Marking of screws or bolts

Name, standard number, nominal diameter, pitch, nominal length, material, twist form, surface treatment

1. Name Use the standard name specified in the national standard, such as: screws, bolts, nuts, tapping screws, screw assemblies, plastic screws, etc.
2. The standard number is marked with the national label, ministry label or enterprise label (do not write the year number), if the enterprise is designed by itself, it is marked with the product model.
3. Pitch is only applicable to fine thread, thick teeth are omitted.
4. If the material is carbon steel material, this part is omitted, otherwise it should be noted, such as Cu(copper), C1(stainless steel). Stainless steel material code for details GB3098.6, including: austenite, A1, A2, A4; Martensite, C1, C3, C4; Ferrite, F1.)
5. If the wrench form is the wrench form specified in the standard, it is omitted, otherwise it should be noted, such as the composite groove.
6. If the surface treatment is galvanized passivation of carbon steel material, it is omitted, otherwise it should be noted, such as Cu/Ni(copper plated nickel), Cu/Ni6b(copper plated bright nickel), Nickel layer thickness 6μm), Cu/Sn(copper tin plating), Cu/Sn(60)Pb(copper lead tin plating), Fe/Ni6bCr0.3r(carbon steel nickel-chromium plating), O(surface oxidation), stainless steel materials usually do not need plating.

If the coating complies with the ROHS directive, it is marked after surface treatment and placed in brackets.

Note 1: If the material and surface treatment are not indicated in the marking of the fastener, it means that the material of the fastener is carbon steel galvanized passivation (that is, colored zinc plating).

Note 2: There are two types of self-tapping screws, C type and F type, C type is the tip surface, F type is the flat end. But the self-tapping locking screw is not shaped.

Note 3: The difference between the disc head and the cylinder head is that the head disc diameter of the disc head is slightly larger than the cylinder head, but the head thickness is slightly thinner than the cylinder head.

Note 4: The difference between countersunk head and semi-countersunk head is that the head of the countersunk head is a flat end face, the head of the semi-countersunk head is a curved end face, and the head of the countersunk head is thinner than that of the semi-countersunk head.

Note 5: The difference between the set screw and the ordinary screw is that the head shape of the ordinary screw is T-shaped, and the set screw has no T-shaped head.

Note ⑥ : Slotted indicates that the head is a slot. Composite slot, cross slot and slot can be common, but the same batch of products should be unified.

Note 7: For stainless steel fasteners, since our staff is not familiar with its code, it can be noted "stainless steel" after the material code, placed in brackets.

Note ⑧: The difference between screws and bolts

Screw: composed of two parts of the head and screw, used in places with prefabricated threads, do not need to be used with nuts. Commonly used in the wrench, the head often points.

Bolt: composed of head and screw two parts, need to be used with nuts, used to fasten the connection of two parts with through holes. External wrench, usually hexagonal head.

Note 9: If the screw assembly conforming to the target of XXXX enterprise is selected, the marks are respectively: screw assembly

ZBY1(two combinations of screw and round flat washer), ZBYA1(three combinations of screw and round flat washer and round spring washer), ZBF1(two combinations of screw and square flat washer), ZBFA1(three combinations of screw and square flat washer and square spring washer).