• Liu Peng

Articles written in Bulletin of Materials Science

• Fine structure in the inter-critical heat-affected zone of HQ130 super-high strength steel

The microstructure in the inter-critical heat-affected zone (ICHAZ) of HQ130 steel, has been investigated by thermo-simulation test, SEM and TEM. The problem of toughness decrease in the ICHAZ (𝑇p = 800°C) as well as the effect of M–A constituent and carbide precipitation on brittleness was analysed. The test results indicated that the microstructure in the ICHAZ of HQ130 steel was mostly a mixture of lath martensite (ML) and granular bainite (Bg) with a fine but nonuniform grain structure. The cause of brittleness in the ICHAZ was related to production of the M–A constituent in the local region and carbide precipitation. By controlling the welding heat input carbide precipitation and the formation of the M–A constituent can be avoided or decreased.

• Effect of weld heat input on toughness and structure of HAZ of a new super-high strength steel

Fracture morphology and fine structure in the heat-affected zone (HAZ) of HQ130 super-high strength steel are studied by means of SEM, TEM and electron diffraction technique. Test results indicated that the structure of HAZ of HQ130 steel was mainly lath martensite (ML), in which there were a lot of dislocations in the sub-structure inside ML lath, the dislocation density was about (0.3 ∼ 0.9) × 1012/cm2. No obvious twin was observed in the HAZ under the condition of normal weld heat input. By controlling weld heat input ($E \leq$ 20 kJ/cm), the impact toughness in the HAZ can be assured.

• # Bulletin of Materials Science

Volume 43, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019