CN104404241B - The blue crisp process of a kind of low-alloy steel low power fracture - Google Patents
The blue crisp process of a kind of low-alloy steel low power fracture Download PDFInfo
- Publication number
- CN104404241B CN104404241B CN201410644819.1A CN201410644819A CN104404241B CN 104404241 B CN104404241 B CN 104404241B CN 201410644819 A CN201410644819 A CN 201410644819A CN 104404241 B CN104404241 B CN 104404241B
- Authority
- CN
- China
- Prior art keywords
- fracture
- blue
- crisp
- temperature
- sample
- 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.)
- Active
Links
Landscapes
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
Abstract
The invention discloses the blue crisp process of a kind of low-alloy steel low power fracture, including to entrusting sample heat treatment, be machined out, break, then carry out blue crisp process；Have developed the blue crisp Technology for Heating Processing of low-alloy steel fracture: determine heating-up temperature, temperature retention time, laying method, firing equipment, histomorphometric analysis；Blue crisp effect is made to reach optimum state, thus improve the accuracy of low power field trash grading。
Description
Technical field
The present invention relates to the blue crisp process of a kind of low-alloy steel low power fracture, belong to steel fracture examination technical field。
Background technology
Steel-ferrum-examination criteria (SEP1584): blue crisp test is to detect the existence overview of nonmetallic inclusion on deformed steel product transverse section, these impurity need not amplify instrument just can see (length > 1.5mm, width G reatT.GreaT.GT 0.05mm), in the humidity province of orchid-temper color, about 330 DEG C are heated on orchid-temper color。
National standard only provides theoretical blue crisp temperature, but Technology for Heating Processing and blue crisp effect are not described in detail。All the time, experimenter reaches blue crisp effect only by modes such as many years of experience and increasing tested numbers, even if so, best blue crisp effect should why state be also very fuzzy。In order to meet national standard requirement, it is easier to the grading of tissue field trash state is judged by macroscopic examination, it is to be understood that affect the factor of the blue crisp effect of fracture, the blue crisp heat-treatment technology method of exploitation, it is determined that best blue crisp effect。
Summary of the invention
Low power fracture surface occur blue crisp time, its inclusion morphology can present white granular or fine strip shape, defect is easier to manifest, grading in order to meet steel low power fracture field trash judges, become apparent from exactly the field trash structural state of fracture sample being carried out low power analysis, the present invention provides a kind of low-alloy steel low power fracture blue crisp process, have developed the blue crisp Technology for Heating Processing of low-alloy steel fracture, blue crisp effect is made to reach optimum state, thus improve the accuracy of low power field trash grading。
The blue crisp process of a kind of low-alloy steel low power fracture provided by the invention, including to entrusting sample heat treatment, is machined out, breaks, then carry out blue crisp process；It is characterized in that specifically including herein below:
1, heating-up temperature
Heating-up temperature is that low power fracture produces blue crisp principal element。The crisp theoretical temperatures of orchid of low-alloy steel is about 300 DEG C, by the test of heat treatment different temperatures, it is determined that the temperature range of choice is at 370 ~ 410 DEG C, and best blue crisp temperature is 400 DEG C, it is desirable to sample to arrive temperature and enter stove。
When heating-up temperature is lower than 350 DEG C, the blue crisp degree of fracture face is shallower, is unfavorable for that grading judges；When temperature is higher than 420 DEG C, blue crisp speed-shifting is too fast, owing to two pieces of fracture sample stack together, cause that the crisp fringe time of orchid of two pieces of samples is different, below one piece complete blue crisp time, above also carry out blue crisp, when complete above blue crisp time, below blue crisp decreased effectiveness, it is impossible to control blue crisp optimum efficiency。So the heating temperature range finally determined is as shown in table 1。
Table 1
2, temperature retention time
