JPH07214313A - Weld repairing method for high cr cast iron product - Google Patents
Weld repairing method for high cr cast iron productInfo
- Publication number
- JPH07214313A JPH07214313A JP2899094A JP2899094A JPH07214313A JP H07214313 A JPH07214313 A JP H07214313A JP 2899094 A JP2899094 A JP 2899094A JP 2899094 A JP2899094 A JP 2899094A JP H07214313 A JPH07214313 A JP H07214313A
- Authority
- JP
- Japan
- Prior art keywords
- cast iron
- temperature
- welding
- product
- weld
- 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.)
- Granted
Links
- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 14
- 238000003466 welding Methods 0.000 claims abstract description 36
- 238000001816 cooling Methods 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 238000005266 casting Methods 0.000 claims description 17
- 230000007547 defect Effects 0.000 claims description 13
- 238000010791 quenching Methods 0.000 claims description 6
- 230000000171 quenching effect Effects 0.000 claims description 6
- 238000005496 tempering Methods 0.000 claims description 4
- 238000010583 slow cooling Methods 0.000 abstract 1
- 239000000463 material Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
- Arc Welding In General (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、従来その溶接補修が困
難とされていた高Ｃｒ鋳鉄品の溶接補修を可能となす技
術に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique capable of welding and repairing a high Cr cast iron product which has conventionally been difficult to weld and repair.
【０００２】[0002]
【従来の技術】Ｃｒを多量に含む高Ｃｒ鋳鉄は、優れた
耐熱性、耐食性を有すると共に、Ｃ含有量も多いため炭
化物が形成され耐摩耗性にも優れた特性を有している。
ところがこの高Ｃｒ鋳鉄は、鋳造に際して溶解温度なら
びに鋳込み温度が高すぎると凝固組織が粗大化し、機械
的性質が低下するという性質があるため、溶解温度なら
びに鋳込み温度を厳しく管理しなければならない結果、
鋳造品の寸法、形状などについて鋳造欠陥の発生が避け
られない場合がある。そして、鋳造後に欠陥が発生した
場合、一般的な鋳物に対しては溶接補修が実施されてい
るが、高Ｃｒ鋳鉄は硬い炭化物が多量に基地中に存在し
ているために、延性が低く、さらに鋳造に伴い発生した
残留応力が存在するために、溶接補修中に亀裂が発生
し、むしろ欠陥の成長を助長する結果となる場合が多
く、溶接補修は困難とされていた。2. Description of the Related Art High Cr cast iron containing a large amount of Cr has excellent heat resistance and corrosion resistance, and since it contains a large amount of C, it forms carbides and has excellent wear resistance.
However, this high Cr cast iron has the property that the melting temperature and the casting temperature are too high during casting, the solidified structure is coarsened, and the mechanical properties deteriorate, so that the melting temperature and the casting temperature must be strictly controlled,
Occurrence of casting defects may be unavoidable with respect to the size and shape of the cast product. Then, when defects occur after casting, welding repair is carried out for general castings, but high Cr cast iron has a large amount of hard carbides in the matrix, so ductility is low, Furthermore, since there are residual stresses generated by casting, cracks often occur during welding repair, which often promotes the growth of defects, which makes welding repair difficult.
【０００３】[0003]
【発明が解決しようとする課題】上述した如く、高Ｃｒ
鋳鉄は、その材質的な理由及び鋳造の際に発生する残留
応力の存在により、鋳造時に発生した欠陥に対する溶接
補修が困難なため、僅かな鋳造欠陥の発生により製品を
廃棄し、再度鋳造しなおさなければならないという問題
点があった。本発明では上記問題点を解決するために、
高Ｃｒ鋳鉄が延性を回復すると共に、降伏応力の低下に
より残留応力が低下、消失する温度範囲で熱管理を実施
し乍ら溶接補修を行う方法を提供することを目的とする
ものである。As described above, high Cr content
Due to the material properties of cast iron and the presence of residual stress that occurs during casting, it is difficult to repair welds due to defects that occur during casting.Therefore, a slight casting defect occurs and the product is discarded and recast again. There was a problem that it had to be. In order to solve the above problems in the present invention,
An object of the present invention is to provide a method for performing weld repair by performing heat management in a temperature range in which high Cr cast iron recovers ductility and residual stress decreases and disappears due to decrease in yield stress.
