Necessary Knowledge Of Fasteners - Bolts
Feb 14, 2023
(1) The reference standard for inch bolts is ANSI/ASME B18.2.1, and the Japanese standard refers to JIS B1180 (Webster's thread). Inch system refers to BSW916 (Webster tooth).
①HEX MACHINE BOLT: no washer, with beam end, half tooth hexagonal bolt;
②HEX TAP BOLT: no washer, no beam end, full tooth hexagonal bolt;
③HEX CAP SCREWS: Hexagon bolts with washers, beam ends, and half teeth;
(2) The reference standards for metric bolts are as follows, and their differences are shown in the table:
02. Carriage screws / round head square neck bolts
Carriage screws/round head square neck bolts (Carriage Bolts): ANSI/ASME B18.5; DIN603; ISO 8677; GB12; GB14
03. Hexagon socket bolt
Hexagon socket-head cap screws: DIN912; GB70; ISO4762; ANSI /ASME B18.3
04. Hex wood screws
Hexagon Head Lag Screws: ANSI/ASME B18.2.1 DIN 571
05. Furniture screws
Furniture screws (Furniture screws): according to customer standards
06. Hex flange bolts
Hexagon Flange Bolt (Hexagon Flange Bolt): IFI111; GB5787; DIN 921
product identification
01. Diagram of each part of the bolt:
02. Identification of bolts:
Marking, performance class
01. Logo
Hexagon head bolts and screws (thread diameter ≥ 5mm). It is necessary to use a raised or concave mark on the top of the head, or a concave mark on the side of the head. Including performance level and factory standard.
Carbon steel: The strength grade marking code consists of two numbers separated by "·". The meaning of the number before the "·" in the mark code indicates the nominal tensile strength, such as "4" in grade 4.8 indicates 1/100 of the nominal tensile strength 400N/MM2.
The meaning of "·" in the mark code and the number after the point indicates the yield strength ratio, that is, the ratio of the nominal yield point or the nominal yield strength to the nominal tensile strength. For example, the yield point of grade 4.8 products is 320 N/mm2.
The strength grade mark of stainless steel products consists of two parts separated by "—". The symbol before "—" in the symbol code indicates the material. Such as: A2, A4 and other signs "—" indicate strength, such as: A2-70
02. Grade
Carbon steel: The mechanical performance grades of metric bolts can be divided into 10 performance grades: 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, and 12.9. Stainless steel is divided into three categories: 60,70,80 (austenite); 50,70,80,110 (martensite); 45,60 (ferrtenite).