Temperature retention time is one of blue crisp key factor of low power fracture。Owing to the blue crisp transformation of fracture is a pilot process, the length of time plays conclusive effect。If the time is too short, blue crisp transformation is formed not exclusively；If the time is oversize, then blue crisp transformation terminates。Find according to experiment, the blue crisp process of whole fracture be by heating initial stage → rubescent → blue indigo plant → dark blue → light blue → burnt hair and complete to change, fracture blue crisp is a pilot process, so strictly to control temperature retention time well, it is prevented that blue crisp transformation terminates。
The range of choice according to heating-up temperature is between 370 ~ 410 DEG C, it is determined that corresponding temperature retention time is 100min ~ 30min, and heat treatment orchid Embrittlement Fracture sample quantities is two pieces of 1 stove every time。
3, laying method
Uniform in order to ensure blue crisp transformation, being determined by experiment sample needs to be parallel to the placement of fire door direction；Secondly, to take safeguard procedures in sample shove charge or when coming out of the stove, protect fracture face and any collision does not occur, correctly grading in order to avoid affecting low power。
The placement location of fracture examination sample decides blue crisp effect, is that fracture produces one of blue crisp key factor。When fracture surface of sample face be perpendicular to fire door place time, by the impact of oxygen crisp atmosphere time, there is blue crisp phenomenon at first in fracture face close to fire door position, but when burner hearth rear portion section occur blue crisp time, the blue crisp end of fire door section is changed into again other colors；When fracture face is placed upward in heating furnace, fracture face will also result in blue crisp degree non-uniform phenomenon。
4, firing equipment
Owing to low power fracture examination size of sample is generally diameter × thickness=(200 ~ 400) mm × 20mm, so to select the fire door width firing equipment more than steel diameter when selecting heating furnace；
Table 2
Being first according to table 2 technique test, after center burst, sample is limited by heating furnace burner hearth internal diameter, and two fracture faces can only stack towards thermal element direction。Finding in process of the test, the blue crisp degree of fracture is very uneven, close to fire door position section turn blue time, the inside fracture face has not occurred change, but when the inside fracture face turns blue, fire door position fracture face shoals again indigo plant or brown, if it is desired that whole fracture face blue shortness is uniform, the time is difficult to hold。
According to blue crisp principle, sample generation orchid is crisp must good oxidizing atmosphere, and the sufficient preferential generation orchid of the oxygen content of fire door is crisp。In experiments it is found that, whole orchid crisp transition process time is critically important factor, and the laying method position of sample also drastically influence blue crisp effect。
Table 3
Then according to the engineer testing that table 3 sets, adopt big heating furnace to be heated, the placement of two fracture faces of sample is adopted different towards, be that fire door direction, furnace roof direction, three kinds of thermal element direction method are tested respectively。Result of the test finds, fracture is more uniform towards the blue crisp ratio of fire door direction entirety, but, the fracture face fracture uneven part of convex-concave, it is impossible to produce blue crisp。It addition, find in experimentation, when heat treatment temperature is lower than 350 DEG C, low power fracture can not produce blue crisp phenomenon, and when heat treatment temperature is more than 420 DEG C, the blue crisp speed of low power fracture face is too fast, after transformation completes, the blue crisp field color that first occurs having has turned to Lycoperdon polymorphum Vitt。
5, histomorphometric analysis
Test piece fracture adopts 50 tons of Apparatus for Bending at low-temp vertical depression static force to produce, and post-rift fracture exists larger difference, and the different shape of fracture directly affects the blue crisp effect of test piece。When fracture surface tear shape tissue more time, blue crisp effect is very uneven, tears shape tissue surface and does not almost occur blue crisp；When fracture surface fracture uniformly, without tear shape tissue exist time, blue crisp effect is very uniform。Accordingly, it is considered to this phenomenon is relevant with the structural state of steel。
Through understanding, the condition of delivery of steel is generally normalizing state and annealed state。By metallographic, different fracture states having been analyzed, when steel are in normalizing state, fracture surface fracture is uniformly；When steel are in annealed state, fracture surface fracture is very uneven。
