CN109321742A - A kind of Medium frequency induction secondary heat treatment technique of pipe welding port - Google Patents
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port Download PDFInfo
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- CN109321742A CN109321742A CN201811525435.2A CN201811525435A CN109321742A CN 109321742 A CN109321742 A CN 109321742A CN 201811525435 A CN201811525435 A CN 201811525435A CN 109321742 A CN109321742 A CN 109321742A
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- 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
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
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- 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
- C21D1/34—Methods of heating
- C21D1/42—Induction heating
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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Abstract
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, step are as follows: 1) ball hardness number detection is carried out to the weld bond that need to carry out Medium frequency induction secondary heat treatment respectively and metallographic detects；2) Medium frequency induction secondary heat treatment technology establishment；3) thermocouple binding and fixing；4) weld bond is bound, and heat-preservation cotton is wrapped in outside weld bond, then by heat-preservation cotton, weld bond and thermocouple bandage binding and fixing, checks weld bond binding；5) induction coil is wound, and by induction coil uniform winding outside heat-preservation cotton, determines whether induction coil quantity meets heating requirements, adjusts induction coil spacing；6) Medium frequency induction secondary heat treatment technological parameter is inputted；7) start intermediate frequency induction heating device；8) Physico-chemical tests and non-destructive testing；Have the characteristics that thermal treatment quality is good, technological operation is simple, high production efficiency and energy conservation and environmental protection.
Description
Technical field
The invention belongs to pipe welding port technical field of heat treatment, and in particular to a kind of Medium frequency induction second heat of pipe welding port
Treatment process.
Background technique
Currently, mainly using resistance heating technique when domestic pipeline weld bond is heat-treated.Resistance heating technique it is main
The disadvantage is that weld bond uneven heating is even, inside and outside wall temperature difference is big and operating process is complicated etc..Therefore, the contour conjunction of P91 martensite heat-resistant steel
Golden material weld bond, according to resistance heating technique, is difficult the ball hardness number on weld bond surface being reduced to specification in heat treatment
It is required that but the weld bond of such material can be at most heat-treated twice.Regulations requirement, the Brinell hardness on P91 weld bond surface
Value should control between 180 ~ 270HB.When P91 weld bond is once heat-treated, first-time qualification rate is less than 60%, and weld bond
For superficial hardness number usually between 250 ~ 270HB, thermal effectiveness is bad；It is required according to Regulations, after primary heat treatment, cloth
Family name's hardness number is more than that the P91 weld bond of 270HB must carry out secondary heat treatment, but the secondary qualification rate of P91 weld bond is less than 30%, because
This, final qualification rate of the P91 weld bond after primary heat treatment and secondary heat treatment is less than 72%, and weld bond surface ball hardness number
Substantially all between 250 ~ 270HB.By above-mentioned statistical result, when illustrating to be heat-treated using resistance heating technique, P91 weldering
The thermal treatment quality of mouth is bad, and the secondary heat treatment qualification rate of special P91 weld bond is lower.Resistance heating technique is easily damaged simultaneously
P91 pipe welding port heating zone base material, according to statistical result, the hardness number on P91 pipe welding port heating zone base material surface is compared to original
It is more than 93% that ball hardness number, which reduces by 15 ~ 30HB proportion, and 40HB can be reduced when more serious.If will after being once heat-treated,
Ball hardness number is more than the P91 weld bond of 270HB, and when using mid-frequency induction heating technique progress secondary heat treatment instead, P91 weld bond is secondary
Qualification rate is improved to 95% or more, and ball hardness number control, between 210 ~ 250HB, final qualification rate is more than 98%, and to mother
The hurt degree very little of material, significantly improves the qualification rate and thermal treatment quality of P91 weld bond.
