CN102248116A - Manufacturing process for bolt with high strength of more than phi 30 - Google Patents
Manufacturing process for bolt with high strength of more than phi 30 Download PDFInfo
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- CN102248116A CN102248116A CN2011100785677A CN201110078567A CN102248116A CN 102248116 A CN102248116 A CN 102248116A CN 2011100785677 A CN2011100785677 A CN 2011100785677A CN 201110078567 A CN201110078567 A CN 201110078567A CN 102248116 A CN102248116 A CN 102248116A
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Abstract
The invention discloses a manufacturing process for a bolt with high strength of more than phi 30. The manufacturing process comprises the following steps of: forging; performing heat treatment and after treatment, wherein the heating forging temperature is between 1,100 and 1,300 DEG C, and the heating forging time is between 2 and 5 minutes; directly feeding workpieces into a mesh belt furnace quickly after forging for high temperature tempering, wherein the mesh belt furnace comprises a preheating area, a first heating area, a second heating area and a heat preservation area; preheating the workpieces through the preheating area after the workpieces are fed into the mesh belt furnace, and heating the workpieces through the first heating area and the second heating area; preserving the heat through the heat preservation area; cooling the workpieces which are subjected to the high temperature tempering; and trimming the cooled workpieces. By the manufacturing process, the workpieces are directly fed into the mesh belt furnace for high temperature tempering after being heated and forged, the excess heat of the forged workpieces is fully used, and time and energy are saved. The workpieces have a tempered sorbite structure after the high temperature tempering, grains are refined, and the phenomena that the grains are coarse and a martensite structure and a raw material structure are blended are prevented.
Description
Technical field
The present invention relates to material and forge and heat treatment technics, be specifically related to the forging and the Technology for Heating Processing of the high-strength bolt of a kind of Φ more than 30.
Background technology
High-strength bolt is used for the connection of bridge, rail, high pressure and extra-high tension unit for imposing the bolt of big pretightning force more.Need very strong bearing capacity when high-strength bolt is used to use, the raw material intensity of employing is very high, therefore processing technology is had relatively high expectations.
The high-strength bolt of Φ more than 30 must adopt heats forged because its specific (special) requirements can not be adopted cold-heading molding, forges the back and can form unnecessary edge at head, need excise.When the heats forged process of high-strength bolt, the heats forged temperature is forged the back product needed long period and is cooled off than higher.Because cool time is long, the head of bolt forms martensite easily and organizes crystal grain thick in respect of the bar portion of position, heating part in advance, owing to have that martensitic structure is easy goes into the bursting apart of head, causes bolt to scrap when cutting edge.On the other hand, when heat treatment because there is the line and staff control of martensitic structure and raw material tissue in bolt, like this when quenching since structural stress inhomogeneous cause bolt to ftracture easily and cause bolt to scrap.
At present, scrap problem at the bolt cracking that causes owing to the appeal reason, people carry out normalized treatment to workpiece after adopting heats forged usually, to reach thinning microstructure, improve the purpose of cutting ability.Because the temperature height is generally about 860 ℃, and temperature retention time is long, the type of cooling is taked the air cooling to this method when normalizing.The holding temperature of this method than higher, heat time heating time is long, will consume many electric energy, cost is higher.The second, this method is owing to adopt normalized treatment, the temperature height, and the type of cooling is an air, the list of bolts face easily forms oxide layer like this, influence the outward appearance and the size of bolt, influences use.In addition, the cooling air mode of this method is generally the open type cooling air mode, and the list of bolts surface temperature is higher, and cooling can be slow, like this at bolt circumferential surface temperature height, like this can be higher in the bolt environment temperature, and cause labor strength also high.
Summary of the invention
The objective of the invention is to:, the invention provides a kind of manufacturing process of Φ 30 above high-strength bolts in order to overcome the deficiencies in the prior art.Manufacturing process of the present invention can effectively reduce the cracking of bolt, has reduced the scrappage of high-strength bolt, simultaneously again can energy saving.
