How are stainless steel bolts and nuts used together?
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This post was last edited by 511948814 on 2021-1-14 at 15:55. In the standard HG/T 20614-2009, Tables 3.0 and 3.1 specify the selection and application ranges for bolts and nuts; bolts of grade 8.8 paired with nuts of grade 8 are denoted as 8.8/8, indicating that a bolt of grade 8.8 is used together with a nut of grade 8. The stainless steel bolts and nuts are specified as A2-50, A4-50, A2-70, A4-70 – without any slashes (“/”). How should these stainless steel bolts and nuts be used together?
Your reply is such a generic one. . :L
Without a slash, the bolt and nut are made of the same material.
You can take a look at his previous replies; they apply to almost all posts. :)
The meaning of AX-XX: A stands for stainless steel； The number following it indicates the material: 2 represents 304 stainless steel, while 4 represents 316 stainless steel ； - The number that follows indicates the tensile strength: 50 means that the tensile strength must be no less than 500, while 70 means it must be no less than 700.
On pressure vessels and pressure pipelines, when the strength is insufficient, nuts suffer from gradual loosening, a slow process; whereas bolts and studs break. The damage to just one bolt or stud causes an abrupt increase in the load on the remaining ones, leading quickly to their complete failure and resulting in an accident. Therefore, for safety reasons, nuts are generally made from material of lower quality than bolts, at most using the same grade as bolts, to ensure that the bolts do not break.
Choose the nut of a lower grade; for example, if the stud is of grade A2-70, then the nut should be of grade A2-50. In case of problems, this ensures that the stud remains intact while the nut is the one to fail first
According to you, that table should be represented as A2-70/A2-50, but it’s not shown that way in the table. Also, if the stud is selected as A2-50, how should the nut be chosen? Studs are also available in A2-50 material.
According to you, that table should be represented as A2-70/A2-50, but it’s not shown that way in the table.