JPH0233785B2 - - Google Patents
Info
- Publication number
- JPH0233785B2 JPH0233785B2 JP58139104A JP13910483A JPH0233785B2 JP H0233785 B2 JPH0233785 B2 JP H0233785B2 JP 58139104 A JP58139104 A JP 58139104A JP 13910483 A JP13910483 A JP 13910483A JP H0233785 B2 JPH0233785 B2 JP H0233785B2
- Authority
- JP
- Japan
- Prior art keywords
- concentration
- furnace
- gas
- enrichment
- curve
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 claims description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 230000002123 temporal effect Effects 0.000 claims description 10
- 238000005255 carburizing Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 description 23
- 239000004071 soot Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000012159 carrier gas Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Description
【発明の詳細な説明】
本発明はバツチ型浸炭炉の浸炭雰囲気の制御方
法に関するもので、被処理品の装入、昇温完了時
点の浸炭開始時の炭素ポテンシヤルに対応する炉
内の特定ガス濃度を実測し、該実測値を基準とし
てその後の時間的濃度変動曲線を演算により求
め、エンリツチガスの流量を可変制御することを
特徴とするものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the carburizing atmosphere in a batch-type carburizing furnace. The present invention is characterized in that the concentration is actually measured, a subsequent temporal concentration fluctuation curve is calculated using the measured value as a reference, and the flow rate of the enrichment gas is variably controlled.
従来、上記浸炭処理は所要濃度のCOを含む変
成ガスあるいは不活性ガスをベースに炭化水素等
のガスを添加し、変成炉で自己変成させたキヤリ
アガスを炉内に供給し、一定の炭素濃度勾配で行
つている。 Conventionally, the above carburizing process involves adding gases such as hydrocarbons to a base of metamorphosed gas or inert gas containing CO at the required concentration, and supplying a carrier gas that has been self-transformed in a shift furnace to create a constant carbon concentration gradient. I'm going there.
しかしながら、炉内温度が上昇すると、キヤリ
アーガス中のCOが酸化され、CO濃度が低下して
CO2濃度が上昇する。 However, when the temperature inside the furnace increases, the CO in the carrier gas is oxidized and the CO concentration decreases.
CO 2 concentration increases.
そのため、CO2を還元し、所定の炭素濃度を得
るため、炭化水素系のエンリツチガスが添加され
る。 Therefore, a hydrocarbon-based enrichment gas is added to reduce CO 2 and obtain a predetermined carbon concentration.
しかしながら炉内温度、ガス組成、被処理品の
表面炭素濃度の平衡範囲以上の量のエンリツチガ
スが添加されると煤が発生し、以後雰囲気のバラ
ンスが崩れ雰囲気の制御が困難となる。 However, if the enrichment gas is added in an amount that exceeds the equilibrium range of the furnace temperature, gas composition, and surface carbon concentration of the workpiece, soot will be generated, and the atmosphere will become unbalanced, making it difficult to control the atmosphere.
したがつて、エンリツチガスの最大添加量の算
出は極めて重大である。 Therefore, calculating the maximum amount of enrichment gas to be added is extremely important.
従来、上記のごとき雰囲気の制御方法と定量エ
ンリツチ方式あるいは特公昭56−31355号公報に
掲載された方法が採用されている。 Conventionally, the above-mentioned atmosphere control method and quantitative enrichment method or the method disclosed in Japanese Patent Publication No. 31355/1987 have been employed.
上記定量エンリツチ方式は経験的に煤が発生し
ない少めのエンリツチガスを定量的に供給するも
のであり、あるいはさらに制御値に達した後に自
動制御する方式であるが、悪までも経験的である
ため正確な制御が困難である。 The quantitative enrichment method described above is a method that quantitatively supplies a small amount of enrichment gas that does not generate soot, or a method that automatically controls after reaching a control value, but it is also a method that is empirically proven to be bad. Accurate control is difficult.
すなわち、炉材、被処理品の量（浸炭表面積）
等によりCO2の発生量に変化があり、また、被処
理品の材質により雰囲気と表面炭素濃度に変化が
あり、それらに順応したエンリツチガスの供給が
行われない場合があつた。 In other words, the amount of furnace material and workpiece (carburized surface area)
There were changes in the amount of CO 2 generated due to various factors, and changes in the atmosphere and surface carbon concentration depending on the material of the product to be treated, so there were cases where enrichment gas was not supplied in accordance with these changes.
