CN107619921B - A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond - Google Patents
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond Download PDFInfo
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Abstract
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, step are as follows: 1) get the martensite heat-resistant steel weld bond through low-temperature transformation, heating coefficient needed for setting heat treatment ready；2) fixation of thermocouple wraps up fixed thermocouple keeping the temperature the iron wire of the thermocouple far-end other than width, with bandage by thermocouple and weld bond binding and fixing together；3) heat-preservation cotton is wrapped up, and heat-preservation cotton is wrapped in the outside of weld bond, with bandage binding and fixing；4) induction coil is wound, and Medium frequency induction coil is wrapped in outside heat-preservation cotton, it is ensured that number of coils and coil-span are met the requirements；5) heat treatment parameter is arranged；6) frequency heating device starting/stopping determines wiring and the errorless rear starter of heat treatment parameter；7) by martensite heat-resistant steel weld bond slow cooling to room temperature, outer coil and heat-preservation cotton are removed when being reduced to room temperature；It is simple with technological operation, at low cost, the feature of high production efficiency and environmental protection.
Description
Technical field
The invention belongs to weld bond processing technology fields, and in particular at a kind of Medium frequency induction heat of martensite heat-resistant steel weld bond
Science and engineering skill.
Background technique
P91 belongs to ferrite type high-temperature refractory steel, its main feature is that weldability is poor, heat treatment difficulty is big, weld bond easily occurs
The higher situation of hardness, seriously affects P91 weld bond quality, and P91 weld bond is also known as martensite heat-resistant steel weld bond.Currently, being welded for P91
Mouth heat treatment process is still based on resistance heating technique.In terms of thermal treatment quality: the qualification rate of resistance heating heat treatment process is only
It is 85%, wherein first-time qualification rate is no more than 60%.Since mid-frequency induction heating speed is fast, if heat treatment process is improper, it will tight
Ghost image rings P91 weld bond thermal treatment quality and increases security risk to influence weld bond properties.
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 intermediate frequencies of martensite heat-resistant steel weld bond
Induction heat treatment process has technological operation simple, at low cost, the feature of high production efficiency and environmental protection.
To achieve the above object, the technical solution adopted by the present invention is that: a kind of Medium frequency induction of martensite heat-resistant steel weld bond
Heat treatment process, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking geneva
Body heat resisting steel weld bond local environment, is arranged the heating coefficient of heat treatment；
Step 2, the fixation of thermocouple, specific practice are: keeping the temperature, thermocouple far-end iron wire wrapping other than width is solid
Thermocouple is determined, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, and the line of induction is arranged
The quantity and spread ratio of circle；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
When between 25-85mm, saturating magnetic infiltration coefficient is between 0.60 ~ 0.88；Maximum heating rate take 6250/ effective thickness DEG C/h with
Smaller value in 150 DEG C/h；Maximum cooling rate takes the smaller value in 6250/ weldment wall thickness DEG C/h and 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: after determining that wiring and heat treatment parameter are accurate
Starter；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
The heating coefficient of heat treatment described in step 1 is 0.75 ~ 3.50.
The spread ratio of Medium frequency induction coil described in step 4 is 1.25 ~ 1.75；The circle number of Medium frequency induction coil be 14 ~
19 circles.
The frequency of alternating current described in step 5 is 1600 ~ 2000Hz, and DC current values are 100 ~ 180A；Thermostat temperature is
700-750℃；Constant temperature time is related with pipeline wall thickness, and heat treatment temperature is heat-treated constant temperature in above-mentioned heat treatment constant temperature warm area
Time is 3-6min/mm；Maximum heating rate takes the smaller value in 6250/ effective thickness DEG C/h and 150 DEG C/h；Cooling rate is
6250 with the ratio of wall thickness, but maximum value is no more than 150 DEG C/h.
The thermostat temperature is 720-740 DEG C, constant temperature time 4min/mm.