Technical scheme of the present invention: a kind of manufacturing process of Φ 30 above high-strength bolts, this technology may further comprise the steps:
(1) forges: choose the raw material that forge high-strength bolt,, the raw material of choosing are carried out preliminary treatment according to the line footpath requirement of bolt, forge, forging process is a heats forged again, and the heats forged temperature is 1100～1300 ℃, the heats forged time is 2～5 minutes
(2) heat treatment: the workpiece after the heats forged is sent into meshbeltfurnace rapidly carry out high tempering, described meshbeltfurnace comprises the preheating zone, first thermal treatment zone, second thermal treatment zone and heat preservation zone, workpiece carries out preheating through the preheating zone earlier after entering meshbeltfurnace, preheat temperature is 500～550 ℃, be 30～40 minutes preheating time, heat through first thermal treatment zone and second thermal treatment zone again, heating-up temperature is 550～570 ℃, be 30～40 minutes first thermal treatment zone heat time heating time, be 30～40 minutes second heat time heating time), be incubated through heat preservation zone at last, holding temperature is 550～570 ℃, temperature retention time is 60～80 minutes
(3) post processing: the workpiece to high tempering cools off, and cooling back is to the workpiece processing of cutting edge.
As preferably, described raw material are the 42CrMo steel.The 42CrMo steel belongs to unimach, has high strength and toughness, and quenching degree is also better, and higher fatigue limit and anti-repeatedly impact capacity are arranged after the modifier treatment, and low-temperature impact toughness is good, utilizes the 42CrMo forging to make high-strength bolt and has bigger intensity.
As preferred again, the type of cooling in the described step (3) is a water-cooled.Adopt the type of cooling of water-cooled to reduce cool time after high-strength bolt forges, reduced bolt head and the bar portion martensitic formation in position of heating is arranged and organize the thick phenomenon of crystal grain.
As preferred again, the mode of heating that forges in the described step (1) is an eddy-current heating.
As preferred again, preheat temperature is 500～530 ℃ in the described step (2).
As preferred again, the heating-up temperature of first thermal treatment zone and second thermal treatment zone is 550～560 ℃ in the described step (2).
The manufacturing process of Φ 30 above high-strength bolts of the present invention is with stove to carry out high tempering directly into the king after workpiece is carried out heats forged, made full use of and forged the waste heat that the back workpiece still has, the time that reduced has reached purpose of energy saving, after with high tempering, workpiece be organized as tempered sorbite, refinement crystal grain, fully avoided the mixed phenomenons that exist of two kinds in thick phenomenon of crystal grain and martensitic structure and raw material tissue tissue.
The specific embodiment
The manufacturing process of Φ 30 above high-strength bolts of the present invention selects for use the 42CrMo steel as raw material, selects for use the 42CrMo steel can effectively improve indexs such as tensile strength, hardness, yield strength and the elongation after fracture of high-strength bolt and the contraction percentage of area as raw material.
The manufacturing process of Φ 30 above high-strength bolts of the present invention is carried out high tempering will directly sending into meshbeltfurnace through the workpiece after the heats forged, meshbeltfurnace comprises preheating zone, first thermal treatment zone, second thermal treatment zone and heat preservation zone, workpiece enters advanced preheating of crossing the preheating zone behind the meshbeltfurnace, again through the heating of first thermal treatment zone and second thermal treatment zone, enter heat preservation zone again and be incubated, at last the workpiece of high tempering is carried out post processing processing after the water-cooled.
Embodiment 1
Select for use the 42CrMo steel as raw material, line footpath requirement according to bolt, raw material are carried out carrying out heats forged after the preliminary treatment, the heats forged temperature is 1100 ℃, the heats forged time is 5 minutes, the hardness of high-strength bolt head edge of the present invention is HRC45 after the heats forged, metallographic structure is a martensite, to send into meshbeltfurnace rapidly through the workpiece after the heats forged and carry out high tempering, workpiece enters the preheating zone of at first passing through meshbeltfurnace behind the meshbeltfurnace, preheating is 30 minutes under 550 ℃ temperature, enters first thermal treatment zone again, second thermal treatment zone entered behind first thermal treatment zone under 570 ℃ temperature heating 30 minutes, enter second thermal treatment zone then, heating is 30 minutes under 570 ℃ temperature, enters heat preservation zone at last and is incubated, and is incubated 60 minutes down at 570 ℃.
Workpiece behind the high tempering is taken out, and water cools off, and the metallographic structure of workpiece is pearlite and ferrite after the tempering, hardness to workpiece is tested, record that the case hardness of workpiece is HRC32 after the tempering, workpiece is cut edge again, adding up scrappage at last is 0.09%.
