CN117802446A - Heat treatment process method of low-carbon high-alloy structural steel and hydraulic breaking hammer piston - Google Patents
Heat treatment process method of low-carbon high-alloy structural steel and hydraulic breaking hammer piston Download PDFInfo
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 142
- 238000000034 method Methods 0.000 title claims abstract description 89
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 85
- 239000000956 alloy Substances 0.000 title claims abstract description 85
- 229910000746 Structural steel Inorganic materials 0.000 title claims abstract description 83
- 238000010438 heat treatment Methods 0.000 title claims abstract description 68
- 230000008569 process Effects 0.000 title claims abstract description 60
- 238000005496 tempering Methods 0.000 claims abstract description 63
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 43
- 238000001816 cooling Methods 0.000 claims abstract description 41
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 33
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 23
- 230000000717 retained effect Effects 0.000 claims abstract description 12
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 59
- 238000010791 quenching Methods 0.000 claims description 33
- 230000000171 quenching effect Effects 0.000 claims description 33
- 238000004321 preservation Methods 0.000 claims description 17
- 229910002651 NO3 Inorganic materials 0.000 claims description 14
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 14
- 230000007704 transition Effects 0.000 claims description 13
- 150000003839 salts Chemical class 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 15
- 238000005279 austempering Methods 0.000 abstract description 2
- 230000006641 stabilisation Effects 0.000 description 14
- 238000011105 stabilization Methods 0.000 description 14
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- 238000005255 carburizing Methods 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 230000002045 lasting effect Effects 0.000 description 9
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 239000003350 kerosene Substances 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910001339 C alloy Inorganic materials 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 230000009191 jumping Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 238000012369 In process control Methods 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- 238000007599 discharging Methods 0.000 description 1
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- 238000005065 mining Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
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Abstract
The invention provides a heat treatment process method of low-carbon high-alloy structural steel, which comprises the following steps: s1) carrying out staged carburization on low-carbon high-alloy structural steel, and cooling after precooling; s2) carrying out high-temperature tempering on the low-carbon high-alloy structural steel obtained in the step S1); s3) carrying out austempering on the low-carbon high-alloy structural steel obtained in the step S2); s4) stabilizing the low-carbon high-alloy structural steel obtained in the step S3); s5) carrying out stage-by-stage cryogenic treatment on the low-carbon high-alloy structural steel obtained in the step S4), and finally tempering. The material obtained by the heat treatment process method has uniform and compact structure, the surface mainly comprises acicular martensite, retained austenite, lower bainite and carbide, and the core mainly comprises lath martensite and a small amount of lower bainite; the surface hardness is 58.0-62.0 HRC, the core hardness is 40.0-45.0 HRC, and the effective hardening layer is 2.8-3.2 mm.
Description
Technical Field
The invention relates to the technical field of heat treatment processes, in particular to a heat treatment process method of low-carbon high-alloy structural steel and a hydraulic breaking hammer piston.
Background
The hydraulic breaking hammer is one of replaceable working devices of the excavator, is equipment for converting input hydraulic energy into mechanical impact energy, is commonly used in engineering construction such as civil construction and mining, and has the advantages of high breaking force, flexibility, controllable range and small noise compared with the traditional mechanical breaking mode.
The piston is a key part of the breaking hammer, and the high-frequency reciprocating motion of the piston in the cylinder body is realized by means of high-pressure oil output by the main machine when the breaking hammer works, so that the drill rod is hit, work is done outwards, the piston and the cylinder body have severe friction, and meanwhile, the lower end face frequently impacts the drill rod to bear huge impact stress, so that the working efficiency of the breaking hammer is directly determined by the quality of the piston.
In recent years, a breaking hammer piston generally adopts Korean raw material SNCM26V, which still adopts a heat treatment process adapting to low-carbon alloy steel and medium-carbon alloy steel in China, but the material still has the defects of low tensile strength and low core strength after heat treatment in the actual use process, and the piston still is easy to have serious problems of abrasion, strain, end face depression, collapse and the like under the strong impact power of a large and medium-sized hydraulic breaking hammer.
Disclosure of Invention
The invention solves the technical problem of providing a heat treatment process method for low-carbon high-alloy structural steel, wherein the surface and the core of the low-carbon high-alloy structural steel subjected to the heat treatment process are high in hardness, and the low-carbon high-alloy structural steel has a moderate and reduced hardness gradient.
In view of this, the present application provides a heat treatment process method for low-carbon high-alloy structural steel, comprising the following steps:
s1) carrying out staged carburization on low-carbon high-alloy structural steel at 800-950 ℃, precooling to 800-850 ℃ and cooling;
s2) carrying out high-temperature tempering on the low-carbon high-alloy structural steel obtained in the step S1) at 600-700 ℃;
s3) carrying out isothermal salt bath quenching on the low-carbon high-alloy structural steel obtained in the step S2) at 200-280 ℃;
s4) stabilizing the low-carbon high-alloy structural steel obtained in the step S3) at 100-150 ℃;
and S5) carrying out staged cryogenic treatment on the low-carbon high-alloy structural steel obtained in the step S4) at the temperature of-20 to-130 ℃, and finally tempering at the temperature of 150-200 ℃.
Preferably, the staged carburization comprises five stages:
a stage of: heating the low-carbon high-alloy structural steel to 830-860 ℃ along with a furnace, controlling the carbon potential in the furnace to be 0.84-0.86%, and preserving heat for 55-65 min;
two stages: heating to 890-910 ℃, controlling the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 55-65 min;
three stages: heating to 920-940 ℃, keeping the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 1430-1450 min;
four stages: maintaining the temperature in the furnace at 920-940 ℃, controlling the carbon potential in the furnace at 0.84-0.86%, and preserving the temperature at 700-730 min;
five stages: controlling the temperature in the furnace to be 830-850 ℃, controlling the carbon potential in the furnace to be 0.7-0.9%, and preserving heat for 25-35 min.
Preferably, the high-temperature tempering temperature is 640-680 ℃, and the heat preservation time is 1.75-3.25 h.
