Hi everyone!
I wonder about the effect of boron to submerged arc welding of S700MC steel grade.
Why boron is not desired as an alloy element in S700MC ?
Thank you.
Boron has desirable effects when alloyed in small amounts (≈0.001 wt %) due to enhanced hardenability. When amount of boron exceeded >0.003 wt%, steel becomes brittle due to reduces hardenability and impact toughness.
I agree with David. Small amounts of B are beneficial to hardenability, but the Boron needs to be 'protected' from forming precipitates as soluble B enhances hardenability. Too much soluble B can increase HAZ hardness, thus lowering toughness. Excessive B will precipitate, leading to brittleness.
Additionally B effects also precipitation hardening, with boron nitride precipitate.
Thanks to all nice answers
Please keep in mind that extra boron contents may lead to formation of Boron Carbide (B4C) through Carbothermic process, which is Covalent-bonded, high temperature, hard, brittle and non soluble ceramic and may precipitate in grain boundaries and leads to increase in hardness besides falling the toughness and impact resistance.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Metals
- Alloys
- Steel