Steel grade issue

In 16MnDR, the letter \"D\" stands for low temperature; compared to 16MnR, it can be used at lower temperatures. Additionally, this grade no longer exists nowadays – it has been replaced by Q345R as specified in GB 713. What does the letter \"B\" mean in the bolt grade 40MnB? What does A in 35CrMoA stand for? It’s hard to say for sure; it might be a performance level

What does B stand for in the stud steel grade 40MnB? What does A in 35CrMoA stand for? It is the quality acceptance grade, with A being higher than B

In 16MnDR, the letter D indicates that it is a steel designed for use at low temperatures; in 40MnB, the letter B refers to the element boron, and in 35CrMoA, the letter A denotes that it is high-quality steel with low levels of S and P.

{:3_57:} Thank you, thank you very much

I think it should be corrected: the A in 35CrMoA stands for high-grade quality steel. GB/T3077 is divided into high-quality steel, advanced high-quality steel, and extra-high-quality steel. The main difference lies in the contents of P, S, Cu, and Mo. The poster should refer to that standard for specifics.

The steel grade 16MnR was discontinued and replaced by Q345R in GB713; however, the steel grade 16MnDR remains in use, with the material standard being GB3531-2008 \"Low-alloy steel plates for low-temperature pressure vessels\"

In 40MnB, the “B” refers to the element boron, or is it a grade? The meanings are different for 3.4

This post was last edited by realben on 2010-7-13 at 14:35. B stands for the element boron. 40MnB is a gear steel. It can also be used as a material for high-quality stud nuts. 40MnB possesses good strength, hardness, wear resistance, as well as excellent toughness, making it a new steel grade that has been successful in replacing 40Cr. Used as steering arms, steering knuckles, steering shafts, half-shafts, worms, spline shafts, brake adjustment arms, etc., in automobiles. C: 0.37-0.44%, Mn: 1.10-1.40%, B: 0.0005-0.0035%. The tensile strength reaches 980 Mpa, and the yield strength reaches 785 Mpa. Alloy structural steel: Its grade is indicated by the carbon content of the steel, as well as the types and quantities of alloying elements present. This method of representation (coding) allows one to directly determine the approximate chemical composition and quality grade of the steel from its grade designation, which is quite intuitive and straightforward. The specific grades include: 20Mn2, 30Mn2, 35Mn2, 40Mn2, 45Mn2, 50Mn2, 20MnV, 27MnSi, 35MnSi, 42MnSi, 20SiMn2Mo, 25SiMn2MoV, 37SiMn2MoV, 40B, 45B, 50B, 40MnB, 45MnB, 20MnMoB, 15MnVB, 20MnVB, 40MnVB, 20MnTiB, 25MnTiBRE, 15Cr, 15CrA, 20Cr, 30Cr, 35Cr, 40Cr, 45Cr, etc. as per GB221

D stands for low temperature. Regarding low-temperature steel, domestically available options include 0.5Ni, while foreign options include 3.5Ni