← Glossary

Boron

Boron greatly reduces cooling rate and increases hardenability of steels, which can lead to glass-hard microstructures.

Physico-Chemical Effect Mechanism

Boron reacts with carbon in the molten weld pool and forms boron carbides. This slows down cooling because boron carbides are poor heat conductors.

Metallurgical Relevance & Welding Risks

Too high a boron content can lead to glass-hard martensite, which increases hardness but reduces toughness and dimensional stability. This increases the risk of cracks and fractures.

Shop Practice & Instructions

Use boron in small amounts (about 0.1%) for steels with high carbon content. Ensure slow cooling after welding to control the microstructure. Avoid excessive amounts, as they can lead to glass-hard hardness.

MetallurgieSchweißtechnik

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