【０００４】[0004]
【課題を解決するための手段】上記本発明の目的は次の
如き溶接補修方法を採用することにより達成できる。即
ちその要旨は、鋳造欠陥が生じた高Ｃｒ鋳鉄品を、６０
０〜８００℃の温度に予熱し、溶接補修をする際に６０
０℃以上の温度に保持し、溶接終了後に於いても６００
℃以上の温度で直後熱処理を行い、その後１時間当たり
５０℃以下の冷却速度で室温まで徐冷する高Ｃｒ鋳鉄品
の溶接補修方法である。なお高Ｃｒの種類，使用目的に
より、焼入れ，焼戻しをした後に使用する必要がある製
品については、上記６００℃以上の温度での溶接補修が
終了した直後に、一度室温まで冷却することなく、引き
続き高Ｃｒ鋳鉄の焼入れ温度まで加熱し、熱処理を実施
することも可能である。The above objects of the present invention can be achieved by employing the following welding repair method. That is, the gist of the high-Cr cast iron products with casting defects is 60
Preheat to a temperature of 0-800 ° C, and 60 for welding repair
Maintaining a temperature of 0 ° C or higher, 600 even after welding is completed.
This is a welding repair method for a high Cr cast iron product in which a heat treatment is immediately performed at a temperature of ℃ or more and then slowly cooled to room temperature at a cooling rate of 50 ° C or less per hour. For products that need to be used after quenching and tempering depending on the type and purpose of use of high Cr, immediately after the completion of welding repair at a temperature of 600 ° C or higher, without cooling once to room temperature, continue It is also possible to heat to the quenching temperature of the high Cr cast iron and perform the heat treatment.
【０００５】なお予熱温度を６００〜８００℃に設定し
た理由は、高Ｃｒ鋳鉄は６００℃以上になると、硬さ，
引張り強さが低下すると共に、延性が回復する。従って
この様な温度域に保持することにより塑性変形が可能と
なり、鋳造時に発生していた残留応力を開放することが
できるからであり、一方高Ｃｒ鋳鉄品は８００℃を越え
る温度に長時間保持すると、表面酸化，結晶粒の粗大化
などが生起し材質の劣化が考えられるので上限は８００
℃とした。又溶接補修及び溶接終了後の直後熱処理を６
００℃以上で行うのも上記予熱温度のところで述べたの
と同じ理由でありこの時にもその上限は８００℃とする
のがよい。即ち高Ｃｒ鋳鉄品に発生した鋳造欠陥の位置
によっては、横向きあるいは立向き溶接を実施しなけれ
ばならないことがあるが、このような場合に８００℃以
上の温度に加熱されていると、溶融した溶接金属の粘性
が不足し、補修部に留まらずに流れ落ち溶接が困難とな
ることもあるからである。The reason why the preheating temperature is set to 600 to 800 ° C. is that the hardness of high Cr cast iron becomes higher than 600 ° C.
The tensile strength is reduced and the ductility is restored. Therefore, by holding in such a temperature range, plastic deformation becomes possible and residual stress generated during casting can be released. On the other hand, high Cr cast iron products are kept at a temperature over 800 ° C for a long time. Then, surface oxidation, coarsening of crystal grains, etc. may occur to deteriorate the material. Therefore, the upper limit is 800
℃ was made. Welding repair and heat treatment immediately after welding are completed.
The reason why the temperature is higher than 00 ° C. is the same as that described in the above preheating temperature. At this time, the upper limit is preferably 800 ° C. That is, depending on the position of the casting defect generated in the high Cr cast iron product, it may be necessary to carry out horizontal or vertical welding, but in such a case, if it is heated to a temperature of 800 ° C. or more, it melts. This is because the viscosity of the weld metal may be insufficient and it may be difficult to perform flow-down welding without staying at the repaired portion.
