Toughness Improvement of the HAZ for Machine Structural Carbon and Low Alloy Steels (Report 1) : Effect of Cooling Time and Isothermal Heating Treatment on Medium and High Carbon Steels(Materials, Metallurgy & Weldability)
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In fusion welding processes for medium and high carbon steels. two problems are often experienced. One is, high susceptibility to cold cracking and the other is poor resistance to toughness. This paper has been investigated for the toughness of the simulated HAZ using "Gleeble 1500" with commercial plain carbon steels from 0.24 to 0.89% carbon content. Main conclusions obtained are as follows: (1) In the case of changing cooling time (Δt_<1O73-773K>: Δt_C) in continuous cooling method. S25C (0.24% C) is fairly. S35C and S40C are merely and S55C. SKV70 and SK5 are barely improved in absorbed energy with increasing Δt_C. (2) By an use of isothermal heating treatment method during weld heat cycle, ductility of these all steels can be fairly improved in comparison with the results of continuous cooling method, although the degree of improvement is depeneded on carbon content in steel. Increasing isothermal holding temperature up to 823K increases ductility of these steels.
- Transactions of JWRI
Transactions of JWRI 18(2), 241-246, 1989-12