-speed diesel engine of the present invention is as follows:

[0032] 1) Prepare N journal process test blocks 3 with the same material and specifications as the crankshaft to be tested;

[0033] like Figure 2 , 3 As shown, the journal process test block 3 includes a journal 21, a left flange 13 at the left end of the journal 21 and a right flange 14 at the right end of the journal 21, and the journal 21, the left flange 13 and the right flange 14 are coaxially arranged; a left boss 19 extends outward from the middle of the outer end surface of the left flange 13, and a right boss 20 extends outward from the middle of the outer end surface of the right flange 14, and a circle of left inner groove 15 is opened on the edge of the inner end surface of the left flange 13, and a circle of right inner groove 16 is opened on the edge of the inner end surface of the right flange 14.

[0034] 2) Take a journal process test block 3, assemble the two ends of the journal process test block 3 with the left fixture 2 and the right fixture 4 respectively, and then place them together on the medium frequency quenching machine for clamping and leveling;

[0035] like Figure 6 , 7 As shown, the left tooling 2 and the right tooling 4 have the same structure. The left tooling 2 includes a left flange 22, a left end rod 24 is extended from the outer end surface of the left flange 22, and a left flange groove 23 is opened on the inner end surface of the left flange 22; the right tooling 4 includes a right flange 17, a rod 6 is extended from the right end of the outer end surface of the right flange 17, and a right flange groove 18 is opened on the inner end surface of the right flange 17;

[0036] Embed the left boss 19 of the journal process test block 3 into the left flange groove 23 of the left tooling 2, and connect the left tooling and the left end of the journal process test block 3 with bolts; embed the right boss 20 of the journal process test block 3 into the right flange groove 18 of the right tooling 4, and connect the right end of the right tooling 4 and the journal process test block 3 with bolts.

[0037] 3) If Figure 1 , 4 As shown in , the clamping plate 5 of the concave fillet surface quenching strengthening inductor 1 is connected to the medium frequency quenching machine transformer, and the medium frequency quenching machine is started to make the concave fillet surface quenching strengthening inductor 7 contact with the journal process test block 3; the concave fillet surface quenching strengthening inductor of the present invention adopts the marine engine crankshaft inner fillet and journal quenching device published in the Chinese invention application (application publication number CN115612823A), and the specific process is:

[0038] Start the medium frequency quenching machine, adjust the concave fillet surface quenching and strengthening sensor 1 to the middle of the journal process test block 3, and lower it onto the journal process test block 3, so that the left positioning block 9 of the concave fillet surface quenching and strengthening sensor contacts with the left outer cylindrical surface of the journal process test block 3, and the right positioning block 10 contacts with the right outer cylindrical surface of the journal process test block 3; then open the left sensor 7 and the right sensor 8 of the concave fillet surface quenching and strengthening sensor to the fixed limit position, so that the left protruding induction coil 11 of the concave fillet surface quenching and strengthening sensor 7 is embedded in the left inner groove 15 of the journal process test block 3, and the right protruding induction coil 12 is embedded in the right inner groove 16 of the journal process test block 3.

[0039] 4) Inputting known parameters and adjustment parameters into the concave fillet surface quenching strengthening sensor 7, and starting the crankshaft concave fillet surface quenching strengthening process test; the adjustment parameters include output power, frequency and heating time, and the known parameters include cooling time, quenching medium concentration and machine tool speed;

[0040] 5) After the surface quenching and strengthening is completed in step 4), the journal process test block 3 is taken out, and a U-shaped specimen with a flange having a cross section of 20 mm×20 mm at the journal neck position is cut along the length direction on the surface of the journal process test block 3;

[0041] 6) grinding, polishing and etching the U-shaped specimen in step 5), and after the hardened layer appears, measuring the depth of the hardened layer at the neck portion of the U-shaped specimen, the depth of the hardened layer at the concave fillet portion, and the height of the hardened layer at the concave fillet portion;

[0042] 7) If the depth of the hardened layer at the journal part, the depth of the hardened layer at the concave fillet part and / or the height of the hardened layer at the concave fillet part do not meet the hardened layer requirements of the crankshaft main journal or connecting rod journal to be tested, optimize the adjustment parameters, take another journal process test block 3, and repeat steps 2) to 6) until the test results meet the hardened layer requirements;

[0043] 8) Take a new journal process test block 3 and carry out the crankshaft concave fillet surface quenching strengthening process test according to the last adjustment parameters, repeat 1 to 2 times, if the depth of the hardened layer at the journal neck and the depth and height of the hardened layer at the concave fillet are consistent, then the adjustment parameters are solidified.

[0044] The specific process of optimizing the adjustment parameters is as follows:

[0045] If the depth of the hardened layer at the neck, the depth of the hardened layer at the concave fillet, and the height of the hardened layer at the concave fillet are all too small, increase the output power, increase the heating time, and reduce the frequency;

[0046] If the depth of the hardened layer at the neck and the concave fillet are both too large, and the height of the hardened layer at the concave fillet is too small, increase the frequency and heating time;

[0047] If the depth of the hardened layer at the neck part and the depth of the hardened layer at the concave fillet are both too small, and the height of the hardened layer at the concave fillet is too high, reduce the frequency and shorten the heating time.

