Super PIASTA Full Stainless Steel A4 Self Drilling Screw
Super PiastaTM screws are the combination of the two of the best advantages of Stainless Steel. Austenitic Steel is used for the head and the fastening stank while martensitic stainless steel is dor the drill point and tapping shank. The stated martensitic stainless steel mentioned has an increased hardenability for the drill point.
Super PiastaTM Screws are made from Austenitic Stainless Steel grade 316 and are by nature very corrosion resistant without additional anti-corrosion coating. Stainless Steel grade 316 has better overall corrosion resistant properties than Grade 305 used in PiastaTM screws, particularly higher resistance to pitting and crevice corrosion in chloride environments. By virtue of the molybdenum addition in the 316 Stainless Steel, it can withstand corrosive attack by sodium and calcium brines, hypochlorite solutions, phosphoric acid; and the sulfite liquors and sulfurous acids used in the paper pulp industry. This alloy, therefore, is specified for industrial equipment that handles the corrosive process chemicals used to produce inks, rayons, photographic chemicals, paper, textiles, bleaches, and rubber. Type 316 is also used extensively for surgical implants within the hostile environment of the body.
Super PiastaTM screws, however, come with an additional proprietary RuspertTM coating or Passivation Coating. This RuspertTM coating is a common feature on the PiasTM range of Carbon Steel self-drilling Screws and is able to withstand 1000Hrs of Salt Spray Exposure which is equivalent to more than 10 years of normal weathering (According to Australian Standard AS3566 Class 3). This coating, in addition to providing redundant protection, has lubricative properties, which reduces setting torque and ensuring maximum thread life. The Special Passivation is known to retain the brilliant color of the stainless steel. Moreover Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion by blocking oxygen diffusion to the steel surface and blocks corrosion from spreading into the metal’s internal structure, and, due to the similar size of the steel and oxide ions, they bond very strongly and remain attached to the surface.
Super PiastaTM screws are created for drilling stainless steel sheets efficiently using the SUS-420J2 Stainless Steel which has high head resistance for the drill point and is already patented in Europe.