The beneficial effects of the present invention are:
Compared with prior art, the present invention can control P91 weld bond superficial hardness number between 200-240HB, once
Being heat-treated qualification rate is more than 95%, and prior heat treatment process is difficult P91 weld bond hardness number being reduced to 240HB hereinafter, primary close
Lattice rate is only 60%；The present invention can substantially reduce the investment of cost of labor, such as: technological operation is simple, reduces the investment of manpower,
Personnel cost is reduced, production efficiency is significant；Cost input is cheap, especially in terms of the investment of auxiliary material, greatly reduces
The use cost of heat-preservation cotton and resistance heater；Energy conservation and environmental protection reduces resource waste.
Specific embodiment
Invention is further described in detail combined with specific embodiments below.
Embodiment 1
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 273 × 50), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 0.75；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
The circle number of circle is 14 circles, and the spread ratio of Medium frequency induction coil is 1.25, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 50mm, saturating magnetic infiltration coefficient is 0.80；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 1600Hz, direct current
Stream is 100A；Thermostat temperature is 700 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 6min/mm；Cooling
Speed maximum value is no more than 125 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 255HB,
Maximum value is 268HB, and average hardness value 261HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 2
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 485 × 85), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 0.75；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
The circle number of circle is 19 circles, and the spread ratio of Medium frequency induction coil is 1.50, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, constant temperature time, frequency and DC current values, when the wall thickness of martensite heat-resistant steel weld bond is in 50mm
When, saturating magnetic infiltration coefficient is 0.88；Maximum heating rate takes 83 DEG C/h；The frequency of alternating current is 2000Hz, and DC current values are
150A；Thermostat temperature is 750 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 3min/mm；Cooling rate
Maximum value is no more than 73 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 208HB,
Maximum value is 218HB, and average hardness value 211HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 3
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 273 × 50), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 0.75；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
The circle number of circle is 14 circles, and the spread ratio of Medium frequency induction coil is 1.75, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 50mm, saturating magnetic infiltration coefficient is 0.80；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 1800Hz, direct current
Stream is 100A；Thermostat temperature is 720 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed maximum value is no more than 125 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 228HB,
Maximum value is 244HB, and average hardness value 235HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 4
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 324 × 45), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 0.75；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
Enclosing quantity is 14 circles, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 45mm, saturating magnetic infiltration coefficient is 0.78；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, direct current
Stream is 100A；Thermostat temperature is 727 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed is the ratio of 6250 with wall thickness, but maximum value is no more than 138 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature；
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 220HB,
Maximum value is 234HB, and average hardness value 228HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification；
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 5
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 735 × 28), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 3.50；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
Enclosing quantity is 17 circles, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 28mm, saturating magnetic infiltration coefficient is 0.64；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, direct current
Stream is 180A；Thermostat temperature is 735 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed is the ratio of 6250 with wall thickness, but maximum value is no more than 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature；
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 232HB,
Maximum value is 243HB, and average hardness value 237HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 6
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 324 × 42), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 1.30；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction line
Enclosing quantity is 14 circles, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 42mm, saturating magnetic infiltration coefficient is 0.76；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, direct current
Stream is 120A；Thermostat temperature is 730 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed is the ratio of 6250 with wall thickness, but maximum value is no more than 148 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature；
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 212HB,
Maximum value is 226HB, and average hardness value 216HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Embodiment 7
A kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, comprising the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation (material specification: P91, Ф 559 × 25), carries out heat treatment
Preceding preparation, specific practice: checking martensite heat-resistant steel weld bond local environment, and heating coefficient needed for setting heat treatment is 2.50；
Step 2, the fixation of thermocouple, specific practice are: being wrapped up in the thermocouple far-end kept the temperature other than width with iron wire
Fixed thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, induction coil number
Amount is 14, and induction coil spread ratio is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: perseverance
Temperature, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond
In 25mm, saturating magnetic infiltration coefficient is 0.60；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, direct current
Stream is 150A；Thermostat temperature is 730 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed is the ratio of 6250 with wall thickness, but maximum value is no more than 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines
Starter after wiring and heat treatment parameter are accurate；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: heat treatment temperature is reduced to 300 DEG C
When, martensite heat-resistant steel weld bond slow cooling state should be kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature；
Step 8, hardness number detects, and specific practice is: hardness determination is carried out using portable hardometer, it is heat-resisting in martensite
Each detection faces of steel weld bond take 5 points, are averaged, and should will test position polishing before detection, guarantee that detection faces are bright and clean, neat
It is flat；
Step 9, heat treatment hardness value determines as a result, specific practice is: the hardness number minimum value of detection position is 235HB,
Maximum value is 244HB, and average hardness value 238HB, above-mentioned hardness number is within the code requirement of 185-270HB, judgement heat
Handling hardness number is qualification.
