JPS61195351A - Non-destructive deciding method for carburizing depth - Google Patents
Non-destructive deciding method for carburizing depthInfo
- Publication number
- JPS61195351A JPS61195351A JP3719185A JP3719185A JPS61195351A JP S61195351 A JPS61195351 A JP S61195351A JP 3719185 A JP3719185 A JP 3719185A JP 3719185 A JP3719185 A JP 3719185A JP S61195351 A JPS61195351 A JP S61195351A
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- Prior art keywords
- hall
- depth
- carburization
- magnetic
- permanent magnet
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y15/00—Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
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- 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
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- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はエチレンクランキングチューブ等の浸炭深さの
非破壊判定方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for non-destructively determining the carburization depth of ethylene cranking tubes and the like.
原料ナフサを高温・高圧下に熱分解してエチレン等を回
収するための反応管であるエチレンクランキングチュー
ブとしては、ＡＳＴＭ ＨＫ ４０（０，４％Ｃ−
２５％Ｃｒ−２０％Ｎｉ）、ＨＰ４５（０，４５％Ｃ−
２５％Ｃｒ−３５％Ｎｉ）、またはＨＰ改良材（ＨＰ材
にＭ Ｏ％ Ｗ −、Ｎ ｂ等を単独もしくは複合添加
したもの）等が使用されている。ASTM HK 40 (0.4%C-
25%Cr-20%Ni), HP45(0,45%C-
25% Cr-35% Ni), or HP improving material (HP material to which MO% W-, Nb, etc. are added singly or in combination).
クランキングチューブは長時間使用されるうちに、管内
の反応に伴って生成する炭素が管内面に付着堆積し、高
温下に管材内部に拡散して浸炭が発生する。管材内部に
侵入した炭素は、Ｃｒ炭化物を形成し、Ｃｒ炭化物の粗
大化に伴って、低温域（約８００℃以下）における管材
の延性を著しく低下させる。また、管材の浸炭部の熱膨
張係数は非浸炭部のそれより小さいので、急速な加熱・
冷却を行うと、引張・圧縮応力の発生と、前記低温域で
の延性低下とが重畳してチューブに破壊が生じることが
ある。As cranking tubes are used for long periods of time, carbon generated as a result of reactions inside the tubes adheres and accumulates on the inner surface of the tubes, and diffuses into the tube material at high temperatures, causing carburization. The carbon that has entered the tube material forms Cr carbide, and as the Cr carbide becomes coarser, the ductility of the tube material in a low temperature range (approximately 800° C. or lower) is significantly reduced. In addition, the coefficient of thermal expansion of the carburized part of the pipe material is smaller than that of the non-carburized part, so rapid heating and
When cooling is performed, the generation of tensile/compressive stress and the decrease in ductility in the low-temperature range may occur, resulting in destruction of the tube.
従って、チューブの破壊を未然に防止し、安全円滑な操
業を維持するには、浸炭検査を定期的に実施し、浸炭の
有無およびその進行状況を適確に把握することが必要で
ある。Therefore, in order to prevent tube breakage and maintain safe and smooth operation, it is necessary to periodically conduct carburization inspections and accurately grasp the presence or absence of carburization and its progress.
浸炭深さを非破壊的に判定する方法としては、浸炭部の
組成変化、すなわちＣｒの欠乏と、ＦｅおよびＮｉの相
対的増量に伴う磁気特性の変化を利用した各種の磁気測
定法が知られており、例えば、電磁誘導によりチューブ
に電流を誘起させ、磁束密度の変化を検出して浸炭深さ
を判定する方法が実施されている。Various magnetic measurement methods are known as methods for non-destructively determining the carburized depth, which utilize changes in the composition of the carburized part, that is, changes in magnetic properties due to Cr deficiency and relative increases in Fe and Ni. For example, a method has been implemented in which the depth of carburization is determined by inducing a current in the tube by electromagnetic induction and detecting changes in magnetic flux density.
しかるに、従来の磁気測定法により得られる浸炭深さ測
定結果と、破壊検査による実測結果とを対比すると、Ｈ
Ｋ４０材チューブについては比較的良い対応が得られる
ものの、ＨＰ材やＨＰ改良材のチューブでは、測定値の
バラツキが大きく、信頼性に乏しい。However, when comparing the carburization depth measurement results obtained by conventional magnetic measurement method with the actual measurement results by destructive inspection, H
Although a relatively good response can be obtained for the K40 material tube, the measurement values for tubes made of HP material or HP improved material vary widely and are poor in reliability.
