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Common marking methods for fasteners

All kinds of fasteners are used in daily life. Do you know the marking methods of these fasteners?

Marking of screws or bolts

Name, standard number, nominal diameter × pitch × nominal length-material-screwing form-surface treatment

Name: Use the standardized name specified by the national standard, such as: screws, bolts, nuts, self-tapping screws, screw assemblies, plastic screws, etc.

Standard number: mark the national mark, department mark or company mark (without the year). If it is designed by our company, mark the product model.

Pitch: Only applicable to fine threads, and coarse threads are omitted.

Material: If carbon steel material is used, this section shall be omitted, otherwise it shall be noted, such as Cu (copper), C1 (stainless steel. For details of stainless steel material codes, please refer to GB3098.6, including: austenite, A1, A2, A4; horse Stenite, C1, C3, C4; Ferrite, F1.)

Twisting form: If the twisting form specified by the standard is adopted, it will be omitted, otherwise it should be injected, such as a composite groove.

Surface treatment: if the carbon steel material is galvanized passivation, omit it, otherwise it should be injected, such as Cu/Ni (copper nickel plating), Cu/Ni6b (copper bright nickel plating, nickel layer thickness 6μm), Cu/Sn (copper Tin plating), Cu/Sn(60)Pb (copper plating lead tin), Fe/Ni6bCr0.3r (carbon steel nickel and chromium plating), O (surface oxidation), stainless steel materials usually do not need plating.

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

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

Note 2: There are two types of self-tapping screws, C type and F type, C type is the tip face, and F type is the flat end face. However, self-tapping locking screws are not classified into types.

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

Note 4: The difference between a countersunk head and a half countersunk head is that the head of the countersunk head has a flat end face, and the head of the half countersunk head has an arc end face.

Note 5: The difference between a set screw and an ordinary screw is that the head of an ordinary screw is T-shaped, while a set screw does not have a T-shaped head.

Note 6: Slotting means that the head is a straight slot. Compound grooves, cross grooves and flat grooves can be used in common, but the same batch of products should be unified.

Note 7: For stainless steel fasteners, since our employees are not familiar with the code, you can remark "stainless steel" after the material code and put it in brackets.

Note 8: The difference between screws and bolts

Screw: It is composed of a head and a screw. It is used where there are prefabricated threads and does not need to be matched with a nut. It is often screwed internally, and there are often holes on the head.

Bolt: It is composed of a head and a screw, which need to be matched with a nut to fasten and connect two parts with through holes. The external wrench is screwed, often with a hexagonal head.

Note 9: If the screw assembly conforming to the XXXX corporate standard is selected, the marks are respectively: screw assembly ZBY1 (two combination of screw and round flat washer), ZBYA1 (three combination of screw and round flat washer, round spring washer), ZBF1 (screw Two combinations with square flat washer), ZBFA1 (three combinations of screw and square flat washer and square spring washer).