Step 10, metallographic structure judgement is as a result, specific practice is: weld seam metallographic structure is tempered martensite/tempering Soxhlet
Body tissue does not find δ-ferrite in metallographic structure, determines that metallographic structure is qualified.
Width of heating: width of heating is excessive to will cause the wasting of resources, and width of heating deficiency will affect thermal treatment quality, therefore
Width of heating is answered and " welds heat treatment technics regulation in the thermal power plant DL/T 819-2010 " subject to requirement.
Wire circle: martensite heat-resistant steel weld bond heating power and width of heating jointly have an impact wire circle,
Middle heating power is related with heat treatment heating coefficient and pipeline specifications.It is heat-treated heating coefficient and input current, frequency, heat dissipation is
Number, material density, thermal conductivity, the Effects of Heat Treatment factor, effective sectional area, magnetic conductivity, pipeline wall thickness, coil outer diameter and heating are wide
The factors such as degree are related, and heating coefficient is between 0.75-3.50.
Medium frequency induction coil-span: Medium frequency induction coil coil-span can be by between spread ratio and coil diameter
Relationship is calculated, and Medium frequency induction coil coil-span=spread ratio × coil diameter, spread ratio range is 1.25 ~ 1.75
Between.
Heating speed: according to P91 material feature, being heat-treated heating speed should not be too fast, and heating speed has with effective thickness
It closes, effective thickness is related with pipeline wall thickness and saturating magnetic permeance coefficient, and saturating magnetic permeance coefficient range is between 0.60 ~ 0.88.
Constant temperature time: constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is calculated by 3-6min/mm.
It is as follows to the related data for carrying out intermediate-frequency induction heating test with martensite heat-resistant steel weld bond:
1) thermally treated test, comprehensive each technological parameter, obtains following applicable heat treatment process parameter:
Being heat-treated thermostat temperature is 700-750 DEG C, and constant temperature time 3-6min/mm is calculated, and specific constant temperature time regards feelings
Depending on condition；1600 ~ 2000Hz of frequency, 100 ~ 180A of DC current, maximum heating rate take 6250/ effective thickness DEG C/h and 150
DEG C/h in smaller value；Maximum cooling rate takes the smaller value in 6250/ weldment wall thickness DEG C/h and 150 DEG C/h；It encloses number and regards pipeline
Depending on specification conditions, but wire circle is no less than 10 circles, and winding space meets the " thermal power plant DL/T 819-2010 sweating heat
Processing technique regulation " requirement.
2) medium-frequency heat processing equipment: maximum power 100KW, DC current maximum value are 200A, and frequency maximum range is
3000Hz, coil diameter 15mm.
3) Medium frequency induction tests material specification: 273 × 50mm of Ф；Ф324×45mm；Ф324×42；Ф559×25mm；
Ф735×28mm；Ф585×85.
