Top-Grade Fasteners for Energy Applications

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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.


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:


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


  • 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.

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