CN105269247A - Processing technology for big high-strength hexagon bolt used for steel structure - Google Patents
Processing technology for big high-strength hexagon bolt used for steel structure Download PDFInfo
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- CN105269247A CN105269247A CN201410330848.0A CN201410330848A CN105269247A CN 105269247 A CN105269247 A CN 105269247A CN 201410330848 A CN201410330848 A CN 201410330848A CN 105269247 A CN105269247 A CN 105269247A
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Abstract
The invention discloses a processing technology for a big high-strength hexagon bolt used for a steel structure, and relates to a processing technology for a high-strength connecting piece. The bolt is made through high-frequency induction current hot forging, cold extruding and other processes. On the basis of a patent application with the patent application number 200810020090.5, in the processing technology, high-frequency induction heating is adopted for hot forging, and frequency is controlled to be 20,000-50,000 Hertz. High-frequency induction heating has the advantages of being high in speed, even in heating and the like, so that an even structure and performance from the core to the surface are obtained on the workpiece surface. The heating evenness of the workpiece is improved so that a better crystal phase structure can be obtained, and the high-strength bolt with the better performance is obtained.
Description
Technical field
The present invention relates to a kind of processing technology of high strength connector, particularly relate to a kind of processing technology of high-strength large hexagon head bolt used for steel structure.
Background technology
High-strength large hexagon head bolt used for steel structure is securing member conventional in machinery industry, current processing mode generally adopts turning mode in addition shaping, its intensity is often difficult to ensure, when tensile strength exceedes certain value, in the place that breach is concentrated as the transition position of bar and head or thread root easily cause delayed fracture and fatigue fracture, construction quality is caused and has a strong impact on, the generation of security incident can be caused due to the inadequate of its bonding strength time serious, therefore need to be studied the production technology of traditional high-strength bolt and improve, can produce in enormous quantities efficiently under the prerequisite guaranteeing its quality, meet the extensive needs of society to high-strength large hexagon head bolt used for steel structure, therefore the patent application that number of patent application is 200810020090.5 provides a kind of processing technology of high-strength large hexagon head bolt used for steel structure, its main inventive point is to have employed few without Cutting Process, employing cold extrusion is processed, to improve workpiece axial surface or internal fiber tissue, salt bath quenching and salt made from earth containing a comparatively high percentage of sodium chloride tempering is adopted in heat treatment simultaneously, reduce the degree of surface of the work oxidation and decarbonization layer, further ensure that the quality of bolt, but emit in first step in forge hot, heat with forge hot stove, there is firing rate slow, heat uneven, cause some position of workpiece overheated, some local underheated defect, easily cause workpiece generation bark pocket, slag inclusion, folder splits, the defects such as cracking, need further to improve.
Summary of the invention
The present invention is directed to above-mentioned defect, object be to provide a kind of at number of patent application be the patent application of 200810020090.5 basis on, further can improve the processing technology of the high-strength large hexagon head bolt used for steel structure of bolt quality.Technical scheme of the present invention is:
Concrete procedure of processing of the present invention is carried out as follows:
(1) get the raw materials ready: select 35CrMo or 20MnTiB to be blank, and according to blank under the large dolly of the specification of bolt.
(2) forge hot is begun to crop up: to begin to crop up to bolt with the temperature of 900 DEG C-1000 DEG C in high frequency induction heater and carry out forge hot, the frequency of high frequency induction current is 2-5 ten thousand hertz, rear cooling.
(3) soft annealing: carry out isothermal spheroidizing in clock hood type furnace, a large amount of carbon rich material matter is put in clock hood type furnace, softening annealing temperature: get 850 DEG C ± 10 DEG C when blank is 35CrMo, 840 DEG C ± 10 DEG C are got when blank is 20MnTiB, temperature retention time is 6-8 hour, be cooled to less than 250 DEG C to come out of the stove with stove after insulation, its hardness controls between HB100-120.
(4) blank surface process and lubrication: carry out phosphorating treatment to spiro rod section and be coated with the process of surface treatment of MoS2, its technological process is: alkali cleaning → washing → pickling → washing → phosphatization → cleaning → oscillator is coated with MoS2.