4) according to " DL/T868-2014 qualification of welding procedure regulation " content, every mechanical property test is unfolded.Mechanical property
In energy index, traditional resistor heating process is difficult P91 weld bond surface hardness being reduced to 240HB hereinafter, impact flexibility index value
Relatively low, specific targets are as shown in table 1.And mid-frequency induction heating technique, P91 weld bond surface hardness and impact flexibility index are superior to
Traditional resistance heating technique.Mid-frequency induction heating technique, from the point of view of indices, plasticity index and tensile property are good, punching
It hits toughness to meet the requirements, superficial hardness number controls between 200-240HB.Above-mentioned all properties meet " DL/T868-2014
Qualification of welding procedure regulation " and " thermal power plant DL/T869-2012 welding technique regulation " related request.Specific detection knot
Fruit is as shown in table 1.
。
Claims (9)
1. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond, which comprises the following steps:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking that martensite is resistance to
Hot steel weld bond local environment, heating coefficient needed for setting heat treatment；
Step 2, the fixation of thermocouple, specific practice are: keeping the temperature the fixed heat of thermocouple far-end iron wire wrapping other than width
Galvanic couple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, finally uses bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, and Medium frequency induction line is arranged
Enclose quantity and coil-span coefficient；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: constant temperature temperature
Degree, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond is 25
When between ~ 85mm, saturating magnetic infiltration coefficient is between 0.60 ~ 0.88；Maximum heating rate takes 6250/ effective thickness DEG C/h and 150
DEG C/h in smaller value；Maximum cooling rate takes the smaller value in 6250/ weldment wall thickness DEG C/h and 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: determining and starts after wiring and heat treatment parameter are accurate
Device；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: when heat treatment temperature is reduced to 300 DEG C, answering
Martensite heat-resistant steel weld bond slow cooling state is kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature；
The frequency of alternating current described in step 5 is 1600 ~ 2000Hz, and DC current values are 100 ~ 180A；Thermostat temperature is 700-
750℃；Constant temperature time is related with pipeline wall thickness, and heat treatment temperature is heat-treated constant temperature time in above-mentioned heat treatment constant temperature warm area
For 3-6min/mm；Maximum heating rate takes the smaller value in 6250/ effective thickness DEG C/h and 150 DEG C/h；Cooling rate is 6250
With the ratio of wall thickness, but maximum value be no more than 150 DEG C/h.
2. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The heating coefficient of heat treatment described in step 1 is 0.75 ~ 3.50.
3. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The spread ratio of Medium frequency induction coil described in step 4 is 1.25 ~ 1.75；The circle number of Medium frequency induction coil is 14 ~ 19 circles.
4. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The thermostat temperature is 720-740 DEG C, and constant temperature time is 4 ~ 4.5min/mm.
5. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 4, which is characterized in that
The constant temperature time is 4min/mm.
6. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The following steps are included:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking that martensite is resistance to
Hot steel weld bond local environment, heating coefficient needed for setting heat treatment are 0.75；
Step 2, the fixation of thermocouple, specific practice are: fixing in the thermocouple far-end iron wire wrapping kept the temperature other than width
Thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction coil number
Amount is 14, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: constant temperature temperature
Degree, lifting/lowering temperature speed, constant temperature time, frequency and DC current values, when the wall thickness of martensite heat-resistant steel weld bond is in 45mm, thoroughly
Magnetic infiltration coefficient is 0.78；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, DC current values 100A；It is permanent
Temperature is 727 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling rate be 6250 with
The ratio of wall thickness, but maximum value is no more than 138 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines wiring
With the accurate rear starter of heat treatment parameter；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: when heat treatment temperature is reduced to 300 DEG C, answering
Martensite heat-resistant steel weld bond slow cooling state is kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
7. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The following steps are included:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking that martensite is resistance to
Hot steel weld bond local environment, heating coefficient needed for setting heat treatment are 3.50；
Step 2, the fixation of thermocouple, specific practice are: fixing in the thermocouple far-end iron wire wrapping kept the temperature other than width
Thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction coil number
Amount is 17, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: constant temperature temperature
Degree, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond exists
When 28mm, saturating magnetic infiltration coefficient is 0.64；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, DC current
Value 180A；Thermostat temperature is 735 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling speed
Degree is 6250 and the ratio of wall thickness, but maximum value is no more than 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines wiring
With the accurate rear starter of heat treatment parameter；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: when heat treatment temperature is reduced to 300 DEG C, answering
Martensite heat-resistant steel weld bond slow cooling state is kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
8. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The following steps are included:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking that martensite is resistance to
Hot steel weld bond local environment, heating coefficient needed for setting heat treatment are 1.30；
Step 2, the fixation of thermocouple, specific practice are: fixing in the thermocouple far-end iron wire wrapping kept the temperature other than width
Thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction coil number
Amount is 14, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: constant temperature temperature
Degree, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond exists
When 42mm, saturating magnetic infiltration coefficient is 0.76；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, DC current
Value is 120A；Thermostat temperature is 730 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling
Speed is the ratio of 6250 with wall thickness, but maximum value is no more than 148 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines wiring
With the accurate rear starter of heat treatment parameter；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: when heat treatment temperature is reduced to 300 DEG C, answering
Martensite heat-resistant steel weld bond slow cooling state is kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
9. a kind of intermediate-frequency induction heating technique of martensite heat-resistant steel weld bond according to claim 1, which is characterized in that
The following steps are included:
Step 1, the martensite heat-resistant steel weld bond through low-temperature transformation prepares, specific practice before carrying out heat treatment: checking that martensite is resistance to
Hot steel weld bond local environment, heating coefficient needed for setting heat treatment are 2.50；
Step 2, the fixation of thermocouple, specific practice are: fixing in the thermocouple far-end iron wire wrapping kept the temperature other than width
Thermocouple, then with bandage by thermocouple and weld bond binding and fixing together；
Step 3, heat-preservation cotton is wrapped up, and heat-preservation cotton: being wrapped in the outside of weld bond by specific practice, with bandage binding and fixing；
Step 4, induction coil is wound, and specific practice: Medium frequency induction coil is wrapped in outside heat-preservation cotton, Medium frequency induction coil number
Amount is 14, and Medium frequency induction coil-span coefficient is 1.33, meets heating power and code requirement；
Step 5, heat treatment parameter is arranged, and specific practice is that the technological parameter being arranged in frequency heating device includes: constant temperature temperature
Degree, lifting/lowering temperature speed, the frequency and DC current values of constant temperature time, alternating current, when the wall thickness of martensite heat-resistant steel weld bond exists
When 25mm, saturating magnetic infiltration coefficient is 0.60；Maximum heating rate takes 150 DEG C/h；The frequency of alternating current is 2000Hz, DC current
For 150A；Thermostat temperature is 730 DEG C；Constant temperature time is related with pipeline wall thickness, and heat treatment constant temperature time is 4min/mm；Cooling speed
Degree is 6250 and the ratio of wall thickness, but maximum value is no more than 150 DEG C/h；
Step 6, frequency heating device starting/stopping, specific practice is: first ensuring that all wiring have connected, determines wiring
With the accurate rear starter of heat treatment parameter；
Step 7, by martensite heat-resistant steel weld bond slow cooling to room temperature, specific practice is: when heat treatment temperature is reduced to 300 DEG C, answering
Martensite heat-resistant steel weld bond slow cooling state is kept, outer coil and heat-preservation cotton are removed when temperature is reduced to room temperature.
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| CN108330271A (en) * | 2018-03-21 | 2018-07-27 | 彭娟 | A kind of intermediate-frequency induction heating technique of pipe welding port |
| CN109321742A (en) * | 2018-12-13 | 2019-02-12 | 王立翀 | A kind of Medium frequency induction secondary heat treatment technique of pipe welding port |
| 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 |
| CN112029983A (en) * | 2020-09-02 | 2020-12-04 | 中国电建集团山东电力建设第一工程有限公司 | Postweld heat treatment process for martensite heat-resistant steel G115 large-diameter thick-wall pipeline |
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