APPLICATION TECHNOLOGY
bigHead fasteners solve corrosion problems
bigHead has developed an innovative solution for a key contractor to major offshore Oil & Gas installations. Secure and versatile, the bigHead fasteners are installed on downward facing steel surfaces to hold safety critical insulation materials in position over long periods of time without corroding.
safety and necessitates costly repairs and maintenance. The bigHead butterfly bracket utilises bigHead’s unique design
A
to avoid welding and allow simple surface bonding with adhesive. In this particular example the bigHeads were surface bonded into position with a new structural adhesive from 3M. Once installed, the bigHead fastener provides a secure fixing for the application
critical objective for the client was to move away from welded pins which suffer from corrosion in severe offshore climates. When securing insulation and fire protection systems in place such corrosion jeopardises
of a wet applied insulation material. bigHead highlights that it was able to come up with design
prototypes within days of the enquiry coming in from the Oil & Gas contractor. Due to its unique process bigHead was also able to provide multiple designs in a short space of time and also test the strength of those designs for the client. “Made with 316 stainless steel the bigHead butterfly bracket
is resistant to the most severe marine climates. This type of application specific design for technical clients is something that we at bigHead have been specialising in for over 40 years.”
New guide to Spirol compression limiters
Spirol Industries says that its compression limiters are the ideal components to meet the specific engineering and cost objectives for manufacturers of plastic assemblies.
S Araldite® I
pirol’s standard range of compression limiters will meet most requirements, but special diameter, length, duty, material, tolerance configurations can also be supplied. The company’s new compression limiter design guide provides details of all the product options available, design considerations and information on the support services available from Spirol Industries. Compression limiters are designed to protect the plastic components of an assembly from the
compressive loads generated by the tightening of bolts and will ensure the continued integrity of the bolted connection. As the bolt is tightened the plastic compresses and the stress in the plastic increases
until the head of the bolt comes into contact with the compression limiter. The compression limiter and plastic will compress at the same rate with the limiter absorbing additional clamping loads, without increased stress in the plastic material. The Spirol compression limiter range includes the moulded-in, split seam and solid knurled designs. The moulded-in type is
produced from low carbon steel and is equipped with radial grooves to provide maximum retention. The split seam type is produced from low carbon and high carbon steel. The solid knurled type is produced from brass and aluminium. Starting with an analysis of a customer’s manufacturing and cost objectives, Spirol application engineers determine the most suitable compression limiter, considering the specifications of the components to be assembled and implications for their assembly.
AV 4600 offers the solution
Erndtebrücker Eisenwerk (EEW), based in Germany, produces a variety of steel pipes for the offshore industry, oil and gas treatment plants, power plant construction, pipelines, chemical and petrochemical plants as well as for civil construction.
n a recent project, EEW’s research and development team worked with Huntsman Advanced Materials and its distributor in Germany - Bodo Möller Chemie, to produce a new economic type of clad pipes, the compound liner clad
steel (CLC) pipe. As the criterion for the CLC pipe was to produce a new, competitive budget-priced pipe, it was decided that the company’s standard facilities for pipe production would be used to create a composite plate compounded out of a CMn-steel plate and a corrosion resistance alloy (CRA) sheet, bonded together with a high performance epoxy. The challenge lay in identifying an epoxy adhesive that could
enable the cladding of steel plates with all commonly used grades of CRA sheets, prior to forming and welding the heavy composite clad plates into pipes. EEW followed the principles of lean engineering in selecting
single package system epoxy adhesives to include in a series of rigorous tests designed to assess differences in break strength and elasticity.
After assembling the composites for testing, the adhesives
were hardened in a hot press at 180°C and differences in the resistance to shear and tensile forces were observed. For most of the products, disbonding occurred with some of the composite samples showing significant signs of breakage. However, one of the adhesives - Araldite®
AV 4600 – emerged as a clear
winner, forming a strong and durable joint without any signs of disbonding and displaying the highest shear strength values of all products on test. Araldite®
AV 4600 is a multipurpose, one component heat
curing thixotropic paste. It offers good chemical resistance, exceptionally good impact strength at sub-zero temperatures as low as -40°C and is heat resistant to 120°C. “Araldite®
AV 4600 proved to be ideal in providing the strength
needed to withstand both bending in production and the shear and tensile stresses that the pipe would be subject to in offshore applications,” said Markus Bockelmann, leader of research and development at EEW.
116 Fastener + Fixing Magazine • Issue 73 January 2012
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