Preferably, the isothermal salt bath quenching specifically comprises:
heating the low-carbon high-alloy structural steel obtained in the step S2) to 830-860 ℃, controlling the carbon potential to be 0.6-0.8%, preserving heat for 3.75-4.25 h, and quenching in a nitrate solution at 210-230 ℃ for 3.75-4.25 h; the nitrate solution comprises 50% of NaNO by mass percent 3 +50%KNO 3 。
Preferably, the temperature of the stabilizing treatment is 110-130 ℃, and the heat preservation time is 2.75-3.25 h.
Preferably, the staged cryogenic treatment comprises four stages:
a stage of: the low-carbon high-alloy structural steel obtained in the step S4) is deeply cooled to the temperature of minus 25 to minus 35 ℃ for 18 to 25 minutes;
two stages: the low-carbon high-alloy structural steel subjected to the one-stage deep cooling treatment is deeply cooled to the temperature of-55 to-65 ℃ for 18 to 25 minutes;
three stages: the low-carbon high-alloy structural steel subjected to the two-stage deep cooling treatment is deeply cooled to the temperature of minus 75 to minus 95 ℃ for 18 to 25 minutes;
four stages: and (3) deep cooling the low-carbon high-alloy structural steel subjected to the three-stage deep cooling treatment to the temperature of-115 to-125 ℃ for 85-95 min.
Preferably, the tempering includes a first tempering and a second tempering; the temperature of the first tempering is 150-180 ℃, the temperature is kept for 3.75-4.25 hours, the temperature of the second tempering is 170-190 ℃, and the temperature is kept for 1.75-2.25 hours.
Preferably, the low-carbon high-alloy structural steel comprises SNCM26V, 18Cr2Ni4W, 20Cr2Ni4, 23CrNi3Mo, 34CrNi3Mo or EN30b.
Preferably, the surface structure of the low-carbon high-alloy structural steel obtained in the step S5) comprises needle-shaped martensite, retained austenite and carbide, the transition zone comprises lower bainite and hidden needle martensite, and the core structure comprises lath martensite and lower bainite.
The application also provides a hydraulic breaking hammer piston, which comprises the low-carbon high-alloy structural steel, wherein the heat treatment process method of the low-carbon high-alloy structural steel is the heat treatment process method.
The application arches a heat treatment process method of low-carbon high-alloy structural steel, which comprises the steps of carrying out staged carburization, high-temperature tempering, isothermal quenching, stabilization treatment, staged cryogenic treatment and tempering in sequence, so that the surface and core tissues of the low-carbon high-alloy structural steel are uniform and compact, the hardness is greatly improved, the surface forms a mixed tissue of hidden needle martensite and lower bainite, a transition zone forms a mixed tissue of lower bainite and hidden needle martensite, the core forms a mixed tissue of lath martensite and a small amount of lower bainite, the core strength is ensured, meanwhile, the core has good toughness, and the hardness gradient is reduced moderately.
Drawings
FIG. 1 is a photograph of the metallographic morphology of the piston surface, transition zone and core at various stages of the heat treatment process in example 1;
fig. 2 is a photograph showing the metallographic structure of pistons prepared in example 1 and comparative example 1.
Detailed Description
For a further understanding of the present invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the invention, and are not limiting of the claims of the invention.
In view of the problem of low strength of the piston core of the breaking hammer of the low-carbon high-alloy structural steel in the prior art, the application provides a heat treatment process method of the low-carbon high-alloy structural steel, which ensures the surface and core tissues of the low-carbon high-alloy structural steel to be compact, forms different metallographic tissues, ensures the core strength and has a moderate and reduced hardness gradient through sequentially performing staged carburization, high-temperature tempering, isothermal quenching, stabilization treatment, staged cryogenic treatment and low-temperature tempering. Specifically, the embodiment of the invention discloses a heat treatment process method of low-carbon high-alloy structural steel, which comprises the following steps:
s1) carrying out staged carburization on low-carbon high-alloy structural steel at 800-950 ℃, precooling to 800-850 ℃ and cooling;
s2) carrying out high-temperature tempering on the carburized low-carbon high-alloy structural steel at 600-700 ℃;
s3) carrying out isothermal quenching on the low-carbon high-alloy structural steel obtained in the step S2) at 200-280 ℃;
s4) stabilizing the low-carbon high-alloy structural steel obtained in the step S3) at 100-150 ℃;
and S5) carrying out staged cryogenic treatment on the low-carbon high-alloy structural steel obtained in the step S4) at the temperature of-20 to-130 ℃, and finally tempering at the temperature of 150-200 ℃.
In the heat treatment process method of the low-carbon high-alloy structural steel, the low-carbon high-alloy structural steel is subjected to staged carburization at 800-950 ℃ and precooled to 800-850 ℃ for cooling, the surface of the low-carbon high-alloy structural steel has a certain carburization depth and optimal carbon concentration by limiting carburization temperature and carburization time in the process, and the material with high hardness and wear resistance can be obtained after subsequent quenching and tempering; the structure is as follows: the surface is coarse acicular martensite and a large amount of residual austenite, and the core is coarse lath martensite and ferrite. In the present application, the staged carburization specifically includes five carburization stages performed sequentially, specifically:
a stage of: heating the low-carbon high-alloy structural steel to 830-860 ℃ along with a furnace, controlling the carbon potential in the furnace to be 0.84-0.86%, and preserving heat for 55-65 min;
two stages: heating to 890-910 ℃, controlling the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 55-65 min;
three stages: heating to 920-940 ℃, keeping the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 1430-1450 min;
four stages: maintaining the temperature in the furnace at 920-940 ℃, controlling the carbon potential in the furnace at 0.84-0.86%, and preserving the temperature at 700-730 min;
five stages: controlling the temperature in the furnace to be 830-850 ℃, controlling the carbon potential in the furnace to be 0.7-0.9%, and preserving heat for 25-35 min.