(5) first time is cold extrusion shaped: at room temperature extrude spiro rod section, select 150-200 ton gas position punch press.
(6) second time is extruded: at room temperature extrude thread segment on screw rod, select 70-90 ton gas position punch press.
(7) third time is extruded, at room temperature carries out thread forming, selects Z-28 screw-rolling machine.
(8) quench: quench to profiled member in salt bath furnace, its temperature controls at 860 DEG C ± 10 DEG C, heating-up time 10min-20min, temperature retention time 15min-25min, after having quenched, with oil cooling but, its chilling temperature is less than 80 DEG C.
(9) check: with HR-150A Rockwell Hardness meter, it is tested, be not less than 50 for pieces O.K. with HRC.
(10) tempering: in nitrate furnace, tempering is carried out to pieces O.K., when material is 35CrMo, its temperature control
Built in 530 DEG C ± 10 DEG C, when material is 20MnTiB, its temperature controls at 430 DEG C ± 10 DEG C, and the heating-up time is 25min-35min, and temperature retention time is 50min-70min, after tempering completes, cools at ambient temperature with water.
(11) secondary check: it is tested with HR-150A Rockwell Hardness meter, with HRC in 33-39 for pieces O.K..
(12) orchid is sent out: Bluing treatment is carried out to above-mentioned pieces O.K., to guarantee its non-corrosive.
(13) put in storage.
The present invention is on the basis of the patent application of 200810020090.5 at number of patent application, its forge hot have employed high-frequency induction heating, its FREQUENCY CONTROL is 2-5 ten thousand hertz, utilize the advantages such as high-frequency induction heating speed is fast, homogeneous heating, surface of the work can be made to obtain tissue, the performance of heart portion to surface uniform, improve the being heated evenly property of workpiece, can better crystal phase structure be obtained, obtain the high-strength bolt of better performance.
The mechanism of other step of the present invention is:
The hardness at each position of 35CrMo or 20MnTiB under hot-rolled state is uneven, plasticity is poor, resistance of deformation is large, if directly carry out cold extrusion processing without soft annealing process, then forming difficulty, mould easily damage, extrusion easily cracks, and therefore need to carry out soft annealing process to blank before cold-extrusion shaping.The present invention adopts spheroidizing to make it have lower hardness and good plasticity, and in order to improve the mechanical performance of material further, the present invention also can adopt normalizing process to material softening.
In order to reduce the residual stress of material and improve the surface quality of material, the present invention will carry out lubricated to material before to material cold extrusion, mainly phosphorating treatment, carries out the fatigue behaviour that phosphorating treatment significantly can reduce material after deliberation, is also more conducive to carry out cold extrusion processing to it.
The present invention carry out three times cold extrusion shaped, substantially increase each section of bolt intensity its, bolt quality is good, precision is high, its strength character might as well; Cold extrusion belongs to less, without machining, save raw material; Cold extrusion utilizes mould to be shaped, and it is highly efficient in productivity; Stock utilization greatly improves according to statistics, reach 99.5%-99.7%, working (machining) efficiency is about 1.8 times of traditional cutting technology, unit cost greatly reduces, because it belongs to few without cutting technology, make the material fiber direction of bolt embody globality on bolt body, substantially increase its tensile strength.
Heat treatment of the present invention adopts modifier treatment, namely quenching adds the process of tempering, to obtain the bolt with good combination property, process for quenching of the present invention can adopt the modern quenching modes such as the intercritical hardening of quench hot, high frequency circulation rapid heating and quenching and sub-eutectoid steel, makes bolt of the present invention have better mechanical property.
Detailed description of the invention
Below in conjunction with embodiment, the present invention is further elaborated:
Embodiment one:
Bolt specification of the present invention adopts 35CrMo, specification to adopt 20MnTiB to be blank when M16-M24 when M27-M30, its processing mode is: adopt few without machining, comprising three cold extrusion shaped, hot-forging formings, namely first time is cold extrusion shaped be that screw rod is shaping, second time is cold extrusion shaped is thread forming for thread segment on screw rod is shaping, third time is cold extrusion shaped, and hot-forging forming is that bolt is begun to crop up shaping.
