Molybdenum fasteners possesses a very high melting point of 2620°C, a low coefficient of thermal expansion and a high level of thermal conductivity. Because molybdenum fasteners have the ability to withstand extremely high temperatures without changing shape, expanding or softening significantly, they are ideal for high strength / high temperature applications that are shielded from oxygen. Exposing molybdenum fastener to oxygen above 600°C will cause them to readily oxidize.
STANDARD AND CUSTOMIZED, SMALL BATCH AND LARGE BATCH, IMPERIAL AND METRIC
Molybdenum fasteners find their way into high temperature vacuum furnaces, glass production, military and space applications where oxygen is not present.
Extreme high temperature stability & strength
Maintains strength at elevated temperatures
Low distortion at high temperature
Molybdenum must be used in vacuum or inert gas at high temperatures
Molybdenum Fasteners: Ultra-High Temperature Refractory Metal Bolts, Nuts, Screws, Washers, Studs & Threaded Rods
Pure Mo (≥99.95%) | TZM (Mo-Ti-Zr-C) | MoLa (Mo-La₂O₃) | ASTM B386 / B387
RAYCHIN LIMITED is a leading manufacturer of Molybdenum Fasteners – precision-engineered components produced from pure molybdenum and its alloys, delivering exceptional high-temperature strength, thermal stability, and resistance to creep in extreme environments. With a melting point exceeding 2600°C (4700°F), molybdenum fasteners retain structural integrity under vacuum, reducing atmospheres, and severe thermal cycling. Our comprehensive product line includes molybdenum bolts, molybdenum nuts, molybdenum screws, molybdenum washers, molybdenum stud bolts, and molybdenum threaded rods – all manufactured to the highest precision standards. Available grades include Pure Molybdenum (≥99.95%), TZM alloy (Mo-0.5Ti-0.08Zr-0.02C), and Molybdenum Lanthanum (MoLa) with enhanced recrystallization temperature. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards, including ASTM B386/B387, ISO 4017, ISO 4032, DIN 931, DIN 934, and ASME B18.2.1/18.2.2. Whether you require molybdenum fasteners for high-temperature vacuum furnaces, semiconductor sputtering equipment, sapphire crystal growth systems, glass melting electrodes, or aerospace propulsion components, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).
Molybdenum bolts include hex head bolts, heavy hex bolts, and hex head cap screws in inch and metric series. Manufactured to ASME B18.2.1 (inch), ISO 4014 / DIN 931 (metric), and ISO 4017 / DIN 933 (fully threaded). Available with full or partial thread, precision rolled threads for superior fatigue life. Ideal for high-temperature furnace assemblies, heat shields, and secure connections in ultra-high-vacuum systems.
Molybdenum Nuts
Molybdenum nuts are manufactured in hex, heavy hex, jam, and slotted configurations per ASME B18.2.2 (inch), ISO 4032 / DIN 934 (metric). Precision tapped with class 2B/6H threads. Used in conjunction with molybdenum bolts or studs to create secure, high-temperature-resistant connections in sputtering equipment, crystal growth furnaces, and nuclear applications.
Molybdenum Screws
Molybdenum screws available in socket head cap screws (ISO 4762/DIN 912), pan head (ISO 1580/DIN 85), flat head countersunk (ISO 10642/DIN 7991), and set screws (ISO 4026-4029/DIN 913-916). Precision machined with rolled threads. Designed for critical fastening in high-stress, high-temperature environments such as semiconductor chambers and heating element fixtures.
Molybdenum Washers
Molybdenum washers include flat washers (ASME B18.22.1, ISO 7089, DIN 125), spring washers (DIN 127), and lock washers (ASME B18.21.1). Precision stamped or machined from pure Mo or TZM alloy. Provide load distribution, prevent galling, and maintain clamping force under extreme thermal cycling. Essential for vacuum furnaces and high-temperature processing equipment.
Molybdenum Stud Bolts
Molybdenum stud bolts feature threads on both ends (double-end studs) for flange connections in high-temperature piping, pressure vessels, and furnace access doors. Manufactured to ASME B18.31.2 (inch) and ISO 898-1 (metric). Available in fully threaded or center-shank configurations. Withstand aggressive thermal environments in refineries, power generation, and chemical processing.
Molybdenum Threaded Rods
Molybdenum threaded rods provide continuous threads along the entire length, allowing custom-length fastening solutions. Available in lengths up to 3000mm (120") with UNC, UNF, and metric threads. Ideal for tie rods, anchors, and custom fabricated assemblies in vacuum furnaces, thermal evaporation systems, and semiconductor manufacturing equipment. Can be cut to length and combined with molybdenum nuts/washers.
