HtBolts32.Net

Welcome to HtBolts32.Net® , the Industry Standard in High Temperature Bolts Database Management for Utility companies (Gas, Steam, Coal & Nuclear Power Stations).

Overview:

This power-packed version of HtBolts32.Net combines exciting features with the established functionality ‘HtBolts32’ and ‘HtBolts’ users have come to rely on.

HtBolts32.Net is a full-featured system designed specifically for preventing the failure in service of threaded fasteners (studs, stud bolts and bolts) operating at high temperatures for all Windows operating systems. HtBolts32.Net simplifies the process of creating and maintaining Bolt records and updating those records with any tightening information, etc; It automates the creation of reporting features including:

• Bolts Remaining Life Hours
• Tightening Operations Requirements
• Retighten and Replacement Summaries
• and much more …..

Threaded fasteners operating at temperatures above 370°C can fail catastrophically as a result of accumulated creep damage. However, with appropriate maintenance and a suitable management system, failures can be avoided.

Benefits:

• Registers all plant items.
• Permanently records each assembly and updates on a regular basis.
• Highlights approach to life limits for each fastener on any unit at any time.
• Highlights all bolting that has bolt life of less than specific hours left on any unit at any time and that is manufactured from specific material on any unit at any time.
• Highlights to input a new bolt item on any unit at any time.
• Highlights all bolting that has a specific service temperature on any unit at any time.
• Highlights a bolts’ complete history.
• Links a specific bolt to drawings and their own specific applications.
• Designed to comply with:
• GOM85
• GENSIP
• ERMS
• ES-19
• BEOM102 (NEOM102)
• and many more …..

HtBolts32.Net stresses the need to maintain procedures aimed at preventing the failure in service of threaded fasteners (studs, stud bolts and bolts) operating at temperatures exceeding 370°C. It provides background information and defines acceptable standards of practice based on operational experience and research. This will enable the person responsible (supported when necessary by specialist advice) to establish procedures appropriate to their location.

Tightening techniques have now been divided into categories with the introduction of a partially controlled method (See: The Effect of Tightening on Fastener Life), Additional guidance is given on the treatment of fasteners subjected to differential temperatures and a default penalty included for certain Group 6 steam chest cover fasteners if operating temperatures and gradients have not been measured (See: Penalties for Differential Temperatures in Fasteners and Joints).

Guidance on anti-seizure compounds has been changed in the light of increased knowledge of deleterios effects and the lack of consistency in proprietary specifications.

Hours in Operation should now be counted from the first occasion units are operated within 40°C of nominal operating temperature at the turbine stop valve, instead of the original 20°C. Where appropriate, advice from Regional specialists is now advocated instead of the manufacturers.

Advice on the care of nickel-based alloy fasteners has been extended to cover the avoidance of deleterious environments. Guidance is now given (See: The Sealing of Leaking Joints by Injection Processes) on the treatment of leaking joints sealed using a pressurised sealant: advice is given that this technique should not be applied to joints with nickel-based alloy fasteners.

Fasteners used at temperatures exceeding 370°C have a limited life. This is because the materials used for such fasteners Creep (See: The Care of Nickel-based Alloy Fasteners). They have a limited capacity for creep strain before they crack and fail.

The life of fasteners is dependant on:

• The operating temperature of the fasteners
• Fastener material – its composition and properties
• Design details
• Initial applied strain.
• Frequency and method of tightening.
• Differentials in temperature in the fastener and in the surrounding metal structure.

All the above factors have to be taken into consideration in order to determine when such fasteners should be replaced.

Obviously, the timing of replacement of fasteners should be optimised to avoid unnecessary expense and outages, but fasteners have failed in service, sometimes in a manner which has put personnel and plant at risk. From this and other experiences, warning signs have been identified which provide additional reasons for replacement, i.e. leaking joints; cracked or broken fasteners.