CN108220578A - The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time - Google Patents
The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time Download PDFInfo
- Publication number
- CN108220578A CN108220578A CN201711401863.XA CN201711401863A CN108220578A CN 108220578 A CN108220578 A CN 108220578A CN 201711401863 A CN201711401863 A CN 201711401863A CN 108220578 A CN108220578 A CN 108220578A
- Authority
- CN
- China
- Prior art keywords
- salt bath
- gear wheel
- 18crnimo7
- quenching
- salt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/607—Molten salts
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention belongs to carburizing steel quenching technology fields, more particularly to a kind of judgment method of 6 gear wheel carburization part salt bath quenching times of large size 18CrNiMo7, it is specifically, salt bath quenching cooling will be hung in by the 6 gear wheel carburization parts of large-scale 18CrNiMo7 of heating, record starts salt temperature and timing node t1, salt temperature variation is recorded in real time, when salt temperature reaches peak and begins to decline, records salt temperature and timing node t2, salt bath t=t cooling time at this time2‑t1, continue to cool down the 0.2t times, after cooling, gear wheel carburization part taken out into salt bath and completes quenching.Above-mentioned judgment method can effectively control the cool time, the surface and center portion cooling after parts quenching in place, surface and center portion can intact completion structural transformation and obtain the performances such as required tissue, hardness.
Description
Technical field
The invention belongs to carburizing steel quenching technology fields, and in particular to a kind of large size 18CrNiMo7-6 gear wheel carburization part salt
Bathe the judgment method of cool time.
Background technology
18CrNiMo7-6 carburizing steel, Cr contents are in 1.5-1.8%, and Ni contents are in 1.4-1.7%, as a kind of low-carbon
High alloy carburation steel, thermal conduction rate are relatively lower than low-alloy material.What 18CrNiMo7-6 carburizing steel quenching after carbunse used
Medium is low temperature salt-bath, and salt bath ingredient is+50% sodium nitrite of 50% potassium nitrate, 160-180 DEG C of salt bath temperature in use.It is large-scale
18CrNiMo7-6 carburizing parts are about set to the part that quality is more than 5 tons herein, and salt bath will be entered after austenite heating and thermal insulation
Quenching, the judgement for large-scale carburizing part salt bath cooling time only have general calculation formula both at home and abroad at present, i.e., 10~
For 15min/ per 100mm controlling sections, the influence for batch size, part section size does not have related data explanation.
The different batches of same cross-sectional part are found during practical application and with the different cross section part under batch, quenching cooling
Time, non-simple formula can be calculated accurately.Cooling time is long in salt bath, and easy stabilization of austenite causes surface paralympic
Exceeded, salt bath is too short cooling time, and center portion heat is risen again causes surface hardening layer to soften to surface, and piece surface can not be completed
Martensite transfor mation, unavailable quench-hardened case.So the accurately judgement of salt bath cooling time is particularly significant.
18CrNiMo7-6 material AC3 lines are 820 DEG C or so, and Ms points are 400 DEG C or so, carburizing rear surface concentration of carbon 0.7%
When its Ms point be 120 DEG C or so.Core structure transformation is completed in the 160-180 DEG C of salt bath quenching of 18CrNiMo7-6 carburizing parts, rear
Continuous air-cooled middle completion transformation of the surface overcooling austenite to martensitic structure.
Invention content
Invention broadly provides a kind of judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times,
Cool time can effectively be controlled by this kind of method, the surface and center portion cooling after parts quenching in place, surface and the heart
Intact it can complete structural transformation and obtain the performances such as required tissue, hardness in portion.Its technical solution is as follows：
A kind of judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times is specifically that will pass through and add
The large-scale 18CrNiMo7-6 gear wheel carburizations part of heat hangs in salt bath quenching cooling, and record starts salt temperature and timing node t1,
Record salt temperature variation in real time when salt temperature reaches peak and begins to decline, records salt temperature and timing node
t2, salt bath t=t cooling time at this time2-t1, continue to cool down the 0.2t times, after cooling, gear wheel carburization part taken out into salt bath
Slot completes quenching.
Preferably, the gear wheel carburization part for completing quenching is detected into root portion temperature using infrared temperature detector, if tooth root
Portion's temperature is not fully cooled to position, and gear wheel carburization part is returned salt bath and continues to cool down.
Preferably, the salt bath solution ingredient in salt bath is 50% potassium nitrate and the mixed liquor of 50% sodium nitrite.
Preferably, the initial temperature of the salt bath solution is 160-180 DEG C.
Preferably, the large size 18CrNiMo7-6 gear wheel carburizations part is more than 5 tons of part for quality.
Using the above scheme, the present invention has the following advantages：
(1) present invention abandons general quenching Cooling calculation method, using t+0.2t methods, the table after parts quenching
In place, surface and center portion intact can be completed structural transformation and obtain the performances such as required tissue, hardness for face and center portion cooling,
The practicability and reliability of product actual production can be improved according to the analysis of practical salt temperature delta data；
(2) above-mentioned judgment method can cope with the heat treatment production of different batches and controlling sections part, only to salt
The real time monitoring of bath temperature can complete the quenching heat treatment of part very well, and easy to operate and product quality problem risk is small, fit
It is wide with property.
