Abstract
To decrease Si as well as Mn content is very effective for suppressing the temper embrittlement but it also brings about the diminution of tensile and yeild strength. For example, ordinary low Si-2-1/4Cr-1Mo steel can not meet the specification of tensile strength at room temperature without the addition of other alloying element such as Cu, Ni and V after normalizing and post weld heat treatment.
The addition of slight amount of total B enhances the hardenability for normalizing treatment and causes no harmful effect. Therefore, Al and B treated low Si and low Mn 2-1/4Cr-1Mo steel with low impurity element is supposed to be the best answer to solve the temper embrittlement as well as normalizing hardenability.
