Boron in steels serves what primary function?

Boron in steels serves what primary function?

• A. Improves hardenability of medium carbon steels during heat treatment
• B. Decreases hardness
• C. Is denoted by xxBxx in SAE-AISI
• D. Increases weldability

Answer: (A)

Boron’s main job in steel is to dramatically increase hardenability. Even in tiny amounts, boron shifts how the steel transforms during quenching, promoting martensite formation in thicker sections or with slower quenching media. This lets medium carbon steels achieve high hardness after heat treatment without needing more carbon, which would make the steel harder to weld or process. It doesn’t decrease hardness; rather, it enables higher hardness after quenching. It’s not described by a special SAE‑AISI tag, and while it can affect weldability if not managed properly, its primary, well-known function is improving hardenability.

Boron’s main job in steel is to dramatically increase hardenability. Even in tiny amounts, boron shifts how the steel transforms during quenching, promoting martensite formation in thicker sections or with slower quenching media. This lets medium carbon steels achieve high hardness after heat treatment without needing more carbon, which would make the steel harder to weld or process. It doesn’t decrease hardness; rather, it enables higher hardness after quenching. It’s not described by a special SAE‑AISI tag, and while it can affect weldability if not managed properly, its primary, well-known function is improving hardenability.