【０００６】次に冷却速度であるがこれを１時間当たり
５０℃を越える速度とすると冷却過程に於いて冷却収縮
に伴い亀裂が発生するので、冷却速度は１時間当たり５
０℃以下とする。又溶接補修に際しての溶接方法は、被
覆アーク溶接，ＴＩＧ溶接，ガス溶接などが考えられ、
溶接材料は、高Ｃｒ鋳鉄品の使用目的を考慮し、高張力
鋼系溶接材料，ステンレス鋼系溶接材料，高Ｃｒ鋳鉄と
同じ化学成分系の溶接材料の使用が可能である。そして
使用する溶接材料の特性などを考慮してピーニングを実
施する場合もある。Next, regarding the cooling rate, when the cooling rate is set to a rate exceeding 50 ° C. per hour, cracks are generated due to cooling shrinkage during the cooling process, so the cooling rate is 5 per hour.
It shall be 0 ° C or lower. In addition, the welding method for welding repair may be covered arc welding, TIG welding, gas welding, etc.
As the welding material, in consideration of the purpose of use of the high Cr cast iron product, it is possible to use a high tensile steel welding material, a stainless steel welding material, and a welding material having the same chemical composition as that of the high Cr cast iron. Then, peening may be performed in consideration of the characteristics of the welding material used.
【０００７】[0007]
【実施例】以下本発明をその実施例を示し乍ら詳述す
る。この実施例は、第１表に示した如き化学成分を有す
る高Ｃｒ鋳鉄品に対して行ったものであり、鋳造欠陥部
分をまずグラインダーによって除去する。 The present invention will be described in detail below with reference to its examples. This example was carried out on a high Cr cast iron product having the chemical composition shown in Table 1, and the casting defect portion is first removed by a grinder.
【０００８】上記グラインダーかけの後、熱処理炉に於
いて、図１に示すように７００℃の温度に予熱し、熱処
理炉から取出し補修炉内へ装入し、溶接実施部所のみが
表面に現れるようにする。そして高Ｃｒ鋳鉄系溶接材料
を用いて被覆アーク溶接にて補修を行い、その後予め７
００℃の温度に設定された熱処理炉内へ装入し、１時間
保持した後、焼入れ温度まで加熱し、焼入れ，焼戻しを
実施した。この溶接中にピーニングを実施した。その結
果割れの発生もなく、溶接欠陥も認められなかった。な
おこれはカラーチェックによっても確認した。さらに、
溶接部より試験片を採取し引張り試験を実施したとこ
ろ、いずれの試験片においても母材で破断したことか
ら、溶接部は充分な強度を有していることが判った。ま
た、溶接部の硬さ測定により、均一な硬さ分布が得られ
ていることも確認できた。After the grinder is applied, it is preheated to a temperature of 700 ° C. in a heat treatment furnace as shown in FIG. 1, taken out of the heat treatment furnace and charged into a repair furnace, and only the welding portion appears on the surface. To do so. Then, repairing is performed by covered arc welding using a high Cr cast iron-based welding material, and then 7
After charging into a heat treatment furnace set to a temperature of 00 ° C., holding for 1 hour, heating to a quenching temperature, quenching and tempering were carried out. Peening was performed during this welding. As a result, no crack was generated and no welding defect was recognized. This was also confirmed by color check. further,
When a test piece was taken from the welded portion and a tensile test was carried out, it was found that the welded portion had sufficient strength, because the test piece fractured in the base material. It was also confirmed by measuring the hardness of the welded portion that a uniform hardness distribution was obtained.