In recent years since, discovery ball hardness number is more than that 270HB or more P91 weld bond quantity is more, therefore, such P91 weld bond
Must carry out secondary heat treatment or scarfing and again sweating heat processing (if welding again after scarfing, directly adopt Medium frequency induction
Heat treatment process then belongs to Medium frequency induction and is once heat-treated scope, not within the present invention).If secondary heat treatment continues to use
When resistance heating technique, qualification rate is less than 15%, and ball hardness number is substantially between 250 ~ 270HB, heat treatment qualification rate it is low and
Thermal treatment quality is bad, while also significantly increasing base material degree of injury；If secondary heat treatment uses mid-frequency induction heating work instead
Skill, the qualification rate of P91 weld bond are more than 95%, and ball hardness number is substantially between 210-250HB, and base material degree of injury is small.
In summary, use the progress of mid-frequency induction heating technique secondary for the P91 weld bond that ball hardness number is more than 270HB
When heat treatment, thermal treatment quality is good, and qualification rate significantly improves.
For the heat treatment of P91 weld bond, before Medium frequency induction secondary heat treatment, in addition to P91 weld bond integrally re-starts nothing
Damage detection is outer, also answers metallographic structure and the ball hardness number of emphasis detection P91 welded junction part.DL/T 869-2012 " thermal power generation
Factory's welding technique regulation " and DL/T438-2016 " thermal power plant alloying technology supervise regulation " respectively to ball hardness number and gold
Phase constitution is distinctly claimed.Wherein, the ball hardness number of P91 weld bond heating zone base material is in 185 ~ 250HB, the cloth of P91 weld seam
Family name's hardness number is in 185 ~ 270HB.Such as appearance " weld bond defect is exceeded ", " weld bond metallographic structure is unqualified " and " the base material of heating zone
Ball hardness number for the moment, can determine that P91 weld bond does not have Medium frequency induction secondary heat treatment condition lower than three kinds of situations of 185HB ",
Pipeline should be replaced or cut off weld bond, then welded again again.
When heating power calculates, heating power unit is kilowatt (KW), round off method round numbers part.Lifting/lowering temperature
Speed takes the integer part of calculated result, if calculated result is more than or equal to 180, lifting/lowering temperature speed should take 180 DEG C/h.
When weld bond is bound, thermocouple temperature measurement end should be fixed on axis of a weld, meanwhile, on the basis of axis of a weld, two
The width of heating and heat preservation width of side keep impartial.The measurement unit of width of heating and heat preservation width is equal are as follows: mm.
Intermediate frequency induction heating device can automatically adjust frequency size according to heat treatment process, therefore operator can also not have to
Frequency is input manually into intermediate-frequency induction heating device.According to heat treatment experience, frequency is substantially between 1100 ~ 1500Hz
Interior automatic adjustment.Intermediate frequency induction heating device used by this technique, power supply maximum power is 100KW, DC current is maximum
Value 200A, frequency maximum 3000Hz and 12 ~ 15mm of induction coil diameter etc..Unlike resistance heat treatment process, the present invention
Only a K type thermocouple thermocouple is needed to carry out thermometric, corresponding compensating line should be matched with thermocouple type, and power supply wire length
Degree should meet test/execution conditions.
DL/T 679 " welder technology examination regulation " has to welding position clearly stipulate that the wherein vertical fixation of pipeline welding
Position indicates that the fixed position of the level of pipeline welding is indicated with 5G with 2G.
Summary of the invention
To overcome above-mentioned the deficiencies in the prior art, the object of the present invention is to provide a kind of Medium frequency induction of pipe welding port is secondary
Heat treatment process has the characteristics that thermal treatment quality is good, technological operation is simple, high production efficiency and energy conservation and environmental protection.
