In accordance with varying process requirements, the specifications for Mn and S content are stricter than the GB150-1998 standard, with S content less than 0.015%, with actual levels below 0.010%. Additionally, referring to the corresponding provisions of the GB3531-1996 standard "Steel Plates for Low-Alloy Steel for Low-Temperature Pressure Vessels," the requirement for acid-soluble aluminum content in steel grades has been increased. The tensile strength range has been narrowed, and the demand for the stability of steel pipe strength has been elevated. Seamless steel tubes of 09MnD and 09MnNiD with the same technical requirements have very similar chemical compositions between each batch, demonstrating excellent low-temperature impact properties. The molten steel produced for low-temperature steel has a high purity level, with grain size exceeding 8 grades.