GB2184553A - Device for determination of phase transformations in metals and alloys - Google Patents
Device for determination of phase transformations in metals and alloys Download PDFInfo
- Publication number
- GB2184553A GB2184553A GB08630166A GB8630166A GB2184553A GB 2184553 A GB2184553 A GB 2184553A GB 08630166 A GB08630166 A GB 08630166A GB 8630166 A GB8630166 A GB 8630166A GB 2184553 A GB2184553 A GB 2184553A
- Authority
- GB
- United Kingdom
- Prior art keywords
- probe
- metals
- phase transformations
- determination
- alloys
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000009466 transformation Effects 0.000 title claims abstract description 21
- 239000002184 metal Substances 0.000 title claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 14
- 238000000844 transformation Methods 0.000 title claims abstract description 12
- 150000002739 metals Chemical class 0.000 title claims abstract description 8
- 239000000956 alloy Substances 0.000 title description 4
- 229910045601 alloy Inorganic materials 0.000 title description 4
- 239000000523 sample Substances 0.000 claims abstract description 13
- 230000008859 change Effects 0.000 claims description 3
- 238000001816 cooling Methods 0.000 abstract description 5
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 230000004907 flux Effects 0.000 abstract 1
- 238000010348 incorporation Methods 0.000 abstract 1
- 239000000463 material Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 2
- 229920006362 Teflon® Polymers 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/023—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance where the material is placed in the field of a coil
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
A probe is provided for determination of the phase transformations which occur in metals, generally at high temperatures, during cooling or heating. Due to the incorporation of an appropriate resonance circuit 6 having a coil 7 protected by a heat-resistant cooled structure 4, 5 which does not impede electromagnetic flux, the probe is sensitive to variations in certain physical characteristics connected with phase transformations which occur in metals. <IMAGE>
Description
SPECIFICAMON Device for determination of phase transformations in metals and alloys
This invention relates to a device which is capable of determining the phase transformations which occur in
metals and alloys during cooling or heating.
The device can be preferably used directly on works lines where it is very important to have accurate
information on what phases are present in what percentages in a metal object which is being treated, so asto be able to take decisions during the treatment process, since the technological characteristics of the metal depend on the phases present.
Despite the efforts made to date in this direction, there exist no known devices for direct determination of this important parameter. At the present time the phases must be evaluated indirectlythrough temperature
measurements which, in turn, are compared with known COT curves or with results obtained on dilatometer
specimens in the laboratory.
It is evident that, with the adoption of ever more rigorous operating practices during the hotworking of
metallic materials, such indirect methods of phasetransformation determination have become less and less
satisfactory, not least because there are inevitably differences, which may be quite significant, between the theoretical situation described in the curves or detected by means of dilatometer specimens in the laboratory
and the actual situation in the works, for example due to the differences in the composition ofthe alloy or in the real dynamic conditions during heat treatment.
It isan object of the invention to provide a device which is capable of being used for indirect,on-line
determination of such phase transformations.
According to the present invention there is provided a probefordirect, on-line determination of phase transformations in metals, which includes an oscillating circuit arranged to be supplied by an oscillatorwith
alternating current of a frequency corresponding to the resonance frequency of the circuit and incorporating
a coil adapted to produce a change in voltage at its output terminals when metal presented to the probe
undergoes a phase transformation.
The present invention is based on the change which phase transformation induces in the resonance circuit of the probe located nearthe surface of the material being inspected. Indeed, it has surprisingly been found that, by supplying an appropriate resonance circuitwith alternating current atthe resonance frequency of the circuit, e.g. between 150 and 250kHz, voltage variations are generated at the terminals of the coil, which is
placed close to the surface under inspection, only when modifications occurring within the material itself-for
instance, the variations of the magnetic permeability or the electrical resistivity which accompany a phase transformation - alterthe reluctance of the circuit and hence the apparent inductance of the coil.