The temperature of the first stage is 830 ℃, 832 ℃, 835 ℃, 838 ℃, 840 ℃, 845 ℃, 848 ℃, 850 ℃, 855 ℃, 858 ℃ or 860 ℃, the carbon potential is 0.84%, 0.85% or 0.86%, and the heat preservation time is 55min, 56min, 57min, 58min, 59min, 60min, 61min, 62min, 63min, 64min or 65min. The first stage is a heat preservation stage, so that the temperature of the inner surface and the outer surface of the low-carbon high-alloy structural steel is uniformly heat-penetrated, and meanwhile, the surface preliminarily obtains a certain carbon concentration, and the surface decarburization is prevented.
The temperature of the two stages is 890 ℃, 892 ℃, 895 ℃, 897 ℃, 900 ℃, 902 ℃, 905 ℃, 908 ℃ or 910 ℃ and the carbon potential is 1.14%, 1.15% or 1.16%, and the heat preservation time is 55min, 56min, 57min, 58min, 59min, 60min, 61min, 62min, 63min, 64min or 65min. The two stages are pre-carburization stages of carburization, and the carburizing agent starts to fully crack out active carbon atoms under the atmosphere of high Wen Gaotan concentration.
The three-stage temperature is 920 ℃, 922 ℃, 925 ℃, 927 ℃, 930 ℃, 931 ℃, 933 ℃, 935 ℃, 938 ℃ or 940 ℃, the carbon potential is 1.14%, 1.15% or 1.16%, and the temperature is kept for 1430min, 1432min, 1438min, 1440min, 1442min, 1445min, 1448min or 1450min. The three stages are strong carburization stages, the carburizer fully decomposes active carbon atoms and the absorption of the active carbon atoms, and the surface of the low-carbon high-alloy structural steel absorbs the active carbon atoms with high concentration.
The four stages are 920 ℃, 922 ℃, 925 ℃, 927 ℃, 930 ℃, 931 ℃, 933 ℃, 935 ℃, 938 ℃ or 940 ℃ and the carbon potential is 0.84%, 0.85% or 0.86%, and the temperature is kept for 700min, 703min, 707min, 710min, 712min, 715min, 718min, 720min, 721min, 725min, 727min, 729min or 730min. The four stages are diffusion stages of carburization, active carbon atoms absorbed by the surface of the low-carbon high-alloy structural steel migrate to the depth through the stages, and a carburized layer with a certain thickness, namely a carbon concentration gradient from high carbon to low carbon, is formed after heat preservation for a certain time.
The temperature of the five stages is 830 ℃, 832 ℃, 835 ℃, 837 ℃, 839 ℃, 840 ℃, 842 ℃, 845 ℃, 846 ℃, 848 ℃ or 850 ℃, the carbon potential is 0.7%, 0.72%, 0.75%, 0.78%, 0.8%, 0.82%, 0.85%, 0.86% or 0.9%, and the time for heat preservation is 25min, 27min, 28min, 30min, 31min, 33min or 35min. The five stages are pre-cooling and heat-preserving stages of carburization, and compared with a high-temperature direct quenching step without the stages, the stages can prevent coarse microstructures from occurring and properly reduce stress after quenching.
The above is five stages of carburization, each of which is indispensable; if the first stage is absent, the inside and outside temperature of the low-carbon high-alloy structural steel is uneven, and surface decarburization is caused, so that the subsequent carburization concentration is affected; if the second stage is absent, the carbon concentration of the surface of the low-carbon high-alloy structural steel in the carburization process is uneven; if the third and fourth stages are absent, the carbon concentration gradient, namely a carburized layer, from the surface to a certain depth of the low-carbon high-alloy structural steel cannot be completed; if the fifth stage is absent, coarse microstructure can appear after high temperature direct quenching, and meanwhile, the quenching stress of the low-carbon high-alloy structural steel is increased, and even the risk of quenching crack is increased.
And precooling to 800-850 ℃ for cooling after carburization, wherein the precooling temperature is 810-840 ℃, and the cooling is air cooling.
The method comprises the steps of carrying out high-temperature tempering on low-carbon high-alloy structural steel, wherein the temperature of the high-temperature tempering is 640-680 ℃ and the heat preservation time is 1.75-3.25 h; specifically, the high-temperature tempering temperature is 645-675 ℃, more specifically, the high-temperature tempering temperature is 650 ℃, 655 ℃, 658 ℃, 660 ℃, 665 ℃, 670 ℃ or 675 ℃, and the heat preservation time is 2h, 2.15h, 2.3h, 2.75h or 3h. The high-temperature tempering is performed to promote the martensite in the surface carburized region to be decomposed into tempered sorbite, the residual austenite is converted into martensite to be decomposed into tempered sorbite, and the carbide in the sorbite cannot be completely dissolved in the austenite under the condition of subsequent quenching, heating and heat preservation, so that the alloying degree in solid solution is reduced, and more martensite can be obtained during quenching. At this time, the surface structure is transformed into tempered sorbite and tempered martensite, and the core is tempered sorbite.
Carrying out isothermal quenching on the low-carbon high-alloy structural steel, specifically, heating the low-carbon high-alloy structural steel to 830-860 ℃, controlling the carbon potential to 0.6-0.8%, preserving heat for 3.75-4.25 h, and quenching in a nitrate solution at 210-230 ℃ for 3.75-4.25 h; the nitrate solution comprises 50% of NaNO by mass percent 3 +50%KNO 3 。
In the above-mentioned austempering process, the heating temperature is 835-855 ℃, more specifically 838 ℃, 840 ℃, 842 ℃, 845 ℃, 848 ℃, 850 ℃, 852 ℃ or 855 ℃. The carbon potential is specifically 0.65-0.78%, more specifically 0.68%, 0.70%, 0.71%, 0.73%, 0.75% or 0.77%. The heat preservation time is 3.9h, 3.95h, 4.0h, 4.05h, 4.15h, 4.2h or 4.25h. The quenching temperature is 200-280 ℃, specifically 210-250 ℃, more specifically 215-228 ℃, and 215-218 ℃, 219 ℃, 220 ℃, 222 ℃, 225 ℃ or 228 ℃. The nitrate bath of the nitrate solution replaces the traditional oil-cooled quenching, compared with the traditional oil-cooled quenching, the quenching stress of a hydraulic breaking hammer piston can be reduced, meanwhile, the surface structure of a carburized layer is preliminarily obtained into fine needle-shaped quenched martensite, a large amount of residual austenite, lower bainite and carbide, the carburized transition region structure is obtained into lower bainite, and the strength and the toughness are high.