To achieve the above object, the technical solution adopted by the present invention is that: at a kind of Medium frequency induction second heat of pipe welding port
Science and engineering skill, comprising the following steps:
Step 1, ball hardness number detection is carried out to the weld bond that need to carry out Medium frequency induction secondary heat treatment and metallographic detects, specifically done
Method: using the ball hardness number of portable Leeb Hardness Tester detection weld bond, metallographic microscope analyzes metallographic structure, further according to detection
Outcome evaluation port welding performance；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter, outer diameter/wall thickness
Value, heating power and the induction coil number of turns, determine coil-span, width of heating, heat preservation width, thermostat temperature, constant temperature time and
Lifting/lowering temperature speed；Coil-span is 10 ~ 20mm, and width of heating is L=wire circle × coil diameter+(wire circle+1) × line
Enclose spacing；Heat preservation width is B >=width of heating+200；Thermostat temperature is 730 ~ 750 DEG C；Constant temperature time is 3 ~ 5min/mm；Rise/
Cooling rate is related with pipeline wall thickness, takesDEG C with 180 DEG C in smaller value；
Step 3, thermocouple binding and fixing, specific practice: determining the position that weld bond and thermocouple are fixed first, then wide in heat preservation
The external application iron wire of degree wraps up fixed thermocouple cold junction, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and checks thermoelectricity
It is even whether to be fixed well；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, input Medium frequency induction secondary heat treatment technological parameter, specific practice: constant temperature time is 3 ~ 5min/mm, constant temperature temperature
Degree is 730 ~ 750 DEG C, and lifting/lowering temperature speed isSmaller value DEG C with 180 DEG C, DC current 100-180A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.
Lifting/lowering temperature speed described in step 2 is related with pipeline wall thickness；The unit of width of heating L and heat preservation width B are equal are as follows:
mm。
The beneficial effects of the present invention are:
1) thermal treatment quality is good, and P91 weld seam ball hardness number controls between 210-250HB, and Brinell hardness Distribution value is equal
Even, the ball hardness number deviation between weld seam any two points is no more than 20HB.
2) after being heat-treated, the heating zone P91 base material degree of injury is small.
3) after intermediate-frequency induction heating, the metallographic structure of P91 weld bond is qualified, meets code requirement.
Specific embodiment
Invention is further described in detail combined with specific embodiments below.
Embodiment 1
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, comprising the following steps:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 306 × 50) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 193 ~ 199HB and 192 ~
197HB, weld seam ball hardness number are 287 ~ 302HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 12mm, outer diameter/
Wall thickness value 6.12, heating power 15KW and the induction coil number of turns 10 are enclosed, and determine coil-span 10mm, width of heating 230mm, heat preservation
Width is 500mm, thermostat temperature is 730 DEG C, constant temperature time is 5min/mm and lifting/lowering temperature speed is 150 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 730 DEG C, constant temperature time is
5min/mm and lifting/lowering temperature speed are 150 DEG C/h, DC current 100A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 189 ~ 192HB and 188 ~ 192HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 237 ~ 248HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 2
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 608 × 72) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 198 ~ 208HB and 199 ~
207HB, weld seam ball hardness number are 295 ~ 311HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 8.44, heating power 49KW and the induction coil number of turns 14 are enclosed, and determine coil-span 12mm, width of heating 390mm, heat preservation
Width is 700mm, thermostat temperature is 735 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 104 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in vertical fixed position 2G first, the heat of thermocouple
End is fixed on axis of a weld any position, then wraps up fixed thermocouple cold junction in the external application iron wire of heat preservation width, finally exists
The area Jin Feng bandage binding and fixing pyrometer fire-end simultaneously checks whether thermocouple is fixed well；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 735 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 104 DEG C/h, DC current 150A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 193 ~ 201HB and 193 ~ 202HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 226 ~ 238HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 3
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 728 × 42) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 195 ~ 202HB and 192 ~
197HB, weld seam ball hardness number are 275 ~ 293HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 17.33, heating power 43KW and the induction coil number of turns 13 are enclosed, and are determined coil-span 15mm, width of heating 405mm, are protected
Warm width is 650mm, thermostat temperature is 740 DEG C, constant temperature time is 3.5min/mm and lifting/lowering temperature speed is 178 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 740 DEG C, constant temperature time is
3.5min/mm and lifting/lowering temperature speed are 178 DEG C/h, DC current 150A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 190 ~ 200HB and 188 ~ 195HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 233 ~ 247HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 4
