BOLTED

A forum about optimizing
bolt securing

All posts for the tag “HV Nuts”

Understanding the markings on nuts and bolts

First published in Bolted #2 2017.

Q: What do the markings on bolts and nuts mean?
A:  Bolt heads and nuts are often marked with numbers, letters, dashes, slashes, dots, or an assortment of other marks. Fasteners commonly have two different markings: a unique manufacturer identification symbol – such as letters or an insignia – and information about the fastener strength. Such markings differ based on how the fasteners were made. See the table for the alloyed steel metric and stainless-steel metric fasteners that comply with ISO standards. UNC thread fasteners mainly comply with ASTM standards.

Due to lack of space, markings can be missing on smaller sizes, such as those with diameters below M5 according to ISO 898-1. However, the bolt class must be marked on the head above this size.

 

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Q: What do the markings on bolts and nuts mean?
A:  Bolt heads and nuts are often marked with numbers, letters, dashes, slashes, dots, or an assortment of other marks. Fasteners commonly have two different markings: a unique manufacturer identification symbol – such as letters or an insignia – and information about the fastener strength. Such markings differ based on how the fasteners were made. See the table to the right for the alloyed steel metric and stainless-steel metric fasteners that comply with ISO standards. UNC thread fasteners mainly comply with ASTM standards.Due to lack of space, markings can be missing on smaller sizes, such as those with diameters below M5 according to ISO 898-1. However, the bolt class must be marked on the head above this size.

ASK THE EXPERTS
Do you have a question about bolt securing?
Put the Nord-Lock experts to the test.
Email your questions about bolt securing to
experts@nord-lock.com

The Experts: The benefit of SC-washers

First published in Bolted #1 2016.

Q: What is a SC-washer and when should I use it?

A: Nord-Lock has developed a range of washers specially designed for use in steel construction applications and to fit HV sets (bolts and nuts in accordance to the European standard EN 14399-4 / EN 14399-8), as the standard washers can’t be used (see picture). These washers are named “SC” (Steel Construction washers). Their purpose is to replace plain chamfered washers according to EN 14399-6 in order to add safety to high-strength structural preloaded assemblies encountered in steel construction, when exposed to dynamic loads or vibration.

 

ASK THE EXPERTS
Do you have a question about bolt securing?
Put the Nord-Lock experts to the test.
Email your questions about bolt securing to
experts@nord-lock.com

Securing bridges over cooling water

Nord-Lock SC-washers installed in place to secure bolted joints on the bridge

The Port of Rotterdam (Netherlands) receives every year the visit of around 35,000 seagoing vessels and 130,000 inland vessels. This makes the Port of Rotterdam the largest port in Europe and third-largest port in the world. Several years ago, the intensive increase of shipping traffic created a capacity problem, which made obvious the need to expand the Port.

A building consortium was appointed to build the Maasvlakte 2 subproject of expansion in the sea off the coast of the existing Maasvlakte. The work comprised the construction of sea defences, the first port sites, some 3 km of quay and the roads and railways necessary to provide access to the Maasvlakte 2 area. They were also responsible to build temporary bridges for rail and road traffic at the Yangtzehaven. This bridging of a first water connection between Maasvlakte 2 and the Yangtzehaven was necessary for the discharge of E.ON cooling water during the period when the sea wall would temporary be closed. The construction of the rail bridge required a large-scale interruption to rail services during a certain period of time.

Janson Bridging Group, a company leader in building bridges, pontoons and roro’s, built the temporary rail bridges for this project. Bolted joints of the standard steel bridge are fastened with bolts and nuts. Considering the high demands of ProRail (Dutch government organization responsible for the maintenance and extensions of the national railway network infrastructure) regarding an eventual bolt loosening due to continuous vibration, Janson Bridging chose Nord-Lock SC-washers to secure the bolted joints of the bridges. Janson Bridging tightens the longitude and transverse beams of their bridge systems through a bolted joint which is partly used as a preloaded bolted joint. The preloaded bolted joints are tightened with calibrated torque tools.