Tungsten Hex Nuts are known for their extreme high density; because of this unique attribute, they are often used for balancing rotating parts. Tungsten’s high mass also makes these fasteners radiopaque. This allows Tungsten Hex Nuts to block radiation and show up well on x-rays – even better than lead. Another unique attribute of tungsten is its extrmely high melting point of 3420°C. The high temperature stability of tungsten fasteners make them ideal for some of the hottest vacuum furnace environments. Beyond their high mass and temperature stability, tungsten fasteners are also very corrosion resistant.
Tungsten Hex Nuts are usually made from tungsten alloys per ASTM B777, and range from 90% to 97% pure tungsten, alloyed with nickel and copper or nickel and iron. Fasteners can also be made from Commercially Pure (CP) Tungsten.
Ultra-high density & high temperature / strength stability
Very high density of 19.3 gm/cc
Radiopaque to x-rays and other radiation
High strength at extreme high temperatures (vacuum)
Excellent corrosion resistance
Mechanical properties of tungsten fasteners
Tungsten material datasheet
Applications
The aerospace industry depends on the tungsten fasteners for their combination of high density and mechanical strength which allows them to reduce the physical size of components, offering greater control of weight distribution for propellers, inertial systems and fluid control systems to name a few.
The heat treating / furnace industry uses tungsten fasteners in high temperature vacuum furnaces due to tungstens great high temperature strength & stability.
The oil & gas industry uses tungsten fasteners for radiation shielding properties to protect equipment used in oil and gas detection, as well as down hole logging for density and ability to withstand intense hydrostatic pressure
Tungsten fasteners also play a role in the medical community for their low magnetic properties as well as their radiopaque properties.
Resources: Tungsten Torque Specs
Tungsten Nuts: Hex Nuts, Lock Nuts
Custom Availability
Diameter sizes: Standard #00 – 4” in diameter / Metric M1.2 – M100
Threads: UNC, UNF, UNJ, UNR, Rolled,Cut
Minimum Volume – Typically 10pcs, depending on size and stock
Custom to print
Tungsten Locknut Features and Beneifts
A tungsten locknut resists loosening from vibrations and torque. One of the most common styles is a prevailing torque locknut. This kind of tungsten locknut has a prevailing torque feature which deforms elastically, preventing it from freely spinning like a standard nut.
The two most common and reliable forms of prevailing torque locknuts are the flexloc style and the polymer insert lock nut. A tungsten flexloc nut is all-metal in composition with a segmented collar that creates six “locking fingers,” that act as a spring. Tungsten polymer insert lock nuts are often referred to as nylon insert locknuts, although various high performance polymers can be used for the screw threads to “bite into.” Both flexlock and polymer insert locknuts are available in both hexagonal and 12 point configurations.