According to the invention, stabilizing the austempered low-carbon high-alloy structural steel, wherein the temperature of the stabilizing treatment is 110-140 ℃, and the heat preservation time is 2.75-3.25 h; specifically, the temperature of the stabilization treatment is 115-135 ℃, and the heat preservation time is 2.9-3.15 h; more specifically, the temperature of the stabilization treatment is 118 ℃, 120 ℃, 122 ℃, 125 ℃, 128 ℃, 130 ℃, 132 ℃ or 135 ℃, and the incubation time is 2.95h, 3h, 3.02h, 3.05h, 3.06h, 3.1h, 3.12h or 3.15h. The stabilization treatment stabilizes the tissue and relieves stress on a portion of the piston. The surface of the carburized layer of the low-carbon high-alloy structural steel after the stabilization treatment is fine needle-shaped tempered martensite, a large amount of retained austenite, lower bainite and carbide, and a carburized transition zone is divided into the lower bainite, the retained austenite and a core tempered martensite, and a lower bainitic structure.
The method comprises the steps of carrying out staged cryogenic treatment on the low-carbon high-alloy steel subjected to the stabilization treatment at the temperature of minus 20 to minus 130 ℃, wherein the staged cryogenic treatment comprises four stages:
a stage of: deep cooling the low-carbon high-alloy structural steel obtained by the stabilization treatment to the temperature of minus 25 to minus 35 ℃ for 18-25 min;
two stages: the low-carbon high-alloy structural steel subjected to the one-stage deep cooling treatment is deeply cooled to the temperature of-55 to-65 ℃ for 18 to 25 minutes;
three stages: the low-carbon high-alloy structural steel subjected to the two-stage deep cooling treatment is deeply cooled to the temperature of minus 75 to minus 95 ℃ for 18 to 25 minutes;
four stages: and (3) deep cooling the low-carbon high-alloy structural steel subjected to the three-stage deep cooling treatment to the temperature of-115 to-125 ℃ for 85-95 min.
The staged cryogenic treatment replaces direct cryogenic treatment at the temperature of minus 120 ℃, so that the structural stress caused by the structural transformation of the surface of the low-carbon high-alloy structural steel piston in the cryogenic process can be greatly reduced, meanwhile, the stress of the piston is relaxed and fully released, and the risk of cracking the piston is reduced. Specifically, the temperature of the one-stage cryogenic treatment is-25 ℃, -26 ℃, -27 ℃, -28 ℃, -29 ℃, -30 ℃, -31 ℃, -32 ℃, -33 ℃, -34 ℃ or-35 ℃ and the duration is 18min, 19min, 20min, 21min, 22min, 23min, 24min or 25min. The two-stage cryogenic treatment has a temperature of-55 ℃, -56 ℃, -57 ℃, -58 ℃, -59 ℃, -60 ℃, -61 ℃, -62 ℃, -63 ℃, -64 ℃ or-65 ℃ for 18min, 19min, 20min, 21min, 22min, 23min, 24min or 25min. The three-stage cryogenic treatment has a temperature of-75 ℃, -76 ℃, -77 ℃, -78 ℃, -79 ℃, -80 ℃, -681 ℃, -82 ℃, -83 ℃, -84 ℃, -85 ℃, -86 ℃, -87 ℃, -88 ℃, -89 ℃ or-90 ℃ for 18min, 19min, 20min, 21min, 22min, 23min, 24min or 25min. The four-stage cryogenic treatment has a temperature of-115 ℃, -116 ℃, -117 ℃, -118 ℃, -119 ℃, -120 ℃, -121 ℃, -122 ℃, -123 ℃, -124 ℃ or-125 ℃ for a duration of 85min, 86min, 87min, 88min, 89min, 91min, 92min, 93min, 94min or 95min.
The four stages of the above-mentioned cryogenic treatment are very critical and necessary, if the first three stages are missing, the surface stress release of the low-carbon high-alloy structural steel piston is excessively intense, the risk of cracking the piston is increased, if the fourth stage is missing, the residual austenite in the microstructure of the piston surface is excessive, the stability of the size of the piston is affected in the subsequent processing process, and finally the mechanical properties of the piston are poor, such as too low hardness and poor wear resistance. The step promotes the transformation of the quenched microstructure from the residual austenite to the tempered martensite, and simultaneously retains a small amount of the residual austenite, so that the microstructure has high hardness and wear resistance in terms of performance and good toughness; the deep-cooling treated structure is a carburized layer surface fine needle-shaped tempered martensite, retained austenite, lower bainite and carbide, a carburized transition zone is formed into a lower bainite, retained austenite and a core tempered martensite, and a small amount of lower bainite structure.
