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Advances in Materials Research Volume 7, Number 3, September 2018 , pages 195-201 DOI: https://doi.org/10.12989/amr.2018.7.3.195 |
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Effect of simulated double cycle welding on HAZ microstructure for HSLA steels |
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Emad F. El-Kashif and Morsy A. Morsy
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| Abstract | ||
| High Strength low alloy steels containing various levels of C, Nb and Mn were used and for each of which, a simulated double thermal cycle was applied with the same first peak temperature and different second peak temperatures to produce HAZ microstructure corresponding to multi-pass weld. Effect of double cycle second temperature on the microstructure was observed and compared with single cycle results obtained from previous works, it was found that the percentage of martensite austenite constituent (MA) increases by Nb addition for all steels with the same Mn content and the increase in Mn content at the same Nb content shows an increase in MA area fraction as well. MA area fraction obtained for the double cycle is larger than that obtained for the single cycle for all steels used which imply that MA will have great role in the brittle fracture initiation for double cycle and the inter-pass temperature should be controlled for medium and high-carbon Mn steel to avoid large area fraction of MA. The beneficial effects of Niobium obtained in single pass weld were not observed for the double cycle or multi pass welds. | ||
| Key Words | ||
| HAZ; double cycle; multi pass weld; microstructure; carbon; manganese; niobium; MA | ||
| Address | ||
| (1) Emad F. El-Kashif: Department of Mechanical Design and Production Engineering, Cairo University, Egypt; (2) Morsy A. Morsy: Welding and NDT Laboratory, CMRDI, Cairo, Egypt. | ||
