INVISI-GARD (316) Stainless Steel Doors
The most corrosion-resistant
material in its class
316 Grade has virtually the same mechanical, physical and fabrication characteristics as 304 grade, but with better corrosion resistance, particularly to pitting corrosion. There are some key differences between the two grades of stainless steel that pose both benefits and shortcomings depending on which grade you choose. Due to these differences in chemical composition 304 Stainless Steel is not as corrosion resistant as 316 Stainless Steel. "Tea Staining" and surface pitting or corrosion, are potential problems with 304 grade stainless steel but pose less of a threat to products manufactured from 316 grade stainless steel.
Why doesn't INVISI-GARD 316
Grade Stainless Steel Mesh cut like
so many others?
The difference is in the tensile strength of the wire used to weave the mesh. As the wire used in the INVISI-GARD mesh is of such high tensile strength, the weaving process is made more difficult. The mesh is much harder to keep flat and straight and requires specialised weaving equipment and techniques to achieve the quality and flatness that is a hallmark of INVISI-GARD mesh. This explains why many cheap imported meshes either pass the knife-shear test but fail on weave quality and flatness, or pass on weave quality and flatness but can be cut like butter.
Grade 316 should be selected as a
minimum within five kilometres
of the surf.
The less expensive grades (such as 304) will probably become tea stained or even suffer more severe corrosion. Grade 316 has excellent corrosion resistance in a wide range of media. Its main advantage over grade 304 is its increased ability to resist pitting and crevice corrosion. It resists ordinary rusting in virtually all architectural applications, and is often chosen for more aggressive environments such as sea-front buildings and fittings on wharves and piers.
Grade 316 has virtually the same mechanical, physical and fabrication characteristics as 304 with better corrosion resistance, particularly to pitting corrosion.
EGP (Extreme Grip Protection) Retention System
Only INVISI-GARD Stainless Steel Security Products incorporate the Patented EGP (Extreme Grip Protection) Retention Method which locks the 316 Marine Grade Stainless Steel Mesh into the Heavy Duty Extruded Aluminium perimeter framing.
The EGP Retention Method completely isolates the Stainless Steel from the Aluminium as the mesh is captured between the Insulator (an "L" shaped co-extrusion) and the Keeper (a straight, ribbed co-extrusion). A rigid PVC Wedge is driven into the receiver channel around the full perimeter of the screen applying uniform pressure at all points and locking the mesh into the frame.
This innovative configuration grips the 316 Marine Grade Stainless Steel Mesh so well that it easily passes the Australian Standards requirements for security screens and doors AS5039-2008.
INVISI-GARD Stainless Steel Security Products do not require screws or any other form of mechanical fixing to secure the mesh to the perimeter frame. As a result the potential for corrosion through dissimilar metals contact is avoided.
Premium powder coating improves
aesthetics and optical clarity
The powder coat finish on INVISI-GARD has been specially developed to ensure great looks, clear vision and long life. INVISI-GARD 316 Marine Grade Stainless Steel Mesh is coated with a black polyester powder coat finish. This coating cuts down light reflection allowing clear visibility and is suitable for outdoor applications. Some competing systems use hybrid epoxy powder coatings which are completely unsuitable to outdoor environments leading to reduced product longevity.
The strongest material in its class
Some companies claim that their 0.9mm 304 grade stainless steel mesh is stronger than INVISI-GARD 0.8mm 316 Marine Grade Stainless Steel Mesh because it is thicker.
INVISI-GARD 316 Marine Grade Stainless Steel Mesh gains its strength from the Ultra High Tensile wire (900 MPa) from which it is woven. Even thicker wires can be easily cut if they are "Soft" or of low tensile strength.
ALSPEC have had INVISI-GARD mesh independently tested to Australian Standards and INVISI-GARD 316 Marine Grade Stainless Steel Mesh passes the Australian Standards AS5041-2008 for Knife-Shear.
Stainless Steel - The Facts
Stainless steel is a generic term for a family of corrosion resistant alloy steels containing 10.5% or more chromium. All stainless steels have a higher resistance to corrosion than their mild steel counterparts. This resistance to attack is due to the naturally occurring chromium-rich oxide film formed on the surface of the steel. Although extremely thin, this invisible, inert film is tightly adherent to the metal and extremely protective in a wide range of corrosive media. The film is rapidly self-repairing in the presence of oxygen. Damage by abrasion, cutting or machining is quickly repaired.
INVISI-GARD Stainless Steel
Security Products use only 316
Marine Grade Stainless Steel.
You can rest assured your new security doors and screens will look great for years with only a moderate amount of maintenance. And unlike some other competing products your warranty is not subject to the ongoing use of a proprietary cleaning product.
The ‘Tech Stuff’ on Galvanic
Corrosion:
Why are some products more likely
to corrode?
When two dissimilar metals are connected or in contact and are in the presence of a conducting electrolyte such as water or even dust, the more active metal will corrode and protect the less active metal. Aluminium is more active than stainless steel and will preferentially corrode in the vicinity of the contact zone between the metals. In the case of security screens, the aluminium is more active than the stainless steel mesh or any stainless steel fasteners, and so will corrode first, while the stainless steel will be protected by this galvanic phenomenon. The rate of galvanic corrosion is governed by the size of the potential difference between the metals in contact, and by the conductivity of the electrolyte.
As a rule of thumb, if the potential difference is less than 0.1 volt, then it is unlikely that galvanic corrosion will be significant. In the case of Stainless Steel and Aluminium the current difference ranges from between 0.175 and 0.55 volts depending on the specific alloys concerned. It can be seen that there is a high likelihood that corrosion will occur in any installation where the two metals are allowed to come into contact, either directly, or by way of mechanical fixing.
All INVISI-GARD Stainless Steel Security Products incorporate the Patented EGP Retention Method which locks the 316 Marine Grade Stainless Steel Mesh into the Heavy Duty Extruded Aluminium perimeter framing.
The Pressure Retention Method completely isolates the Stainless Steel from the Aluminium and because it does not rely on screws, or any other form of mechanical fixing, corrosion through dissimilar metals contact is avoided.
