Structure stability in micro-alloyed weldable bainitic structural steels
In recognition of the more stable structure of bainitic steels after heating when compared with martensitic steels, an investigation was made a) to establish the impact of more economical, i.e. high-speed welding procedures for structural steel components upon the mechanical properties of high-strength bainitic construction steels and b) to determine the influence in that situation of micro-alloying such steels with titanium. Ten specially-prepared batches of steel with varying levels of titanium content were subjected to a wide range of simulated welding conditions including a spread of cooling times (7 - 300s) and a spread of energy input rates (27 - 112 kJ/cm). The notched-bar impact test was used to evaluate the mechanical properties of the steels used. A martensitic steel (Type N-A-XTRA 70) was also tested for comparison purposes. The results indicated that the combination of a more stable bainitic structure and a slower rate of grain-size growth on heating due to the separation of TiN could be expected to permit the introduction of high-speed welding procedures. Energy input rates of up to 50 kJ/cm appear acceptable and pre-heating is not necessary.
Bibliographic Reference: EUR 18484 DE (1998) 150pp.
Availability: Available from OOPEC Sales agents
ISBN: ISBN 92-828-4418-8
Record Number: 199910892 / Last updated on: 1999-06-18
Original language: de
Available languages: de