Alloy Grades: TZM & MoLa
TZM alloy fasteners (Mo-0.5Ti-0.08Zr-0.02C) offer higher recrystallization temperature, improved strength, and creep resistance compared to pure Mo. MoLa alloy fasteners (Mo doped with La₂O₃) exhibit enhanced ductility and high-temperature stability. Both alloys available across all fastener types for applications exceeding 1400°C in vacuum or reducing atmospheres.
Aerospace & Military Standards
Our molybdenum fasteners meet applicable sections of NAS1351/1352 (socket head), NAS1802 (hex head), NASM 20426, MS16995, and AN42-AN73. Full compliance with ASTM B386 (plate/sheet/foil) and ASTM B387 (rod/bar/wire) for material and mechanical properties. Silver plating per AMS 2410 available for anti-galling. Cleanroom packaging available for semiconductor and aerospace applications.
Custom & Non-Standard Fasteners
Need special head configurations, proprietary drives (Torx, Robertson), non‑standard lengths, or unique thread forms? RAYCHIN engineers design and produce custom molybdenum fasteners to your exact specifications – any grade (pure Mo, TZM, MoLa), any condition (stress relieved, recrystallized), with full material traceability. Prototype to production volumes supported. In-house metallurgical laboratory ensures optimal performance.
Manufacturing Standards for Molybdenum Fasteners
RAYCHIN LIMITED manufactures Molybdenum fasteners to the following national and international standards, ensuring full compliance for projects worldwide. Both standard and non-standard custom configurations are available.
Molybdenum Fastener Styles
Molybdenum 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
Molybdenum Bolts
Hex Head Bolts Shoulder Bolts Wedge Anchor Bolts
• DIN 931 • DIN 933 • ISO 4014 • ISO 4017 • ISO 7370
Molybdenum 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
Molybdenum Studs/Rod
Studs Threaded Rod Weld Studs
• DIN 975 • DIN 976
Molybdenum Washers
Flat Washers Lock Washer
• DIN 125 / ISO 7089 / ISO 7090 • DIN 126 / ISO 7091 • DIN 127 / ISO 7090 • DIN 9021 / ISO 7093
Molybdenum Hose Clamps
Medium Duty Hose Clamps
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Molybdenum Screws
12 Point Screws
Molybdenum 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
Molybdenum 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
Molybdenum 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 Inconel 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
Molybdenum 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
Molybdenum 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 Molybdenum screws resistance to unwanted tampering or removal due to the fact that they cannot be removed using an ordinary driver. Inconel security screws are available in several different drive styles, as well as custom per print.
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Set Screws
Molybdenum 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
Molybdenum 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
Molybdenum 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. Inconel vented screws are available in any style.
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Molybdenum Bolts
Hex Head Bolts
Molybdenum 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
Molybdenum 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
Molybdenum wedge anchor bolts offer a safe secure fastening solution for attaching equipment and other materials to concrete in corrosive environments.
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Molybdenum Nuts
Hex Nuts
Molybdenum 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
Molybdenum 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
Molybdenum Studs & Threaded Rod
Studs
Molybdenum studs are fully threaded or partially threaded and made to custom lengths.
• ASME B18.31.2 • DIN 976
Threaded Rod
Molybdenum 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
Molybdenum 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.
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Molybdenum Washers
Flat Washers
Molybdenum 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
Molybdenum 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
Critical Applications of Molybdenum Fasteners
High-Temperature Vacuum Furnaces
Molybdenum fasteners are essential in vacuum furnace construction, including hot zones, heating element supports, heat shields, and hearth assemblies. They maintain structural integrity at temperatures exceeding 1700°C (3090°F) in vacuum or inert gas environments where tungsten is too expensive and superalloys fail. Used in sintering furnaces, brazing furnaces, and annealing furnaces.
Semiconductor & Sputtering Equipment
Molybdenum fasteners in semiconductor manufacturing equipment, including sputtering targets, PVD chambers, ion implanters, and wafer processing systems. Molybdenum's low coefficient of thermal expansion, high thermal conductivity, and non-contaminating properties (no outgassing) make it ideal for ultra-high-vacuum (UHV) environments. Essential for securing electrodes, shields, and process kits.
Sapphire Crystal Growth & Glass Melting
Molybdenum fasteners used in sapphire crystal growth furnaces (Kyropoulos, Czochralski) and glass melting electrodes. Molybdenum withstands molten glass corrosion and extreme temperatures required for LED sapphire substrate production. Fasteners secure crucible assemblies, heat shields, and electrode holders in aggressive molten environments.
