Full-threaded studs: The entire bolt is threaded. This type of bolt is stronger than hexagonal head bolts and stud bolts and has a higher range of use. Hexagonal bolts and stud bolts are commercial-grade bolts and are expressed by performance levels.
The full-threaded stud is a special grade bolt, and the material designation is used. The material substitution of the chemical plant must be confirmed after the design is confirmed. Once I saw the use of 4.5 hex bolts instead of 8.8 bolts on site. This 4.5-grade bolt is not chemically used.
Especially frequently used in the project is the use of 35CrMo/30CrMo stud nuts. I believe people in the same industry know that, even more, all materials in a project are such bolts and nuts. Some pure design projects do not consider material prices to a large extent. If it is a general contracting project, I think it should be used separately. If it is an American standard, there is nothing to say.
35CrMo/30CrMo, the front is the stud material, and the back is the nut material. The designation method of this material is the expression method in HG/T20613 and HG/T20634.
35CrMoA/30CrMoA, the material grade representation method is the representation method in SH/T3404. Explain the difference between material grades with A and without A. A after the material designation represents high-quality steel. Not adding A represents ordinary high-quality steel, and adding A is better than not adding it. Adding A is the same as not adding A.
This grade of material is a high-strength bolt, which is suitable for all pressure conditions. Because this material grade is low-alloy steel, the applicable temperature is the same as that of low-alloy steel, and the applicable temperature range is -100° to 525°. ASME is often used A193 R.B7/A194 GR.2H this kind of coordination.