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 859 × 41) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 202 ~ 210HB and 199 ~
208HB, weld seam ball hardness number are 293 ~ 317HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 20.95, heating power 69KW and the induction coil number of turns 12 are enclosed, and are determined coil-span 17mm, width of heating 401mm, are protected
Warm width is 800mm, thermostat temperature is 750 DEG C, constant temperature time is 3min/mm and lifting/lowering temperature speed is 180 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 750 DEG C, constant temperature time is
3min/mm and lifting/lowering temperature speed are 180 DEG C/h, DC current 180A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 194 ~ 203HB and 192 ~ 204HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 223 ~ 236HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 5
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 538 × 39) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 195 ~ 202HB and 199 ~
207HB, weld seam ball hardness number are 285 ~ 302HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 13.79, heating power 25KW and the induction coil number of turns 12 are enclosed, and are determined coil-span 10mm, width of heating 310mm, are protected
Warm width is 600mm, thermostat temperature is 735 DEG C, constant temperature time is 4.5min/mm and lifting/lowering temperature speed is 180 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 735 DEG C, constant temperature time is
4.5min/mm and lifting/lowering temperature speed are 180 DEG C/h, DC current 150A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 189 ~ 198HB and 192 ~ 200HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 225 ~ 240HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 6
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 279 × 50) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 198 ~ 206HB and 201 ~
209HB, weld seam ball hardness number are 278 ~ 297HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 13mm, outer diameter/
Wall thickness value is 5.58, heating power is 13KW and the induction coil number of turns 10 enclose, determine coil-span 20mm, width of heating 350mm,
Heat preservation width is 550mm, thermostat temperature is 740 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 150 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in vertical fixed position 2G first, the heat of thermocouple
End is fixed on axis of a weld any position, then wraps up fixed thermocouple cold junction in the external application iron wire of heat preservation width, finally exists
The area Jin Feng bandage binding and fixing pyrometer fire-end simultaneously checks whether thermocouple is fixed well；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 740 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 150 DEG C/h, DC current 130A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 192 ~ 198HB and 194 ~ 201HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 219 ~ 234HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 7
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 324 × 50) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 197 ~ 205HB and 197 ~
208HB, weld seam ball hardness number are 282 ~ 305HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value is 6.48, heating power is 15KW and the induction coil number of turns 14 enclose, determine coil-span 16mm, width of heating 450mm,
Heat preservation width is 650mm, thermostat temperature is 740 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 150 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 740 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 150 DEG C/h, DC current 130A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 191 ~ 200HB and 190 ~ 201HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 221 ~ 235HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
Embodiment 8
A kind of Medium frequency induction secondary heat treatment technique of pipe welding port, the following steps are included:
Step 1, the heat resisting steel weld bond (material P91, specification Ф 558 × 27) that need to carry out Medium frequency induction secondary heat treatment is carried out
Performance Evaluation, specific practice: P91 weld bond non-destructive testing is qualified, two sides base material Brinell hardness be respectively 194 ~ 202HB and 195 ~
204HB, weld seam ball hardness number are 294 ~ 313HB, and base material and weld seam metallographic structure meet code requirement, P91 weld bond have into
Row Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value is 20.67, heating power is 28KW and the induction coil number of turns 9 enclose, determine coil-span 15mm, width of heating 285mm,
Heat preservation width is 800mm, thermostat temperature is 745 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 180 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in vertical fixed position 2G first, the heat of thermocouple
End is fixed on axis of a weld any position, then wraps up fixed thermocouple cold junction in the external application iron wire of heat preservation width, finally exists
The area Jin Feng bandage binding and fixing pyrometer fire-end simultaneously checks whether thermocouple is fixed well；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 745 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 180 DEG C/h, DC current 170A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.Medium frequency induction secondary heat treatment
Afterwards: P91 weld seam two sides base material ball hardness number range is 190 ~ 199HB and 193 ~ 201HB, and base material ball hardness number is qualified；P91
Weld seam ball hardness number range is 227 ~ 243HB, and P91 weld seam ball hardness number is qualified；The metallographic structure of P91 base material and weld seam is closed
Lattice, meet code requirement, and non-destructive testing is qualified.
