Steel & Tube is pleased to announce the upgrading of our coating specification for Yellow / Gold Zinc plated Studbolts in line with the latest environmental standards and RoHS compliance.
Yellow zinc plating generally comes in two types:
Trivalent (colour – Light Yellow with Iridescent Silver tinge)
Hexavalent Yellow (colour – Dark Yellow)
Our new coating is Trivalent, which is accepted by all New Zealand Petrochemical majors.
Only trivalent yellow zinc plating is compliant to the Restriction of Hazardous Substances (RoHS) directive, which bans the use of certain substances such as the carcinogenic*, hexavalent chromium (used in the hexavalent yellow plating process), due to health and environmental concerns. Our experience is that most industries are moving towards compliance with RoHS.
Performance-wise, trivalent yellow zinc plating offers the same corrosion protection provided by hexavalent yellow zinc plating.
Our trivalent yellow zinc plating is still 25 microns thick and complies with requirements set out in international standards such as ASTM-B633.
*Hexavalent chromium [Cr(VI)] is recognized as a human carcinogen via inhalation.
Steel & Tube provide an extensive range of Studbolts designed to withstand harsh conditions and provide outstanding temperature, chemical, abrasion and corrosion resistance.
B7 Studbolts c/w 2H Nuts, Carbon and Alloy Steel Bolt and Nut materials for service temperature of -30°C to 400°C.
L7 Studbolts c/w Gr.4 Nuts, Carbon and Alloy Steel Bolt and Nut materials for service temperature of -100°C to -30°C.
B8M Class 2 Studbolts c/w 8M Nuts, Stainless Steel Bolt and Nut materials for service temperature of -150°C to 575°C.
B16 Studbolts c/w Gr.4 Nuts, Carbon and Alloy Steel Bolt and Nut materials for service temperature of 0°C to 525°C.
Note: Other grades available upon request.
Black, which is an uncoated finish with light oil.
Gold Passivated, also commonly referred to as Yellow or Zinc plated. Steel and Tubes stock of Gold Passivated Studbolts are coated to a minimum of 25 microns thick (Fe/Zn 25).
Hot Dipped Galvanised. Coating thickness is generally in the order of 50 microns. It is primarily used to protect Studbolts from the effects of weather and industrial atmospheres.
SermaGard 1105/1280 is aluminium filled basecoat/topcoat system designed to provide outstanding salt corrosion protection and UV resistance for Studbolts exposed to offshore atmospheric and sub sea environments.
Xylan1014 is a resin-bonded PTFE, thermoset, dry-film lubricant. It is primarily used on Studbolts to prevent corrosion and facilitate make-up torque.
More information about Studbolts is available in our Reticulation Product Catalogue (7.29Mb PDF)