上記欠点を除去するため、本願出願人は特公昭
56−31355号公報に掲載された方法を提供したも
のである。 In order to eliminate the above-mentioned drawbacks, the applicant has
This method provides the method published in Publication No. 56-31355.
上記方法は炉内に装入される「被処理品の浸炭
面積（表面積）に応じた定流量の初期エンリツチ
ガスを供給して特定ガス（CO2、CO等）を基準
濃度に対応する炭素ポテンシヤルよりもかなり低
いが制御可能な炭素ポテンシヤルに対応する所定
の初期濃度に達せしめた後、前記特定ガスの濃度
が前記基準濃度に近づくにつれてその濃度の変化
の割合いが少くなるような予め定められた時間的
濃度変動曲線に従つて変動するように前記エンリ
ツチガス流量を可変制御しつつ、前記エンリツチ
ガスを炉内に供給する」ものである。 The above method involves supplying a constant flow of initial enrichment gas according to the carburized area (surface area) of the product to be treated, which is charged into the furnace, and controlling the specific gas (CO 2 , CO, etc.) from the carbon potential corresponding to the standard concentration. After reaching a predetermined initial concentration corresponding to a fairly low but controllable carbon potential, a predetermined rate of change in the concentration of said specific gas decreases as it approaches said reference concentration. The enrichment gas is supplied into the furnace while variably controlling the enrichment gas flow rate so as to vary according to a temporal concentration variation curve.
上記被処理品の浸炭面積を基準とする処理方法
は従来の定量エンリツチ方式に比べて優れた効果
を得ることができるが、浸炭開始時の現実の炭素
ポテンシヤルと予め定められた時間的濃度変動曲
線の値がかけはなれる場合があつた。 The above-mentioned treatment method based on the carburized area of the product to be treated can achieve superior effects compared to the conventional quantitative enrichment method. There were cases where the values of
そして、例えば、予め定められた値より炭素ポ
テンシヤルが低い場合、短時間にエンリツチガス
を供給すると炉内に煤が発生する危険があつた。 For example, if the carbon potential is lower than a predetermined value, there is a risk that soot will be generated in the furnace if enrichment gas is supplied for a short period of time.
本発明は上記のごとき問題を解決し、浸炭開始
時の炭素ポテンシヤルを無理なく目標とする値に
制御することを特徴とするものである。 The present invention is characterized by solving the above problems and controlling the carbon potential at the start of carburization to a target value without difficulty.
まず、従来の浸炭雰囲気の制御例を述べると、
従来はすでに述べたごとく、バツチ型浸炭炉にお
ける初期エンリツチ量は被処理品の浸炭面積（表
面積）の炭素ポテンシヤル、処理温度等から決定
され、それをもとに浸炭開始時およびその近傍の
炭素ポテンシヤルを計算及び経験値により推定
し、雰囲気をプログラム制御するものであつた。 First, let us describe an example of conventional carburizing atmosphere control.
As previously mentioned, the initial enrichment amount in a batch-type carburizing furnace is determined from the carbon potential of the carburized area (surface area) of the workpiece, the treatment temperature, etc. Based on this, the carbon potential at the start of carburizing and in the vicinity was estimated based on calculations and empirical values, and the atmosphere was controlled by a program.
しかしながら、上記方法の場合、設定した値は
悪まで推定値であり、実測値とかけはなれている
場合があつた。 However, in the case of the above method, the set value is an estimated value and may be far from the actual measured value.
例えば、雰囲気の炭素ポテンシヤルをCO2濃度
により測定する場合、従来のプログラム制御にあ
つては第２図示のごとく、炉内CO2濃度設定曲線
ａに対して炉内CO2濃度の実測値が高い場合（点
線ｂ）には設定値との差をなくするためエンリツ
チガス供給量を多くする動作（一点鎖線ｃ）を行
うが、このとき過剰なエンリツチガスにより炉内
に煤が発生する危険があり、煤が発生すると雰囲
気のバランスが崩れ、後の制御が不可能となる。
また、炉内CO2濃度設定曲線ａに対して炉内CO2
濃度の実測値が低い場合（点線ｄ）には設定値と
の差をなくするためエンリツチガス供給量を少く
する動作（一点鎖線ｅ）を行うが、初期のCO2濃
度より高い値に制御するという無駄を生じ、かつ
雰囲気の安定性に問題を生じるものであつた。 For example, when measuring the carbon potential of the atmosphere using the CO 2 concentration, in conventional program control, as shown in Figure 2, the actual value of the CO 2 concentration inside the furnace is higher than the CO 2 concentration setting curve a. In this case (dotted line b), the enrichment gas supply amount is increased (dotted chain line c) to eliminate the difference from the set value, but at this time there is a risk that soot will be generated in the furnace due to excessive enrichment gas. If this occurs, the balance of the atmosphere will be disrupted, making subsequent control impossible.
