Countersunk cross self-tapping

Self-tapping screw surface treatment: Most self-tapping screws are coated with zinc coating or zinc phosphate coating. Name Cross countersunk head self tapping screw Cross Recessed Countersunk (Flat) Head Tapping Screws Cross Recessed Countersunk Head Tapping Screws Standard DIN 7982 DIN EN ISO 7050 GB _T 846 Size M2.9～M6.3 Length 25mm～120mm Grade 4.8 5.8 6.8 8.8 Material Although there are many types of self-tapping screws, they all have the following main characteristics: (1) are generally made of carburizing steel (accounting for 99% of the total product). It can also be made of stainless steel or non-ferrous metals. (2) The product must undergo heat treatment. Carbon steel tapping screws must be carburized, stainless steel tapping screws must be solution hardening treatment. In order to make the tapping screw to meet the standard requirements of mechanical properties and performance. (3) The product surface hardness is high, the core toughness is good. That is, "soft inside, tough outside". This is a major feature of tapping screw performance requirements. Such as low surface hardness, screw into the matrix; If the core toughness is poor, a twist on the broken, can not be used. Therefore, "soft inside and rigid outside" is a self-tapping screw to meet the requirements of performance. (4) The surface of products all need surface protection treatment, usually electroplating treatment. The surface of some products needs phosphate treatment (phosphating). Such as: wall tapping screws for phosphating. (5) Production by cold heading technology. It is recommended to use high speed cold header, high speed wire rolling machine or high speed planetary wire rolling machine to ensure product quality. This production of self - tapping screw head molding good, high thread quality. Surface Self-tapping screw surface treatment: Most self-tapping screws are coated with zinc coating or zinc phosphate coating. Description Self-tapping screw definition refers to the self-tapping screw that does not need to be used with the nut. The tooth thread is self-tapping type and the tail tip. When the triangle self extrusion screw is screwed into the hole of plastic metal material, it can form internal thread and form reliable locking thread connection in the hole by extrusion action. Construction operation technology Self - tapping screws from head to tail are composed of the head, the rod and the rod end of three parts. Each self-tapping screw has four main elements: the shape of the head, the way of pulling, the type of thread, and the type of the end. Head shapes. - Heads come in all shapes. There are round head (half round head), flat head, round head flange (with pad), flat head flange (with pad), pan head, pan head flange (with pad), countersunk head, half countersunk head, cylinder head, spherical cylinder head, horn head, hexagonal head, hexagonal flange head, hexagona