Fracture toughness of welded joints of a high strenghth low alloy steel
Description
The fracture toughness of welded joints of a high strength low alloy atmospheric corrosion resistant steel was investigated. The welded joints were produced using the manual metal arc welding process and fracture toughness was evaluated by the COD method. An effort was made in order to correlate the microstructure of the different regions of the welded joints and their critical COD values. The results appear to indicate that when the structure of the heat affected zone is formed mainly by bainite and ferritic grains the fracture toughness tends to increase. Also, an increase on the amount of acicular ferrite on the weld metal tends to improve its fracture toughness. The fusion boundary showed a structure formed mainly by bainite and ferrite grains and its fracture toughness was higher than that of the parent metal at room temperature whereas it was lower at 00C. Both at 00C and room temperature the fracture toughness of the weld metal was better than those of the other regions of the welded joints. The correlations between critical values of COD and the microstructures of the different regions of the welded joints were very difficult. (Author)
Availability note (English)
Available from Instituto de Engenharia Nuclear, RJ, Brazil.Abstract (Portuguese)
Foi feito um estudo da tenacidade a fratura de juntas soldadas de um aco Niocor II pelo processo de soldagem com eletrodo revestido. Procurou-se relacionar as microestruturas de cada regiao das juntas soldadas com os seus respectivos valores criticos de COD. A caracterizacao das microestruturas e da morfologia da fratura foi feita atraves de microscopia otica e eletronica de varreduara, respectivamente, tendo sido efetuadas tambem medidas de microdureza. Verificou-se que as microestruturas bainitica mais graos ferriticos da zona afetada pelo calor e ferrita acicular do metal de solda tenderam a aumentar a tenacidade nestas regioes, apesar das correlacoes entre os valores criticos de COD e as microestruturas das diferentes regioes de junta soldada, quando existentes, serem extremamente dificeis. A linha de fusao, onde a microestrutura bainitica mais graos ferriticos foi predominante, apresentou uma tenacidade a fratura superior ao seu metal de base na temperatura ambiente e inferior na temperatura de 00C. Das diferentes regioes da junta soldada, o metal de solda foi o que apresentou melhor tenacidade a fratura, tanto para a temperatura ambiente quanto para 00C. (Autor)Additional details
Additional titles
- Original title (Portuguese)
- Tenacidade a fratura de juntas soldadas de um aco de alta resistencia e baixa liga
Publishing Information
- Imprint Pagination
- 132 p.
INIS
- Country of Publication
- Brazil
- Country of Input or Organization
- Brazil
- INIS RN
- 16063357
- Subject category
- S36: MATERIALS SCIENCE;
- Resource subtype / Literary indicator
- Thesis, Non-conventional Literature
- Descriptors DEI
- FRACTURE PROPERTIES; HEAT AFFECTED ZONE; MICROSTRUCTURE; NIOBIUM ALLOYS; TEMPERATURE DEPENDENCE; WELDED JOINTS
- Descriptors DEC
- ALLOYS; CRYSTAL STRUCTURE; JOINTS; MECHANICAL PROPERTIES