この原因について調査した結果、）ＩＰ材やＨＰ改良材
のチューブでは、その外表面に生成した脱炭層（その層
深さはチューブの使用温度・使用時間に依存し、高温・
長時間となる程、深さが増す）に脱炭と共に脱Ｃｒが生
じ、その部分の透磁率が高くなることによるという事実
が判明した。As a result of investigating the cause of this problem, we found that in tubes made of IP materials and HP improved materials, a decarburized layer (the depth of which depends on the operating temperature and time of use of the tube) is formed on the outer surface of the tube.
It has been found that this is due to the fact that decarburization and chromium desorption occur as the depth increases as the time increases, and the magnetic permeability of that part increases.
すなわち、これらのチューブにあっては、高温下に長時
間使用されると、管内面に浸炭が生じていなくても、外
表面に生じた脱炭層（層深さ：約５０〜５００μｍ）が
貰い磁気強度を帯びているために、これが浸炭発生と見
誤られてしまうわけである。In other words, when these tubes are used at high temperatures for long periods of time, even if the inner surface of the tube is not carburized, a decarburized layer (layer depth: approximately 50 to 500 μm) forms on the outer surface. Because it has magnetic strength, this can be mistaken for carburization.
従って、これまでのところ、チューブの浸炭の有無およ
びその深さを検証するには、チューブ外表面の脱炭層を
予めグラインダ等で研削除去したうえで、再測定し評価
せねばならないというのが実情である。かかる測定方法
は、測定個所がわずかである場合はともかく、多数の個
所を測定しようとすれば、多大の手間と時間を費やさね
ばならず、実用性の点で問題が多い。Therefore, in order to verify the presence or absence of carburization in a tube and its depth, the reality is that the decarburized layer on the outer surface of the tube must be removed with a grinder, etc., and then remeasured and evaluated. It is. This measurement method has many problems in terms of practicality, as it requires a great deal of effort and time when measuring a large number of locations, even if the number of locations to be measured is small.
本発明は、この点に鑑み、脱炭層をグラインダ処理する
ことなく、ガウスメータ等の磁気検量器を用いて簡易・
迅速に浸炭深さを精度良く判定するための改良された判
定方法を提供しようとするものである。In view of this point, the present invention has developed a simple method using a magnetic calibrator such as a Gauss meter without grinding the decarburized layer.
The present invention aims to provide an improved determination method for quickly and accurately determining carburization depth.
本発明の浸炭深さ判定方法は、永久磁石と、その永久磁
石の磁場内に配置されたホール素子とを内蔵するホール
プローブを用いて、浸炭部の磁気による永久磁石の磁場
の変化に伴って発生するホール起電圧の変化量に基づい
て浸炭深さを判定するものである。The carburization depth determination method of the present invention uses a Hall probe that includes a permanent magnet and a Hall element placed in the magnetic field of the permanent magnet. The carburization depth is determined based on the amount of change in the generated Hall electromotive force.
本発明の判定方法について図面を参照して説明すると、
第１図は本発明に使用される磁気検量器であり、（２０
）は検量器本体（例えば、ガウスメータ本体） 、（３
０）は検量器本体（２０）に接続されているホールプロ
ーブである。（３２）は永久磁石であり、永久磁石（３
２）はホール素子（３１）の近傍（ホール素子から、例
えば２〜３ｆｌ離れて）に位置してホール素子（３１）
と共にプローブ（３０）に内蔵されている。The determination method of the present invention will be explained with reference to the drawings.
Figure 1 shows the magnetic calibrator used in the present invention, (20
) is the calibrator body (e.g. Gauss meter body), (3
0) is a Hall probe connected to the calibrator body (20). (32) is a permanent magnet, and permanent magnet (3
2) is located in the vicinity of the Hall element (31) (for example, 2 to 3 fl away from the Hall element).
It is also built into the probe (30).
図の例では、ホール素子（３１）は永久磁石（３２）の
Ｎ極とＳ極との中間部において永久磁石（３２）に平行
に磁界内に位置している。この状態において、ホール素
子を横切る磁力線（ｍ）は、第４図に示すようにホール
素子（３１）に対して平行であるから、ホール素子（３
１）に励起電流を通しても、ホール効果は生じず、ホー
ル起電圧はゼロである。In the illustrated example, the Hall element (31) is located parallel to the permanent magnet (32) in the magnetic field at an intermediate portion between the N and S poles of the permanent magnet (32). In this state, the magnetic field lines (m) that cross the Hall element are parallel to the Hall element (31) as shown in FIG.
Even if an excitation current is passed through 1), no Hall effect occurs and the Hall electromotive voltage is zero.