According to heat treatment experience, Medium frequency induction secondary heat treatment technique can be executed according to following related process parameters:
1) heating power size is related with pipeline specifications and heating coefficient, the corresponding corresponding heating in outer diameter/wall thickness value location
Coefficient, circular are as follows: heating power=heating coefficient × outer diameter tube × pipeline wall thickness.
2) it is tested according to the intermediate-frequency induction heating to P91 weld bond, thermostat temperature generally selects 730 ~ 750 DEG C, and constant temperature
Time is 3 ~ 5min/mm.
3) induction coil quantity is excessive or very few, not only generates adverse effect to thermal effectiveness, also seriously affects intermediate frequency
Induction heat treatment service using life.The induction coil diameter that the intermediate frequency induction heating device that the present invention uses uses be 12 ~
15mm, induction coil quantity is related with outer diameter/wall thickness value and heating power, minimum induction coil quantity, outer diameter/wall thickness value and add
Corresponding relationship is as shown in table 1 between thermal power.When induction coil quantity selects, number of coils should be not less than specified in table 1 most
Few induction coil quantity.
4) induction coil spacing is larger to intermediate-frequency induction heating influential effect, induction coil spacing according to the present invention
For 10 ~ 20mm.
5) heat-preservation cotton thickness has larger impact to thermal effectiveness, and hard heat-insulated cotton thickness control is between 30 ~ 70mm
Preferably, hard heat-insulated cotton used in the present invention is with a thickness of 60mm.
6) when using Medium frequency induction secondary heat treatment, when frequency is more than 2000Hz or electric current is greater than 180A, if intermediate frequency sense
Answer heating device that automatic trip occurs, heat treatment personnel should stop being heat-treated work at once.Again before being heat-treated, should confirm
Whether frequency sensing device can operate normally.
The minimum wire circle of table 1, outer diameter/wall thickness value and heating power corresponding relationship
Claims (5)
1. a kind of Medium frequency induction secondary heat treatment technique of pipe welding port, which comprises the following steps:
Step 1, ball hardness number detection is carried out to the weld bond that need to carry out Medium frequency induction secondary heat treatment and metallographic detects, specifically done
Method: using the ball hardness number of portable Leeb Hardness Tester detection weld bond, metallographic microscope analyzes metallographic structure, further according to detection
Outcome evaluation port welding performance；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter, outer diameter/wall thickness
Value, heating power and the induction coil number of turns, determine coil-span, width of heating, heat preservation width, thermostat temperature, constant temperature time and
Lifting/lowering temperature speed；Coil-span is 10 ~ 20mm, and width of heating is L=wire circle × coil diameter+(wire circle+1) × line
Enclose spacing；Heat preservation width is B >=width of heating+200；Thermostat temperature is 730 ~ 750 DEG C；Constant temperature time is 3 ~ 5min/mm；Rise/
Cooling rate is related with pipeline wall thickness, takesDEG C with 180 DEG C in smaller value；
Step 3, thermocouple binding and fixing, specific practice: determining the position that weld bond and thermocouple are fixed first, then wide in heat preservation
The external application iron wire of degree wraps up fixed thermocouple cold junction, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and checks thermoelectricity
It is even whether to be fixed well；
Step 4, weld bond is bound, and heat-preservation cotton: being first wrapped in outside weld bond by specific practice, then by heat-preservation cotton, weld bond and thermocouple
With bandage binding and fixing；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is input in intermediate frequency induction heating device, specific practice: constant temperature
Time, thermostat temperature, lifting/lowering temperature speed, DC current 100-180A；
Step 7, start intermediate frequency induction heating device, specific practice: verifying Medium frequency induction secondary heat treatment technological parameter, confirm nothing
Restart intermediate frequency induction heating device after accidentally；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing.