Drawing through experiment, optimized heat treatment process parameter is: heating-up temperature preferably 400 DEG C, and corresponding temperature retention time is 40 minutes。
When consignment sample condition of heat treatment is normalizing state, it is made directly machining, breaks, then blue crisp process is carried out, consider best blue crisp effect, work efficiency and saving energy factor, determine that the blue crisp technique of heat treatment is 400 DEG C, temperature retention time is 40 minutes, it is desirable to sample enters stove to temperature, and the blue crisp effect of low power fracture face is navy blue；When consignment sample condition of heat treatment is annealed state, first carrying out normalizing, Technology for Heating Processing is temperature 850 DEG C, is incubated 30 minutes, and air cooling is machined out to room temperature, breaks, and then carries out blue crisp heat treatment, and technique is 400 DEG C and enters stove, and temperature retention time is 40 minutes；When not can determine that structural state, after confirming its structural state by Metallographic Analysis, carry out next step technological operation again。
Beneficial effects of the present invention: determine the blue crisp heat-treatment technology method of low-alloy steel fracture, the reference standard that blue crisp effect can judge as grading by testing。The method had both met national standard requirement, again concrete technology and effect had been determined, the grading for the blue crisp field trash of steel fracture judges to provide a set of practicable test method, specify that the process technique of the blue crisp inspection of low-alloy steel fracture。Treatment in accordance with the present invention method, fracture is after blue crisp heat treatment, and its white inclusion morphology substantially manifests, it is possible to steel defect effectively carries out grading and judges。
Detailed description of the invention
Further illustrate the present invention by the examples below, but be not limited to following example。
Embodiment:
1, heat treatment process test
According to standard-required, low power fracture examination size of sample is generally diameter × thickness=(200 ~ 400) mm × 20mm of steel, understands process of thermal treatment temperature according to relevant information, it is determined that process route, launches test。
Testing according to table 2 technique, after center burst, sample is limited by heating furnace burner hearth internal diameter, and two fracture faces can only stack towards thermal element direction。Finding in process of the test, the blue crisp degree of fracture is very uneven, close to fire door position section turn blue time, the inside fracture face has not occurred and becomes fragile, but when the inside fracture face turns blue, fire door position fracture face shoals again indigo plant or brown, if it is desired that whole fracture face orchid is crisp uniformly, the time is difficult to hold。
According to blue crisp principle, sample generation orchid is crisp must the crisp atmosphere of good oxygen, and the sufficient preferential generation orchid of the oxygen content of fire door is crisp。In experiments it is found that, whole orchid crisp transition process time is critically important factor, and the laying method position of sample also drastically influence blue crisp effect。
According to table 3 engineer testing, adopt big heating furnace to be heated, the placement of two fracture faces of sample is adopted different towards, be that fire door direction, furnace roof direction, three kinds of thermal element direction method are tested respectively。Result of the test finds, fracture is more uniform towards the blue crisp ratio of fire door direction entirety, but, the fracture face fracture uneven part of convex-concave, it is impossible to produce blue crisp,
It addition, find in experimentation, when heat treatment temperature is lower than 350 DEG C, low power fracture can not produce blue crisp phenomenon, and when heat treatment temperature is more than 420 DEG C, the blue crisp speed of low power fracture face is too fast, after moment all changed, some field color have turned to Lycoperdon polymorphum Vitt。
2, heating-up temperature and temperature retention time