The application finally carries out low-temperature tempering, which comprises a first tempering and a second tempering; the temperature of the first tempering is 150-180 ℃, the temperature is kept for 3.75-4.25 h, the temperature of the second tempering is 170-190 ℃, and the temperature is kept for 1.75-2.25 h; specifically, the temperature of the first tempering is 155-170 ℃, the heat is preserved for 3.9-4.15 h, more specifically, the temperature of the first tempering is 158 ℃, 160 ℃, 162 ℃, 165 ℃, 168 ℃ or 170 ℃, and the heat is preserved for 4h, 4.05h or 4.15h. The temperature of the second tempering is 175-190 ℃, more specifically, the temperature of the second tempering is 175 ℃, 178 ℃, 180 ℃, 181 ℃, 182 ℃, 185 ℃, 188 ℃ or 190 ℃, and the temperature is kept for 1.85h, 1.9h, 2.0h or 2.05h. According to the method, through two low-temperature tempering, the microstructure of the low-carbon high-alloy structural steel piston can be stabilized, the stress of the piston is eliminated, the dimensional stability of the piston in subsequent processing is kept, and finally the best toughness, strength and hardness matching is obtained. If the first stage is lacking, the structure of the piston after the cryogenic process is not stable, so that the stability of the size of the piston is affected, and if the second stage is lacking, the structure of the large-size piston is not sufficiently stable, and the mechanical property is not well adapted. And the low temperature tempering is carried out for a plurality of times to stabilize the structure and eliminate the stress of the piston, so that the dimensional stability of the piston in subsequent processing is maintained, and finally, the optimal toughness, strength and hardness matching is obtained. The low-carbon high-alloy structural steel subjected to low-temperature tempering has a structure of fine needle-shaped tempered martensite, a small amount of residual austenite, lower bainite and carbide on the surface of a carburized layer, and a carburized transition zone is divided into a lower bainite, hidden needle martensite, a small amount of residual austenite, and a core lath tempered martensite and a small amount of lower bainite.
The heat treatment process provided herein is directed to low carbon high alloy structural steels known to those skilled in the art, examples of which include SNCM26V, 18Cr2Ni4W, 20Cr2Ni4, 23CrNi3Mo, 34CrNi3Mo, or EN30b, and in particular embodiments, the low carbon high alloy structural steels are SNCM26V materials. The application provides a heat treatment process method, in particular to a hydraulic breaking hammer piston of SNCM26V material.
The application provides a hydraulic breaking hammer piston, which comprises low-carbon high-alloy structural steel, wherein the heat treatment process method of the low-carbon high-alloy structural steel is the heat treatment process method of the scheme.
Aiming at low-carbon high-alloy structural steel, particularly SNCM26V piston materials, the invention ensures that the surface and the core structure of the piston are uniform and compact, the hardness is greatly improved, hidden needle martensite is formed on the surface, a mixed structure of lower bainite and hidden needle martensite is formed in a transition region, a small amount of lower bainite is formed in the core, the strength of the core is ensured, meanwhile, the toughness is good, and the hardness gradient is reduced. The heat treatment process is simple and convenient to operate, is successfully applied to production, meets the production and actual use requirements, and is more stable in process control process, more uniform and compact in obtained material structure, less prone to deformation, higher in mechanical property of workpieces and more durable in use compared with the existing heat treatment method.
In order to further understand the present invention, the heat treatment process method of the low-carbon high-alloy structural steel and the hydraulic breaking hammer piston provided by the present invention are described in detail below with reference to examples, and the scope of protection of the present invention is not limited by the following examples.
Example 1
A hydraulic breaking hammer piston heat treatment process method of SNCM26V material comprises the following steps:
(1) The whole carburization and precooling process is divided into five stages, a piston (workpiece) made of SNCM26V material adopts a hoisting tool, the specification of a supporting cylinder is 1400mm, a carburizing agent adopts kerosene and methanol, the furnace is fed for 2 hours to reach 850 ℃, the carbon potential is 0.84%, the heat is preserved for 1 hour, a 2 nd stage program is immediately jumped in, the temperature reaches 900 ℃ after 1.6 hours, the carbon potential is 1.15%, the heat is preserved for 1 hour, a 3 rd stage program is jumped in, the carbon potential is kept unchanged for 1.15%, the temperature reaches 930 ℃ for 6 minutes, and the strong carburization stage is adopted at the moment, and the heat is preserved for 24 hours; jumping into a 4 th stage program, and reducing the carbon potential from 1.15% to 0.85%, wherein the carbon potential belongs to a diffusion stage at the moment, and the diffusion time is 12 hours; jumping into a 5 th stage program, reducing the temperature in the furnace from 930 ℃ to 840 ℃, reducing the carbon potential from 0.85% to 0.80%, preserving heat for 30min, and discharging the furnace for fan air cooling after carburization is finished;
(2) After the high-temperature tempering air cooling is finished, placing the workpiece into a furnace with the temperature of 650 ℃, and preserving heat for 3 hours;
(3) After finishing isothermal quenching tempering and cooling, placing the workpiece into a furnace with the temperature of 850 ℃, controlling the carbon potential in the furnace to be 0.7%, preserving heat for 4 hours, directly placing the workpiece into nitrate solution after finishing heat preservation, and preserving heat for 4 hours when the temperature of the nitrate solution reaches 220 ℃;
(4) And (5) stabilizing treatment. After isothermal quenching is finished, taking out the workpiece to wash nitrate, putting the workpiece into a furnace with the temperature of 120 ℃, and preserving heat for 3 hours;
(5) The cryogenic treatment comprises the steps of placing a workpiece cooled after the stabilization treatment into a cryogenic furnace, adopting a staged cooling method, and keeping the temperature in the cryogenic furnace at-30 ℃ for 20min at one stage; two stages, the temperature in the deep cooling furnace is minus 60 ℃ and lasts for 20min; three stages, the temperature in the cryogenic furnace is-90 ℃ and lasts for 20min; four stages, the temperature in the cryogenic furnace is 120 ℃ below zero and lasts for 90min;
(6) After low-temperature tempering and deep cooling, firstly placing a workpiece into a furnace with the temperature of 160 ℃ for tempering once, and preserving heat for 4 hours; taking out and cooling, putting the workpiece into a furnace with the temperature of 180 ℃ again for secondary tempering, and preserving heat for 2 hours.
Fig. 1 shows the metallographic morphology from the surface to the core of the piston after the heat treatment process in this embodiment, as can be seen from fig. 1, the structure of the piston after the heat treatment process is uniform and compact, the surface is mainly composed of acicular martensite+retained austenite+lower bainite+carbide, the transition region forms a mixed structure of lower bainite and hidden needle martensite, and the core is mainly composed of lath martensite and a small amount of lower bainite; table 1 is a table of rockwell hardness data for pistons at different stages of the heat treatment process;
TABLE 1 Rockwell hardness data Table for pistons at different stages of the Heat treatment Process
After the series of heat treatment processes, the surface hardness of the piston is 59.0-60.0 HRC, the core hardness is 42.5-43.5 HRC, and the thickness of the effective hardening layer is 2.87-3.25 mm.
