Carbide-free bainite matrix
A carbide-free bainitic matrix consists of needle-shaped ferrite and stabilized retained austenite without carbide precipitates. It offers excellent combinations of strength and ductility.
Physical-Chemical Mechanism of Action
The bainitic matrix forms through controlled cooling of the steel, where carbides are not fully austenitized. The result is a microstructure of ferrite and retained austenite, without visible carbide tubes.
Metallurgical Relevance & Welding Risks
This matrix offers a balanced combination of strength and ductility, which is especially beneficial in high-load applications. However, incorrect cooling conditions can lead to uneven cooling and cause cracking or distortion in the material.
Shop Practice & Action Instructions
To achieve a carbide-free bainitic matrix, it is crucial to control the cooling of the steel. This requires careful selection of welding methods and parameters. With TIG welding, cooling should be slower to achieve the desired microstructure.