All Metal Flexloc Lock Nut | 
Polymer/Nylon Insert Lock Nut |
Can be used at high temperatures Distributes load evenly due to the fact that it is manufactured as one solid piece. Is THE most reliable all-metal self-locking nut. As it is all metal, it is best for high temperature or corrosive applications One of the only all-metal lock nuts that is certified to 15 cycles of prevailing torque – which is military standard.
| Overall the most reliable locknut, with the only limitation of application temperature Best for low temp applications, typically less than 350°F Various polymers inserts available (Nylon, Vespel, PVDF, etc.) for higher temp. or corrosive applications. Excellent reusability – can reliably be re-used 15 times Eliminates galling and cold-welding common with exotic alloys
|
Other all metal lock nuts available include the tungsten stover and elliptical styles. Though these styles are often a cheaper initial cost, they are less reliable than the flexloc style. As these styles delivering less prevailing torque cycles and often result in more failures, the flexloc style is a better investment for both reliability and cost savings.
Tungsten Styles
Tungsten Screws | 12 Point Screws Button Head Cap Screws Flat Head Screws Hex Head Cap Screws Pan Head Screws Security Screws Set Screws Socket Head Cap Screws Vented Screws | • DIN 603 / ISO 8677 • DIN 912 / ISO 4762 • DIN 913 / ISO 4026 • DIN 914 / ISO 4027 • DIN 915 / ISO 4028 • DIN 916 / ISO 4029 • DIN 921 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017 • DIN 961 / ISO 8676 • DIN 965 / ISO 7046 • DIN 966 / ISO 7047 • DIN 7991 / ISO 10642 • DIN 7380 / ISO 7380 • DIN 84 / ISO 1207 • DIN 85 / ISO 1580 • DIN 34822 • DIN 34821 • DIN 7504 / ISO 15480 • DIN 7984 • DIN 963 / ISO 2009 |
Tungsten Bolts | Hex Head Bolts Shoulder Bolts Wedge Anchor Bolts | • DIN 931 • DIN 933 • ISO 4014 • ISO 4017 • ISO 7370 |
Tungsten Nuts | Hex Nuts Lock Nuts | • DIN 439 / ISO 4035 • DIN 934 / ISO 4032 • DIN 985 / ISO 7040 • DIN 986 • DIN 980 / ISO 7042 / ISO 19513 • DIN 6923 / ISO 4161 |
Tungsten Studs/Rod | Studs Threaded Rod Weld Studs | • DIN 975 • DIN 976 |
Tungsten Washers | Flat Washers Lock Washers | • DIN 125 / ISO 7089 / ISO 7090 • DIN 126 / ISO 7091 • DIN 127 / ISO 7090 • DIN 9021 / ISO 7093 |
Tungsten Hose Clamps | Medium Duty Hose Clamps |
|
Tungsten Screws

12 Point Screws | Tungsten 12 point screws allow for higher torque to be applied than a socket head cap screw or head head bolt, however they are be less economical due to the complex head design. Available in 1/4" or larger sizes. | • IFI-115 • MIL SPEC • DIN 34822 • DIN 34821 |

Button Head Cap Screws | Tungsten button head screws offer a wide clamping area and low profile. They are best for fastening material that is too thin to counter bore. | • ASME B18.3 • ASME 18.3.4M • DIN 7380 / ISO 7380 |

Flat Head Screws | Tungsten flat head screws are most commonly offered in an 82° countersink angle, but can be customized to other angles from 60° -120° and are designed to be flush with the surface. Available in slotted and socket drivers. Phillips, 6-lobe, torx and tamperproof drivers in Tungsten flat head screws can be made require special manufacturing. | • ASME B18.3 • ASME B18.3.6 • DIN 963 / ISO 2009 • DIN 965 / ISO 7046 • DIN 7991 / ISO 10642 |

Hex Head Cap Screws | Tungsten hex head cap screws offer the added washer face to the bolt head which is lacking on a hex bolt and tighter dimensional tolerances. Ideal for a high clamping force applications with ease of access. Generally availabe in #2 - 1/2" sizes and metric sizes. | • ASME B18.6.3 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017 • DIN 961 / ISO 8676 |

Pan Head Screws | Tungsten pan head screws offer a rounded top are best used for small diameter faster needs. Offered in slotted and they are ideal for low torque applications. | • ASME B18.6.3 • DIN 7985 • DIN 921 • DIN 85 / ISO 1580 • DIN 84 / ISO 1207 (cheese head) • DIN 966 / ISO 7047 (raised counter sunk) |

Security Screws | Unique driver designs offer these Tungsten screws resistance to unwanted tampering or removal due to the fact that they cannot be removed using an ordinary driver. Tungsten security screws are available in several different drive styles, as well as custom per print. |
|

Set Screws | Tungsten set screws are available in cup, cone, flat, dog and half-dog points. Set screws have no head and are equiped with a socket or slotted driver at one end. | • ASME B18.3 • DIN 913 / ISO 4026 • DIN 914 / ISO 4027 • DIN 915 / ISO 4028 • DIN 916 / ISO 4029 |

Socket Head Cap Screws | Tungsten socket head cap screws are ideal for limited access situations where there is little clearance around the screws. They offer a safe, reliable and economic solution. | • ASMET B18.3 • DIN 912 / ISO 4762 • DIN 7984 |
Vented Screws | Tungsten vented screws are best for vacuum environments because the hole drilled through its axis (from head through threads) allow gases and other contaminents to vent. Tungsten vented screws are available in any style. |
|
Tungsten Bolts