Claims

1. A method for debugging the surface quenching strengthening parameters of the concave fillet of a medium- and high-speed diesel engine crankshaft, characterized in that: The debugging method is as follows: 1) Making N journal process test blocks (3) with the same material and specifications as the crankshaft to be tested; 2) Take a journal process test block (3), assemble the two ends of the journal process test block (3) with the left tool (2) and the right tool (4) respectively, and then place them together on the medium frequency quenching machine for clamping and leveling; 3) Connecting the concave fillet surface quenching strengthening sensor to the medium frequency quenching machine transformer, starting the medium frequency quenching machine, and making the concave fillet surface quenching strengthening sensor (7) contact the journal process test block (3); 4) inputting known parameters and adjustment parameters into the concave fillet surface quenching strengthening sensor (7) to start the crankshaft concave fillet surface quenching strengthening process test; the adjustment parameters include output power, frequency and heating time; 5) After the surface quenching and strengthening is completed in step 4), the journal process test block (3) is taken out, and a U-shaped specimen with a flange at the journal neck position is cut along the length direction on the surface of the journal process test block 3; 6) grinding, polishing and etching the U-shaped specimen in step 5), and after the hardened layer appears, measuring the depth of the hardened layer at the neck portion of the U-shaped specimen, the depth of the hardened layer at the concave fillet portion, and the height of the hardened layer at the concave fillet portion; 7) If the depth of the hardened layer at the journal part, the depth of the hardened layer at the concave fillet part and / or the height of the hardened layer at the concave fillet part do not meet the hardened layer requirements of the crankshaft main journal or connecting rod journal to be tested, optimize the adjustment parameters, take a new journal process test block (3), and repeat steps 2) to 6) until the test results meet the hardened layer requirements.

2. The process for quenching and strengthening the inner concave fillet surface of a medium- and high-speed diesel engine crankshaft according to claim 1, characterized in that: After the step 7), a new journal process test block (3) is taken to perform a crankshaft concave fillet surface quenching strengthening process test according to the last adjustment parameters, and repeated 1 to 2 times. If the depth of the hardened layer at the journal neck and the depth and height of the hardened layer at the concave fillet are consistent, the adjustment parameters are solidified.

3. The process for quenching and strengthening the inner concave fillet surface of a medium- and high-speed diesel engine crankshaft according to claim 1, characterized in that: In step 7), the specific process of optimizing the adjustment parameters is as follows: If the depth of the hardened layer at the neck, the depth of the hardened layer at the concave fillet, and the height of the hardened layer at the concave fillet are all too small, increase the output power, increase the heating time, and reduce the frequency; If the depth of the hardened layer at the neck and the concave fillet are both too large, and the height of the hardened layer at the concave fillet is too small, increase the frequency and heating time; If the depth of the hardened layer at the neck part and the depth of the hardened layer at the concave fillet are both too small, and the height of the hardened layer at the concave fillet is too high, reduce the frequency and shorten the heating time.

4. The process for quenching and strengthening the concave fillet surface of a medium- and high-speed diesel engine crankshaft according to claim 1, characterized in that: The journal process test block (3) comprises a journal (21), a left flange (13) at the left end of the journal (21) and a right flange (14) at the right end of the journal (21), and the journal (21), the left flange (13) and the right flange (14) are coaxially arranged; a left boss (19) extends outwardly from the middle of the outer end surface of the left flange (13), and a right boss (20) extends outwardly from the middle of the outer end surface of the right flange (14); a circle of left inner groove (15) is formed on the edge of the inner end surface of the left flange (13), and a circle of right inner groove (16) is formed on the edge of the inner end surface of the right flange (14).

5. The process for quenching and strengthening the inner concave fillet surface of a medium- and high-speed diesel engine crankshaft according to claim 4, characterized in that: The left tooling (2) comprises a left flange (22), a left end rod (24) extending from the outer end surface of the left flange (22), and a left flange groove (23) opening on the inner end surface of the left flange (22); the right tooling (4) comprises a right flange (17), a rod (6) extending from the right end of the outer end surface of the right flange (17), and a right flange groove (18) opening on the inner end surface of the right flange (17); The left boss (19) of the journal process test block (3) is embedded in the left flange groove (23) of the left tooling (2), and the left tooling and the left end of the journal process test block (3) are connected by bolts; the right boss (20) of the journal process test block (3) is embedded in the right flange groove (18) of the right tooling (4), and the right tooling (4) and the right end of the journal process test block (3) are connected by bolts.

6. The process for quenching and strengthening the concave fillet surface of a crankshaft of a medium- and high-speed diesel engine according to claim 4, characterized in that: In the step 3), the medium frequency quenching machine is started, the concave fillet surface quenching strengthening sensor (1) is adjusted to the middle of the journal process test block (3), and lowered onto the journal process test block (3), so that the left positioning block (9) of the concave fillet surface quenching strengthening sensor contacts the left outer cylindrical surface of the journal process test block (3), and the right positioning block (10) contacts the right outer cylindrical surface of the journal process test block (3); then the left sensor (7) and the right sensor (8) of the concave fillet surface quenching strengthening sensor are opened, so that the left protruding induction coil (11) of the concave fillet surface quenching strengthening sensor (7) is embedded in the left inner groove (15) of the journal process test block (3), and the right protruding induction coil (12) is embedded in the right inner groove (16) of the journal process test block 3.

7. The process for quenching and strengthening the inner concave fillet surface of a medium- and high-speed diesel engine crankshaft according to claim 1, characterized in that: The known parameters include cooling time, quenching medium concentration and medium frequency quenching machine speed.

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