Top-Grade Fasteners for Energy Applications

Home Safety Critical Fasteners

Unisys distributes Safety Critical Fasteners for the Power Generation, Oil and Gas, Gas Pipeline, Nuclear, Rail, Marine, Petrochemical, Wind, and other energy industries. Unisys supply special bolting and CNC machined components for use in Safety Critical Applications.

We supply largest product range in all dimensions and grades and in any standards as well (ASTM, DIN, ASME, RCCM …). All our materials are certified HIGH INTEGRITY – “no compromise on quality”.

Our principal having all the key manufacturing processes, such as forging, heat treatment, thread-rolling, surface treatment, machining, testing, are performed in-house in order to guarantee the integrity of manufactured products.

We supply bespoke components to recognised standards such as BS, DIN, ISO, ANSI, or to customer specific requirements by means of drawings or samples. Our scope of supply covers all materials, and we specialise in components for use in Heat Resistant, Pressure Resistant or Corrosion Resistant applications.

Quantity:

We supply to order,ranging from one-offs, to small and medium batch quantities.

Size Range:

M2 to M200 (and imperial equivalents), all lengths available (lengths in excess of 4 metres can be catered).

Hot Forging:

We can supply headed components (Hex Bolts, Socket Head Capscrews, etc.) in all grades of alloys.

Thread forms	All metric & imperial thread forms.
Bolts & Screws	Hexagon, 12 Point, Socket, Slotted, Square.
Studs	Double Ended, Waisted, Collar, Stud bolts.
Nuts	Hexagon, 12 Point, Capnuts, Round, Slotted, Barrel.
Washers	Round, Square, Spherical, Spring, Taper, Tab.
Machined Parts	Clevis Blocks & Pins, Tie Rods, Shafts, Spindles.

Safety critical fasteners are used in the rotors, combustion chamber, exhaust and casing of a gas turbine. They provide a critical role in the assembly of the turbine and they are highly specified and must be made to tight tolerances to ensure efficient and safe functioning.

Stuctural bolts for casings

Fasteners are used to connect the main shaft to the impeller
For casings around the blades,it require high grade horizontal join bolts to hold the entire assembly in place
Fasteners are also applied on the foundation of the gas turbine

Bespoke special bolting for use in rotor applications

Roter fasteners on rotor blades are used to attach to the rotating
Specially fasteners with highest critically are used in combuster chamber due to very high temperatures
Both specially fasteners and standard bolts are used to fix compressor rows
Fasteners bolt large sections together for exhaust applications

Our scope of supply includes, but is not limited to, the grades listed below.

304,304L,304H
316,316L
310
321
410
904L
317L
RA330
347SST
Alloy 20
C276
Monel 400

Duplex 2205
A193 B7,A193 L7
Inconel 718 & 800
Brass
A36
1008
1018
1020
GR.50
GR.55
Copper
Aluminium

We are also able to supply products with additional processes such as surface coating and heat treatment, including but not limited to:

SURFACE COATINGS

Xylan / PTFE
Zinc Plated
HDG
Phosphated
Molykote
Sherardized
Silver Plated
Nickel Plated
Zinc Nickel Plated
Copper Plated

HEAT TREATMENT

Case Hardening
Tempering
Plasma Nitriding
Solution Annealing
Age Hardening
Nitro Carburising
Normalising
Strengthening
Quenching

All components can be supplied with full material certification, to ensure full traceability of components throughout the production and certification processes.

Our safety critical fasteners meet the strict requirements and standards of the power generation industry. The following are important performance characteristics for fasteners for power generation:

Excellent corrosion and oxidation resistance
High tensile, shear, and fatigue strength
Heavy-duty construction for high-strength applications
High immunity to wear and vibration to prevent loosening
High wear resistance
Capable of operating under extremely harsh environments, including low and high temperatures and pressures

We supply fastening systems to the following:

Gas and steam turbines : rotor bolts, coupling and casing.

Hydraulic turbines : studs and screws for Pelton, Francis, Kaplan turbines, bulb group, coupling and piping

Diesel engines : studs and connecting rod / cylinder head screws

Alternators : pole screws, non-magnetic screws

Valves and pumps

Completely controlled thread rolling for parts operating under fatigue.

Types of Fasteners

Double-Ended Studbolts
Waisted Engineer Studbolts
Bi-Hex Bolts & Screws (Ferryheads or 12-Point Bolts)
Cap Nuts
Pole Screws
Glass Mica Insulated Bolts

Certain material types are more desirable in the power generation industry due to them demonstrating superior performance in extreme temperatures and pressures. These materials, often when coated, also provide excellent resistance to solvents, chemicals, steam, and gases.

Stainless steel stud bolts and double end studs

Types of Material

A193 B7, B16, B7M, A320 L7, L7M, L43, B8, B8M, B8T, A 453 Gr 660, EN 10269, 21CrMo4,2H,2HM,4, 7, 7M, 8 (S1), 8M (S1) and 8T (S1), ASTM A193 B8MX, ASTM A193 B8C, ASTM A193 B8TX, Alloy/Hastelloy™ C4, C22 + C276, Duplex UNS S31803 (F51), UNS S32550 (Ferralium® 255), UNS S31254 (254SMO/6Mo), Super Duplex UNS S32760 (F55), UNS S32750 (F53), Alloy/Monel™ 400 + K500, Alloy/Inconel™ 600, 601, 625, 718 + 825, Incoloy™ 800 H/HT, 925, 904L (Uranus® B6), Carpenter® 20 (CB20)
Durehete 900 (T22), 950 (T31) & 1055 (T41)
Esshete 1250
Jethete M152 & M448
Nimonic™ 80A
21CrMoV57
Waspalloy Grades
Alloy/Hastelloy™ C4
C22 + C276
Alloy/Monel™ 400 + K500
Alloy/Inconel™ 600
Inconel™ 601, 625, 718, 825, Incoloy™ 800 H/HT, 925, 904L (Uranus® B6)
Carpenter® 20 (CB20)
AISI 422
17/4PH

We use the following:

Steel Alloy Materials:

Grade 2, grade 5, B5, B6, B7, B7M, B16, L7, A490, A325, 2H and more.

Non-ferrous materials

We use a wide variety of materials to suit any fastener application, including the following:

Copper, brass and bronze
:
aluminium bronze, silicon bronze 655, silicon bronze 651, phosphorous bronze, brass, naval brass
Stainless steel
: Grade 8, B8, B8M, 302, 303, 304, 304L, 309, 310, 316, 316B, 316L, 317, 317LM, 321, 330, 347, 410, 416, 422, 430, 431, 440cC and 501
Aluminium
: 2024, 6061 and 7075
Exotics
: 904L, alloy 50, alloy 60, alloy 20, Ferralium® 255, Tantalum, A-286, Haynes® 230, Titanium, Nitronic™ alloy 50, Nitronic™ alloy 60, Waspaloy®, Zirconium, Monel™ Nickel 200, Nickel alloy C276, Nickel alloy B, B3 and G-3
Inconel™ alloys
: 600, 601, 625, 718, 800, 800H, 825, 925 and X750
Hastelloy™ alloys
: C-276, B,C-4, G, C-2000, X, and C-22
Monel™ alloys
: 400, 405, K500, and 200