本文件规定了热轧可焊细晶粒结构钢在正火\/正火轧制交货条件下，厚度≤250 mm的平直和长形产品的交货技术条件，其等级和质量见表1-3（化学成分）和表4-6（机械性能）。本文件中规定的钢材特别适用于焊接结构的重载部件，如桥梁、防淹门、储罐、供水罐等，以在环境和低温下使用。

This document specifies technical delivery conditions for flat and long products of hot rolled weldable fine grain structural steels in the normalized/normalized rolled delivery condition in the grades and qualities given in Tables 1 to 3 (chemical composition) and Tables 4 to 6 (mechanical properties) in thickness ≤ 250 mm. The steels specified in this document are especially intended for use in heavily loaded parts of welded structures such as, bridges, flood gates, storages tanks, water supply tanks, etc., for service at ambient and low temperatures.