Concrete procedure of processing of the present invention is carried out as follows:
(1) get the raw materials ready: select 35CrMo or 20MnTiB to be blank, and according to blank under the large dolly of the specification of bolt.
(2) forge hot is begun to crop up: to begin to crop up to bolt with the temperature of 900 DEG C in high frequency induction heater and carry out forge hot, the frequency of high frequency induction current is 20,000 hertz, rear cooling.
(3) soft annealing: carry out isothermal spheroidizing in clock hood type furnace, a large amount of carbon rich material matter is put in clock hood type furnace, softening annealing temperature: get 850 DEG C when blank is 35CrMo, 840 DEG C are got when blank is 20MnTiB, temperature retention time is 6 hours, be cooled to less than 250 DEG C to come out of the stove with stove after insulation, its hardness controls between HB100-120.
(4) blank surface process and lubrication: carry out phosphorating treatment to spiro rod section and be coated with the process of surface treatment of MoS2, its technological process is: alkali cleaning → washing → pickling → washing → phosphatization → cleaning → oscillator is coated with MoS2.
(5) first time is cold extrusion shaped: at room temperature extrude spiro rod section, select 150 tons of gas position punch presses.
(6) second time is extruded: at room temperature extrude thread segment on screw rod, select 70 tons of gas position punch presses.
(7) third time is extruded, at room temperature carries out thread forming, Z-28 screw-rolling machine.
(8) quench: quench to profiled member in salt bath furnace, its temperature controls at 860 DEG C, heating-up time 10min, temperature retention time 15min, after having quenched, with oil cooling but, its chilling temperature is less than 80 DEG C.
(9) check: with HR-150A Rockwell Hardness meter, it is tested, be not less than 50 for pieces O.K. with HRC.
(10) tempering: in nitrate furnace, tempering is carried out to pieces O.K., when material is 35CrMo, its temperature controls at 530 DEG C, when material is 20MnTiB, its temperature controls at 430 DEG C, and the heating-up time is 25min, and temperature retention time is 50min, after tempering completes, cool at ambient temperature with water.
(11) secondary check: it is tested with HR-150A Rockwell Hardness meter, with HRC in 33-39 for pieces O.K..
(12) orchid is sent out: Bluing treatment is carried out to above-mentioned pieces O.K., to guarantee its non-corrosive.
(13) put in storage.
Detailed description of the invention two:
Bolt specification of the present invention adopts 35CrMo, specification to adopt 20MnTiB to be blank when M16-M24 when M27-M30, its processing mode is: adopt few without machining, comprising three cold extrusion shaped, hot-forging formings, namely first time is cold extrusion shaped be that screw rod is shaping, second time is cold extrusion shaped is thread forming for thread segment on screw rod is shaping, third time is cold extrusion shaped, and hot-forging forming is that bolt is begun to crop up shaping.
Concrete procedure of processing of the present invention is carried out as follows:
(1) get the raw materials ready: select 35CrMo or 20MnTiB to be blank, and according to blank under the large dolly of the specification of bolt.
(2) forge hot is begun to crop up: to begin to crop up to bolt with the temperature of 1000 DEG C in high frequency induction heater and carry out forge hot, the frequency of high frequency induction current is 50,000 hertz, rear cooling.
(3) soft annealing: carry out isothermal spheroidizing in clock hood type furnace, a large amount of carbon rich material matter is put in clock hood type furnace, softening annealing temperature: get 860 DEG C when blank is 35CrMo, 850 DEG C are got when blank is 20MnTiB, temperature retention time is 8 hours, be cooled to less than 250 DEG C to come out of the stove with stove after insulation, its hardness controls between HB100-120.
(4) blank surface process and lubrication: carry out phosphorating treatment to spiro rod section and be coated with the process of surface treatment of MoS2, its technological process is: alkali cleaning → washing → pickling → washing → phosphatization → cleaning → oscillator is coated with MoS2.