このホールプローブ（３０）を、第２図に示すようにチ
ューブ（Ｔ）の外表面にそって走査しながら行う浸炭検
査において、チューブ（Ｔ）内面に浸炭の発生がなけれ
ば永久磁石（３２）の磁場に変化はなく、従ってホール
効果による起電圧はゼロのままである。In the carburization test, which is performed while scanning the Hall probe (30) along the outer surface of the tube (T) as shown in Figure 2, if there is no carburization on the inner surface of the tube (T), the permanent magnet (32) There is no change in the magnetic field of , so the electromotive force due to the Hall effect remains zero.
いま、ホールプローブ（３０）が、第３図に示すように
チューブ（Ｔ）内面に浸炭が生じている部分（Ｃ）に近
づくと、永久磁石（３２）の磁場が浸炭部（Ｃ）の強い
磁気の影響を受け、第５図に示すようにホール素子（３
１）を横切る磁力線に傾きが生じるため、ホール効果に
よる起電圧が発生する。このホール起電圧は浸炭部の浸
炭深さと一定の相関 ゛を示す。Now, when the Hall probe (30) approaches the part (C) where carburization has occurred on the inner surface of the tube (T) as shown in Figure 3, the magnetic field of the permanent magnet (32) is strong in the carburized part (C). Under the influence of magnetism, the Hall element (3
1) Since the lines of magnetic force that cross the line are tilted, an electromotive voltage is generated due to the Hall effect. This Hall electromotive force shows a certain correlation with the carburization depth of the carburized part.
このホールプローブを用いる測定においては、チューブ
の外表面に脱炭層（Ｄ）が存在する場合、脱炭層の磁気
の影響により永久磁石の磁束分布に変化が生じるが、脱
炭層（Ｄ）はチューブ（Ｔ）の外周面にほぼ均一な層厚
をなして一様に存在するので、ホール素子（３１）を横
切る磁力線はホール素子に対して平行なままであり、従
って、脱炭層の存在によってホール起電圧が生じること
はなく、それ故脱炭層が存在していても、これを浸炭層
と見誤ることはない。In measurements using this Hall probe, when a decarburized layer (D) exists on the outer surface of the tube, the magnetic flux distribution of the permanent magnet changes due to the magnetic influence of the decarburized layer, but the decarburized layer (D) Since the magnetic field lines that cross the Hall element (31) remain parallel to the Hall element, the existence of the decarburized layer prevents Hall generation. No voltage is generated, so even if a decarburized layer is present, it cannot be mistaken for a carburized layer.
従って、上記ホールプローブを用いたチューブの浸炭検
査により得られるホール起電圧の測定値と、破壊検査等
により得られた浸炭深さの実測値とを予め対応させて両
者の相関を求めておけば、ホール起電圧の測定値から、
直ちに浸炭の有無とその深さを正確に判定することがで
きる。この場合、ホールプローブをガウスメータ本体に
接続してガウスメータとして使用し、その指示値（ガウ
ス）と浸炭深さとを対応させて浸炭深さを判定するよう
にしてもよい。Therefore, it is a good idea to correlate the measured value of the Hall electromotive force obtained by carburizing the tube using the Hall probe with the actual value of the carburizing depth obtained from the destructive test in advance to find a correlation between the two. , from the measured value of Hall electromotive force,
The presence or absence of carburization and its depth can be immediately and accurately determined. In this case, the Hall probe may be connected to the Gaussmeter body and used as a Gaussmeter, and the indicated value (Gauss) may be associated with the carburization depth to determine the carburization depth.
なお、第７図に示すように永久磁石を内蔵しない通常の
ホールプローブ（３０’）を用い、浸炭部（Ｃ）が帯有
する磁気によりホールを素子（３１）に生じる起電圧を
検出する方法も考えられるが、浸炭部（Ｃ）の磁気強度
が微弱なこと等により、精度良く浸炭深さを判定するこ
とは実際上殆ど不可能であり、実用し得ない。In addition, as shown in Fig. 7, there is also a method of detecting the electromotive force generated in the hole element (31) by the magnetism of the carburized part (C) using a normal Hall probe (30') that does not have a built-in permanent magnet. However, due to the weak magnetic strength of the carburized portion (C), it is practically impossible to accurately determine the carburized depth, and it is not practical.
上記説明では、永久磁石（３２）の磁力線がホール素子
（３１）を平行に横切る位置関係に両者を設定した例を
挙げたが、むろんそれに限定されるものではなく、磁力
線がホール素子（３１）を斜めに横切る位置関係に配置
してもよい。その場合は、浸炭部（Ｃ）の残留磁気によ
り生じる磁力線の傾き角度の変化に伴うホール起電圧の
変化量を検出するようにすればよい。In the above explanation, an example was given in which the magnetic force lines of the permanent magnet (32) cross the Hall element (31) in parallel, but the present invention is not limited to this, and the magnetic force lines cross the Hall element (31). may be arranged in a positional relationship that crosses diagonally. In that case, the amount of change in the Hall electromotive force due to the change in the inclination angle of the lines of magnetic force caused by the residual magnetism of the carburized part (C) may be detected.
