Standard No.:	GB/T 3098.20-2004
Chinese Name:	紧固件机械性能蝶形螺母 保证扭矩
English Name:	Mechanical properties of fasteners—Wing nuts with specified proof torque
Professional Classification:	J13 Fastener
Professional Classification:	GB National Standard
ICS Classification:	21.060.20 Nuts
Issued by:
Issued on:	2004-02-10
Implemented on:	2004-08-01
Status:	VALID
Language:	English
File Format:	PDF
Word Count:	2000 words
Price(USD):	60 (USD)
Delivery:	via email in 1-3 business day

1 Scope

This part specifies proof torque class, proof torque value and test method of wing nut applicable to national standard.

2 Proof Torque Class and Proof Torque Value

The proof torque class of wing nut is composed of a Roman numeral, which is only a code not expresses class difference. It's applicable to wing nut specified by national standard.

The proof torque of wing nut shall be in accordance with those specified in Table 1. Where test is conducted under normal temperature according to the method specified in Chapter 4, the thread of wing nut shall be free from thread-off or fracture and the wing part shall also be free from obvious deformation; after removing torque, nut shall be capable of being screwed out by hands or it shall be loosened by wrench but shall not exceed half thread. During test, if bolt is damaged, the test is invalid.