Application of Martensitic Stainless Steel Self-drilling Self-tapping Screws in Building Envelope System
The steel structure enclosure system includes roofing system, wall system, lighting belt, edging and flooding, gutter and thermal insulation cotton. The enclosure system is one of the most important components of the light steel structure, which determines the ornamental appearance of the building, the waterproof and thermal insulation effect of the building. As an auxiliary fastener, self-drilling self-tapping screws play a vital role in the performance, quality and life of the overall building. It is not optimistic that as such an important basic component, our attention and research are far behind the attention and research on the main components of the building. The most prominent point is the neglect of the performance of fasteners and the main components of the building envelope system. match.
And one of the biggest factors of failure or collapse of all structures or equipment due to corrosion is the first failure or collapse of the fastening system! Due to the special structure of fasteners, the environment and the mission, the fasteners bear the brunt in the corrosive environment and are most likely to be corroded first. Therefore, improving the corrosion resistance of fasteners is the most basic battle that must be first defeated in the declaration of war between humans and corrosion. At present, there are too many examples of the wrong use of screws in industrial manufacturing and construction. The common reason is to ignore the life matching of screws and fasteners, such as stainless steel or high-grade surface anti-corrosion treatment of equipment or components. Carbon steel fasteners to fasten, the results are as follows:
We know that ordinary carbon steel has low corrosion resistance. Once rust occurs, it is pulverized rust.
Since the screw connection mainly depends on the small threads to mesh with each other, once the crushed corrosion of the thread part occurs, the pull-out resistance of the screw is reduced, and the strength of the connection between the screw and the building substrate will be greatly reduced. In the event of a storm, or a sudden explosion in the workshop, the enclosure system is in danger of falling apart.
Features and advantages of martensitic stainless steel fasteners
In the stainless steel material family, only martensitic stainless steels can be hardened by heat treatment. From the standpoint of mechanical properties, corrosion resistance, ease of processing, and economy, SUS410 (national designation 1Gr13) martensitic stainless steel is the most suitable. The carbon content of SUS410 material is less than 0.15% and the chromium content is more than 12%, which belongs to the category of martensitic stainless steel. After special vacuum heat treatment, the surface hardness of SUS410 screw can reach HV580-700, and the core hardness is HV350-450 The difference between surface hardness and core hardness can reach more than HV150, which not only ensures the strong drilling and tapping ability of the screw, but also ensures the superior flexibility of the screw. Its tensile strength and mechanical torque are more than 150% of ordinary carbon steel.
In addition, SUS410 red hardness is far superior to carbon steel, especially at 500 ° C, it has a strong drilling and attack ability, which creates very favorable conditions for some ultra-thick, super-hard or stainless steel construction substrate fastener .
Through the corrosion test, SUS410 screws show superior corrosion resistance than carbon steel screws. From the experimental results, the corrosion resistance of SUS410 screws is much higher than that of carbon steel screws, and their performance can meet or exceed the current The construction industry standard is a kind of construction fastener that deserves the attention and promotion of all staff.