(5) first time is cold extrusion shaped: at room temperature extrude spiro rod section, select 200 tons of gas position punch presses.
(6) second time is extruded: at room temperature extrude thread segment on screw rod, select 90 tons of gas position punch presses.
(7) third time is extruded, at room temperature carries out thread forming, selects Z-28 screw-rolling machine.
(8) quench: in salt bath furnace, profiled member is quenched, its temperature controls at 870 DEG C, heating-up time 20min, certainly, above-mentioned explanation is not limitation of the present invention, the present invention is also not limited to above-mentioned citing, those skilled in the art, in essential scope of the present invention, the change made, remodeling, add or replace, the technical staff that should belong to the industry of the present invention should understand, the present invention is not restricted to the described embodiments, what describe in above-described embodiment and description just illustrates principle of the present invention, without departing from the spirit and scope of the present invention, the present invention also has various changes and modifications, these changes and improvements all fall in the claimed scope of the invention.Application claims protection domain is defined by appending claims and equivalent thereof.
Claims (1)
1. the processing technology of high-strength large hexagon head bolt used for steel structure, is characterized in that, its concrete procedure of processing is carried out as follows:
(1) get the raw materials ready: select 35CrMo or 20MnTiB to be blank, and according to blank under the large dolly of the specification of bolt;
(2) forge hot is begun to crop up: to begin to crop up to bolt with the temperature of 900 DEG C-1000 DEG C in high frequency induction heater and carry out forge hot, the frequency of high frequency induction current is 2-5 ten thousand hertz, rear cooling;
(3) soft annealing: carry out isothermal spheroidizing in clock hood type furnace, a large amount of carbon rich material matter is put in clock hood type furnace, softening annealing temperature: get 850 DEG C ± 10 DEG C when blank is 35CrMo, 840 DEG C ± 10 DEG C are got when blank is 20MnTiB, temperature retention time is 6-8 hour, be cooled to less than 250 DEG C to come out of the stove with stove after insulation, its hardness controls between HB100-120;
(4) blank surface process and lubrication: carry out phosphorating treatment to spiro rod section and be coated with the process of surface treatment of MoS2, its technological process is: alkali cleaning → washing → pickling → washing → phosphatization → cleaning → oscillator is coated with MoS2;
(5) first time is cold extrusion shaped: at room temperature extrude spiro rod section, select 150-200 ton gas position punch press;
(6) second time is extruded: at room temperature extrude thread segment on screw rod, select 70-90 ton gas position punch press;
(7) third time is extruded, at room temperature carries out thread forming, selects Z-28 screw-rolling machine;
(8) quench: quench to profiled member in salt bath furnace, its temperature controls at 860 DEG C ± 10 DEG C, heating-up time 10min-20min, temperature retention time 15min-25min, after having quenched, with oil cooling but, its chilling temperature is less than 80 DEG C;
(9) check: with HR-150A Rockwell Hardness meter, it is tested, be not less than 50 for pieces O.K. with HRC;
(10) tempering: carry out tempering to pieces O.K. in nitrate furnace, when material is 35CrMo, its temperature controls
At 530 DEG C ± 10 DEG C, when material is 20MnTiB, its temperature controls at 430 DEG C ± 10 DEG C, and the heating-up time is 25min-35min, and temperature retention time is 50min-70min, after tempering completes, cools at ambient temperature with water;
(11) secondary check: it is tested with HR-150A Rockwell Hardness meter, with HRC in 33-39 for pieces O.K.;