【０００９】[0009]
【発明の効果】以上述べて来た如く、本発明方法によれ
ば、高Ｃｒ鋳鉄品に発生した鋳造欠陥の溶接補修が可能
であり、その結果も亀裂の発生や溶接欠陥もなく健全な
ものである。従って鋳造欠陥が生起した高Ｃｒ鋳鉄品の
再生が可能であり、再度新たに鋳造しなおすことと比
べ、低コスト化を図ることができると共に、製品製造期
間の短縮化を図ることができるという効果を奏する。As described above, according to the method of the present invention, it is possible to repair the welding defects in the high Cr cast iron products by welding, and as a result, there are no cracks and welding defects, which are sound. Is. Therefore, it is possible to recycle the high Cr cast iron product in which the casting defect has occurred, and it is possible to reduce the cost and to shorten the product manufacturing period as compared with the case of re-casting again. Play.
【００１０】[0010]
【図１】本発明実施例の予熱から焼戻しまでの温度−時
間線図である。FIG. 1 is a temperature-time diagram from preheating to tempering in an example of the present invention.
Claims (2)
０〜８００℃の温度に予熱し、溶接補修をする際に６０
０℃以上の温度に保持し、溶接終了後に於いても６００
℃以上の温度で直後熱処理を行い、その後１時間当たり
５０℃以下の冷却速度で室温まで徐冷することを特徴と
する高Ｃｒ鋳鉄品の溶接補修方法。1. A high Cr cast iron product having a casting defect is
Preheat to a temperature of 0-800 ° C, and 60 for welding repair
Maintaining a temperature of 0 ° C or higher, 600 even after welding is completed.
A method for welding and repairing a high Cr cast iron product, which comprises immediately performing heat treatment at a temperature of ℃ or more and then gradually cooling to room temperature at a cooling rate of 50 ° C or less per hour.
理終了後、一度室温まで冷却することなく、高Ｃｒ鋳鉄
の焼入れ温度まで加熱し、その後に焼入れ、焼戻しを行
うことを特徴とする高Ｃｒ鋳鉄品の溶接補修方法。2. The method according to claim 1, characterized in that after the immediate heat treatment is finished, it is heated to the quenching temperature of the high Cr cast iron without being once cooled to room temperature, and then quenching and tempering are performed. Welding repair method for high Cr cast iron products.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02899094A JP3534321B2 (en) | 1994-01-31 | 1994-01-31 | Welding repair method for high Cr cast iron products |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02899094A JP3534321B2 (en) | 1994-01-31 | 1994-01-31 | Welding repair method for high Cr cast iron products |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07214313A true JPH07214313A (en) | 1995-08-15 |
| JP3534321B2 JP3534321B2 (en) | 2004-06-07 |
Family
ID=12263857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02899094A Expired - Lifetime JP3534321B2 (en) | 1994-01-31 | 1994-01-31 | Welding repair method for high Cr cast iron products |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3534321B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8720056B2 (en) | 2008-02-14 | 2014-05-13 | Mitsubishi Heavy Industries, Ltd. | Turbine rotor blade repair method |
| CN108637428A (en) * | 2018-05-18 | 2018-10-12 | 共享铸钢有限公司 | A kind of high intensity gear ring class cast steel part defect weldering repair renovation method |
| CN115401428A (en) * | 2022-10-13 | 2022-11-29 | 承驰传动科技(山东)有限公司 | Nodular cast iron traction motor welding process for rail transit |
-
1994
- 1994-01-31 JP JP02899094A patent/JP3534321B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8720056B2 (en) | 2008-02-14 | 2014-05-13 | Mitsubishi Heavy Industries, Ltd. | Turbine rotor blade repair method |
| CN108637428A (en) * | 2018-05-18 | 2018-10-12 | 共享铸钢有限公司 | A kind of high intensity gear ring class cast steel part defect weldering repair renovation method |
| CN108637428B (en) * | 2018-05-18 | 2020-10-27 | 共享铸钢有限公司 | Repair welding repair repairing method for defects of high-strength gear ring type steel castings |
| CN115401428A (en) * | 2022-10-13 | 2022-11-29 | 承驰传动科技(山东)有限公司 | Nodular cast iron traction motor welding process for rail transit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3534321B2 (en) | 2004-06-07 |
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