Example 2
A hydraulic breaking hammer piston heat treatment process method of SNCM26V material comprises the following steps:
(1) The carburizing pre-cooling carburizing agent adopts kerosene and methanol, and in one stage, a piston (workpiece) made of SNCM26V material is heated to 855 ℃ along with a furnace, the carbon potential in the furnace is controlled to be 0.86%, the opening of an auxiliary control valve is 100%, and the duration is 60 minutes; two stages, heating to 910 ℃, controlling the carbon potential in the furnace to be 1.14%, and lasting for 65min; three stages, heating to 940 ℃, controlling the carbon potential in the furnace to be 1.16%, and continuously maintaining for 1440min; four stages, maintaining the temperature in the furnace at 940 ℃, controlling the carbon potential in the furnace to be 0.84%, adjusting the opening of the auxiliary control valve to be 80%, and lasting 715min; fifthly, controlling the temperature in the furnace to 840 ℃, controlling the carbon potential in the furnace to be 0.9%, and lasting for 30min;
(2) The temperature in the high-temperature tempering furnace is 660 ℃ and the duration time is 1.75h;
(3) The temperature in the isothermal quenching furnace is 830 ℃, the carbon potential in the furnace is controlled to be 0.8%, and the duration is 4.25h; carrying out isothermal quenching for 3.75 hours in a nitrate solution at 230 ℃;
(4) Stabilizing the temperature in the treatment furnace to 130 ℃ for 2.75 hours;
(5) The cryogenic treatment comprises the steps of placing a workpiece cooled after the stabilization treatment into a cryogenic furnace, adopting a staged cooling method, and keeping the temperature in the cryogenic furnace at-30 ℃ for 20min at one stage; two stages, the temperature in the deep cooling furnace is minus 60 ℃ and lasts for 20min; three stages, the temperature in the cryogenic furnace is-90 ℃ and lasts for 20min; four stages, the temperature in the cryogenic furnace is 120 ℃ below zero and lasts for 90min;
(6) Tempering once at 170 ℃ in a low-temperature tempering furnace for 3.75 hours; tempering is carried out once at 190 ℃ for 2 hours.
After a series of heat treatment processes, the surface of the piston of the embodiment mainly comprises needle-shaped martensite, retained austenite, lower bainite and carbide, a transition region forms a mixed structure of lower bainite and hidden needle martensite, and a core mainly comprises lath martensite and a small amount of lower bainite; the surface hardness of the piston is 58.0-59.5 HRC, the core hardness is 43.5-44.5 HRC, and the effective hardening layer is 2.85-3.10 mm.
Example 3
A hydraulic breaking hammer piston heat treatment process method of SNCM26V material comprises the following steps:
(1) The carburizing pre-cooling carburizing agent adopts kerosene and methanol, and in one stage, a piston (workpiece) made of SNCM26V material is heated to 830 ℃ along with a furnace, the carbon potential in the furnace is controlled to be 0.84%, the opening of an auxiliary control valve is 100%, and the duration is 55min; two stages, heating to 890 ℃, controlling the carbon potential in the furnace to be 1.14%, and lasting for 65min; three stages, heating to 920 ℃, controlling the carbon potential in the furnace to be 1.16%, and lasting for 1430min; four stages, maintaining the temperature in the furnace at 920 ℃, controlling the carbon potential in the furnace to be 0.84%, adjusting the opening of the auxiliary control valve to be 80%, and continuing 730min; fifthly, controlling the temperature in the furnace to be 830 ℃, controlling the carbon potential in the furnace to be 0.9%, and lasting for 35min;
(2) The temperature in the high-temperature tempering furnace is 640 ℃ and the duration time is 2.15h;
(3) The temperature in the isothermal quenching furnace is 850 ℃, the carbon potential in the furnace is controlled to be 0.65%, and the duration is 4.15 hours; carrying out isothermal quenching in a nitrate solution at 220 ℃ for 4.15 hours;
(4) Stabilizing the temperature in the treatment furnace to 125 ℃ for 2.75 hours;
(5) The cryogenic treatment comprises the steps of placing a workpiece cooled after the stabilization treatment into a cryogenic furnace, adopting a staged cooling method, and keeping the temperature in the cryogenic furnace at-30 ℃ for 20min at one stage; two stages, the temperature in the deep cooling furnace is minus 60 ℃ and lasts for 20min; three stages, the temperature in the cryogenic furnace is-90 ℃ and lasts for 20min; four stages, the temperature in the cryogenic furnace is 120 ℃ below zero and lasts for 90min;
(6) Tempering once at 165 ℃ in a low-temperature tempering furnace for 3.75 hours; tempering is carried out once at 185 ℃ for 1.85h.
After a series of heat treatment processes, the surface of the piston of the embodiment mainly comprises needle-shaped martensite, retained austenite, lower bainite and carbide, a transition region forms a mixed structure of lower bainite and hidden needle martensite, and a core mainly comprises lath martensite and a small amount of lower bainite; the surface hardness of the piston is 58.0-59.0 HRC, the core hardness is 43.5-45 HRC, and the effective hardening layer is 2.8-3.2 mm.