Learning according to above-mentioned heat treatment process test process, heating-up temperature is that low power fracture produces blue crisp principal element。The crisp theoretical temperatures of orchid of low-alloy steel is about 300 DEG C, by the test of heat treatment different temperatures, it is determined that the temperature range of choice is at 370 ~ 410 DEG C, and best blue crisp temperature is 400 DEG C, it is desirable to sample to arrive temperature and enter stove。
That determines reason is that when heating-up temperature is lower than 350 DEG C, and the blue crisp degree of fracture face is shallower, is unfavorable for that grading judges；When temperature is higher than 420 DEG C, blue crisp speed-shifting is too fast, owing to two pieces of fracture sample stack together, cause that the crisp fringe time of orchid of two pieces of samples is different, below one piece complete blue crisp time, above also carry out blue crisp, when complete above blue crisp time, below blue crisp decreased effectiveness, it is impossible to control blue crisp optimum efficiency。So the heating temperature range finally determined is as shown in the table。
Temperature retention time is one of blue crisp key factor of low power fracture。Owing to the blue crisp transformation of fracture is a pilot process, the length of time plays conclusive effect。If the time is too short, blue crisp transformation is formed not exclusively；If the time is oversize, then blue crisp transformation terminates。The range of choice according to heating-up temperature is between 370 ~ 410 DEG C, it is determined that corresponding temperature retention time is 100min ~ 30min, and heat treatment orchid Embrittlement Fracture sample quantities is two pieces of 1 stove every time。
3, laying method
Uniform in order to ensure blue crisp transformation, being determined by experiment sample needs to be parallel to the placement of fire door direction。Owing to low power fracture examination size of sample is generally diameter 200 ~ 400mm × 20mm (thickness), so to select the fire door width firing equipment more than steel diameter when selecting heating furnace。Secondly, to take safeguard procedures in sample shove charge or when coming out of the stove, protect fracture face and any collision does not occur, correctly grading in order to avoid affecting low power。
The placement location of fracture examination sample decides blue crisp effect, is that fracture produces one of blue crisp key factor。When fracture surface of sample face be perpendicular to fire door place time, the impact of oxidated atmosphere time, there is blue crisp phenomenon at first close to fire door position in fracture face, but when burner hearth rear portion section occur blue crisp time, the blue crisp end of fire door section is changed into again other colors；When fracture face is placed upward in heating furnace, fracture face will also result in blue crisp degree non-uniform phenomenon。
4, fabric analysis
Test piece fracture adopts 50 tons of Apparatus for Bending at low-temp vertical depression static force to produce, and post-rift fracture exists larger difference, and the different shape of fracture directly affects the blue crisp effect of test piece。When fracture surface tear shape tissue more time, blue crisp effect is very uneven, tears shape tissue surface and does not almost occur blue crisp；When fracture surface fracture uniformly, without tear shape tissue exist time, blue crisp effect is very uniform。Accordingly, it is considered to this phenomenon is relevant with the structural state of steel。
Through understanding, the condition of delivery of steel is generally normalizing state and annealed state。By metallographic, different fracture states having been analyzed, when steel are in normalizing state, under metallographic, grain size is more than 7 grades, and fracture surface fracture is uniformly；When steel are in annealed state, under metallographic, grain size is less than 7 grades。Fracture surface occurs that fracture is very uneven。
Structural state decides fracture and produces blue crisp optimum efficiency, is one of key factor。When steel are annealed state, it is organized as pearlitic structrure。As can be seen from the test results, when structural state is annealed state, it is more that shape tissue is torn in its fracture surface of sample face, and section manifests concavo-convex uneven state, blue crisp transition effect is very poor, after heat treatment normalizing, crystal grain refines, and forms sorbite tissue, sample is after breaking, fracture face is without tearing shape tissue, and tissue distribution is uniform, and blue crisp effect is fine。
5, prepared by sample
The blue crisp test sample of fracture, first passes around machining apparatus and carries out cutting, it is desirable to the degree of depth cannot be greater than the 30% of diameter or thickness, then more than 50 tons Apparatus for Bending at low-temp are adopted to produce fracture sample, sample from after fracture to before heat treatment, fracture face must not carry out contacting and colliding, and keeps totally intact。
