클래드강 맞대기 용접부의 후열처리 유지시간에 따른 델타 페라이트 거동 (δ-Ferrite Behavior of Butt Weld Zone in Clad Steel Plates Depended on Holding Time of PWHT)

서지정보

· 발행기관 : 대한용접접합학회
· 수록지 정보 : 대한용접접합학회지 / 32권 / 2호 / 29 ~ 36페이지
· 저자명 : 박재원, 이철구

초록

Recently, in order to enhance the function and usefulness of products, cladding of dissimilar materialsthat maximizes the performance of the material is being widely used in all areas of industry as an importantprocess. Clad steel plate, produced by cladding stainless steel plate, an anticorrosive material, on carbon steelplate, is being used to produce pressure vessels. Stainless steel plate has good corrosion resistance, andcarbon steel plate has good rigidity and strength; clad steel can satisfy all of these qualities at once. Thisstudy aims to find the δ-ferrite behavior, mechanical properties, structure change, integrity and reliability ofclad steel weld on hot rolled steel plates. For this purpose, multi-layer welding, repair welding and post weldheat treatment were implemented according to welding procedure specifications (WPS). In order to observethe mechanical properties and toughness of clad steel weld zone, post weld heat treatment was carried outaccording to ASME Sec. VIII Div.1 UW-40 procedure for post weld heat treatment. With heat treatment at625 ℃, the hold time was used as the process variable, increased by intervals that were doubled each time,from 80 to 1,280 min. The structure of weld part was typical cast structure; localized primary austenite areasappeared near central vermicular ferrite and fusion line. The heat affected zone showed rough austenitestructure created by the weld heat input. Due to annealing effects of heat treatment, the mechanical properties(tensile strength, hardness, impact value) of the heat affected area tended to decrease. From the results ofthis study, it is possible to conclude the integrity of clad steel welds is not affected much in field welding,repair welding, multi-layer welding, post weld heat treatment, etc.

영어초록

Recently, in order to enhance the function and usefulness of products, cladding of dissimilar materialsthat maximizes the performance of the material is being widely used in all areas of industry as an importantprocess. Clad steel plate, produced by cladding stainless steel plate, an anticorrosive material, on carbon steelplate, is being used to produce pressure vessels. Stainless steel plate has good corrosion resistance, andcarbon steel plate has good rigidity and strength; clad steel can satisfy all of these qualities at once. Thisstudy aims to find the δ-ferrite behavior, mechanical properties, structure change, integrity and reliability ofclad steel weld on hot rolled steel plates. For this purpose, multi-layer welding, repair welding and post weldheat treatment were implemented according to welding procedure specifications (WPS). In order to observethe mechanical properties and toughness of clad steel weld zone, post weld heat treatment was carried outaccording to ASME Sec. VIII Div.1 UW-40 procedure for post weld heat treatment. With heat treatment at625 ℃, the hold time was used as the process variable, increased by intervals that were doubled each time,from 80 to 1,280 min. The structure of weld part was typical cast structure; localized primary austenite areasappeared near central vermicular ferrite and fusion line. The heat affected zone showed rough austenitestructure created by the weld heat input. Due to annealing effects of heat treatment, the mechanical properties(tensile strength, hardness, impact value) of the heat affected area tended to decrease. From the results ofthis study, it is possible to conclude the integrity of clad steel welds is not affected much in field welding,repair welding, multi-layer welding, post weld heat treatment, etc.

참고자료

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