Embodiment 2
Select for use the 42CrMo steel as raw material, line footpath requirement according to bolt, raw material are carried out carrying out heats forged after the preliminary treatment, the heats forged temperature is 1200 ℃, the heats forged time is 3 minutes, the hardness of high-strength bolt head edge of the present invention is HRC50 after the heats forged, metallographic structure is a martensite, to send into meshbeltfurnace rapidly through the workpiece after the heats forged and carry out high tempering, workpiece enters the preheating zone of at first passing through meshbeltfurnace behind the meshbeltfurnace, preheating is 30 minutes under 530 ℃ temperature, enters first thermal treatment zone again, second thermal treatment zone entered behind first thermal treatment zone under 560 ℃ temperature heating 35 minutes, enter second thermal treatment zone then, heating is 30 minutes under 560 ℃ temperature, enters heat preservation zone at last and is incubated, and is incubated 70 minutes down at 560 ℃.
Workpiece behind the high tempering is taken out, and water cools off, and the metallographic structure of workpiece is pearlite and ferrite after the tempering, hardness to workpiece is tested, record that the case hardness of workpiece is HRC34 after the tempering, workpiece is cut edge again, adding up scrappage at last is 0.1%.
Embodiment 3
Select for use the 42CrMo steel as raw material, line footpath requirement according to bolt, raw material are carried out carrying out heats forged after the preliminary treatment, the heats forged temperature is 1300 ℃, the heats forged time is 2 minutes, the hardness of high-strength bolt head edge of the present invention is HRC55 after the heats forged, metallographic structure is a martensite, to send into meshbeltfurnace rapidly through the workpiece after the heats forged and carry out high tempering, workpiece enters the preheating zone of at first passing through meshbeltfurnace behind the meshbeltfurnace, preheating is 40 minutes under 500 ℃ temperature, heated 40 minutes under 550 ℃ temperature after entering first thermal treatment zone, enter second thermal treatment zone then, heating is 40 minutes under 550 ℃ temperature, enter heat preservation zone at last and be incubated, be incubated 80 minutes down at 550 ℃.
Workpiece behind the high tempering is taken out, and water cools off, and the metallographic structure of workpiece is pearlite and ferrite after the tempering, hardness to workpiece is tested, record that the case hardness of workpiece is HRC35 after the tempering, workpiece is cut edge again, adding up scrappage at last is 0.11%.
The high-strength bolt hardness of the fabrication process of Φ 30 above high-strength bolts of the present invention is HRC32～35, product rejection rate is about 0.1%, and the high-strength bolt that adopts prior art to produce, i.e. method through directly taking after the heats forged to cut edge, its scrappage is about 5%, and the present invention effectively reduces the scrappage when producing the above high-strength bolt of Φ 30.
Claims (7)
1. the manufacturing process of Φ 30 above high-strength bolts is characterized in that this technology may further comprise the steps:
(1) forges: choose the raw material that forge high-strength bolt,, the raw material of choosing are carried out preliminary treatment according to the line footpath requirement of bolt, forge, forging process is a heats forged again, and the heats forged temperature is 1100～1300 ℃, the heats forged time is 2～5 minutes
(2) heat treatment: the workpiece after the heats forged is sent into meshbeltfurnace rapidly carry out high tempering, described meshbeltfurnace comprises the preheating zone, first thermal treatment zone, second thermal treatment zone and heat preservation zone, workpiece carries out preheating through the preheating zone earlier after entering meshbeltfurnace, preheat temperature is 500～550 ℃, be 30～40 minutes preheating time, heat through first thermal treatment zone and second thermal treatment zone again, heating-up temperature is 550 ℃～570 ℃, be 30～40 minutes first thermal treatment zone heat time heating time, be 30～40 minutes second heat time heating time, is incubated through heat preservation zone at last, and holding temperature is 550 ℃～570 ℃, temperature retention time is 60～80 minutes
(3) post processing: the workpiece to high tempering cools off, and cooling back is to the workpiece processing of cutting edge.
2. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: described raw material are the 42CrMo steel.
3. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: the type of cooling in the described step (3) is a water-cooled.
4. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: the mode of heating that forges in the described step (1) is an eddy-current heating.
5. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: preheat temperature is 500～530 ℃ in the described step (2).
6. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: the heating-up temperature of first thermal treatment zone and second thermal treatment zone is 550～560 ℃ in the described step (2).