2. a kind of Medium frequency induction secondary heat treatment technique of pipe welding port according to claim 1, which is characterized in that step
Thermocouple binding and fixing described in 3, when weld bond is in horizontal fixed position 5G, the hot end of thermocouple is fixed on axis of a weld
The top, i.e. the 12 of axis of a weld point or 0 position；When weld bond is in vertical fixed position 2G, the hot end of thermocouple is answered
It is fixed on axis of a weld any position.
3. a kind of intermediate-frequency induction heating technique of pipe welding port according to claim 1, which is characterized in that including following
Step:
Step 1, Performance Evaluation, specific practice: P91 weld bond are carried out to the heat resisting steel weld bond that need to carry out Medium frequency induction secondary heat treatment
Non-destructive testing is qualified, and two sides base material Brinell hardness is respectively 198 ~ 208HB and 199 ~ 207HB, and weld seam ball hardness number is 295 ~
311HB, base material and weld seam metallographic structure meet code requirement, and P91 weld bond, which has, carries out Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 8.44, heating power 49KW and the induction coil number of turns 14 are enclosed, and determine coil-span 12mm, width of heating 390mm, heat preservation
Width is 700mm, thermostat temperature is 735 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 104 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in vertical fixed position 2G first, the heat of thermocouple
End is fixed on axis of a weld any position, then wraps up fixed thermocouple cold junction in the external application iron wire of heat preservation width, finally exists
The area Jin Feng bandage binding and fixing pyrometer fire-end simultaneously checks whether thermocouple is fixed well；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 735 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 104 DEG C/h, DC current 150A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing；
After Medium frequency induction secondary heat treatment: P91 weld seam two sides base material ball hardness number range is 193 ~ 201HB and 193 ~ 202HB,
Base material ball hardness number is qualified；P91 weld seam ball hardness number range is 226 ~ 238HB, and P91 weld seam ball hardness number is qualified；P91
The metallographic structure of base material and weld seam is qualified, meets code requirement, and non-destructive testing is qualified.
4. a kind of intermediate-frequency induction heating technique of pipe welding port according to claim 1, which is characterized in that including following
Step:
Step 1, Performance Evaluation, specific practice: P91 weld bond are carried out to the heat resisting steel weld bond that need to carry out Medium frequency induction secondary heat treatment
Non-destructive testing is qualified, and two sides base material Brinell hardness is respectively 202 ~ 210HB and 199 ~ 208HB, and weld seam ball hardness number is 293 ~
317HB, base material and weld seam metallographic structure meet code requirement, and P91 weld bond, which has, carries out Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value 20.95, heating power 69KW and the induction coil number of turns 12 are enclosed, and are determined coil-span 17mm, width of heating 401mm, are protected
Warm width is 800mm, thermostat temperature is 750 DEG C, constant temperature time is 3min/mm and lifting/lowering temperature speed is 180 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 750 DEG C, constant temperature time is
3min/mm and lifting/lowering temperature speed are 180 DEG C/h, DC current 180A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing；
After Medium frequency induction secondary heat treatment: P91 weld seam two sides base material ball hardness number range is 194 ~ 203HB and 192 ~ 204HB,
Base material ball hardness number is qualified；P91 weld seam ball hardness number range is 223 ~ 236HB, and P91 weld seam ball hardness number is qualified；P91
The metallographic structure of base material and weld seam is qualified, meets code requirement, and non-destructive testing is qualified.