Example 4
A hydraulic breaking hammer piston heat treatment process method of SNCM26V material comprises the following steps:
(1) The carburizing pre-cooling carburizing agent adopts kerosene and methanol, and in one stage, a piston (workpiece) made of SNCM26V material is heated to 855 ℃ along with a furnace, the carbon potential in the furnace is controlled to be 0.84%, the opening of an auxiliary control valve is 100%, and the duration is 60 minutes; two stages, heating to 895 ℃, controlling the carbon potential in the furnace to be 1.15%, and lasting for 65min; three stages, heating to 925 ℃ and keeping the carbon potential in the furnace at 1.15 percent for 1450min; four stages, maintaining the temperature inside the furnace at 935 ℃, controlling the carbon potential inside the furnace to be 0.84%, adjusting the opening of the auxiliary control valve to be 80%, and lasting for 700min; fifthly, controlling the temperature in the furnace to 850 ℃, controlling the carbon potential in the furnace to be 0.8%, and lasting for 35min;
(2) The temperature in the high-temperature tempering furnace is 650 ℃ and the duration time is 2h;
(3) The temperature in the isothermal quenching furnace is 860 ℃, the carbon potential in the furnace is controlled to be 0.8%, and the duration time is 4 hours; carrying out isothermal quenching in a nitrate solution at 230 ℃ for 4.15 hours;
(4) Stabilizing the temperature in the treatment furnace to 115 ℃ for 3 hours;
(5) The cryogenic treatment comprises the steps of placing a workpiece cooled after the stabilization treatment into a cryogenic furnace, adopting a staged cooling method, and keeping the temperature in the cryogenic furnace at-30 ℃ for 20min at one stage; two stages, the temperature in the deep cooling furnace is minus 60 ℃ and lasts for 20min; three stages, the temperature in the cryogenic furnace is-90 ℃ and lasts for 20min; four stages, the temperature in the cryogenic furnace is 120 ℃ below zero and lasts for 90min;
(6) Tempering once at 170 ℃ in a low-temperature tempering furnace for 4.15 hours; tempering is carried out once at 190 ℃ for 1.75 hours.
After a series of heat treatment processes, the surface of the piston of the embodiment mainly comprises needle-shaped martensite, retained austenite, lower bainite and carbide, a transition region forms a mixed structure of lower bainite and hidden needle martensite, and a core mainly comprises lath martensite and a small amount of ferrite; the surface hardness of the piston is 58.5-59.5 HRC, the core hardness is 44.5-45.5 HRC, and the effective hardening layer is 2.77-3.17 mm.
Comparative example 1
Substantially the same as in example 1, except that: after the diffusion stage of the fourth stage in the carburizing and precooling process is finished, the direct fan air cooling treatment is carried out, then the high-temperature tempering and isothermal quenching are sequentially carried out as described in the embodiment 1, the stabilization treatment and the deep cooling treatment are not carried out in the middle, and the tempering at 180 ℃ is only carried out once in the final low-temperature tempering process, and the heat preservation time is 2 hours.
The surface hardness of the piston is 56.0-57.0 HRC, the core hardness is 43.0-44.5 HRC, and the effective hardening layer is 2.60-2.70 mm.
The products prepared in example 1 and the corresponding comparative examples were tested according to the GB/T230.1 and GB/T25744 standards, and as shown in FIG. 2, the product (right image) produced according to the process of comparative example 1 was found to have a coarse needle-like martensite surface microstructure with a large amount of retained austenite, which eventually resulted in a piston with low surface hardness and low effective hardened layer. On the one hand, the product (left diagram) produced in the embodiment 1 eliminates coarse flaky martensite through a carburizing and precooling process, on the other hand, adopts a cryogenic process and two subsequent low-temperature tempering processes after stabilization, improves the depth of quenching, reduces the residual austenite content to the maximum extent, and obtains relatively fine needle-shaped martensite, lower bainite and a very small amount of residual austenite, so that the final surface hardness of the piston is high, the core hardness is moderate, the effective hardening layer is high, and the comprehensive performance is good.
The above description of the embodiments is only for aiding in the understanding of the method of the present invention and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A heat treatment process method of low-carbon high-alloy structural steel comprises the following steps:
s1) carrying out staged carburization on low-carbon high-alloy structural steel at 800-950 ℃, precooling to 800-850 ℃ and cooling;
s2) carrying out high-temperature tempering on the low-carbon high-alloy structural steel obtained in the step S1) at 600-700 ℃;
s3) carrying out isothermal salt bath quenching on the low-carbon high-alloy structural steel obtained in the step S2) at 200-280 ℃;
s4) stabilizing the low-carbon high-alloy structural steel obtained in the step S3) at 100-150 ℃;
and S5) carrying out staged cryogenic treatment on the low-carbon high-alloy structural steel obtained in the step S4) at the temperature of-20 to-130 ℃, and finally tempering at the temperature of 150-200 ℃.
2. The heat treatment process of claim 1, wherein the staged carburization comprises five stages:
a stage of: heating the low-carbon high-alloy structural steel to 830-860 ℃ along with a furnace, controlling the carbon potential in the furnace to be 0.84-0.86%, and preserving heat for 55-65 min;
two stages: heating to 890-910 ℃, controlling the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 55-65 min;
three stages: heating to 920-940 ℃, keeping the carbon potential in the furnace to be 1.14-1.16%, and preserving heat for 1430-1450 min;
four stages: maintaining the temperature in the furnace at 920-940 ℃, controlling the carbon potential in the furnace at 0.84-0.86%, and preserving the temperature at 700-730 min;
five stages: controlling the temperature in the furnace to be 830-850 ℃, controlling the carbon potential in the furnace to be 0.7-0.9%, and preserving heat for 25-35 min.
3. The heat treatment process according to claim 1, wherein the high temperature tempering temperature is 640-680 ℃ and the heat preservation time is 1.75-3.25 h.
4. The heat treatment process according to claim 1, characterized in that the isothermal salt bath quenching is specifically:
heating the low-carbon high-alloy structural steel obtained in the step S2) to 830-860 ℃, controlling the carbon potential to be 0.6-0.8%, preserving heat for 3.75-4.25 h, and quenching in a nitrate solution at 210-230 ℃ for 3.75-4.25 h; the nitrate solution comprises 50% of NaNO by mass percent 3 +50%KNO 3 。
5. The heat treatment process according to claim 1, wherein the temperature of the stabilizing treatment is 110-130 ℃ and the heat preservation time is 2.75-3.25 h.
