The application of composite metal self drilling screws in buildings.
Objective: in the architectural decoration, doors, windows and curtain walls, steel structure building system, architectural design units and the construction units often encountered confusion comes from the fastening connection: use ordinary carbon steel self drilling and tapping screw it, anti rust and corrosion resistant is not enough; the austenitic stainless steel self drilling tapping screws it, the hardness and strength of the screw is not enough. Therefore, a have both high resistance to corrosion and high strength fasteners, mechanical properties, become a thing of the industry has been waiting for.
In recent years, China's building decoration, walls and windows, steel structure building system design and construction, often encounter from the environment and the corrosion resistance of the higher demand, and as a key building in the cold joint self drilling tapping screws on the node, its anticorrosion ability and effective fastening life, is the most exciting the headache was the most critical part has been in the industry; the usual after plating or surface coated by carbon steel self drilling screws, it is understood that the carbon steel self drilling screws is generally made of low carbon steel, low carbon steels due to low corrosion resistance itself, so screw usually must be plated or coated the surface treatment to improve its corrosion resistance. But this kind of self drilling screws once in hard metal fastening construction after plating or coating the surface inevitably due to friction, puncture was broken The screw metal itself is exposed to the air in the environment of the building, so that the corrosion resistance of the fastening system is rapidly decreased, and the fastening life is 1--10 years. In some highly corrosive environment (such as coastal or high environmental pollution area), building fastening systems even within a few months immediately collapse, resulting in buildings damaged short life.
On the other hand, austenitic stainless steel self drilling tapping screws, though they have excellent protection against rust and corrosion resistance, but because it is not after heat treatment hardening, the hardness and mechanical strength cannot reach the requirements of design and construction, and also been rejected.
Therefore, a blend of high corrosion and high strength and hardness and self drilling tapping screws will come into being, which is complex metal self drilling tapping screws.
The more popular composite metal self drilling and tapping screw head and a screw locking part for austenitic stainless steel (such as SUS304, SUS316), to attack the tooth part and apex drill tail part of the heat treatment and hard alloy steel (low carbon alloy steel), two kinds of materials by special welding together, after heat treatment and surface treatment, bolt not only can penetrate the carbon steel plate, and has austenitic stainless steel excellent rust corrosion resistance.
With the upgrading of China's fastener design and manufacturing capabilities, and development of stainless steel heat treatment technology, a new type of composite metal self drilling tapping screws in Jiaxing state machinery technology Co., Ltd. was born, thus ending the history of domestic of the screw of dependence on imports, and in the performance in one fell swoop beyond the imported products. Synthetic state science and technology of the composite metal self drilling tapping screws thread lock tight and head also is austenitic stainless steel, but the attack apex tooth part and tail part of the drill is a martensitic stainless steel sus410, after heat treatment, surface treated by a special process penetrating force and rust and corrosion resistance are beyond the alloy steel composite metal screws and up to the ultimate double effect! Compared with imported screw, composite metal bond technology since the performance characteristics of drilling screws are as follows:
1, screw "attack speed" faster, more effort
Drill tail cutter head made of sus410 materials, after a special heat treatment, the cutting edge of the knife head surface hardness as high as more than HV580 and core hardness is between the HV350-450, strength and toughness are beyond the alloy knife head, plus unique drill tail shape of the knife head design, achieve the construction labour, the most rapid effect. For high altitude or based on the difficulty of construction operation, labor saving and ease the burden on the effect.
2, more widely applicable, can penetrate the stainless steel plate
Sus410 stainless steel has excellent "hard red" performance, in 550 DEG C can still maintain a strong attack drill ability, therefore can successfully penetrate up to 18mm, carbon steel, stainless steel or thick; and alloy material at a temperature of more than 250 DEG C, hardness decreased rapidly, is difficult to penetrate the stainless steel plate or thick steel plate, even if successful penetration, the next tapping and fastening work is also difficult to successfully completed.
3, the perfect combination of strength and corrosion resistance, the maximum corrosion resistance
SUS304/SUS316 of austenitic stainless steel materials resistant to corrosion performance excellent, sus410 martensitic stainless steel corrosion resistance, while rival, but much stronger than carbon alloy steel, hardness and strength and also is superior to the latter, screws and the State Science and technology special surface processing (zinc, aluminum and other metal powder coating processing), after assembly to building components, threaded portion and bare in the head are SUS304/SUS316 austenitic stainless steel, resistant to wind and rain and acid-base environment erosion and in general neutral inland environment sustainable security effectively serving more than 80 years.
4, more economical, more efficient service
Bond technology of composite metal self drilling screws on behalf of performance data:
(1) anti pulling force of iron (Pulling Strength)
(2) cutting force (Strength Shearing)
(3) anti torsion (Strength Twisting)
(4) attack speed test (Speed Test Attack)
(5) the scope of application (Scope Applicable)
Composite metal tapping screws for the scope of the project and application examples
Metal composite self drilling tapping screws for high polluting environment and coastal areas of high temperature, damp, easy corrosion environment; corrosive environment of chemical industry, metallurgy and other industrial and mining plants, suitable for various corrosion resistance requirements of products and building for, such as stainless steel kitchenware, doors, windows, signs, PC mining mask, airport, dock, chemical plant, power plant, clean workshop and longevity Prepainted Steel sheet plant, stadiums, airport terminal, the high iron platform roofing works, below for engineering application examples:
(the author of this article: Huang Yuezhi, Jiaxing United Nations machinery science and Technology Co., Ltd.