5. a kind of intermediate-frequency induction heating technique of pipe welding port according to claim 1, which is characterized in that including following
Step:
Step 1, Performance Evaluation, specific practice: P91 weld bond are carried out to the heat resisting steel weld bond that need to carry out Medium frequency induction secondary heat treatment
Non-destructive testing is qualified, and two sides base material Brinell hardness is respectively 197 ~ 205HB and 197 ~ 208HB, and weld seam ball hardness number is 282 ~
305HB, base material and weld seam metallographic structure meet code requirement, and P91 weld bond, which has, carries out Medium frequency induction secondary heat treatment condition；
Step 2, Medium frequency induction secondary heat treatment technology establishment, specific practice: according to pipeline specifications, coil diameter 15mm, outer diameter/
Wall thickness value is 6.48, heating power is 15KW and the induction coil number of turns 14 enclose, determine coil-span 16mm, width of heating 450mm,
Heat preservation width is 650mm, thermostat temperature is 740 DEG C, constant temperature time is 4min/mm and lifting/lowering temperature speed is 150 DEG C/h；
Step 3, thermocouple binding and fixing, specific practice: when determining that weld bond is in horizontal fixed position 5G first, the heat of thermocouple
End is fixed on axis of a weld the top, i.e. the 12 of axis of a weld point or 0 position, then in the external application iron wire of heat preservation width
Fixed thermocouple cold junction is wrapped up, finally in the area Jin Feng bandage binding and fixing pyrometer fire-end and to check whether thermocouple is fixed good
It is good；
Step 4, weld bond bind, heat-preservation cotton: being wrapped in outside weld bond by specific practice first, then again by heat-preservation cotton, weld bond and
Thermocouple bandage binding and fixing finally check whether weld bond binding and fixing are good；
Step 5, induction coil is wound, specific practice: first by induction coil uniform winding outside heat-preservation cotton, then determining sense
It answers whether number of coils meets heating requirements, finally adjusts induction coil spacing, it is ensured that coil-span is uniform, meets technique and wants
It asks；
Step 6, Medium frequency induction secondary heat treatment technological parameter is inputted, specific practice: thermostat temperature is 740 DEG C, constant temperature time is
4min/mm and lifting/lowering temperature speed are 150 DEG C/h, DC current 130A；
Step 7, start intermediate frequency induction heating device, specific practice: conscientiously verifying Medium frequency induction secondary heat treatment technological parameter, really
Recognize it is errorless after restart intermediate frequency induction heating device；
Step 8, Physico-chemical tests and non-destructive testing, specific practice: after intermediate-frequency induction heating works, when temperature is down to room temperature
When, then heat-preservation cotton and thermocouple are removed, last butt welding mouth carries out Physico-chemical tests and non-destructive testing；
After Medium frequency induction secondary heat treatment: P91 weld seam two sides base material ball hardness number range is 191 ~ 200HB and 190 ~ 201HB,
Base material ball hardness number is qualified；P91 weld seam ball hardness number range is 221 ~ 235HB, and P91 weld seam ball hardness number is qualified；P91
The metallographic structure of base material and weld seam is qualified, meets code requirement, and non-destructive testing is qualified.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109825680A (en) * | 2019-03-12 | 2019-05-31 | 中核工程咨询有限公司 | One kind being used for big wall thickness bimetal compound pipeline heat treatment method |
| CN115505719A (en) * | 2022-08-31 | 2022-12-23 | 华能秦煤瑞金发电有限责任公司 | Postweld heat treatment process for large-diameter thick-wall pipeline |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107619921A (en) * | 2017-09-29 | 2018-01-23 | 彭娟 | A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond |
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2018
- 2018-12-13 CN CN201811525435.2A patent/CN109321742A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107619921A (en) * | 2017-09-29 | 2018-01-23 | 彭娟 | A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109825680A (en) * | 2019-03-12 | 2019-05-31 | 中核工程咨询有限公司 | One kind being used for big wall thickness bimetal compound pipeline heat treatment method |
| CN109825680B (en) * | 2019-03-12 | 2020-12-08 | 中核工程咨询有限公司 | Heat treatment method for large-wall-thickness bimetal composite pipeline |
| CN115505719A (en) * | 2022-08-31 | 2022-12-23 | 华能秦煤瑞金发电有限责任公司 | Postweld heat treatment process for large-diameter thick-wall pipeline |
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Application publication date: 20190212 |