Hex Head Bolts | Tungsten hex bolts are similar to hex head cap screws but without the added washer face. They are ideal for high clamping force applications with ease access. | • ASME B18.2.1 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017 |

Shoulder Bolts | Tungsten shoulder bolts are made up of a head, shoulder and threaded segment. The smooth shoulder section allows for rotating parts. Typically available with socket drivers. | • ASME • DIN 7379 / ISO 7379 • ISO 7370 |

Wedge Anchor Bolts | Tungsten wedge anchor bolts offer a safe secure fastening solution for attaching equipment and other materials to concrete in corrosive environments. |
|
Tungsten Nuts

Hex Nuts | Tungsten hex nuts are available in a variety of styles including finished hex nuts, jam nuts and heavy hex nuts. | • ASME B18.16.3 • ASME B18.2.2 • DIN 439 / ISO 4035 • DIN 934 / ISO 4032 • DIN 986 |

Lock Nuts | Tungsten lock nuts are available in all metal and polymer insert styles. All-metal lock provide even load distribution and can be used at high temperatures. Polymer insert styles are more economical and are best for temperatures under than 350°F. | • ASME B18.16.3M • DIN 980 / ISO 7042 / ISO 19513 • DIN 6923 / ISO 4161 • DIN 985 / ISO 10511 / ISO 7040 |
Tungsten Studs & Threaded Rods

Studs | Tungsten studs are fully threaded or partially threaded and made to custom lengths. | • ASME B18.31.2 • DIN 976 |

Threaded Rod | Tungsten threaded rod or all thread are available in lengths greater than 1 foot. Minimum order quantity is a total of 6 feet of length. | • ASME B1.1 • DIN 975 |

Weld Studs | Tungsten weld studs are available in both arc or capacitor discharge (CD) styles. Weld studs provide an extremely secure fastening solution when one side of the stud needs to be permanently fix to a part and the other side with the threads accessible. |
|
Tungsten Washers

Flat Washers | Tungsten washers are most commonly offered in SAE sizes, but also availabe in USS, oversized and custom sizes upon request. | • ASME 18.21.1 • SAE / USS • DIN 125 / ISO 7089 / ISO 7090 • DIN 126 / ISO 7091 |

Lock Washers | Tungsten lock washers are offered as split lock washers. Belleville spring lock washers can also be made upon request. | • ASME B18.21.1 • DIN 127 / ISO 7090 • DIN 6796 / ISO 10690
|
Tungsten Chemistry & Specifications
Tungsten Specifications: ASTM B777, Mil Spec T-21014D
Tungsten AlloyASTM-B777 | Class 1 | Class2 | Class 3 | Class 4 | CP Tungsten |
Material Composition | 90% W6%Ni4%Cu | 92.5% W5.25% Ni2.25% Fe | 95% W3.5% Ni1.5% Cu | 97% W2.1% Ni0.9% Fe | 99.95% W |
Density | 17 gm/cc | 17.5 gm/cc | 18 gm/cc | 18.5 gm/cc | 19.3 gm/cc |
Density; Ibs/in3 | 0.6 | 0.6 | 0.7 | 0.7 | 0.697 |
Mil. Spec. T-21014 D | Class 1 | Class 2 | Class 3 | Class 4 |
|
Type | Type II & III | Type II & III | Type II & III | Type II & III |
|
Hardness; Rockwell C | 24.0 | 26.0 | 27.0 | 28.0 | 31.0 |
Ultimate TensileStrength; PSI | 94,000 | 110,000 | 94,000 | 100,000 | 142,000 |
Yield Strength, .2% Offset; PSI | 75,000 | 75,000 | 75,000 | 75,000 | 109,000 |
Modulus of Elasticity; PSI | 40X10E6 | 47xlOE6 | 45 x10E6 | 53 X10E6 | 58x10E6 |
Coefficient of Thermal Expansion x | 5.4 | 4.6 | 4.4 | 4.5 | 4.2 |
ElectricalConductivity; %IACS | 14 | 13 | 16 | 17 | 18 |