7. the manufacturing process of Φ 30 above high-strength bolts according to claim 1 is characterized in that: the holding temperature of heat preservation zone is 550～560 ℃ in the described step (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100785677A CN102248116A (en) | 2011-03-30 | 2011-03-30 | Manufacturing process for bolt with high strength of more than phi 30 |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100785677A CN102248116A (en) | 2011-03-30 | 2011-03-30 | Manufacturing process for bolt with high strength of more than phi 30 |
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| CN102248116A true CN102248116A (en) | 2011-11-23 |
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| CN2011100785677A Pending CN102248116A (en) | 2011-03-30 | 2011-03-30 | Manufacturing process for bolt with high strength of more than phi 30 |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102756071A (en) * | 2012-08-05 | 2012-10-31 | 贵州航天新力铸锻有限责任公司 | Forging method for AP1000 type nuclear power station reactor pressure vessel main bolt |
| CN103240382A (en) * | 2013-05-10 | 2013-08-14 | 西安航空动力股份有限公司 | Post-forging treatment method for TC11 titanium alloy miniature precisely forged blade |
| CN103436803A (en) * | 2013-08-13 | 2013-12-11 | 武汉重工铸锻有限责任公司 | Processing method for pump head body of five-cylinder plunger pump |
| CN103526004A (en) * | 2013-10-21 | 2014-01-22 | 无锡市德力流体科技有限公司 | Method for ensuring impact toughness of low-temperature fastener |
| CN103614530A (en) * | 2013-11-20 | 2014-03-05 | 大连赛瑞金属制品有限公司 | Quenching process in production technology of suspension insulator cryogenic steel foot |
| CN103982519A (en) * | 2014-05-29 | 2014-08-13 | 贵州航天精工制造有限公司 | Bidirectional orthogonal clamping bolt and preparing method thereof |
| CN109746360A (en) * | 2018-12-28 | 2019-05-14 | 江苏海宇机械有限公司 | A kind of manufacturing method improving forging part dimensional accuracy |
| CN109971936A (en) * | 2019-04-09 | 2019-07-05 | 舞阳钢铁有限责任公司 | Reduce 2.25Cr-1Mo-0.3V side edge of steel plate hardness method |
| CN110695627A (en) * | 2019-10-31 | 2020-01-17 | 李秋文 | Hot heading processing technology for fastener |
| CN111922266A (en) * | 2020-07-29 | 2020-11-13 | 陕西建科方圆汽车零部件有限公司 | Hot forging bolt processing method |
-
2011
- 2011-03-30 CN CN2011100785677A patent/CN102248116A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102756071A (en) * | 2012-08-05 | 2012-10-31 | 贵州航天新力铸锻有限责任公司 | Forging method for AP1000 type nuclear power station reactor pressure vessel main bolt |
| CN103240382B (en) * | 2013-05-10 | 2015-04-29 | 西安航空动力股份有限公司 | Post-forging treatment method for TC11 titanium alloy miniature precisely forged blade |
| CN103240382A (en) * | 2013-05-10 | 2013-08-14 | 西安航空动力股份有限公司 | Post-forging treatment method for TC11 titanium alloy miniature precisely forged blade |
| CN103436803A (en) * | 2013-08-13 | 2013-12-11 | 武汉重工铸锻有限责任公司 | Processing method for pump head body of five-cylinder plunger pump |
| CN103526004A (en) * | 2013-10-21 | 2014-01-22 | 无锡市德力流体科技有限公司 | Method for ensuring impact toughness of low-temperature fastener |
| CN103614530A (en) * | 2013-11-20 | 2014-03-05 | 大连赛瑞金属制品有限公司 | Quenching process in production technology of suspension insulator cryogenic steel foot |
| CN103614530B (en) * | 2013-11-20 | 2015-09-30 | 大连赛瑞金属制品有限公司 | Quenching technology in the production technique of suspension insulator cryogenic steel foot |
| CN103982519A (en) * | 2014-05-29 | 2014-08-13 | 贵州航天精工制造有限公司 | Bidirectional orthogonal clamping bolt and preparing method thereof |
| CN103982519B (en) * | 2014-05-29 | 2016-02-10 | 贵州航天精工制造有限公司 | A kind of orthogonal clamping bolt and preparation method |
| CN109746360A (en) * | 2018-12-28 | 2019-05-14 | 江苏海宇机械有限公司 | A kind of manufacturing method improving forging part dimensional accuracy |
| CN109971936A (en) * | 2019-04-09 | 2019-07-05 | 舞阳钢铁有限责任公司 | Reduce 2.25Cr-1Mo-0.3V side edge of steel plate hardness method |
| CN110695627A (en) * | 2019-10-31 | 2020-01-17 | 李秋文 | Hot heading processing technology for fastener |
| CN111922266A (en) * | 2020-07-29 | 2020-11-13 | 陕西建科方圆汽车零部件有限公司 | Hot forging bolt processing method |
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Application publication date: 20111123 |