The probe can be constructed by making a number of changes-essentially relating to the power supply frequency and the method of processing the electrical signal -to a known device used for monitoring the surface defects of metal bodies at high temperature, as described in the Applicants' Published Patent
Application No. 2,161 ,938A, so asto renderthe device insensitive to surface defects but extremely sensitive to phase transformations.
The resonance circuit ofwhich the coil forms part should be made very sensitive to inductance variations so that the phase transformation induces a significant variation in the circuit output voltage and the greater the percentage of material which has undergone phase transformation the greaterthe variation in the output voltage.
According to another aspect of the present invention, a sensitive element, such as the coil in the above resonance circuit, is protected from ambient conditions, and especially from radiated heat, by a hollow-walled casing which does not impede magneticfluxand within which a cooling, preferably gaseous, fluid is circulated.
The invention also provides, in combination, the above probe and an oscillator for supplying the circuit, and preferably also means for detecting the output signal of the circuit, such as a recorder, data logger orthe like.
It is evident from the foregoing that, for detection of phase transformation. using the device ofthe invention, it is not necessary for there to be direct contact between the sensitive element and the metal surface under examination. This fact greatly simplifies the construction of the instrument and its installation in the works.
As already indicated, the invention finds application in most hotworking operations, such as heat treatments, hot-pressing, hot-rolling, etc.
In orderthatthe invention may be more fully understood, reference will now be made, by way of example, to the accompanying drawing in which the single figure shows a schematic vertical section of a preference embodiment of the invention.
Referring to the figure an outer stainless steel frame 1 supports a crucible 2 of refractory material which is penetrated bya stainless steel tube 3 designed to carry the probe, to transport the cooling air and to protect thecablesforthe power supply and the output signal.
Aflanged end ofthetube3 supports a toroidal containercomprising a solid upperpart4and a hollow lower part 5 made of a heat-resistant dielectric material such as Teflon (Teflon is a Registered Trade Mark) and carrying an oscillating circuit 6, which includes the probe coil 7, as well as protecting the circuit 6from the cooling airwhich is expelled from openings in the top part of the frame 1.
This embodiment, which is supplied with alternating current at a frequency of about 170 kHz, has been thoroughlytested, even on steel plate at temperatures in excess of 90000, two check on constructional reliability and on the accuracy of the phase transformations indicated, these being compared with those obtained in the laboratory on dilatometer specimens of identical material.
Table 1 summarises one of the tests performed.
TABLE 1 y-a phase transformation in steel: comparison of data obtained with the above described device and data acquired with the dilatometer specimens.
Material Electromagnetic probe Dilatometermethod
Startof End of Startof End of
trans- trans- trans- trans
formation formation formation formation
temp. temp. temp. temp.
OC OC OC OC X60 735-740 615 735 610
X70 750-760 650 750 640
The good agreement between the transformation temperatures measured by means of the device in accordance with the invention and the temperatures obtained by means of the dilatometer specimens clearly demonstrates the reliability of the device. The solution described also proves sound from the constructional point ofview, since it ensures temperatures inside the device and around the input and output cables which are well belowthe safety limits, whilst also allowing easy and quick replacement ofthevadous components, if necessary.
Claims (2)
1. A probe for direct, on-line determination of phase transformations in metals, which includes an oscillating circuit arranged to be supplied by an oscillator with alternating current of a frequency corresponding to the resonance frequency of the circuit and incorporating a coil adapted to produce a change in voltage at its output terminals when metal presented to the probe undergoes a phase transformation.
