Problems with high strength fasteners

With the development and progress of the society, its industrial demand for fasteners is getting higher and higher. At present, high strength fasteners have a good prospect of development. However, there are still some problems with homemade high-strength fasteners.

1. Fastener is not qualified in hardness
Hardness is an important index of assessment fasteners, mechanical properties, for each performance level product adopted by the material is different, fasteners, choose when mechanical performance level is an important basis, the installation and use of working load should be determined according to the level of performance and installation torque, for a specific material, hardness should be controlled in a reasonable level, high hardness may reduce the fatigue resistance of the products, some enterprises in order to improve the strength of the product, the hardness at higher levels, caused part of the product.

2. The fastener guarantees the load and the wedge load is unqualified
Ensuring load and wedge load is the key item A for testing the mechanical properties of products under tensile load, especially for high strength fasteners.The guarantee load is to check the product's resistance to plastic deformation under the specified tension load. If the index fails to meet the requirement, the plastic deformation may be generated due to the effect of the pre-tightening force and the working load, thus reducing the pre-tightening force and making the connection loose.Wedge load test is to examine the tensile strength of bolt product and the combined strength of head rod. This index is unqualified. Under the action of large working load, especially the impact load, or when the support surface is under the action of partial load, it will break or turn around, resulting in connection failure and even safety accident.

3. Fastener size is out of tolerance
Fastener is a generic components, the size of the interchangeability requirement is higher, super bad will directly affect the compatibility, and even affect the connection strength, locking performance or life. The main cause of unqualified size one is the improper control of technical process, in order to save material will be part of the size control near the lower limit, no timely adjust equipment in the production process, using the ultra poor workers die: the second is the lack of inspection, process inspection and delivery inspection is lax, make some unqualified batch of qualified;Third, the measuring equipment in use can not be measured regularly, or even use more than the wear limit of the gauge.

4. The fastener decarburization layer is out of standard
The decarburization layer is also A type A project. Due to decarburization, the surface hardness and strength of the parts are greatly reduced, which seriously affects the surface contact strength and fatigue life of the fasteners. Decarburization is mainly caused by decarburization of raw materials, decarburization in the process of material reform and product heat treatment.

Qiangtuo Fastener Co., Ltd established since 2001,we can provide high quality high strength fasteners,including stainless steel eye bolts,stainless steel screws,stainless steel Hex Nuts,etc.Non-standard parts are also available.