6. The heat treatment process of claim 1, wherein the staged cryogenic treatment comprises four stages:
a stage of: the low-carbon high-alloy structural steel obtained in the step S4) is deeply cooled to the temperature of minus 25 to minus 35 ℃ for 18 to 25 minutes;
two stages: the low-carbon high-alloy structural steel subjected to the one-stage deep cooling treatment is deeply cooled to the temperature of-55 to-65 ℃ for 18 to 25 minutes;
three stages: the low-carbon high-alloy structural steel subjected to the two-stage deep cooling treatment is deeply cooled to the temperature of minus 75 to minus 95 ℃ for 18 to 25 minutes;
four stages: and (3) deep cooling the low-carbon high-alloy structural steel subjected to the three-stage deep cooling treatment to the temperature of-115 to-125 ℃ for 85-95 min.
7. The heat treatment process according to claim 1, wherein the tempering comprises a first tempering and a second tempering; the temperature of the first tempering is 150-180 ℃, the temperature is kept for 3.75-4.25 hours, the temperature of the second tempering is 170-190 ℃, and the temperature is kept for 1.75-2.25 hours.
8. The heat treatment process according to claim 1, wherein the low carbon high alloy structural steel comprises SNCM26V, 18Cr2Ni4W, 20Cr2Ni4, 23CrNi3Mo, 34CrNi3Mo or EN30b.
9. The heat treatment process according to any one of claims 1 to 8, wherein the surface structure of the low-carbon high-alloy structural steel obtained in step S5) includes needle-like martensite, retained austenite and carbide, the transition region includes lower bainite and hidden needle martensite, and the core structure includes lath martensite and lower bainite.
10. A hydraulic breaking hammer piston comprising low-carbon high-alloy structural steel, wherein the heat treatment process method of the low-carbon high-alloy structural steel is the heat treatment process method of any one of claims 1-9.
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Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102776471A (en) * | 2012-07-10 | 2012-11-14 | 镇江中船设备有限公司 | Carburizing quenching technology for low-carbon alloy steel parts |
| CN105238912A (en) * | 2015-11-17 | 2016-01-13 | 中国重汽集团济南动力有限公司 | Heating treatment technology for piston pin |
| CN105274309A (en) * | 2015-11-12 | 2016-01-27 | 张贺佳 | Subzero treatment technique for improving surface hardness of gear |
| CN105385835A (en) * | 2015-12-11 | 2016-03-09 | 上海交通大学 | Thermal treatment method for improving strength and toughness of high-strength steel piece of medium-thickness plate |
| CN105400944A (en) * | 2015-12-01 | 2016-03-16 | 张贺佳 | Cryogenic heat treatment technology for improving performances of countershaft gear |
| CN106086771A (en) * | 2016-08-10 | 2016-11-09 | 奇瑞汽车股份有限公司 | Gas carburizing Technology for Heating Processing for gasoline engine timing chain bar bearing pin |
| CN108118283A (en) * | 2017-12-25 | 2018-06-05 | 南京工程学院 | A kind of surface peening heat treatment method for improving hardness gradient |
| CN111057952A (en) * | 2019-12-31 | 2020-04-24 | 昆山奥马热工科技有限公司 | High-isotropy hot work die steel and heat treatment process thereof |
| CN114673787A (en) * | 2022-03-31 | 2022-06-28 | 山东天瑞重工有限公司 | Large-size hydraulic breaking hammer piston and manufacturing method thereof |
| CN114686650A (en) * | 2022-05-06 | 2022-07-01 | 宁夏天地西北煤机有限公司 | Gradient decreasing type deep carburizing process for backstop of large belt conveyor and backstop |
| CN114774837A (en) * | 2022-04-28 | 2022-07-22 | 南京高精齿轮集团有限公司 | Carburizing and quenching process |
| CN115233147A (en) * | 2022-08-09 | 2022-10-25 | 郑州机械研究所有限公司 | Heat treatment process for improving surface hardness of Cr-Ni steel |
| CN117535503A (en) * | 2023-12-25 | 2024-02-09 | 山东海纳精密工业有限公司 | Heat treatment method for high-strength alloy steel bevel gear |
-
2024
- 2024-03-01 CN CN202410233055.0A patent/CN117802446A/en active Pending
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102776471A (en) * | 2012-07-10 | 2012-11-14 | 镇江中船设备有限公司 | Carburizing quenching technology for low-carbon alloy steel parts |
| CN105274309A (en) * | 2015-11-12 | 2016-01-27 | 张贺佳 | Subzero treatment technique for improving surface hardness of gear |
| CN105238912A (en) * | 2015-11-17 | 2016-01-13 | 中国重汽集团济南动力有限公司 | Heating treatment technology for piston pin |
| CN105400944A (en) * | 2015-12-01 | 2016-03-16 | 张贺佳 | Cryogenic heat treatment technology for improving performances of countershaft gear |
| CN105385835A (en) * | 2015-12-11 | 2016-03-09 | 上海交通大学 | Thermal treatment method for improving strength and toughness of high-strength steel piece of medium-thickness plate |
| CN106086771A (en) * | 2016-08-10 | 2016-11-09 | 奇瑞汽车股份有限公司 | Gas carburizing Technology for Heating Processing for gasoline engine timing chain bar bearing pin |
| CN108118283A (en) * | 2017-12-25 | 2018-06-05 | 南京工程学院 | A kind of surface peening heat treatment method for improving hardness gradient |
| CN111057952A (en) * | 2019-12-31 | 2020-04-24 | 昆山奥马热工科技有限公司 | High-isotropy hot work die steel and heat treatment process thereof |
| CN114673787A (en) * | 2022-03-31 | 2022-06-28 | 山东天瑞重工有限公司 | Large-size hydraulic breaking hammer piston and manufacturing method thereof |
| CN114774837A (en) * | 2022-04-28 | 2022-07-22 | 南京高精齿轮集团有限公司 | Carburizing and quenching process |
| CN114686650A (en) * | 2022-05-06 | 2022-07-01 | 宁夏天地西北煤机有限公司 | Gradient decreasing type deep carburizing process for backstop of large belt conveyor and backstop |
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