In addition, for the in-furnace CO 2 concentration setting curve a, the in-furnace CO 2
When the actual concentration value is low (dotted line d), the enrichment gas supply amount is reduced (dotted chain line e) to eliminate the difference from the set value, but the CO 2 concentration is controlled to a value higher than the initial CO 2 concentration. This resulted in waste and caused problems in the stability of the atmosphere.
本発明は上記のごとき欠点を除去するもので、
浸炭開始時の炭素ポテンシヤルに対応する炉内の
特定ガス濃度を実測し、該実測値を基準としてそ
の後の時間的濃度変動曲線を演算により求め、エ
ンリツチガスの流量を可変制御するものである。 The present invention eliminates the above-mentioned drawbacks,
The concentration of a specific gas in the furnace corresponding to the carbon potential at the start of carburization is actually measured, and the subsequent temporal concentration fluctuation curve is calculated using the measured value as a reference, and the flow rate of the enrichment gas is variably controlled.
第１図についてその一例を説明すると、被処理
品の装入、昇温完了時点の浸炭開始時（ｆ点）に
おけるCO2濃度が赤外線ガス分析計等により実測
される。 To explain an example with reference to FIG. 1, the CO 2 concentration at the start of carburization (point f) at the time when the article to be treated is charged and the temperature has been raised is actually measured using an infrared gas analyzer or the like.
そして、浸炭開始時（ｆ点）から時間（Ｔ）後
に炉内CO2濃度を（C1）に達せしめる浸炭処理に
おいて、理想的な時間的濃度変動曲線Ｂを演算器
に記憶させ、浸炭開始時（ｆ点）の炉内CO2濃度
の実測値を起点として理想的な時間的濃度変動曲
線Ｂを補正演算した設定曲線（実測値が高い場
合、点線Ａ、実測値が低い場合点線Ｃに従つて浸
炭開始時（ｆ点）から時間（Ｔ）後に目標とする
炉内CO2濃度（c1）に達するよう制御するもので
ある。 Then, in the carburizing process in which the CO 2 concentration in the furnace reaches (C 1 ) after a time (T) from the start of carburization (point f), the ideal temporal concentration fluctuation curve B is stored in the calculator, and carburization is started. A set curve that is calculated by correcting the ideal temporal concentration fluctuation curve B using the actual measured value of the CO 2 concentration in the furnace at point f as the starting point (if the actual measured value is high, dotted line A; if the actual measured value is low, dotted line C) Therefore, control is performed so that the target in-furnace CO 2 concentration (c 1 ) is reached after a time (T) from the start of carburization (point f).
つぎに、上記CO2濃度曲線式を例えば二次曲線
とした場合について第３図を参照して述べる。 Next, the case where the above CO 2 concentration curve equation is made into, for example, a quadratic curve will be described with reference to FIG. 3.
二次曲線の一般式
Ｙ＝aX2＋bX＋ｃ ……(1)
において、
(1)式により
dY／dX＝2aX＋ｂ ……(2)
（Ｘ、Ｙ）＝（０、yi）を(1)式に代入して
ｃ＝yi ……(3)
（Ｘ、Ｙ）＝（xs、yf）のときdY／dX＝０であ
るから(2)式に代入して
ｂ＝−2axs ……(4)
(1)式に(3)(4)式及び（Ｘ、Ｙ）＝（xs、yf）を代入
して
ａ＝yi−yf／xs2 ……(5)
(5)式を４式に代入して
ｂ＝−２（yi−yf）／xs ……(6)
(3)(5)(6)式を(1)式に代入することによつて求める
曲線の式は
Ｙ＝（yi−yf）・X2／xs2−２（yi−yf）・X2／xs＋yi
……(7)
となる。 In the general formula of a quadratic curve Y=aX 2 +bX+c...(1), by equation (1), dY/dX=2aX+b...(2) (X, Y)=(0, yi) into equation (1) Substitute c=yi...(3) When (X, Y)=(xs, yf), dY/dX=0, so substitute into equation (2) and get b=-2axs...(4) ( Substitute equations (3) and (4) and (X, Y) = (xs, yf) into equation 1) and get a=yi−yf/xs 2 ...(5) Substitute equation (5) into equation 4. b = -2 (yi - yf) / xs ... (6) The equation of the curve obtained by substituting equations (3), (5) and (6) into equation (1) is Y = (yi - yf )・X 2 /xs 2 −2 (yi − yf)・X 2 /x s +yi
...(7) becomes.