6, criterion
Owing to the form of field trash is white strip or granular, by contrasting, when section is navy blue, the color phenotypes of its field trash can become apparent from, and is conducive to grading to judge。
7, transition process
The blue crisp process of whole fracture be by heating initial stage → rubescent → blue indigo plant → dark blue → light blue → burnt hair and complete to change, fracture blue crisp is a pilot process, so strictly to control temperature retention time well, it is prevented that blue crisp transformation terminates。
8, influence factor
Finding in process of the test, affect low power fracture blue crisp because of have heating-up temperature, temperature retention time, laying method and structural state, various factors supplements and complements each other and low power fracture face generation orchid just can be made crisp, indispensable。
9, process route is determined
When consignment sample condition of heat treatment is normalizing state, it is made directly machining, breaks, then blue crisp process is carried out, consider best blue crisp effect, work efficiency and saving energy factor, determine that the blue crisp technique of heat treatment is 400 DEG C, temperature retention time is 40 minutes, it is desirable to sample enters stove to temperature, and the blue crisp effect of low power fracture face is navy blue；When consignment sample condition of heat treatment is annealed state, first carrying out normalizing, Technology for Heating Processing is temperature 850 DEG C, is incubated 30 minutes, and air cooling is machined out to room temperature, breaks, and then carries out blue crisp heat treatment, and technique is 400 DEG C and enters stove, and temperature retention time is 40 minutes；When not can determine that structural state, after confirming its structural state by Metallographic Analysis, carry out next step technological operation again。
Claims (4)
1. the blue crisp process of low-alloy steel low power fracture, including to entrusting sample heat treatment, is machined out, breaks, then carry out blue crisp process；It is characterized in that: blue crisp process specifically includes herein below:
(1) heating-up temperature
The crisp temperature range of choice of orchid of low-alloy steel is at 360 ~ 410 DEG C, it is desirable to sample to arrive temperature and enter stove；
(2) temperature retention time
The range of choice according to heating-up temperature is between 360 ~ 410 DEG C, it is determined that corresponding temperature retention time is 100min ~ 30min, and heat treatment orchid Embrittlement Fracture sample quantities is two pieces of 1 stove every time；
(3) laying method
Uniform in order to ensure blue crisp transformation, sample needs to be parallel to fire door direction and places；
To take safeguard procedures in sample shove charge or when coming out of the stove, protect fracture face and any collision does not occur；
(4) firing equipment
Owing to low power fracture examination size of sample is generally diameter × thickness=(200 ~ 400) mm × 20mm, so to select the fire door width firing equipment more than steel diameter when selecting heating furnace；
(5) histomorphometric analysis
Sample is normalizing state, and under metallographic, grain size is more than 7 grades, is made directly machining, then adopts 50 tons of Apparatus for Bending at low-temp vertical depression static force to produce and breaks, and fracture surface fracture is uniformly。
2. the blue crisp process of low-alloy steel low power fracture according to claim 1, it is characterised in that: described heating-up temperature is 400 DEG C, and corresponding temperature retention time is 40 minutes。
3. the blue crisp process of low-alloy steel low power fracture according to claim 1, it is characterized in that: when carrying out step (5), when sample condition of heat treatment is annealed state, under metallographic, grain size should first carry out normalizing less than 7 grades, and Technology for Heating Processing is temperature 850 DEG C, is incubated 30 minutes, air cooling is machined out to room temperature, breaks, then carrying out blue crisp process, technique is 400 DEG C and enters stove, and temperature retention time is 40 minutes。