2. A probe for direct, on-line determination of phase transformations in metals, which probe is substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT48965/85A IT1182103B (en) | 1985-12-20 | 1985-12-20 | DEVICE FOR THE DETECTION OF PHASE TRANSFORMATIONS IN METALS AND ALLOYS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8630166D0 GB8630166D0 (en) | 1987-01-28 |
| GB2184553A true GB2184553A (en) | 1987-06-24 |
Family
ID=11269204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08630166A Withdrawn GB2184553A (en) | 1985-12-20 | 1986-12-17 | Device for determination of phase transformations in metals and alloys |
Country Status (8)
| Country | Link |
|---|---|
| BE (1) | BE905927A (en) |
| DE (1) | DE3643121A1 (en) |
| ES (1) | ES2001462A6 (en) |
| FR (1) | FR2592166A1 (en) |
| GB (1) | GB2184553A (en) |
| IT (1) | IT1182103B (en) |
| NL (1) | NL8603141A (en) |
| SE (1) | SE8605429L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988010420A2 (en) * | 1987-06-27 | 1988-12-29 | Stiftung Institut für Werkstofftechnik | Process for determining the edge layer condition of objects |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1255179A (en) * | 1968-12-03 | 1971-12-01 | Nat Res Dev | Non-destructive testing of materials |
| GB1385198A (en) * | 1971-07-16 | 1975-02-26 | British Iron Steel Research | Method and apparatus for testing ferromagnetic material |
| GB1468852A (en) * | 1973-06-29 | 1977-03-30 | Siderurgie Fse Inst Rech | Method and device for eddy-current detection of a change in magnetic behaviour of a material |
| EP0039019A1 (en) * | 1980-04-24 | 1981-11-04 | Siemens Aktiengesellschaft | Equipment for the continuous contactless control of the structural condition of a cold-drawn band |
| EP0146638A1 (en) * | 1983-06-15 | 1985-07-03 | Nippon Steel Corporation | Method for measuring transformation rate |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1191605B (en) * | 1962-09-26 | 1965-04-22 | Aeg | Process and device for carrying out metallurgical investigations |
-
1985
- 1985-12-20 IT IT48965/85A patent/IT1182103B/en active
-
1986
- 1986-12-10 NL NL8603141A patent/NL8603141A/en not_active Application Discontinuation
- 1986-12-16 BE BE0/217531A patent/BE905927A/en not_active IP Right Cessation
- 1986-12-17 GB GB08630166A patent/GB2184553A/en not_active Withdrawn
- 1986-12-17 DE DE19863643121 patent/DE3643121A1/en not_active Ceased
- 1986-12-17 SE SE8605429A patent/SE8605429L/en not_active Application Discontinuation
- 1986-12-18 ES ES8603500A patent/ES2001462A6/en not_active Expired
- 1986-12-18 FR FR8617726A patent/FR2592166A1/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1255179A (en) * | 1968-12-03 | 1971-12-01 | Nat Res Dev | Non-destructive testing of materials |
| GB1385198A (en) * | 1971-07-16 | 1975-02-26 | British Iron Steel Research | Method and apparatus for testing ferromagnetic material |
| GB1468852A (en) * | 1973-06-29 | 1977-03-30 | Siderurgie Fse Inst Rech | Method and device for eddy-current detection of a change in magnetic behaviour of a material |
| EP0039019A1 (en) * | 1980-04-24 | 1981-11-04 | Siemens Aktiengesellschaft | Equipment for the continuous contactless control of the structural condition of a cold-drawn band |
| EP0146638A1 (en) * | 1983-06-15 | 1985-07-03 | Nippon Steel Corporation | Method for measuring transformation rate |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988010420A2 (en) * | 1987-06-27 | 1988-12-29 | Stiftung Institut für Werkstofftechnik | Process for determining the edge layer condition of objects |
| WO1988010420A3 (en) * | 1987-06-27 | 1989-01-12 | Inst Werkstofftech Stiftung | Process for determining the edge layer condition of objects |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8605429L (en) | 1987-06-21 |
| IT8548965A0 (en) | 1985-12-20 |
| BE905927A (en) | 1987-04-16 |
| FR2592166A1 (en) | 1987-06-26 |
| GB8630166D0 (en) | 1987-01-28 |
| DE3643121A1 (en) | 1987-06-25 |
| NL8603141A (en) | 1987-07-16 |
| SE8605429D0 (en) | 1986-12-17 |
| ES2001462A6 (en) | 1988-05-16 |
| IT1182103B (en) | 1987-09-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |