BoltShield® caps are screw-on metal caps designed to protect bolts and nuts from thread damage, and to considerably help prevent corrosion (together with a proper paste / corrosion inhibitor).
By using BoltShield® caps you will extend the life of bolts and nuts and make maintenance and repair procedures easier and faster. This will help to reduce expensive plant downtimes, thus saving money and time.
BoltShield® caps are used in refineries and oil rigs, petrochemical plants, LNG plants, power plants, offshore platforms, steel structures. BoltShield® are commonly installed on pipelines, heat exchangers, reactors and equipment operating at temperatures up to 550° C and over, where common plastic caps would melt.
You can find BoltShield® caps to protect bolts and nuts on pipeline flanges, valves, traffic sign posts, bridges, wind turbines and several other applications where bolts and nuts need to be protected.
BoltShield® metal protection caps have a special thread, named Screw-On System, that ensures a strong and secure fastening.
BoltShield® are designed to be installed manually; no extra tools are required, and they can be easily installed and removed when needed.
We offer two types of BoltShield® caps with different levels of protection.
Both types of caps are available made of ALUMINIUM, STAINLESS STEEL (304/316), CARBON STEEL, ZINC ELECTROPLATED CARBON STEEL for bolt sizes ranging from ½” to 6”, M12 to M100.
COATINGS and CUSTOM-MADE CAPS ARE ALSO AVAILABLE.
- Caps made of metal designed to protect bolts and nuts from thread damage, dirt and corrosion;
- Special internal thread, named SCREW-ON SYSTEM, that ensures a strong and secure fastening to the bolt (a minimum of 4 – 5 threads protrusion from the nut is needed to allow fastening).
- Two types of caps available: TYPE TD caps protect both the exposed threads and the nut, TYPE TR caps protect the exposed bolt threads only;
- Both types of BoltShield can be supplied for bolt sizes ranging from Ø ½” to 6” / M12 to M100;
- All caps are available for both imperial and metric thread sizes;
- CUSTOMIZED SOLUTIONS are available to meet customers’ needs;
- Grease /paste /CORROSION INHIBITORS can also be supplied;
- Rubber / Silicon /PTFE washers also available for EXTRA SEALING.
- Materials available: STAINLESS STEEL (304, 316L) / ALUMINIUM / CARBON STEEL / ZINC
- ELECTROPLATED CARBON STEEL;
- COATINGS AVAILABLE UPON REQUEST – CAPS WITH GREASE NIPPLE ALSO AVAILABLE;
- Rated for temperatures up 550°c (aluminium caps) and over (steel).
Light but strong, aluminium is the most widely used material where ASTM A193 B7 stud bolts and A194 2H hex nuts on pipelines, heat exchangers, vessels, columns and other process equipment in the oil & gas and petrochemical industries have to be protected. Aluminium bolt caps are also a good solution for the protection of ASTM A320 L7 bolts in low-temperature service applications, as well as for foundation anchor bolts. Last but not least, aluminium bolt protection caps have a beautiful appearance, shiny and aesthetic.
Available sizes: up to 4” – M100 for TD type up to 6” for TR type
(AISI 304 / AISI 316) Our top-line BoltShield caps. Stainless steel protection caps are in high use in offshore applications, plants located near the coastline or high corrosive environments. Stainless steel caps are the right choice to protect B8 and B8M stud bolts and nuts. Can you think of a better protection for your stainless steel bolts than stainless steel protective caps?
Available sizes: up to 2” – M52 for TD type up to 2”1/2 – M64 for TR type
Carbon steel caps are the best solution for coated bolts and nuts, as they are also suitable for coatings (hot dip, zinc, epoxy, paint, cadmium, PTFE etc.).
Available sizes: up to 4” – M100 for TD type up to 4” – M100 for TR type
ZINC ELECTROPLATED CARBON STEEL
This is an excellent coated solution that we offer at the same price of raw carbon steel caps. Zinc is applied to the raw material (sheet metal carbon steel) through electrolysis, thus creating a layer that protect the metal base against corrosion. BoltShield made of zinc electroplated carbon steel are the right choice if you need to protect galvanized bolts and nuts, or when you want to provide extra protection from corrosion thanks the properties of zinc.
Available sizes: up to 4” – M100 for TD type up to 4” – M100 for TR type
üEXTEND THE LIFE OF BOLTS AND NUTS
üEASIER AND FASTER MAINTENANCE
üLESS TIME SPENT ON REPAIR
üHELP TO REDUCE PLANT DOWNTIMES
üSAVINGS BY OPTING TO AVOID EXPENSIVE COATINGS
üNO NEED FOR TIME-CONSUMING AND MONEY-WASTING DESTRUCTIVE BOLT REMOVAL
There are several reasons for using BoltShield® caps, the two most important being:
1. THREAD PROTECTION: BoltShield® caps protect bolts from accidental thread damage that may occur during handling, transportation and maintenance procedures.
2. CORROSION PREVENTION: Together with a proper paste / corrosion inhibitor, BoltShield® caps are proven to considerably help in preventing corrosion on bolts and nuts.
Mechanical protection and corrosion prevention translate into easier and faster
maintenance as the bolt threads won’t suffer any damage and will be protected from dirt and corrosion, which would lead to serious problems during maintenance and repair operations.
Think of the inconvenience and the waste of time that a rusted bolt may cause and multiply it by the number of unprotected bolts that you have in your assets: needless to remark how annoying that would be.
With BoltShield® caps, maintenance and repair will be much easier and faster, and this will help to considerably reduce expensive plant downtimes, thus saving money and time.
BoltShield® caps are cost-effective not only because they help to reduce the time, thus the cost, of maintenance operations and plant downtimes, but also because their use will prominently extend the life of your bolts and nuts.
BoltShield® caps are reusable and once tightly fixed onto bolts they will last for years. Indeed there are other ways to
Indeed there are other ways to prevent corrosion, such as coatings or stainless steel. However,
However, coatings are expensive and may not be enough to prevent corrosion, as during transportation, handling and assembling they may wear out. Re-coating is expensive and time-wasting. This will result in unprotected bolts and nuts, which will soon be affected by corrosion.
Stainless steel is clearly a good choice to prevent corrosion, but it is expensive.
Last but not least: coatings and stainless steel CANNOT prevent the bolt threads from accidental damage that could compromise the integrity of your bolts.
BoltShield® protection caps provide thread protection and corrosion prevention at a cheaper price.
BoltShield® caps TYPE TD offer the best protection, as they cover both the exposed bolt threads (size HT of the chart) and the nut (size HD).
Available made of:
ALUMINIUM →up to 6” – M100
STAINLESS STEEL →up to 2”1/2 – M64
CARBON STEEL (also zinc electroplated) →up to 4” – M100
If you are interested in protecting the bolt threads only, BoltShield® caps TYPE TR offer the best thread protection.
They are designed to protect only the exposed bolt threads (size HT of the chart below). BoltShield® caps TYPE TR do not cover the nut, which remains exposed.
We offer our customers standard size (see chart), ranging from ½” to 6”, M12 to M100, according to the material required.
We also provide custom-made sizes and bespoke solutions for any application in order to meet all customers’ needs.
Corrosion on bolts and nuts is a serious widespread issue, especially for applications located in aggressive environments (e.g. offshore, marine etc.).
Rusted bolts often need to be cut off and replaced, with a consequent loss of time and money.
BoltShield® caps can considerably help to prevent corrosion on bolts and nuts. Together with a corrosion inhibitor or a proper paste, the use of BoltShield® caps can reduce corrosion substantially, thus extending the life of your bolts and nuts.
For particularly aggressive environments where extra sealing is needed, we can provide silicon, rubber or PTFE washers.
BoltShield® caps were tested for corrosion prevention. The picture above refers to ASTM B-117 salt fog test. Such test was performed to determine to what extend the use of BoltShield metal caps can help to prevent corrosion on bolts and nuts. It provides a comparison, in terms of corrosion, between bolts and nuts protected by BoltShield caps and unprotected ones. Time of exposure to salt fog: 600 hours.
Several combinations of bolted joints protected with BoltShield caps (with and without rubber washers and paste) have been tested. After 600 hours of exposure of the specimens to salt fog, results document that bolts and nuts protected with BoltShield caps show marginal corrosion only, as it can be seen from the picture.
The official Test Report test is available upon request.
BoltShield® caps are now available with extra lengths to fit foundation anchor bolts on wind turbines.
BoltShield® caps are designed to be installed manually. They have a special thread, named Screw-On System, that ensures a strong and secure fastening.
No extra tools are required, and caps can be easily installed and removed when needed.
BoltShield® caps are “screw-on” type, not “snap-on”. This means that installation and tightening are obtained by turning/ screwing/ fastening the cap onto the bolt manually, NOT by pushing or snapping the cap onto the bolt (this would only be counterproductive and would complicate the installation procedure). A minimum of 4 to 5 threads protrusion from the nut is needed to allow fastening.
In order to properly install the caps:
1. Take the BoltShield® cap and place it onto the bolt.
2. Do not push! Pushing is not necessary for the reasons explained above.
3. Now slowly start turning the cap clockwise.
4. When you feel that the screw-on system (the punchings you see on the cap) has properly matched the bolt thread (thus allowing screwing), you can go on turning the cap clockwise until it touches the flange.
5. Now tighten firmly with your hands. Thanks to the Screw-on System, BoltShield® caps will remain in place and withstand high vibrations.