4. the blue crisp process of low-alloy steel low power fracture according to claim 1 or 3, it is characterised in that: when carrying out step (5), when not can determine that structural state, after confirming its structural state by Metallographic Analysis, carry out next step technological operation again。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410644819.1A CN104404241B (en) | 2014-11-14 | 2014-11-14 | The blue crisp process of a kind of low-alloy steel low power fracture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410644819.1A CN104404241B (en) | 2014-11-14 | 2014-11-14 | The blue crisp process of a kind of low-alloy steel low power fracture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104404241A CN104404241A (en) | 2015-03-11 |
| CN104404241B true CN104404241B (en) | 2016-06-22 |
Family
ID=52641904
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410644819.1A Active CN104404241B (en) | 2014-11-14 | 2014-11-14 | The blue crisp process of a kind of low-alloy steel low power fracture |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104404241B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105021534B (en) * | 2015-07-21 | 2017-07-18 | 河北钢铁股份有限公司邯郸分公司 | A kind of method of detection 20CrMnTi structure of steel composition and content |
| CN105203383B (en) * | 2015-09-08 | 2018-08-28 | 西宁特殊钢股份有限公司 | A kind of fracture examination method of turning blue of simple possible |
| CN105891102A (en) * | 2016-04-01 | 2016-08-24 | 江苏藤仓亨通光电有限公司 | Method for detecting layering defect of copper or copper alloy contact lines |
| CN111855733A (en) * | 2020-07-24 | 2020-10-30 | 山西太钢不锈钢股份有限公司 | Blue brittleness process method for detecting inclusions and white spots at macroscopic fracture of medium alloy steel |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103898413B (en) * | 2014-03-18 | 2016-01-20 | 莱芜钢铁集团有限公司 | V n micro alloying frotton steel and preparation method thereof |
-
2014
- 2014-11-14 CN CN201410644819.1A patent/CN104404241B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN104404241A (en) | 2015-03-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104404241B (en) | The blue crisp process of a kind of low-alloy steel low power fracture | |
| CN103894792B (en) | Method for machining forge piece of large-scale single-flange anti-explosion motor main shaft of all-fiber texture | |
| CN104907470B (en) | 13Cr9Mo2Co1NiVNbNB steel forged piece manufacturing method | |
| WO2009073316A3 (en) | Method and apparatus for controlling a gas cluster ion beam formed from gas mixture | |
| CN106513925B (en) | method for screening reasonable welding process parameters based on impact toughness | |
| CN108517461A (en) | A kind of high-performance martensitic stain less steel flange and forging and its manufacturing method | |
| CN103753023B (en) | The welding method of hot rolling nano reinforcement steel plate | |
| Feng et al. | The microstructure evolution of lean duplex stainless steel 2101 | |
| Li et al. | Microcrack nucleation and early crack growth of a nuclear grade nitrogen alloyed austenitic stainless steel X2CrNiMo18. 12 under thermomechanical fatigue loading | |
| CN108998643A (en) | A method of improving flexbile gear raw material banded structure | |
| Li et al. | Embrittlement of intercritically reheated coarse grain heat-affected zone of ASTM4130 steel | |
| CN106248715A (en) | Thermal modeling test determines the test method of quenching rate of cooling | |
| CN101956048B (en) | Heat treatment process of ship carbon-manganese steel casting | |
| CN203295556U (en) | Heat-treatment furnace system for waste heat recovery | |
| CN103184388A (en) | Integral normalizing process of 95CrMo steel for rock drilling rod | |
| CN102062719A (en) | Method for detecting air permeability of sintering mixture and sintering device | |
| CN106756763A (en) | A kind of method that part of different materials carries out glow discharge nitriding with stove | |
| CN104004890A (en) | Method for determining temper temperature of 20SiMn2MoV structural alloy steel | |
| Jabłońska et al. | Heat treatment of high manganese type X57MnAl27-5 austenitic steel | |
| CN106868279A (en) | A kind of elimination 20CrMnTiH residual forging heats isothermal normalizing produces the Technology for Heating Processing of acicular ferrite | |
| Su et al. | Novel CRISPR/SpRY system for rapid detection of CRISPR/Cas-mediated gene editing in rice | |
| CN102443688A (en) | Protective gas treatment device and method of annealing region and bluing region of motor core heat treatment furnace | |
| CN112763508A (en) | Method for judging cause of edge cracking crack of medium plate | |
| CN108733862B (en) | Creep induction period prediction method considering restraint effect under steady-state creep condition | |
| CN106636558A (en) | Carbothermy-based hot metal pretreatment in-situ desulphurization method for magnesite-based desulfurizers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |