Steel must be rust free and the work will benefit from a light sand-blast .

钢架不得生锈，这可以通过轻微抛丸处理来达到。

youdao

Automobile manufacturers were well aware that rust occurred in interior recessed areas, also noting that flat exposed areas, such as roofs, were often rust free.

汽车制造厂商们早已注意到汽车内部隐蔽处的锈蚀，但暴露在外的平面部位，如车顶却不易锈蚀。

youdao

Whatever the practical challenges of trying to renegotiate Nafta, or, indeed, the truth of its negative impact on the US economy, criticism of free trade seems to strike a particular chord in blue collar, Rust Belt states, such as Pennsylvania and Ohio, which have been shedding manufacturing jobs over the past few years.

BBC: Trade and jobs to fore in US election