ホールプローブにホール素子と共に内蔵される永久磁石
としては、アルニコ磁石、サマリウムーコバル） （Ｓ
ｍ−Ｃｏ）磁石等、各種の磁石を使用することができる
。永久磁石の必要な残留磁気強度は、測定対象材の肉厚
等により、すなわち磁界を深く入れるかそうでないかに
よって適宜選択される。その強度は、いくつかの磁石を
組み合わせることによって８周整することもできる。な
お、磁石の形状は、例えば円柱状、直方体、立方体等で
あってよい。Permanent magnets built into the Hall probe together with the Hall element include alnico magnets, samarium-cobal) (S
Various types of magnets can be used, such as m-Co) magnets. The required residual magnetic strength of the permanent magnet is appropriately selected depending on the thickness of the material to be measured, that is, whether the magnetic field is applied deeply or not. Its strength can also be adjusted to 8 rounds by combining several magnets. Note that the shape of the magnet may be, for example, a cylinder, a rectangular parallelepiped, a cube, or the like.
また、ホール素子は、ガリウム−砒素（Ｇａ −Ａｓ）
素子、インジウム−砒素（Ｉｎ−Ａｓ）素子、ゲルマニ
ウム（Ｇｅ）素子、シリコン（Ｓｉ）素子等であってよ
い。In addition, the Hall element is made of gallium-arsenic (Ga-As)
The device may be an indium-arsenide (In-As) device, a germanium (Ge) device, a silicon (Si) device, or the like.
ガウスメータ本体に、前記図示のごときホールプローブ
を接続して、浸炭検査を行った。その浸炭検査により得
られたガウスメータの指示値と、破壊検査により求めら
れた浸炭深さの実測値との相関を第６図に示す。A carburization test was conducted by connecting a Hall probe as shown in the figure to the Gaussmeter body. FIG. 6 shows the correlation between the Gaussmeter reading obtained from the carburization test and the actual value of the carburization depth obtained from the destructive test.
（Ｉ）ホールプローブ
！１１ ホール素子：Ｇａ−Ａｓ素子（２）永久磁石
：アルニコ５゜表面の磁束密度：８００ガウス。(I) Hall probe! 11 Hall element: Ga-As element (2) Permanent magnet: Alnico 5° surface magnetic flux density: 800 Gauss.
（３）ホール素子は、永久磁石の磁場内に磁力線が平行
に横切るように設置。(3) The Hall element is installed so that the lines of magnetic force cross in parallel within the magnetic field of the permanent magnet.
（ｎ）被測定材
クランキングチューブ（ＨＰ４５材）、外径９０ｍ、肉
厚８１１１１０外表面には層厚約０．１０の脱炭層がほ
ぼ一様に生成している。(n) Material to be measured Cranking tube (HP45 material), outer diameter 90 m, wall thickness 811110 A decarburized layer with a thickness of about 0.10 is formed almost uniformly on the outer surface.
被測定材には脱炭層が存在しているにも拘らず、第６図
に示すように、ガウスメータの指示値には脱炭層による
影響はなく、その指示値から浸炭層の有無とその深さを
正確に判定し得ることがわかる。Although there is a decarburized layer in the material to be measured, as shown in Figure 6, the readings of the Gaussmeter are not affected by the decarburized layer, and the readings indicate the presence or absence of a carburized layer and its depth. It can be seen that it is possible to determine accurately.
本発明方法は、ＨＰ材やＨＰ改良材からなるクランキン
グチューブを測定対象とする場合にも、表面の脱炭層の
存否に関係なく、磁気検量器の指示値から浸炭の有無お
よび深さを正確に判定することができ、従来法を用いる
場合のような脱炭層を除去するためのグラインダ処理等
の煩わしい手間は一切不要であり、実用性に冨み、信顛
性のすぐれた方法である。本発明方法は、上記チューブ
に限らず、ＨＫ材、ステンレス鋼材等からなるチューブ
、その他の各種構造部材の浸炭判定法として有用なこと
は言うまでもない。Even when measuring a cranking tube made of HP material or HP-improved material, the method of the present invention can accurately determine the presence or absence of carburization and the depth from the readings of the magnetic calibrator, regardless of the presence or absence of a decarburized layer on the surface. This method does not require any troublesome work such as grinding to remove the decarburized layer, which is required when using conventional methods, and is highly practical and highly reliable. It goes without saying that the method of the present invention is useful as a carburization determination method not only for the above-mentioned tubes but also for tubes made of HK materials, stainless steel materials, etc., and other various structural members.