Aerospace & Defense
Molybdenum fasteners in rocket engine components, nozzle assemblies, re-entry vehicle heat shields, and supersonic aircraft skin elements. Molybdenum alloys maintain strength at extreme temperatures where other metals would soften or melt. Used in thrust vector control systems and high-temperature structural joints.
Nuclear Engineering
Molybdenum fasteners in nuclear reactors, particle accelerators, and experimental fusion devices. Molybdenum exhibits excellent resistance to radiation damage and retains mechanical properties under neutron irradiation. Used for fuel cladding supports, control rod mechanisms, and plasma-facing component fasteners.
Medical & X-ray Equipment
Molybdenum fasteners in X-ray tube assemblies, radiation shielding components, and medical isotope production equipment. Molybdenum's high atomic number and thermal properties make it suitable for X-ray targets and collimators. Fasteners secure targets and cathodes under high-voltage, high-temperature operation.
International Standards & Global Designations – Molybdenum Fasteners
RAYCHIN LIMITED manufactures molybdenum fasteners from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to the most widely used national and international specifications. All material is traceable to the mill.
Chemical Composition (Weight %) – Molybdenum Alloys for Fasteners
Our molybdenum fasteners are produced from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to ASTM B386/B387 and industry standards.
Metallurgical note: Molybdenum is a refractory metal with a body-centered cubic (BCC) crystal structure. Pure molybdenum fasteners are typically supplied in stress-relieved condition (recrystallization temperature ~1100°C). TZM alloy offers significantly higher recrystallization temperature (~1400°C) and improved creep strength through carbide dispersion strengthening. MoLa (lanthanated molybdenum) maintains ductility after high-temperature exposure due to oxide dispersion pinning grain boundaries. All molybdenum fasteners should be handled with care due to limited ductility at room temperature, becoming more ductile above ductile-to-brittle transition temperature (DBTT).
Molybdenum fasteners are supplied in various conditions (stress relieved, recrystallized) per ASTM B387. Data represent typical values based on industry standards.
Mechanical Properties – Pure Molybdenum (Stress Relieved)
Condition
Tensile Strength (MPa)
Tensile Strength (ksi)
Yield Strength 0.2% (MPa)
Yield Strength 0.2% (ksi)
Elongation (%)
Hardness
Stress Relieved (typical)
620-760
90-110
550-620
80-90
10-20
250 HV (2500 MPa)
Recrystallized (annealed)
485-550
70-80
415-450
60-65
20-30
200 HV (2000 MPa)
Mechanical Properties – TZM Alloy
Condition
Tensile Strength (MPa)
Tensile Strength (ksi)
Yield Strength 0.2% (MPa)
Yield Strength 0.2% (ksi)
Elongation (%)
Hardness
Stress Relieved
860-1035
125-150
690-860
100-125
8-15
300 HV (3000 MPa)
Recrystallized
620-760
90-110
550-620
80-90
15-25
230 HV (2300 MPa)
Physical Properties – Molybdenum
Property
Metric
Imperial
Notes
Density
10.22 g/cm³
0.369 lb/in³
Pure Mo
Density (TZM)
10.16 g/cm³
0.367 lb/in³
Slightly lower due to alloying
Melting Point
2617°C
4743°F
Pure Mo
Boiling Point
4612°C
8334°F
Elastic Modulus (E)
324-329 GPa
47.0-47.7 x 10³ ksi
Stress relieved condition
Poisson's Ratio
0.293-0.31
0.293-0.31
Thermal Expansion (20-100°C)
5.1 x 10⁻⁶ /K
2.8 x 10⁻⁶ /°F
Very low CTE
Thermal Conductivity
138 W/m·K
960 BTU·in/(hr·ft²·°F)
Excellent conductivity
Electrical Resistivity
5.7 µΩ·cm
2.24 µΩ·in
At 20°C
Specific Heat
251 J/kg·K
0.06 BTU/lb·°F
At 25°C
High‑Temperature Performance of Molybdenum Fasteners
Molybdenum and its alloys are renowned for exceptional high-temperature strength and stability. Pure molybdenum maintains useful mechanical properties up to 1700°C (3090°F) in vacuum or reducing atmospheres, with TZM extending capability further through carbide strengthening. However, molybdenum oxidizes rapidly above 400°C in air, limiting use to vacuum, inert gas, or reducing environments unless protected by coatings.