Description of the drawings
Fig. 1 is part salt bath quenching temperature changing curve diagram in embodiment 1；
Fig. 2 is to organize metallograph after parts quenching in embodiment 1；
Fig. 3 is to organize metallograph after parts quenching in comparative example 1.
Specific embodiment
Experimental method in following embodiment is conventional method unless otherwise required, involved experiment reagent and material
Material is conventional biochemical reagent and material unless otherwise required.
Embodiment 1
18CrNiMo7-6 gear wheel carburization part of one mass more than 5 tons through austenitizing is heated, is hung in after the completion of heat preservation
160-180 DEG C of+50% sodium nitrite salt bath of 50% potassium nitrate quenching cooling, record start salt temperature and timing node t1；
In real time record salt temperature variation, when salt temperature reaches peak and begins to decline, record salt temperature and when segmentum intercalaris
Point t2, salt bath t=t cooling time at this time2-t1, continue to cool down the 0.2t times.After cooling, record quenching cooling finishes salt
Gear wheel carburization part is taken out salt bath and completes quenching by bath temperature and timing node.Air-cooled behaviour is carried out again after the completion of quenching
Make.
For the present invention by judging parts quenching cooling time to the variation node of salt temperature, principle is as follows：
During part salt bath quenching, the transmission of heat is made of the heat dissipation of part and the cooling heat absorption of salt bath, and part is in salt bath
Interior heat release, salt bath temperature liter, salt bath cooling blower unlatching at this time, salt temperature reaches peak after quenching, and salt temperature starts
During decline, illustrate that part heat release and salt bath cooling blower absorb heat to form heat suction and be laid flat weighing apparatus, part center portion temperature has reduced at this time
To lower temperature and complete core structure transformation, but Central of the parts regional temperature is also at 300-400 DEG C, surface with salt temperature
Unanimously, continuing cooling a period of time after makes 300-400 DEG C of center portion further decline to soften surface hardening layer to prevent non-return temperature, after this
Continuous cooling time quenches the 20% of cooling time for early period.Cooling finishes part and goes out quenching salt tank, can be red after salt bath by going out
Outside line temperature monitor accurately detects tooth root temperature and judges whether part is fully cooled to position, if finding tooth root temperature compared with Gao Zeke
To continue salt bath cooling and not influence cooling effect.
Specific Central of the parts regional temperature variation, piece surface temperature change, salt bath solution temperature variations such as Fig. 1 institutes
Show.Its tissue metallograph of the 18CrNiMo7-6 gear wheel carburizations part completed through above method quenching is as shown in Figure 2.
Comparative example 1
The 18CrNiMo7-6 gear wheel carburization parts of quality same as Example 1 through austenitizing are heated, are hung after the completion of heat preservation
Enter 160-180 DEG C, the quenching cooling of+50% sodium nitrite salt bath of 50% potassium nitrate, cooling total time, (t was with implementing for t+0.3t
Calculation in example 1 is identical).Its tissue metallograph of the 18CrNiMo7-6 gear wheel carburizations part that quenching is completed is as shown in figure 3, can
Know that surface is paralympic exceeded.
Hardness determination
The carburizing part of embodiment 1 and comparative example 1 is subjected to hardness determination respectively, the results are shown in Table 1：
1 gear wheel carburization part thermal treatment quality result of table
As shown in Table 1, the ME grades that the part quality completed through the quenching of 1 method of embodiment meets ISO6336-5-2016 will
It asks.The paralympic nonattainment area hardness number of piece surface is relatively relatively low in comparative example 1, paralympic height in the 0.15mm regions of surface, corresponds to hard
Spend only 642HV1, few zone hardness paralympic much smaller than secondary surface layer.
It will be apparent to those skilled in the art that technical solution that can be as described above and design, make other various
Corresponding change and deformation, and all these changes and deformation should all belong to the protection domain of the claims in the present invention
Within.
Claims (5)
1. a kind of judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times, it is characterised in that：To through and adding
The large-scale 18CrNiMo7-6 gear wheel carburizations part of heat hangs in salt bath quenching cooling, and record starts salt temperature and timing node t1,
Record salt temperature variation in real time when salt temperature reaches peak and begins to decline, records salt temperature and timing node
t2, salt bath t=t cooling time at this time2-t1, continue to cool down the 0.2t times, after cooling, gear wheel carburization part taken out into salt bath
Slot completes quenching.
2. the judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times according to claim 1, special
Sign is：The gear wheel carburization part for completing quenching is detected into root portion temperature using infrared temperature detector, if root portion temperature is not
Position is fully cooled to, gear wheel carburization part is returned into salt bath and continues to cool down.
3. the judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times according to claim 1, special
Sign is：Salt bath solution ingredient in salt bath is 50% potassium nitrate and the mixed liquor of 50% sodium nitrite.
4. the judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times according to claim 3, special
Sign is：The initial temperature of the salt bath solution is 160-180 DEG C.