(12) orchid is sent out: Bluing treatment is carried out to above-mentioned pieces O.K., to guarantee its non-corrosive;
(13) put in storage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410330848.0A CN105269247A (en) | 2014-07-14 | 2014-07-14 | Processing technology for big high-strength hexagon bolt used for steel structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410330848.0A CN105269247A (en) | 2014-07-14 | 2014-07-14 | Processing technology for big high-strength hexagon bolt used for steel structure |
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| Publication Number | Publication Date |
|---|---|
| CN105269247A true CN105269247A (en) | 2016-01-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410330848.0A Withdrawn CN105269247A (en) | 2014-07-14 | 2014-07-14 | Processing technology for big high-strength hexagon bolt used for steel structure |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106086362A (en) * | 2016-08-08 | 2016-11-09 | 常熟市常力紧固件有限公司 | A kind of Technology for Heating Processing of high hardness combination bolt |
| CN107282998A (en) * | 2017-07-21 | 2017-10-24 | 江苏军威电子科技有限公司 | A kind of saw blade forges moulding process |
| CN107345264A (en) * | 2017-07-21 | 2017-11-14 | 江苏军威电子科技有限公司 | A kind of rust resistance and corrosion resistance hammer head processing technology |
| CN107354465A (en) * | 2017-07-21 | 2017-11-17 | 江苏军威电子科技有限公司 | A kind of high intensity hammer head processing technology |
| CN107363203A (en) * | 2017-07-21 | 2017-11-21 | 江苏军威电子科技有限公司 | A kind of cold-heading molding technique of drill bit |
| CN107414420A (en) * | 2017-07-21 | 2017-12-01 | 南通安赛乐紧固件有限公司 | A kind of processing technology of high-strength large hexagon head bolt used for steel structure |
| CN107414012A (en) * | 2017-07-21 | 2017-12-01 | 南通安赛乐紧固件有限公司 | A kind of cold-heading molding technique of big hexagon head bolt |
| CN107486683A (en) * | 2017-07-21 | 2017-12-19 | 南通安赛乐紧固件有限公司 | A kind of steel structure bolt forges moulding process |
| CN107598484A (en) * | 2017-07-21 | 2018-01-19 | 南通安赛乐紧固件有限公司 | A kind of rust resistance and corrosion resistance Elements of Space Grid Truss bolt processing technic featuring |
| CN107598483A (en) * | 2017-07-21 | 2018-01-19 | 南通安赛乐紧固件有限公司 | A kind of high strength steel rack bolt processing technology |
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2014
- 2014-07-14 CN CN201410330848.0A patent/CN105269247A/en not_active Withdrawn
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106086362A (en) * | 2016-08-08 | 2016-11-09 | 常熟市常力紧固件有限公司 | A kind of Technology for Heating Processing of high hardness combination bolt |
| CN107282998A (en) * | 2017-07-21 | 2017-10-24 | 江苏军威电子科技有限公司 | A kind of saw blade forges moulding process |
| CN107345264A (en) * | 2017-07-21 | 2017-11-14 | 江苏军威电子科技有限公司 | A kind of rust resistance and corrosion resistance hammer head processing technology |
| CN107354465A (en) * | 2017-07-21 | 2017-11-17 | 江苏军威电子科技有限公司 | A kind of high intensity hammer head processing technology |
| CN107363203A (en) * | 2017-07-21 | 2017-11-21 | 江苏军威电子科技有限公司 | A kind of cold-heading molding technique of drill bit |
| CN107414420A (en) * | 2017-07-21 | 2017-12-01 | 南通安赛乐紧固件有限公司 | A kind of processing technology of high-strength large hexagon head bolt used for steel structure |
| CN107414012A (en) * | 2017-07-21 | 2017-12-01 | 南通安赛乐紧固件有限公司 | A kind of cold-heading molding technique of big hexagon head bolt |
| CN107486683A (en) * | 2017-07-21 | 2017-12-19 | 南通安赛乐紧固件有限公司 | A kind of steel structure bolt forges moulding process |
| CN107598484A (en) * | 2017-07-21 | 2018-01-19 | 南通安赛乐紧固件有限公司 | A kind of rust resistance and corrosion resistance Elements of Space Grid Truss bolt processing technic featuring |
| CN107598483A (en) * | 2017-07-21 | 2018-01-19 | 南通安赛乐紧固件有限公司 | A kind of high strength steel rack bolt processing technology |
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Application publication date: 20160127 |