Elevated Temperature Capabilities
Property
Pure Molybdenum
TZM Alloy
MoLa Alloy
Max Service Temp (vacuum/inert)
1700°C (3090°F)
1400-1500°C (2550-2730°F)
1700°C (3090°F)
Recrystallization Temp
1100°C (2010°F)
1400°C (2550°F)
1300-1500°C
Creep Resistance
Good
Excellent
Very Good
Tensile Strength @ 1000°C
~300 MPa (43 ksi)
~450 MPa (65 ksi)
~350 MPa (51 ksi)
Oxidation Onset in Air
400°C (750°F) – rapid formation of volatile MoO₃
High-Temperature Comparison – Refractory Metals
Alloy
Max Service Temp (Vacuum)
Density (g/cm³)
Typical Application
Molybdenum (Pure)
1700°C
10.22
Furnace hot zones, electrodes
TZM Alloy
1500°C
10.16
High-strength furnace components, rocket nozzles
MoLa (La₂O₃)
1700°C
10.20
Heating elements, wire applications
Tungsten (W)
2500°C
19.3
Highest temperature, but 2x density
Stainless Steel 316
~900°C
8.0
Lower temperature limit
Note: All molybdenum fasteners must be used in vacuum, inert gas, or reducing atmosphere (H₂) above 400°C to prevent catastrophic oxidation. For air applications, protective coatings (MoSi₂, etc.) may be applied.
Corrosion Resistance of Molybdenum Fasteners
Molybdenum exhibits excellent resistance to many corrosive media, particularly in reducing environments and in the absence of oxidizing agents. However, rapid oxidation occurs in air above 400°C.
Acid Resistance: Excellent resistance to hydrochloric acid (HCl), sulfuric acid (H₂SO₄) at moderate temperatures, and phosphoric acid (H₃PO₄). Resists most non-oxidizing mineral acids. Rapid attack in nitric acid (HNO₃) and other oxidizing acids.
Alkalis: Generally good resistance, but can be attacked by fused alkalis. Resistant to many molten salts.
Liquid Metals: Excellent resistance to liquid lithium, sodium, potassium, and bismuth, making it valuable in nuclear coolant systems.
Halogens: Resistant to fluorine, chlorine, and bromine at moderate temperatures; attacks at higher temperatures.
Oxidation: Forms volatile MoO₃ above 400°C in air; requires protective atmosphere or coating for high-temperature air service.
Hydrogen: Excellent resistance to hydrogen attack even at high temperatures (unlike steel).
Sulfur Compounds: Good resistance to sulfur, hydrogen sulfide, and sulfur dioxide.
Glass Corrosion: Outstanding resistance to molten glass, widely used in glass melting electrodes and stirrers.
Bimetallic Corrosion: Can be safely connected to tungsten, tantalum, and graphite. Avoid direct contact with aluminum, zinc, and copper at high temperatures due to eutectic formation.
Manufacturing Standards – Molybdenum Fasteners
All molybdenum fasteners are manufactured and tested to meet the following standards:
We offer surface finishes: black (as-machined), chemical cleaned, ground, polished, and passivated. Special coatings (MoSi₂, Al₂O₃, Y₂O₃) available for oxidation protection. Full traceability and destructive/non‑destructive testing available (UT, PMI, MPI). ISO 13485 certified for medical applications with cleanroom packaging available.
Why RAYCHIN LIMITED – The Molybdenum Fastener Authority
Refractory metal expertise: Decades of experience with molybdenum, TZM, and MoLa alloys. We ensure precise processing: stress relieving, recrystallization annealing, and surface finishing per ASTM B386/B387 standards. In‑house PMI verifies chemistry of every heat. Our molybdenum fasteners achieve full traceability and certified properties.
Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All fasteners supplied with EN 10204 3.1/3.2 certifications, material test reports, and NACE compliance when required.
Precision machining & thread rolling: CNC turning and precision thread rolling ensure accurate head geometry and thread form per ASME, ISO, and DIN standards. Class 2A/3A/6g thread fit. 100% inspection available. Special tooling for molybdenum's unique machining characteristics (brittle behavior at room temperature).
Custom solutions: Special head configurations, proprietary drives, non‑standard lengths, custom alloys, and tailored packaging. In-house metallurgical laboratory and failure analysis capabilities. Prototype to production volumes supported. Cleanroom wash and packaging available for semiconductor and medical applications.
Contact the molybdenum fastener experts
Request a quotation for molybdenum bolts, nuts, screws, washers, stud bolts, threaded rods – any grade (Pure Mo, TZM, MoLa) – any standard (ASME, ISO, DIN, NAS) – any condition (stress relieved, recrystallized), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.