5. the judgment method of large size 18CrNiMo7-6 gear wheel carburization part salt bath quenching times according to claim 1, special
Sign is：The large size 18CrNiMo7-6 gear wheel carburizations part is more than 5 tons of part for quality.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711401863.XA CN108220578A (en) | 2017-12-22 | 2017-12-22 | The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711401863.XA CN108220578A (en) | 2017-12-22 | 2017-12-22 | The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108220578A true CN108220578A (en) | 2018-06-29 |
Family
ID=62648425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711401863.XA Pending CN108220578A (en) | 2017-12-22 | 2017-12-22 | The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108220578A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109338275A (en) * | 2018-11-09 | 2019-02-15 | 常州天山重工机械有限公司 | A kind of middle-size and small-size cylinder body carburizing multistage quenching technical of 18CrNiMo7-6 steel |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103710497A (en) * | 2013-12-19 | 2014-04-09 | 常州天山重工机械有限公司 | Thermal treatment process for controlling contraction of common normal line of high-alloy carburizing steel quenching gear |
| CN103820624A (en) * | 2012-11-19 | 2014-05-28 | 林州重机集团股份有限公司 | Salt-bath furnace quenching method for teeth of chain wheel |
| CN104846157A (en) * | 2015-03-31 | 2015-08-19 | 常州天山重工机械有限公司 | Novel tempering technology for high-precision high-speed heavy-duty gear salt bath quenching |
| CN105755266A (en) * | 2014-12-13 | 2016-07-13 | 重庆环德科技有限公司 | Gear quenching technology |
-
2017
- 2017-12-22 CN CN201711401863.XA patent/CN108220578A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103820624A (en) * | 2012-11-19 | 2014-05-28 | 林州重机集团股份有限公司 | Salt-bath furnace quenching method for teeth of chain wheel |
| CN103710497A (en) * | 2013-12-19 | 2014-04-09 | 常州天山重工机械有限公司 | Thermal treatment process for controlling contraction of common normal line of high-alloy carburizing steel quenching gear |
| CN105755266A (en) * | 2014-12-13 | 2016-07-13 | 重庆环德科技有限公司 | Gear quenching technology |
| CN104846157A (en) * | 2015-03-31 | 2015-08-19 | 常州天山重工机械有限公司 | Novel tempering technology for high-precision high-speed heavy-duty gear salt bath quenching |
Non-Patent Citations (2)
| Title |
|---|
| 刘永铨: "《钢的热处理》", 28 February 1981, 冶金工业出版社 * |
| 吴玉程: "《工程材料基础》", 31 December 2014, 合肥工业大学出版社 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109338275A (en) * | 2018-11-09 | 2019-02-15 | 常州天山重工机械有限公司 | A kind of middle-size and small-size cylinder body carburizing multistage quenching technical of 18CrNiMo7-6 steel |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106222606B (en) | A kind of process controlling carburized workpiece non-martensite depth | |
| CN104879572B (en) | A kind of spring support hanging frame fitting fastening and preparation method thereof | |
| CN100584962C (en) | Bainite auctile iron isothermal quenching technology | |
| CN105369015A (en) | 42 CrMo shaft part quenching and heat-treatment technology | |
| CN108103300A (en) | A kind of high-speed steel tool heat treatment process | |
| CN108220578A (en) | The judgment method of large-scale 18CrNiMo7-6 gear wheel carburizations part salt bath quenching time | |
| CN107475487A (en) | A kind of production method of low-carbon and low-alloy high intensity high/low temperature toughness steel-casting | |
| CN110283974A (en) | A kind of heat treatment process of pressure vessel 12Cr2Mo1V steel forgings | |
| US20150144234A1 (en) | Microtreatment of carbide containing iron-based alloy and articles resulting therefrom | |
| CN106086360A (en) | A kind of heat treatment method of Industrial Steam Turbine Rotors Aided forging | |
| CN106011425A (en) | Hardening and tempering treatment technique for low-alloy heat-resistant steel fasteners | |
| CN102828143A (en) | High-temperature carburizing technology for workpiece | |
| CN105132634B (en) | A kind of process for quenching of self-elevating ocean platform spud leg rack steel plate | |
| Ohaeri et al. | EBSD Microstructural studies on quenched-tempered API 5L X65 pipeline steel | |
| CA1210672A (en) | Method for at least partial isothermal bainitizing of workpieces made of ferrous materials | |
| CN104694719A (en) | Thick-specification pipeline steel cooling method | |
| CN108277323A (en) | A kind of salt bath quenching process of bearing ring component | |
| Song et al. | Numerical simulation on temperature and microstructure during quenching process of large-sized AISI P20 steel die blocks | |
| JPS59107018A (en) | Heat treatment of cast iron parts | |
| CN108424999B (en) | A kind of heat treatment process of shallow-tank separator driving chain components | |
| CN105925773A (en) | Heat treatment method for steel | |
| CN106854746B (en) | A kind of high-speed rail surface peening rare earth high-carbon chromium steel and its preparation process | |
| US3009843A (en) | Steel products and method for producing same | |
| Tensi et al. | Proposal to monitor agitation of production quench tanks | |
| CN104117830A (en) | Gear production technology facilitating gear surface quality and segregation degree |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20180629 |