China Self Tapping Screw Manufacturers, Suppliers, Factory

Minfeng is a China Self Tapping Screw Manufacturers and China Self Tapping Screw suppliers. We have been specializing in self tapping screws production for 16 years and It also cooperates with customers in the United States, Russia,  Britain, Germany, Switzerland, Brazil, Chile, Singapore, Thailand, India and other countries. Samples can be sent when placing an order.
System introduction
Self tapping screws is a kind of screw with drill bit. It is constructed by special electric tools, and drilling, tapping, fixing and locking are completed at one time. Self tapping screws are mainly used for connection and fixation of some thin plate parts, such as the connection between color steel plates and color steel plates, the connection between color steel plates and purl-ins, wall beams, etc. Their penetration capacity is generally not more than 6mm, and the maximum is not more than 12mm. Self tapping screws are often exposed outdoors and have strong corrosion resistance; The rubber sealing ring can ensure that the screw is impermeable and has good corrosion resistance. Self tapping screws are usually described by three parameters:screw diameter series, number of threads per inch length and screw length. The more threads per inch length, the stronger the self tapping ability.
Structural elements
The self tapping screws is composed of the head, the rod and the end of the rod from the beginning to the end.Each self tapping screw has four major elements: head shape,screwing method, thread type and end type. Head shape-head shapes vary. There are round head (half round head), flat round head, round head flange(with PAD), flat round head flange(with PAD), pan head, pan head flange (with PAD), countersunk head,semi countersunk head, cylindrical head, spherical cylindrical head, horn head, hexagon head, hexagon flange head, hexagon flange (with PAD), etc. Screwing methods - there are various screwing methods.External wrench: Hexagon, hexagon flange face, hexagon flange, hexagon flower shape, etc; Internal wrenching: straight groove, cross groove H (Phillips), cross groove Z (pozidriv), cross groove f (frearson), square groove (scrulox), compound groove, internal spline, internal hexagon flower (plum blossom groove), internal triangle, internal hexagon, internal 12 angle, clutch groove, six blade groove, high torque cross groove,etc. Thread types-there are many kinds of threads. There are self tapping thread(wide thread), machine thread, dry wall nail thread, fiber board nail thread, and some other special threads.
surface treatment
Most self tapping screws are coated with zinc or zinc phosphate. Cadmium plating is rarely used because of its high cost and toxicity. If appearance is important, nickel or chromium can be selected.
Main features:
(1) It is generally made of carbon steel(accounting for 99% of the total product). Stainless steel or non-ferrous metal may also be used.
(2) The product must undergo heat treatment.Carbon steel self tapping screws must undergo carburize treatment, and stainless steel self tapping screws must undergo solution hardening treatment. So that the self tapping screw can meet the mechanical performance and service performance required by the standard.
(3) The product has high surface hardness and good core toughness. That is, "soft inside and hard outside". This is a major feature of the performance requirements of self tapping screws. If the surface hardness is low, it cannot be screwed into the base; If the toughness of the core is poor, it will break once screwed and cannot be used. Therefore, "soft inside and hard outside" is that self tapping screws meet the requirements of service performance.
(4)The product surface needs surface protection treatment, generally electroplating treatment.Some products need phosphate treatment(phosphating) on the surface. For example, the self tapping screws of wallboard are mostly photostatted. 
(5) It is produced by cold heading process. It is recommended to use high-speed cold heading machine, high-speed wire rolling machine or high-speed planetary wire rolling machine to ensure product quality. The self tapping screw produced in this way has good head forming and high thread quality.