なお、上記(7)式において、
yi（イニシヤルCO2）、yf（フアイナルCO2）、xs
（設定時間）、Ｘ（経過時間）、Ｙ（Xmin経過後の
CO2SV）等はデーター値により定められる。 In addition, in the above equation (7), yi (initial CO 2 ), yf (final CO 2 ), xs
(set time), X (elapsed time), Y (after Xmin elapsed)
CO 2 SV) etc. are determined by data values.
上記のごとく、本発明は浸炭開始時の炭素ポテ
ンシヤルに対応する特定ガス濃度を実測し、該実
測値を基準としてその後の時間的濃度変動曲線を
演算により求め、エンリツチガスの流量を可変制
御するため、従来のごとく、推定値制御が排除さ
れ、現実の処理状態及び被処理品の実態を把握し
た有効な雰囲気制御が可能となるものである。 As described above, the present invention actually measures the specific gas concentration corresponding to the carbon potential at the start of carburization, calculates the subsequent temporal concentration fluctuation curve based on the measured value, and variably controls the enrichment gas flow rate. Estimated value control, as in the past, is eliminated, and effective atmosphere control that takes into account the actual processing conditions and the actual conditions of the products to be processed becomes possible.
図面は本発明の一実施例を示すもので、第１図
は雰囲気制御線図、第２図は従来の雰囲気制御例
を示す線図、第３図は二次曲線説明図である。
Ａ……CO2濃度の実測値が高い場合の時間的濃
度変動曲線、Ｂ……CO2の理想的な時間的濃度変
動曲線、Ｃ……CO2濃度の実測値が低い場合合の
時間的濃度変動曲線。
The drawings show one embodiment of the present invention, and FIG. 1 is an atmosphere control diagram, FIG. 2 is a diagram showing a conventional atmosphere control example, and FIG. 3 is a quadratic curve explanatory diagram. A... Temporal concentration variation curve when the actual measured value of CO 2 concentration is high, B... Ideal temporal concentration variation curve of CO 2 , C... Temporal concentration variation curve when the actual measured value of CO 2 concentration is low. Concentration variation curve.
Claims (1)
の炭素ポテンシヤルに対応する炉内の特定ガス濃
度を実測し、該実測値を基準としてその後の時間
的濃度変動曲線を演算により求め、エンリツチガ
スの流量を可変制御することを特徴とするバツチ
型浸炭炉の浸炭雰囲気の制御方法。1.Actually measure the specific gas concentration in the furnace corresponding to the carbon potential at the start of carburization at the time of charging the product to be treated and completing the temperature rise, calculate the subsequent temporal concentration fluctuation curve based on the measured value, A method for controlling a carburizing atmosphere in a batch-type carburizing furnace, characterized by variable control of the flow rate of enrichment gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13910483A JPS6029461A (en) | 1983-07-29 | 1983-07-29 | Controlling method of carburizing atmosphere for batch type carburizing furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13910483A JPS6029461A (en) | 1983-07-29 | 1983-07-29 | Controlling method of carburizing atmosphere for batch type carburizing furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6029461A JPS6029461A (en) | 1985-02-14 |
| JPH0233785B2 true JPH0233785B2 (en) | 1990-07-30 |
Family
ID=15237572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13910483A Granted JPS6029461A (en) | 1983-07-29 | 1983-07-29 | Controlling method of carburizing atmosphere for batch type carburizing furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6029461A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5139584A (en) * | 1989-07-13 | 1992-08-18 | Solo Fours Industriels Sa | Carburization process |
| JP3973795B2 (en) * | 1999-05-24 | 2007-09-12 | 東邦瓦斯株式会社 | Gas carburizing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5629668A (en) * | 1979-08-20 | 1981-03-25 | Oriental Eng Kk | Carbon concn. controlling method of carburizing atmosphere |
-
1983
- 1983-07-29 JP JP13910483A patent/JPS6029461A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5629668A (en) * | 1979-08-20 | 1981-03-25 | Oriental Eng Kk | Carbon concn. controlling method of carburizing atmosphere |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6029461A (en) | 1985-02-14 |
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