Stainless steel hex socket cap screws can remain rust-free for many years in the atmosphere, with core materials being SUS304 and SUS316 stainless steel. For screws that comply with national standard requirements, key dimensional tolerances can be measured and verified using conventional measuring tools such as calipers. Stainless steel hex socket cap screws are a general term for a specific category; since their performance is mainly determined by the material's own performance indicators, there is no need to subdivide them into too many subcategories when introducing such products.

Domestic production of stainless steel hex socket cap screws mainly follows two sets of execution standards: national standards (GB) and German standards (DIN). Each specification of screw corresponds to a clear national standard or DIN standard number. It should be noted that the strength of stainless steel hex socket cap screws is mainly determined by the material itself-austenitic stainless steel (such as 304 and 316) generally cannot have its strength improved through subsequent heat treatment. If better performance is required, SUS316 screws offer superior corrosion resistance compared to SUS304. Alternatively, auxiliary methods such as applying thread locker to the threads can be used to increase locking friction and improve connection reliability (not to enhance strength).

304M6304M8304M10

Stainless steel hex socket cap screws are not absolutely rust-proof, but their rust resistance is significantly better than that of carbon steel screws. When used in conventional atmospheric environments, they can remain rust-free for more than 20 years; however, in harsh environments such as high salt spray or high humidity, the rust-proof lifespan will be correspondingly shortened. Fortunately, stainless steel hex socket cap screws are consumables-if individual screws are found to be severely rusted, they can be directly replaced.

Except for washers, retainer rings, nuts, pins, and other categories, hex socket cap screws made of SUS304 and SUS316 stainless steel can be collectively referred to as stainless steel hex socket cap screws. In actual procurement, it is necessary to clearly specify the specific execution standard (such as GB/T 70.1 or DIN 912), otherwise, procurement errors may occur. Therefore, when purchasing, the product's specifications or execution standard should be fully described in writing-different standards correspond to different mechanical properties and application scenarios. Although stainless steel material types include ferritic, martensitic, austenitic, precipitation-hardening, etc., in practical production and application, hex socket cap screws are mainly made of austenitic stainless steel, namely the commonly used SUS304 and SUS316 grades.

304M12304M16304M20

Why distinguish between these two materials? Different materials result in differences in the corrosion resistance lifespan of stainless steel hex socket cap screws. In precision electronic equipment, materials may also affect electromagnetic interference, current transmission, and communication signal stability, all of which have strict design requirements. Austenitic stainless steel has a stable metal composition and certain ductility, which is not only conducive to mold processing and forming but also has good toughness for easy installation. Its nickel content meets rust-proof requirements, and its thermal expansion coefficient matches the temperature environment of common working conditions. However, the main disadvantage of such screws is that they are prone to heating during tightening, and seizing (galling) is likely to occur between stainless steel components.

The standards for stainless steel hex socket cap screws are specifically reflected in the dimensional accuracy of each part and thread passability. For the relief grooves and thread chamfers between the threads and the screw shank, there are no detailed regulations in national standards-products can be judged as qualified as long as they are within the standard tolerance range. At the same time, there are clear specifications for product appearance defects, including the clarity of marks, surface finish, packaging requirements, etc.