第１図は本発明に使用される磁気検量器の模式的構造図
、第２図、第３図は本発明による浸炭検査におけるホー
ルプローブ内の永久磁石の磁場変化を示す断面説明図、
第４図、第５図はホール素子を横切る磁力線の傾きの変
化を模式的に示す斜視図、第６図は本発明方法による磁
気検量器の指示値と浸炭深さの相関の一例を示すグラフ
、第７図は通常のホールプローブを有するガウスメータ
の模式的構造図である。
３０：ホールプローブ、３１：ホール素子、３２：永久
磁石、Ｔ；被測定材、Ｃ：浸炭部、Ｄ：脱炭部。FIG. 1 is a schematic structural diagram of a magnetic calibrator used in the present invention, FIGS. 2 and 3 are cross-sectional explanatory diagrams showing changes in the magnetic field of the permanent magnet in the Hall probe in carburization inspection according to the present invention,
Figures 4 and 5 are perspective views schematically showing changes in the slope of magnetic lines of force that cross the Hall element, and Figure 6 is a graph showing an example of the correlation between the indicated value of the magnetic calibrator and the carburization depth according to the method of the present invention. , FIG. 7 is a schematic structural diagram of a Gaussmeter having a conventional Hall probe. 30: Hall probe, 31: Hall element, 32: permanent magnet, T: material to be measured, C: carburized part, D: decarburized part.
Claims (1)
とを内蔵しているホールプローブを用いて、浸炭部の磁
気による永久磁石の磁場の変化に伴って検出されるホー
ル起電圧の変化に基づいて浸炭深さを判定する浸炭深さ
の非破壊判定方法。(1) Using a Hall probe containing a permanent magnet and a Hall element placed in the magnetic field, changes in the Hall electromotive force are detected as the magnetic field of the permanent magnet changes due to the magnetism of the carburized part. A non-destructive method for determining carburization depth based on
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3719185A JPS61195351A (en) | 1985-02-25 | 1985-02-25 | Non-destructive deciding method for carburizing depth |
| EP86102443A EP0193168A3 (en) | 1985-02-25 | 1986-02-25 | Method of inspecting carburization and probe therefor |
| US07/785,197 US5128613A (en) | 1985-02-25 | 1991-11-01 | Method of inspecting magnetic carburization in a non-permeable material and probe therefore |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3719185A JPS61195351A (en) | 1985-02-25 | 1985-02-25 | Non-destructive deciding method for carburizing depth |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61195351A true JPS61195351A (en) | 1986-08-29 |
| JPH0445071B2 JPH0445071B2 (en) | 1992-07-23 |
Family
ID=12490679
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3719185A Granted JPS61195351A (en) | 1985-02-25 | 1985-02-25 | Non-destructive deciding method for carburizing depth |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61195351A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63308501A (en) * | 1987-06-10 | 1988-12-15 | Kubota Ltd | Nondestructive measuring apparatus for depth of cabonization |
| WO2006103483A3 (en) * | 2005-04-01 | 2008-12-24 | Antal Gasparics | Magnetic imaging equipment for non-destructive testing of magnetic and/or electrically conductive materials |
| JP2009236753A (en) * | 2008-03-27 | 2009-10-15 | Honda Motor Co Ltd | Gear strength evaluation method |
| CN110701990A (en) * | 2019-10-19 | 2020-01-17 | 北京工业大学 | Furnace tube carburized layer thickness evaluation method and system based on magnetic field disturbance and magnetic force double detection rings |
-
1985
- 1985-02-25 JP JP3719185A patent/JPS61195351A/en active Granted
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63308501A (en) * | 1987-06-10 | 1988-12-15 | Kubota Ltd | Nondestructive measuring apparatus for depth of cabonization |
| WO2006103483A3 (en) * | 2005-04-01 | 2008-12-24 | Antal Gasparics | Magnetic imaging equipment for non-destructive testing of magnetic and/or electrically conductive materials |
| JP2009236753A (en) * | 2008-03-27 | 2009-10-15 | Honda Motor Co Ltd | Gear strength evaluation method |
| CN110701990A (en) * | 2019-10-19 | 2020-01-17 | 北京工业大学 | Furnace tube carburized layer thickness evaluation method and system based on magnetic field disturbance and magnetic force double detection rings |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0445071B2 (en) | 1992-07-23 |
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