The building facades requirement is becoming more and more exquisite with the gradual development of building industry and the glass curtain is widely used in building industry now. Maybe some people may ask what is glass curtain, also called point-supporting curtain, mainly composed of glass spider fittings, glass spider joint, transfer piece and other components. The glass spider fittings support glass spider joint and transfer the load impact to the fixed support structure system. Glass spider fitting is an important link component in glass curtain building, which transfers the load to steel structure or other main structures through glass spider joint, its mechanical property plays an important role. Due to the absence of walls and good lighting, indoor space and outdoor space can make people have a sense of integration, and it looks very transparent from the outside.
From the appearance, common glass spider fittings can be divided into four way spider fittings, three way spider fittings, 90° two way spider fittings, 180° two way spider fittings, long single spider fittings, short single spider fittings. Four way spider fittings are often used in the center of curtain. There few three way spider fittings in the market, only some special projects can use three way spider fittings. 90°and 180° two way spider fittings are always used in the connection of the curtain edges. Aesthetically speaking, 90 °two way spider fitting can cooperate with long single spider fitting, 180 ° two way spider fitting can cooperate with short single spider fitting. Except glass spider fittings, glass spider joint is also linked with the glass. The quality of the glass spider joint directly determines the glass curtain. Transfer piece connects the point-supporting and glass spider fittings, is welded with other bar. These three parts are integrated into a set playing the determine role to the glass curtain. They make our glass curtain stronger, more windproof, more pressurized and more secure.
Material: Stainless Steel (SUS 304 or 316)
Glass spider fitting is made of stainless steel with the function of connecting glass curtain. So why does it made of stainless steel since the stainless steel is much more expensive than common cast steel and iron?
All glass curtains are usually exposed to the air all year round and often experience baptism from rain and dew. Common steel or iron castings will be oxidized after touching air for a long time, and occur corrode phenomenon. The surface will appear large area of rusty iron oxide, neither beautiful nor environmental protection. The corrosion resistance of stainless steel makes it best suitable material for glass spider fittings.
The main components of stainless steel are zinc, nickel and chromium. Chromium is the most basic element of corrosion resistance in stainless steel. When chromium element reaches about 12% in steel, chromium reacts with oxygen in the atmosphere to form a thin oxide film on the surface of the steel, which will prevent further corrosion of steel. Therefore, it is reasonable to use stainless steel as the material for glass spider fittings frequently used outside.
The most common material of glass spider fitting is 304 stainless steel and 316 stainless steel. Although the price of 201 stainless steel is little lower, but it is vulnerable to oxidation or corrosion to affect the overall effect of the curtain and hide some safety hazards.
In a dry indoor environment, the curtain can use 304 stainless steel glass spider fitting. But in heavily polluted industrial areas and coastal areas, the surface of curtain is easy dirty, even has large rusting. The aesthetic effect in the outdoor environment cannot be achieved by using 304 alone. The raw material containing nickel must be used, that is 316 stainless steel, which will have better corrosion-resistant than 304.
Stainless Steel Casting Process
Like other stainless steel investment castings, glass spider fittings are normally manufactured by the most precision investment casting method-Silica Sol Casting. The main operation processes of casting stainless steel glass spider fittings include: Making mould→Wax Injection→Coating→Drying→Melting wax→Pour liquid steel→Cooling→Remove coating→Shot blasting.
- Pouring liquid steel is the process that pouring the liquid stainless steel from molten by cupola to the sand mould, thus forming cast glass spider fittings after cooling. The process of pouring liquid steel can easily cause scald or burns. Therefore, please pay attention to safety during pouring.
- Pouring workers are not only exposed the thermal radiation of liquid metal under high temperature, but also harmed from noxious gas, the more obvious direct hazard is scald. Pouring workers should wear labor suit and protective glasses to prevent burns caused by splashing metal.
- Check the empty pouring ladle completely before pouring and ensure whether meeting the requirements. Check if the mechanical transmission device is flexible and reliable. Check if hoisting equipment and delivery equipment are all in good conditions.
- All tools in contact with molten metal, such as slagging bar, tongs and so on, shall be preheated during pouring, because cold tool can cause spatter when contacting. The gas, moulding sand moisture and combustible in the cavity are rapidly expanded, gasified and burnt after being heated, and overflow from the air vent and risers when pouring. Should ignite fire in time, lest cause explosion or carbon monoxide poisoning.
- Pouring ladle of stainless steel glass spider fittings should not cover too full steel liquid, not exceed 80% of the volume, to avoid spatter hurting people. The remaining steel liquid and iron slag shall be dumped into the special sand pit, slag pit or slag ladle after pouring. Either mould assembling or pouring are collective operation. Therefore, there should have dedicated personnel unified command on the site release the command or the gesture signal, lest cause the accident because of the uncoordinated movement.
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Common Types of Glass Spider Fittings
How to measure the size of glass spider fittings? The correct method is using tape or common ruler to measure the distance between the two adjacent holes of the claw piece. The measurement from the center of the hole to the center of the other hole is accurate. If you must start measuring from the edge, end to measure the other hole’s same position. For example, measure from the left side of the first hole to the left side of the other hole and read the values so that the dimensions can be measured accurately. The different sizes of glass spider fittings can be used in different environment related to the size and thickness of glass. If it is applied to a canopy, it should withstand human standing.
150 type glass spider fitting (Size of 150mm): Relatively small, often used in canopy, double glazing but not large. Small size with cheap price.
120 & 160 type glass spider fitting (Size of 120mm, 160mm): Used for handrail and guard bar.
200 type glass spider fitting (Size of 200mm): Common used for canopy, the glass area is between 1.5㎡ and 1.8㎡, the thickness is between 6+6 and 8+8. There are 6 kinds of 200 type glass spider fittings with different weights. The heavier the weight, the better bearing the spider fittings.
250 type glass spider fitting (Size of 250mm): Probably the most widely used specification. The glass area that is less than 3.0㎡ can use this type with strong bearing capacity and high safety. There are also 6 kinds of 250 type glass spider fittings with different weights.
300 type glass spider fitting (Size of 300mm): Large size. The glass area over 3.0㎡ can use this type.