Performance grade and marking of external threaded fasteners

Performance grades and markings of external threaded fasteners:

Three, performance level and mark:

(1) Marks and signs: Marks and signs are two completely different concepts. Marking is the use of concise language (including text and numbers), a highly general description of a product (including product name, size, performance level, surface treatment, etc.), generally used in documents to describe the product. The logo is the symbol printed on the product and the logo printed on the packaged article (including the performance level symbol and the manufacturer or seller's code). So there is a fundamental difference.

In the SAE J429 standard, product performance grades are marked with Arabic numerals. There is no corresponding relationship between numbers and product strength grades as in 1SO898, but the larger the number, the higher the strength. The decimal point and the numbers after the point also have no special meaning.

(2) Performance level: There are nine performance levels specified by SAE J429: 1, 2, 4, 5, 5.1, 5.2, 8, 8.1 and 8.2. (Level 5.2 was cancelled in 2002). (Guide: The difference between cold forging nuts and hot forging nuts)

Bolts and screws have six grades of 1, 2, 5, 5.2, 8 and 8.2 (level 5.2 was cancelled in 2002).

Six studs are graded 1, 2, 4, 5, 8, and 8.1.

Combined screws are grade 5.1.

The most commonly used performance levels for bolts and screw products are level 2, level 5 and level 8. Level 2 is equivalent to level 4.8 in ISO8981, level 5 is equivalent to level 8.8 in ISO8981, and level 8 is equivalent to level 10.9 in ISO898-1.

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