The ultimate non-magnetic stainless steel fasteners are manufactured in extremely small quantities by Hague Fasteners.
The high Nitrogen content of ASTM A193 B8LN fasteners (304LN fasteners) creates an extremely low level of magnetic permeability and these special fasteners are used when is used where an extremely low level of magnetic permeability is required.
Special Fasteners in this specific stainless steel further exhibit the following desirable properties:-
Moderate pitting and crevice corrosion resistance
Excellent impact toughness at sub-zero temperatures
A higher proof stress yield than regular 304L stainless steel fasteners.
Non-magnetic, Very low ferrite level and very resistant to martensitic transformation. Relative magnetic permeability < 1.005
Good weldability.
304LN was originally developed as a higher strength version of 304L by raising the amount of nitrogen. However, the increase in strength is only modest and easily achieved through cold working. Further, duplex grades are now commonly used where higher strength bolting is required.
The grade is now used in specialised applications where a very low magnetic response is needed. In standard 304L, a typical level of relative magnetic permeability is around 1.05-1.1 due to small amounts of ferrite in the austenitic structure. A completely non-magnetic material would have a value of 1.0. 304LN can achieve a maximum value of around 1.005, which is the lowest practical level of any steel grade. It is also very resistant to transformation to the magnetic martensitic phase which can occur on forming or cooling to very low temperatures.
For this reason Hague's manufactured B8LN Special Fasteners are commonly used in specialised equipment where magnetic âinterferenceâ needs to be avoided and also for use in cryogenic equipment such as bolting for Magnetic resonance imaging (MRI) scanners, reinforcing foundation bolts for structures surrounding MRI scanners also special fasteners in pressure vessels, and non standard socket screws in cryogenic applications.
Hague’s British Engineering Group were one of the earliest British manufacturers of Petrochemical Studbolts & Nuts. Their flow line thread rolling production facility in Wolverhampton ensured ASTM quality assured bolting was shipped around the world for Rigs and pipeline maintenance, the original Studbolt Manufacturing Ltd*
However in the late 1980’s due to costing pressures brought about by cheap Asian competition, Hague Fasteners decided to step away from the standard ASTM material production, leaving the regular sized Studbolts & Nuts to the competition. Naturally the market was flooded with often inferior Chinese manufactured cheap bolting, but as was so often seen in the 80’s British Manufacturing simply couldn’t compete with imports from China.
Several British Companies appeared as stockholders to continue the supply of Petrochemical Studbolts and Nuts by importing container loads of Foreign manufactured product. Some even claimed to “Manufacture” but simply cutting lengths of studding to required lengths misleading as the bolts remain imported and not of EU Origin. During this time Hague closed their Studbolt Manufacturing mass production facility and decided to focus their niche on the more specialist material grades where quality & integrity is required above cost alone.Â
To this day, Hague excel in the manufacture and supply of these Superalloy fasteners. Critical bolting in ASTM A453 660, Inconel 718, Inconel 625, Monel 400 along with Duplex & SuperDuplex Grades S31803, S32550, S32750, S32760.Â
It is with increasing regularity now that Hague Fasteners are winning orders against the cheap inferior imports where our High Integrity Customers through all Industries are stipulating that Imported Fasteners particularly of Asian Origin must not be supplied. An about turn and a return to British manufacturing excellence. Saving a few pounds is irrelevant if the quality you’re receiving is substandard or the materials received is not in full compliance with the specification required.Â
Don’t take unnecessary risks, source from the experts in Special Fastener production.Â
The Craftsmen In Fasteners – Risk Free Bolting Solutions Since 1971
* The appearance of “Studbolt Manufacturing Ltd” (now non-trading) in 2003 was as a result of the name being adopted by another firm following the closing down of The Ralin Group’s original named Company in the 1990’s and does not have any connection to Hague Fasteners Limited.
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